Sampling level converting circuit, two-phase and multi- phase developing circuit, and display
Abstract
[Task] Providing a level conversion circuit for reducing the number of terminals and reducing power consumption, and a development circuit equipped with the level conversion circuit.
Solution.Capacities connected to the connection points of the first to third MOS transistors MP1, MN3, MP2 connected in series between the higher power supply and the lower power supply, and the first and second MOS transistors MP1, MN3. It includes a C2, a fourth MOS transistor MN1 connected between the input terminal and the gate terminal of the third MOS transistor MN2, and a capacitance C1 connected to the gate of the third MOS transistor MN2. A sampling pulse signal SMP is commonly input to the gates of the first and second MOS transistors MP1 and MN3, and an inverted signal XSMP of the sampling pulse signal SMP is input to the gate of the fourth MOS transistor MN1.
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Projected expiry passed 3 October 2021, 5 years ago.
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34 claims: 13 independent, 21 dependent
- 1【特許請求の範囲】 【請求項1】入力されるサンプリング制御信号に基づき、セットアップ期間に、出力ノードの充電パスに挿入されているスイッチ素子をオンし前記出力ノードを高位側電源電圧にプリチャージする手段と、入力信号電圧をサンプリングする手段と、を備え、 前記セットアップ期間中、前記入力されるサンプリング制御信号に基づき、前記出力ノードの放電パスはオフ状態に保たれ、 前記入力されるサンプリング制御信号で規定される出力期間には、前記セットアップ期間にサンプリングされた前記入力信号電圧の論理値に応じて、前記出力ノードの放電パスに挿入されているスイッチ素子がオン又はオフされ、前記放電パスに挿入されている前記スイッチ素子がオンのとき、前記放電パスはオン状態とされて、プリチャージされた前記出力ノードの放電が行われ、前記放電パスに挿入されている前記スイッチ素子がオフのとき、プリチャージされた前記出力ノードの放電は行われない、構成とされている、ことを特徴とするサンプリングレベル変換回路。
- 2【請求項2】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第3のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第3のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点には第2の容量が接続され、 前記第1のスイッチ素子と前記第2のスイッチ素子は、それぞれの制御端子に第1のサンプリング制御信号が共通に入力され、一方がオンのとき、他方はオフとされ、 前記第4のスイッチ素子の制御端子には、第2のサンプリング制御信号が入力され、 前記第1の容量の端子電圧が、直接に、又は、間接的に、出力信号として取り出される、ことを特徴とするサンプリングレベル変換回路。
- 3【請求項3】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第2のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第2のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点には第2の容量が接続され、 前記第1のスイッチ素子と前記第3のスイッチ素子は、それぞれの制御端子に第1のサンプリング制御信号が共通に入力され、一方がオンのとき、他方はオフとされ、 前記第4のスイッチ素子の制御端子には、第2のサンプリング制御信号が入力され、 前記第1の容量の端子電圧が、直接に、又は、間接的に、出力信号として取り出される、ことを特徴とするサンプリングレベル変換回路。
- 4【請求項4】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第3のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第3のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点に第2の容量が接続されており、 前記第1のスイッチ素子の制御端子と前記第2のスイッチ素子の制御端子には第1のサンプリング制御信号が共通に入力され、 前記第1のサンプリング制御信号が第2の論理値のとき、前記第1のスイッチ素子がオンし、前記第2のスイッチ素子はオフし、前記第1の容量が前記高位側電源の電源電圧に充電され、 前記第4のスイッチ素子の制御端子には、第2のサンプリング制御信号が入力され、前記第2のサンプリング制御信号が第1の論理値のとき前記第4のスイッチ素子はオンし、前記第2の容量は前記入力信号電圧で充電され、 前記第1のサンプリング制御信号が第1の論理値のとき、前記第1のスイッチ素子はオフし、前記第2のスイッチ素子がオンし、このときの前記第1の容量の端子電圧が、直接に、又は、間接的に、出力信号として取り出される、ことを特徴とするサンプリングレベル変換回路。
- 5【請求項5】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第2のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第2のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点に第2の容量が接続されており、 前記第1のスイッチ素子の制御端子と前記第3のスイッチ素子の制御端子には第1のサンプリング制御信号が共通に入力され、 前記第1のサンプリング制御信号が第2の論理値のとき、前記第1のスイッチ素子がオンし、前記第3のスイッチ素子はオフし、前記第1の容量が前記高位側電源の電源電圧に充電され、 前記第4のスイッチ素子の制御端子には、第2のサンプリング制御信号が入力され、前記第2のサンプリング制御信号が第1の論理値のとき前記第4のスイッチ素子はオンし、前記第2の容量は前記入力信号電圧で充電され、 前記第1のサンプリング制御信号が第1の論理値のとき、前記第1のスイッチ素子はオフし、前記第3のスイッチ素子がオンし、このときの前記第1の容量の端子電圧が、直接に、又は、間接的に、出力信号として取り出される、ことを特徴とするサンプリングレベル変換回路。
- 6【請求項6】前記第2のサンプリング制御信号が、前記第1のサンプリング制御信号を反転した信号である、ことを特徴とする請求項2乃至5のいずれか一に記載のサンプリングレベル変換回路。
- 7【請求項7】前記第1の容量の端子電圧を入力として受け、高位側電源電位と低位側電源電位の振幅の信号を出力するバッファ回路を備えている、ことを特徴とする、請求項2乃至6のいずれか一に記載のサンプリングレベル変換回路。
- 8【請求項8】前記第1の容量の端子電圧、又は、前記第1の容量の端子電圧を入力とし高位側電源電位と低位側電源電位の振幅の信号を出力するバッファ回路の出力を入力として受け、前記第1のサンプリング制御信号が第1の論理値のときオンして、入力した信号を出力し、前記第1のサンプリング制御信号が第2の論理値のときにオフとされる、第1のトランスファスイッチを備えている、ことを特徴とする、請求項2乃至6のいずれか一記載のサンプリングレベル変換回路。
- 9【請求項9】前記第1のトランスファスイッチと、 前記第1のトランスファスイッチの出力を受け、前記第2のサンプリング制御信号が第1の論理値のとき、その値を記憶するフリップフロップと、 を有するマスターラッチと、 前記第1のトランスファスイッチの出力を受け、前記第2のサンプリング制御信号が第1の論理値のときにオンして前記第1のトランスファスイッチの出力信号を出力し、前記第2のサンプリング制御信号が第2の論理値のときにオフとされる、第2のトランスファスイッチと、 前記第2のトランスファスイッチの出力を受け、前記第1のサンプリング制御信号が第1の論理値のとき、前記第2のトランスファスイッチの出力値を記憶するフリップフロップと、 を有するスレーブラッチと、 を備えている、ことを特徴とする、請求項8記載のサンプリングレベル変換回路。
- 10【請求項10】前記バッファ回路が、偶数段のインバータが縦続形態に接続されてなる、ことを特徴とする、請求項7又は8に記載のサンプリングレベル変換回路。
- 11【請求項11】前記第1のトランスファスイッチは、前記第1のサンプリング制御信号が第1の論理値のときオンし、入力した信号を反転出力するクロックドインバータよりなる、ことを特徴とする、請求項8又は9に記載のサンプリングレベル変換回路。
- 12【請求項12】前記第2のトランスファスイッチは、前記第2のサンプリング制御信号が第1の論理値のときオンし、入力した信号を反転出力するクロックドインバータよりなる、ことを特徴とする、請求項9記載のサンプリングレベル変換回路。
- 13【請求項13】前記入力端子に入力される入力信号の振幅電圧が、前記高位側電源電圧よりも低い、ことを特徴とする、請求項1乃至12のいずれか一に記載のサンプリングレベル変換回路。
- 14【請求項14】前記各スイッチ素子が、薄膜トランジスタ(TFT)よりなる、ことを特徴とする請求項1乃至12のいずれか一に記載のサンプリングレベル変換回路。
- 15【請求項15】請求項2乃至6のいずれか一に記載のサンプリングレベル変換回路からなる第1及び第2のサンプリングレベル変換回路を備え、 前記第1及び第2のサンプリングレベル変換回路には、入力信号が共通に入力され、 前記第2のサンプリングレベル変換回路には、前記第1のサンプリングレベル変換回路の前記第1及び第2のサンプリング制御信号の値をそれぞれ反転した値の信号が、第1及び第2のサンプリング制御信号としてそれぞれ対応するスイッチ素子の制御端子に入力され、 前記第1のサンプリングレベル変換回路の出力を、前記第1のサンプリング制御信号に基づき取り込み、前記第2のサンプリング制御信号に基づき出力する第1のマスタースレーブ型のラッチと、 前記第1のマスタースレーブ型のラッチの出力を前記第1のサンプリング制御信号に基づき出力するラッチと、 前記第2のサンプリングレベル変換回路の出力を、前記第2のサンプリング制御信号に基づき取り込み、前記第1のサンプリング制御信号に基づき出力する第2のマスタースレーブ型のラッチと、 を備えている、ことを特徴とする2相展開回路。
- 16【請求項16】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第3のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第3のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点には第2の容量が接続され、 前記第1のスイッチ素子の制御端子と前記第2のスイッチ素子の制御端子には第1のサンプリング制御信号が共通に入力され、 前記第4のスイッチ素子の制御端子には前記第1のサンプリング制御信号の相補の信号である第2のサンプリング制御信号が入力される第1のサンプリングレベル変換回路と、 前記第1の容量の端子電圧を入力とするインバータを初段とし全体で偶数段縦続形態に接続された第1群のインバータと、 前記第1のサンプリング制御信号が第1の論理値のとき前記第1群のインバータの最終段の出力信号を取り込み、前記第2のサンプリング制御信号が第1の論理値のとき前記取り込んだ信号を出力する第1のマスタースレーブ型のラッチと、 前記第1のマスタースレーブ型のラッチの出力信号を受け、前記第1のサンプリング制御信号が第1の論理値のとき奇数信号として出力する第1のラッチと、 前記高位側電源と前記低位側電源間に直列形態に接続されている第5乃至第7のスイッチ素子を備え、 前記第5のスイッチ素子と前記第6のスイッチ素子の接続点には第3の容量が接続され、 前記入力信号が入力される前記入力端子と前記第7のスイッチ素子の制御端子との間に接続された第8のスイッチ素子を備え、 前記第7のスイッチ素子の制御端子と前記第8のスイッチ素子との接続点には第4の容量が接続され、 前記第5のスイッチ素子の制御端子と前記第6のスイッチ素子の制御端子には前記第2のサンプリング制御信号が共通に入力され、 前記第8のスイッチ素子の制御端子には前記第1のサンプリング制御信号が入力される第2のサンプリングレベル変換回路と、 前記第3の容量の端子電圧を入力とするインバータを初段とし全体で偶数段縦続形態に接続された第2群のインバータと、 前記第2のサンプリング制御信号が第1の論理値のとき前記第2群のインバータの最終段の出力を取り込み、前記第1のサンプリング制御信号が第1の論理値のときに前記取り込んだ値を偶数信号として出力する第2のマスタースレーブ型のラッチと、 を備え、 前記奇数信号と前記偶数信号とは、前記第1のサンプリング制御信号の第1の論理値への遷移に同期して、並列に出力される、ことを特徴とする2相展開回路。
- 17【請求項17】高位側電源と低位側電源間に直列形態に接続されている第1乃至第3のスイッチ素子を備え、 前記第1のスイッチ素子と前記第2のスイッチ素子の接続点には第1の容量が接続され、 入力信号が入力される入力端子と前記第3のスイッチ素子の制御端子との間に接続された第4のスイッチ素子を備え、 前記第3のスイッチ素子の制御端子と前記第4のスイッチ素子との接続点には第2の容量が接続され、 前記第1のスイッチ素子の制御端子と前記第2のスイッチ素子の制御端子には第1のサンプリング制御信号が共通に入力され、 前記第4のスイッチ素子の制御端子には前記第1のサンプリング制御信号の相補の信号である第2のサンプリング制御信号が入力される第1のサンプリングレベル変換回路と、 前記第1の容量の端子電圧を入力とするインバータを初段とし全体で偶数段縦続形態に接続された第1群のインバータと、 前記第1のサンプリング制御信号が第1の論理値のとき前記第1群のインバータの最終段の出力信号を取り込み、前記第2のサンプリング制御信号が第1の論理値のとき前記取り込んだ信号を出力する第1のマスタースレーブ型のラッチと、 前記第1のマスタースレーブ型のラッチの出力信号を受け、前記第1のサンプリング制御信号が第1の論理値のとき奇数信号として出力する第1のラッチと、 前記高位側電源と前記低位側電源間に直列形態に接続されている第5乃至第7のスイッチ素子を備え、 前記第5のスイッチ素子と前記第6のスイッチ素子の接続点には第3の容量が接続され、 前記入力信号が入力される前記入力端子と前記第7のスイッチ素子の制御端子との間に接続された第8のスイッチ素子を備え、 前記第7のスイッチ素子の制御端子と前記第8のスイッチ素子との接続点には第4の容量が接続され、 前記第5のスイッチ素子の制御端子と前記第6のスイッチ素子の制御端子には前記第2のサンプリング制御信号が共通に入力され、 前記第8のスイッチ素子の制御端子には前記第1のサンプリング制御信号が入力される第2のサンプリングレベル変換回路と、 前記第3の容量の端子電圧を入力とするインバータを初段とし全体で偶数段縦続形態に接続された第2群のインバータと、 前記第2のサンプリング制御信号が第1の論理値のとき前記第2群のインバータの最終段の出力を取り込み、前記第1のサンプリング制御信号が第1の論理値のとき前記取り込んだ値を偶数信号として出力する第2のマスタースレーブ型のラッチと、 を備え、 前記奇数信号と前記偶数信号とは、前記第1のサンプリング制御信号の第1の論理値への遷移に同期して、並列に出力され、 前記第2のサンプリング制御信号が第1の論理値のとき入力を取り込み、前記第1のサンプリング制御信号の第1の論理値のときに出力するマスタースレーブ型のラッチ(「第1群のマスタースレーブ型のラッチ」という)をM段備え、前記奇数信号が前記第1群のマスタースレーブ型のラッチの初段に入力され、 前記奇数信号と、前記第1群のマスタースレーブ型のラッチの出力とを、前記入力信号を2(M+1)分周した第3の信号でそれぞれラッチする並列配置された(M+1)個のラッチ(「第1群のラッチ」という)と、 を備え、 前記第2のサンプリング制御信号が第1の論理値のときに入力を取り込み、前記第1のサンプリング制御信号の第1の論理値のときに出力するマスタースレーブ型のラッチ(「第2群のマスタースレーブ型のラッチ」という)をM段備え、前記偶数信号が、前記第2群のマスタースレーブ型のラッチの初段に入力され、 前記偶数信号と、前記第2群のマスタースレーブ型のラッチの出力とを、入力信号を前記第3の信号でラッチする、並列配置された(M+1)個のラッチ(「第2群のラッチ」という)と、 を備え、 前記第1群、第2群のラッチの出力から、前記入力信号の周波数の2(M+1)分周のサイクルで、2(M+1)相に展開した信号が並列に出力される、ことを特徴とする多相展開回路。
- 18【請求項18】請求項2乃至5のいずれか一に記載のサンプリングレベル変換回路をn個(nは2以上の所定の正整数)備え、 n個の前記サンプリングレベル変換回路の前記入力端子にはデータ信号線が共通に接続されており、 隣り合う位相が互いに1データサイクル分離間している多相クロック信号を生成する回路を備え、 i番目(ただし、iは1以上n以下の整数)の前記サンプリングレベル変換回路の前記第2のサンプリング制御信号には、前記多相クロック信号のi番目のクロック信号を入力し、前記第1のサンプリング制御信号には、前記多相クロック信号の(i+1)番目のクロック信号を入力し、 i番目の前記サンプリングレベル変換回路の前記第1の容量の端子電圧を受け、(i+1)番目のクロック信号の第1の論理値への遷移で出力し、(i+1)番目のクロック信号の第2の論理値で記憶する第1のラッチ回路を、前記サンプリングレベル変換回路に対応させてn個備え、 前記第1のラッチ回路の出力をそれぞれ入力し、データサイクルをn分周したサイクルのラッチタイミング信号を共通に受けて前記第1のラッチ回路の出力をラッチ出力する第2のラッチ回路をn個備えている、ことを特徴とするn相展開回路。
- 19【請求項19】前記入力端子に入力される入力信号の振幅電圧が、前記高位側電源電圧よりも低い、ことを特徴とする、請求項15又は16記載の2相展開回路。
- 20【請求項20】前記各スイッチ素子と各回路を構成するトランジスタが、薄膜トランジスタ(TFT)よりなる、ことを特徴とする、請求項15又は16記載の2相展開回路。
- 21【請求項21】前記入力端子に入力される入力信号の振幅電圧が、前記高位側電源電圧よりも低い、ことを特徴とする、請求項17記載の多相展開回路。
- 22【請求項22】前記各スイッチ素子と各回路を構成するトランジスタが、薄膜トランジスタ(TFT)よりなる、ことを特徴とする、請求項17記載の多相展開回路。
- 23【請求項23】前記多相クロック信号を生成する回路がシフトレジスタよりなる、ことを特徴とする請求項18記載のn相展開回路。
- 24【請求項24】前記入力端子に入力される入力信号の振幅電圧が、前記高位側電源電圧よりも低い、ことを特徴とする、請求項18記載のn相展開回路。
- 25【請求項25】前記各スイッチ素子と各回路を構成するトランジスタが、薄膜トランジスタ(TFT)よりなる、ことを特徴とする、請求項18記載のn相展開回路。
- 26【請求項26】高位側電源と低位側電源間に直列形態に接続された、第1乃至第3のMOSトランジスタを備え、 前記第1及び第2のMOSトランジスタの接続点に一端が接続され、他端が前記低位側電源に接続されている第1の容量と、 入力信号が入力される入力端子と前記第3のMOSトランジスタのゲート端子との間に接続された第4のMOSトランジスタと、 前記第3のMOSトランジスタのゲート端子に一端が接続され、他端が前記低位側電源に接続されている第2の容量と、 を備え、 前記第1及び第2のMOSトランジスタのゲート端子には第1のサンプリング制御信号が共通入力され、 前記第4のMOSトランジスタのゲート端子には第2のサンプリング制御信号が入力される、ことを特徴とするサンプリングレベル変換回路。
- 27【請求項27】高位側電源と低位側電源間に直列形態に接続された、第1乃至第3のMOSトランジスタを備え、 前記第1及び第2のMOSトランジスタの接続点に一端が接続され、他端が前記低位側電源に接続されている第1の容量と、 入力信号が入力される入力端子と前記第2のMOSトランジスタのゲート端子との間に接続された第4のMOSトランジスタと、 前記第2のMOSトランジスタのゲート端子に一端が接続され、他端が前記低位側電源に接続されている第2の容量と、 を備え、 前記第1及び第3のMOSトランジスタのゲート端子には第1のサンプリング制御信号が共通入力され、 前記第4のMOSトランジスタのゲート端子には第2のサンプリング制御信号が入力される、ことを特徴とするサンプリングレベル変換回路。
- 28【請求項28】前記第1のMOSトランジスタが第1導電型とされ、前記第2乃至第4のMOSトランジスタが第2導電型とされる、ことを特徴とする、請求項26又は27記載のサンプリングレベル変換回路。
- 29【請求項29】前記第1の容量と前記第2の容量として、前記各容量がそれぞれ接続されることになるノードの寄生容量が用いられている、ことを特徴とする、請求項2乃至15、26乃至29のいずれか一に記載のサンプリングレベル変換回路。
- 30【請求項30】複数のデータ線と複数の走査線の交点に画素群がマトリクス状に配置された表示部を有する表示パネルと、 前記複数の走査線に順次電圧を印加する走査線駆動回路と、 上位装置からの表示データを受け該表示データに対応した電圧を前記複数のデータ線に印加するデータ線駆動回路と、 を有する表示装置において、 前記表示パネルの外部に、表示データを格納する表示メモリと、前記表示メモリの制御及び前記上位装置との通信の制御を行うコントローラとが配設され、 前記表示パネルにおいて、前記表示メモリから転送される表示データを受け、より高振幅の信号にレベル変換するレベル変換回路として、請求項1乃至15、26乃至29のいずれか一に記載のサンプリングレベル変換回路を備えている、ことを特徴とする表示装置。
- 31【請求項31】複数のデータ線と複数の走査線の交点に画素群がマトリクス状に配置された表示部を有する表示パネルと、 前記複数の走査線に順次電圧を印加する走査線駆動回路と、 上位装置からの表示データを受け該表示データに対応した電圧を前記複数のデータ線に印加するデータ線駆動回路と、 を有する表示装置において、 前記表示パネルの外部に、表示データを格納する表示メモリと、前記表示メモリの制御及び前記上位装置との通信の制御を行うコントローラとが配設され、 前記表示パネルにおいて、前記表示メモリから転送される表示データを受け、より高振幅の信号にレベル変換する回路として、請求項15、16、20のいずれか一に記載の2相展開回路を備えている、ことを特徴とする表示装置。
- 32【請求項32】複数のデータ線と複数の走査線の交点に画素群がマトリクス状に配置された表示部を有する表示パネルと、 前記複数の走査線に順次電圧を印加する走査線駆動回路と、 上位装置からの表示データを受け該表示データに対応した電圧を前記複数のデータ線に印加するデータ線駆動回路と、 を有する表示装置において、 前記表示パネルの外部に、表示データを格納する表示メモリと、前記表示メモリの制御及び前記上位装置との通信の制御を行うコントローラとが配設され、 前記表示パネルにおいて、前記表示メモリから転送される表示データを受け、より高振幅の信号にレベル変換する回路として、請求項18又は25に記載のn相展開回路を備えている、ことを特徴とする表示装置。
- 33【請求項33】前記表示パネル上に、前記2相展開回路の出力を入力として受けるデジタル・アナログ変換器を備えている、ことを特徴とする、請求項31記載の表示装置。
- 34【請求項34】前記表示パネル上に、前記n相展開回路の出力を入力として受けるデジタル・アナログ変換器を備えている、ことを特徴とする、請求項32記載の表示装置。
Independent claims34
367 paragraphs in 1 section, as filed
Description: TECHNICAL FIELD [Detailed description of the invention]
【0001】
[Technical field to which the invention belongs]
The present invention relates to a level conversion circuit, particularly to a sampling level conversion circuit suitable for use in a liquid crystal display device, an EL (Eletro Luminescence) display device, etc., and a development circuit and a display device including a sampling level conversion circuit. Is.
【0002】
[Conventional technology]
Aiming at miniaturization, cost reduction, and high definition of the liquid crystal display device, the development of a technology for integrating the circuit provided in the liquid crystal display device (module) on the same substrate as the liquid crystal display board is in progress. .. As one example, a liquid crystal display substrate in which a drive circuit using a polycrystalline silicon thin film transistor (hereinafter, also abbreviated as "polysilicon silicon TFT" or "p-Si TFT") is integrated is known. ing. As a method of forming a polycrystalline silicon TFT on a glass substrate or the like at a low temperature, for example, reduced pressure or plasma CVD (Chemical Vapor) A method of depositing a precursor film by Deposition) or the like and annealing it with a laser to polycrystallize it is used. Polycrystalline silicon TFTs have higher mobility than amorphous silicon TFTs, and can integrate part of peripheral circuits such as data line drive circuits, reducing the number of drive LSIs and reducing mounting costs. can do. Then, in the data line drive circuit, a liquid crystal display board equipped with a digital-to-analog converter (abbreviated as "DAC") that converts digital display data into an analog signal is realized.
【0003】
As described above, the video signal input to the liquid crystal display board equipped with the DAC is a digital signal, and the digital signal is usually a signal processing circuit (external signal processing circuit"" provided outside the liquid crystal display board. Is generated by).
【0004】
Normally, this external signal processing circuit is composed of a single crystal silicon CMOS (Complementary MOS) integrated circuit, and its driving voltage is usually lower than the power supply voltage for driving the polycrystalline silicon TFT integrated circuit. is there. For example, an external signal processing circuit operates with a 3.3V power supply, and a polycrystalline silicon TFT integrated circuit is about 10V in order to drive a liquid crystal display board at a sufficient speed or to apply a sufficient voltage to the liquid crystal. Requires power supply voltage. Therefore, the 3.3V logic signal is boosted to about 10V by the level conversion circuit integrated on the liquid crystal display board to drive the polycrystalline silicon TFT circuit.
【0005】
In the case of such a configuration, a level conversion circuit which is an interface circuit between the external signal processing circuit and the polycrystalline silicon TFT circuit becomes an important circuit element.
【0006】
Some circuit configurations of the conventional level conversion circuit will be described. FIG. 24 shows two examples of the conventional level conversion circuit having a sash-type configuration. Referring to FIG. 24 (a), this level conversion circuit is connected to the P-channel MOS transistors MP1 and MP2 whose source is connected to the power supply VDD and the power supply VSS with the source connected in common, and the drain is a P-channel MOS transistor. It is equipped with N-channel MOS transistors MN1 and MN2 connected to the drains of MP1 and MP2, respectively, and the drains of N-channel MOS transistors MN1 and MN2 are cross-connected (hanged) to the gates of P-channel MOS transistors MP1 and MP2, respectively. .. Complementary input signals IN and INB are input to the gates of the N-channel MOS transistors MN1 and MN2, and the output is taken out from the drain of the N-channel MOS transistor MN1.
【0007】
In the configuration shown in Fig. 24 (b), the gates of the P-channel MOS transistors MP3 and MP4 with the source connected to the power supply are the first CMOS inverters (MP1, MN1) that input the complementary input signals VIN and VINB. , Cross-connected with the output of the second CMOS inverter (MP2, MN2). As the configuration of the above-mentioned sash, the description of JP-A-02-37823, JP-A-04-268818, JP-A 02-291719, JP-A-04-284021 and the like is referred to.
【0008】
The above-mentioned shackle configuration has low power consumption because there is no steady current in the steady state (transistor gate / source voltage VGS = 0V leakage current), but IN and its inverted signal are used for one type of signal. (Complementary signal) Two inputs of INB are required. Therefore, when connecting to a data bus having a data bit width of more than 100 bits, for example, the number of terminals of the sash-type level conversion circuit is doubled, and the connection (contact) of a large number of terminals becomes a problem.
【0009】
FIG. 25 (a) shows the configuration of a constant current load type (source grounded amplifier circuit) type level conversion circuit. In this level conversion circuit, an input signal is input to the gate of the N-channel MOS transistor MN1 whose source is grounded, the drain is connected to a constant current load, and the output OUT is taken out from the drain. In the level conversion circuit, the input is a one-input configuration with only IN, but a steady current flows from the high-level power supply to the low-level power supply. Therefore, when a large number of these level conversion circuits are mounted, the power consumption becomes large.
【0010】
FIG. 25 (b) is a diagram showing an inverter type level conversion circuit, in which a drain and a gate are connected between a CMOS inverter (MP1, MN1) or a CMOS inverter (MP1, MN1) and a high-level power supply VDD. It is configured to have an N-channel MOS transistor MN2 (diode-connected).
【0011】
FIG. 25 (c) shows the configuration of the level conversion circuit disclosed in Japanese Patent Application Laid-Open No. 06-164365. In this level conversion circuit, the first drive transistor mn1 and the first load transistor mp1 are connected in series with each other via the midpoint node A, and the second drive transistor mn2 and the second load transistor mp2 are connected in series with each other via the output node B. It is connected. The first drive transistor operates in response to a low-amplitude single-phase input clock pulse φ, suppresses the second load transistor mp2 via the midpoint node A, and conducts the second drive transistor mn2 to conduct the output node B. The output clock pulse Q of high amplitude VDD is set up. The auxiliary transistor mp3 restores the second drive transistor mn2 via the midpoint node A with the release of the single-phase input clock pulse φ, while cutting off the second load transistor mp2 to raise the output clock pulse Q. ..
【0012】
Furthermore, in the literature (IEEE, ISSCC2000, DIGEST OF TECHNICAL PAPERS, pp. 188-189), as shown in FIG. 26, it is mounted on a liquid crystal display (LCD) with a built-in DAC, and has low power consumption and a small number of elements. A shift and latch circuit (sampling latch) is disclosed. This circuit configuration is the same as the latch type sense amplifier used in the memory, and since the input terminal and the power supply (VDD9V) on the high voltage side are connected in a DC (direct current) manner via a switch, the input terminal High voltage may be applied to. Therefore, it is necessary to design the switching timing so as not to destroy the circuit on the low voltage side connected to the input terminal.
【0013】
As a configuration other than the above, for example, in a level conversion circuit using a circuit using a differential pair, an idling current may be required, or a separate power supply for operating the level conversion circuit may be required. is there.
【0014】
[Problems to be Solved by the Invention]
When a sampling level conversion circuit that samples an input signal, converts the level, and outputs it is mounted on the LCD module, the following specifications are required to be realized.
【0015】
-One input terminal for one type of input signal.
【0016】
-Low power consumption (steady current 0: off-leak degree).
【0017】
-It is possible to design a circuit that operates even when the input signal amplitude is 0-3V and the voltage is about the threshold of TFT.
【0018】
-No extra power supply is required.
【0019】
Therefore, the problem to be solved by the present invention is to provide a level conversion circuit for reducing the number of terminals and reducing power consumption, a two-phase and multi-phase expansion circuit provided with the level conversion circuit, and a display device. is there.
【0020】
[Means for solving problems]
The level conversion circuit according to the present invention, which provides means for solving the above problems, has a switch element inserted in the charging path of the output node during the setup period based on the input sampling control signal in one aspect thereof. and means for turning on and precharging the output node to the high-potential power supply voltage, means for sampling the input signal voltage, and in the set-up period, based on the sampling control signal being said input, said output node discharging de The path is kept off and inserted into the discharge path of the output node during the output period specified by the input sampling control signal, depending on the logical value of the input signal voltage sampled during the setup period. When the switch element being turned on or off and the switch element inserted in the discharge path is on, the discharge path is turned on and the precharged output node is discharged. When the switch element inserted in the discharge path is off, the precharged output node is not discharged.
【0021】
The level conversion circuit according to the present invention includes first to third switch elements connected in series between the high-level power supply and the low-level power supply in one aspect thereof, and the first switch element and the above-mentioned first switch element. A first capacitance is connected to the connection point of the second switch element, and a fourth switch element connected between an input terminal into which an input signal is input and a control terminal of the third switch element is provided. A second capacitance is connected to the connection point between the control terminal of the third switch element and the fourth switch element, and the control terminal of the first switch element and the control of the second switch element are controlled. A first sampling control signal is commonly input to the terminals, and when the first sampling control signal has a second logical value, the first switch element is turned on and the second switch element is turned off. The first capacitance is charged to the power supply voltage of the higher power supply, the second sampling control signal is input to the control terminal of the fourth switch element, and the second sampling control signal is the first. When the logical value of, the fourth switch element is turned on, the second capacitance is charged by the input signal voltage, and when the first sampling control signal has the first logical value, the first switch The element is turned off, the second switch element is turned on, and the terminal voltage of the first capacitance at this time is directly or indirectly taken out as an output signal.
【0022】
In another aspect, the two-phase expansion circuit according to the present invention includes the first and second sampling level conversion circuits including the above-mentioned sampling level conversion circuit according to the present invention, and the first and second sampling level conversions are provided. An input signal is commonly input to the circuit, and a signal having a value obtained by inverting the values of the first and second sampling control signals of the first sampling level conversion circuit is input to the second sampling level conversion circuit. Is input to the corresponding switch elements, the output of the first sampling level conversion circuit is taken in based on the first sampling control signal, and is output based on the first sampling control signal. The latch that outputs the output of the first master-slave type latch based on the first sampling control signal, and the output of the second sampling level conversion circuit based on the second sampling control signal. It includes a second master-slave type latch that takes in and outputs based on the first sampling control signal.
【0023】
In still another aspect, the display device according to the present invention has a display panel having a display unit in which pixel groups are arranged in a matrix at intersections of a plurality of data lines and a plurality of scanning lines, and the plurality of scanning lines in sequence. In a display device having a scanning line drive circuit for applying a voltage and a data line drive circuit for receiving display data from a host device and applying a voltage corresponding to the display data to the plurality of data lines, the display panel of the display panel. A display memory for storing display data and a controller for controlling the display memory and communication with the host device are arranged externally, and the display data transferred from the display memory is displayed on the display panel. The sampling level conversion circuit according to the present invention described above is provided as a level conversion circuit that receives and converts the level into a signal having a higher amplitude.
【0024】
In still another aspect, the display device according to the present invention is a circuit that receives display data transferred from the display memory in the display panel and converts the level into a signal having a higher amplitude. It has a phase expansion circuit. Further, the display panel may be provided with a digital-to-analog converter that receives the output of the two-phase expansion circuit.
【0025】
In still another aspect, the n-phase expansion circuit according to the present invention includes n of the sampling level conversion circuits described above (n is a predetermined positive integer of 2 or more), and the input terminals of the n sampling level conversion circuits. Is equipped with a circuit that generates a multi-phase clock signal in which data signal lines are commonly connected and adjacent phases are separated by one data cycle from each other, and the i-th (where i is an integer of 1 or more and n or less). The i-th clock signal of the multi-phase clock signal is input to the second sampling control signal of the sampling level conversion circuit of), and the first sampling control signal is the () of the multi-phase clock signal. The i + 1) th clock signal is input, the terminal voltage of the first capacitance of the i-th sampling level conversion circuit is received, and the transition of the (i + 1) th clock signal to the first logical value. The output of the first latch circuit is provided with n first latch circuits corresponding to the sampling level conversion circuit and stored in the second logical value of the (i + 1) th clock signal. It is equipped with n second latch circuits that input each of the above and latch output with the clock of the cycle that divides the data cycle by n. As will be apparent to those skilled in the art from the following description, the above-mentioned problems will be similarly solved by the invention of each claim in the claims.
【0026】
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described. In one preferred embodiment thereof, the sampling level conversion circuit according to the present invention is based on the input sampling control signals (SMP and XSMP in FIG. 1), and during the setup period, the charging path (capacity C2 and higher side) of the output node. Means for turning on the switch element (MP1 in Fig. 1) inserted in the path between power supplies and precharging the output node to the higher power supply voltage, and means for sampling the input signal voltage (MN1, C1 in Fig. 1). During this setup period, the discharge path of the output node is set to the off state (non-conducting state) based on the input sampling control signal (SMP) (MN3 in Fig. 1 is off), and the setup is performed. In the output period following the period, the switch element (MN2 in Fig. 1) inserted in the discharge path of the output node is turned on according to the logical value (terminal voltage of capacitance C1) of the input signal sampled during the setup period. Or, when the switch element (MN2 in FIG. 1) that is turned off and inserted in the discharge path is on, the discharge path of the output node is in the on state based on the input sampling control signal (MN3 in FIG. 1 is on). When the output node precharged to the higher power supply voltage is discharged and the switch element (MN2 in FIG. 1) inserted in the discharge path is off, the output node is not discharged. , Precharged higher power supply voltage.
【0027】
More specifically, referring to FIG. 1, the sampling level conversion circuit is a first to third MOS transistor connected in series between the higher power supply and the lower power supply to form the first to third switch elements. (MP1, MN3, MN2), capacitance (C2) connected to the connection point of the first and second MOS transistors (MP1, MN3), input terminal and gate terminal of the third MOS transistor (MN2). A first MOS transistor (MN1) connected to and forming a fourth switch element, and a capacitance (C1) connected to the gate of the third MOS transistor (MN2). , The first sampling control signal (SMP) is commonly input to the gate of the second MOS transistor (MP1, MN3), and the second sampling control signal (XSMP) is input to the gate of the fourth MOS transistor (MN1). ) Is entered.
【0028】
To outline the operation of this circuit, when the first sampling control signal (SMP) is the second logical value (setup period), the MOS transistor (MP1) that forms the first switch element is turned on, and the second The MOS transistor (MN3) that forms the switch element of is turned off, and the capacitance (C2) is charged to the power supply voltage of the higher power supply. When the second sampling control signal (XSMP) has the first logical value, the fourth MOS transistor (MN1) forming the fourth switch element is turned on, and the capacitance (C1) is charged by the input signal voltage.
【0029】
When the first sampling control signal (SMP) is the first logical value (output period), the MOS transistor (MP1) forming the first switch element is turned off, and the MOS transistor (MN3) forming the second switch element is turned off. Is turned on, and the terminal voltage of the capacitance (C2) at this time is taken out as an output signal directly or indirectly. In this case, as the second sampling control signal (XSMP), a signal (complementary signal) obtained by inverting the first sampling control signal (SMP) is supplied.
【0030】
When the sampling level conversion circuit according to the present invention is mounted on the display panel, the high-level power supply is the display panel-side power supply, the low-level power supply is ground, and the first MOS transistor MP1 is a P-type TFT. The second to fourth MOS transistors MN3, MN2, and MN1 are composed of N-type TFTs (Thin Film Transistors).
【0031】
In another preferred embodiment thereof, the sampling level conversion circuit according to the present invention is connected in series between the high-level power supply and the low-level power supply to form the first to third switch elements, referring to FIG. 21. The capacitance (C2) connected to the connection points of the first to third MOS transistors (MP1, MN3, MN2) and the first and second MOS transistors (MP1, MN3), the input terminal, and the second The capacitance (C1) connected to the gate of the fourth MOS transistor (MN1), which is connected to the gate terminal of the MOS transistor (MN3) and forms the fourth switch element, and the gate of the second MOS transistor (MN3). ), And the first sampling control signal (SMP) is commonly input to the gates of the first and third MOS transistors (MP1, MN2), and the gate of the fourth MOS transistor (MN1) A second sampling control signal (XSMP) is input. The operation of the sampling level conversion circuit of this embodiment is basically the same as that of the sampling level conversion circuit of the above-described embodiment. For example, when the logical amplitude voltage of the signal input to the input terminal is sufficiently larger than the threshold voltage of the MOS transistor constituting the sampling level conversion circuit, the sampling level conversion circuit of this embodiment is preferably applied and the capacitance ( When C2) have the same capacitance value and the signal voltage input to the input terminal is 0V, the voltage drop due to charge redistribution of the capacitance (C2) is smaller than that of the configuration of the above-described embodiment. It can be suppressed.
【0032】
According to the sampling level conversion circuit of the present invention, the following effects are obtained.
【0033】
1. Low power consumption because steady current does not flow.
【0034】
2. Single-phase input (= no inverting data required) requires a small number of terminals (general level conversion circuits require two inputs, data and inverting data).
【0035】
3. The potential on the high voltage side is not generated at the input terminal, and the possibility of destroying the circuit on the low voltage side is low (when a latch type sense amplifier used in memory etc. is used for the level shifter, it is at the input terminal. A potential on the high voltage side may occur).
【0036】
In the case of a polysilicon TFT LCD, for example, it is configured to have about 200 data input terminals, and the present invention is used in such an application where sampling and level shifting of a large amount of data are required. Especially effective.
【0037】
In one embodiment of the two-phase expansion circuit of the present invention, referring to FIG. 7, the two-phase expansion circuit includes two sampling level conversion circuits (first and second sampling level conversion circuits) of the above-described embodiment. Input signals are commonly input to the first and second sampling level conversion circuits, and the first and second sampling control signals (SMP, XSMP) of the first sampling level conversion circuit are input to the second sampling level conversion circuit. ) Values are inverted signals (that is, XSMP, SMP) are input to the corresponding switch elements as first and second sampling control signals, and the output of the first sampling level conversion circuit is output to the previous first. The output of the first master-slave type latch that is captured based on the sampling control signal (SMP) of 1 and output based on the second sampling control signal (XSMP) and the output of the first master-slave type latch are first sampled. The latch that outputs based on the control signal (SMP) and the output of the second sampling level conversion circuit are taken in based on the second sampling control signal (XSMP) and output based on the first sampling control signal (SMP). The master-slave type latch, and the latch that latches the output of the first master-slave type latch and the output of the second master-slave type latch, the even and oddth signals are sent in parallel. It is output in synchronization with the first sampling control signal (SMP).
【0038】
In one embodiment, the display device according to the present invention includes a display panel (100) having pixel portions arranged in a matrix at the intersections of a plurality of data lines and a plurality of scanning lines, referring to FIG. , A scanning line drive circuit (also referred to as a "scanning circuit") (108) that sequentially applies a voltage to the plurality of scanning lines, and the plurality of data lines that receive display data from a host device and apply a voltage corresponding to the display data. In a display device having a data line drive circuit to be applied to, a display memory (121) for storing display data corresponding to a pixel portion, control of the display memory, and communication and control with a higher-level device are controlled outside the display panel. A controller (122) is provided, and high is received on the display panel (display device board) (100) by receiving display data of a low amplitude logic signal (for example, 0-3V) from the display memory (121). The sampling level conversion circuit according to the present invention described above is provided as a level conversion circuit (101) that converts a level into a logic signal of amplitude (for example, 0-10V).
【0039】
In one embodiment of the present invention, referring to FIG. 16, the display device according to the present invention receives display data of a low-amplitude logic signal from the display memory (121) and converts the level into a high-amplitude logic signal. As the two-phase expansion circuit (102), the two-phase expansion circuit according to the present invention may be provided. The output of the two-phase expansion circuit is input to the digital-to-analog converter (104) and converted into an analog video signal. Provide digital-to-analog converters for the number of data lines and supply the output signal of the digital-to-analog converter to the data lines as it is, or sequentially with the selector (105) that takes the output of the digital-to-analog converter as input. It may be selected and supplied to the data line.
【0040】
Another embodiment of the multi-phase expansion circuit (n-phase expansion circuit) according to the present invention will be described. With reference to FIG. 22, the n-phase expansion circuit according to the present invention includes n sampling level conversion circuits according to the present invention described above (n is a predetermined positive integer of 2 or more), and is composed of n sampling level conversion circuits. A data signal line (DATA) is commonly connected to the input terminal, and a clock generation circuit for generating a multi-phase clock signal whose phases are different from each other by one data cycle is provided. The i-th clock of the multi-phase clock signal is input as the second sampling pulse signal (XSMP) of the i-th (where i is an integer greater than or equal to 1 and n or less) sampling level conversion circuit, and the first sampling pulse signal. As (SMP), the (i + 1) th clock of the polyphase clock signal is input.
【0041】
The terminal voltage of the capacitance (C2) of the sampling level conversion circuit of the i-th (however, i is an integer of 1 or more and n or less) is used as an input, and the transition of the (i + 1) -th clock to the first logical value is performed. The first latch circuit to be output corresponds to the sampling level conversion circuit and consists of n (clocked inverter 211, inverter 212, clocked inverter 213, clocked inverter 311, inverter 312, clocked inverter 313). It is equipped with a latch circuit consisting of a clocked inverter 411, an inverter 412, and a latch circuit consisting of a clocked inverter 413, ...).
【0042】
Furthermore, n second latch circuits (clocked inverter 214, inverter 215, clocked inverter 216) that input the output of the first latch circuit and latch with the latch timing signal of the cycle obtained by dividing the data cycle by n are provided. A latch circuit consisting of a clocked inverter 314, an inverter 315, and a clocked inverter 316, and a latch circuit consisting of a clocked inverter 414, an inverter 415, and a clocked inverter 416, ...). From the n second latch circuits, n bits are output in parallel in synchronization with the latch timing signal. The circuit that generates the multi-phase clock signal is composed of a shift register (1010) that generates a multi-phase clock signal that is out of phase with each other for one data cycle.
【0043】
[Example]
In order to explain the above-described embodiment of the present invention in more detail, examples of the present invention will be described below with reference to the drawings. First, an example of the sampling level conversion circuit according to the present invention will be described. FIG. 1 is a diagram showing a basic configuration of a sampling level conversion circuit according to an embodiment of the present invention.
【0044】
Referring to FIG. 1, the sampling level conversion circuit of this embodiment is a circuit that samples input data having a voltage amplitude of 0-3V and converts the level to 0-10V. More specifically, the P-channel MOS transistor MP1 whose source is connected to the higher power supply (power supply voltage 10V) and the drain are connected to the drain of the P-channel MOS transistor MP1 and the gate is common to the gate of the P-channel MOS transistor MP1. It is equipped with an N-channel MOS transistor MN3 connected to, and a sampling pulse signal SMP, which is a signal for controlling sampling operation, is commonly input to the gate of the P-channel MOS transistor MP1 and the gate of the N-channel MOS transistor MN3. To.
【0045】
In addition, the drain is connected to the source of the N-channel MOS transistor MN3, the source is connected to the lower power supply (ground), the N-channel MOS transistor MN2, and the input terminals IN and N for inputting input data (0-3V). The N-channel MOS transistor MN1 connected to the gate of the channel MOS transistor MN2 and the inverted signal XSMP of the sampling pulse signal SMP is input to the gate.
【0046】
Further, it includes a P-channel MOS transistor MP2 whose source is connected to a higher power supply (power supply voltage 10V) and an N-channel MOS transistor MN4 whose drain is connected to the drain of the P-channel MOS transistor MP2. The gate of the P-channel MOS transistor MP2 and the gate of the N-channel MOS transistor MN4 are commonly connected and connected to the connection point between the drain of the P-channel MOS transistor MP1 and the drain of the N-channel MOS transistor MN3, and the drain of the P-channel MOS transistor MP2. The connection point of the drain of the N-channel MOS transistor MN4 is connected to the output terminal OUT. The MOS transistors MP2 and MN4 form a CMOS inverter, receive the terminal voltage of capacitance C2, and output a binary signal with 0-10V amplitude.
【0047】
A capacitance (capacitor) C1 is connected between the gate of the N-channel MOS transistor MN2 and the lower power supply (ground), and the connection point between the drain of the P-channel MOS transistor MP1 and the drain of the N-channel MOS transistor MN3. , Capacitor C2 is connected between the lower power supply (ground).
【0048】
The N-channel MOS transistor MN1 and the capacitance C1 form a sampling circuit that samples the input signal voltage input to the input terminal. The P-channel MOS transistor MP1 functions as a precharge element having a capacitance C2, the N-channel MOS transistor MN2 functions as an input voltage detection element, and the N-channel MOS transistor MN3 functions as an input voltage evaluation element. In the examples described below, these MOS transistors are composed of polycrystalline silicon TFT elements created on, for example, an insulating substrate (TFT substrate). As the capacitance C1, the parasitic capacitance of the gate of the N-channel MOS transistor MN3 and the connection point node of the N-channel MOS transistor MN1 may be used, and as the capacitance C2, the drain of the P-channel MOS transistor MP1 and the N-channel MOS transistor MN3. The parasitic capacitance of the connection point node of the drain may be used.
【0049】
Next, the basic operation of the level conversion circuit according to the embodiment of the present invention shown in FIG. 1 will be described. FIG. 2 is a schematic diagram for explaining the operating principle of an embodiment of the present invention. As shown in Fig. 2 (a), when the sampling pulse signal SMP is at the low level, the precharge P-channel MOS transistor MP1 is turned on and the signal XSMP is at the high level (10V), so the N-channel MOS transistor MN1 Also turns on. On the other hand, the N-channel MOS transistor MN3 is turned off. Therefore, the capacitance C2 is charged from the higher power supply (10V power supply) through the P-channel MOS transistor MP1 and precharged to the power supply voltage of 10V. Further, since the N-channel MOS transistor MN1 is turned on, the potential of the input signal IN (0-3V) is applied to the capacitance C1 as its terminal voltage and charged. The period during which the sampling pulse signal SMP is at the low level is also referred to as the "setup period".
【0050】
Next, as shown in Fig. 2 (b), when the sampling pulse signal SMP reaches the high level (at this time, the inverting signal XSMP is at the low level), the N-channel MOS transistor MN1 is turned off, and the capacitance C1 is the input terminal IN. Is electrically separated from. In addition, the evaluation N-channel MOS transistor MN3 is turned on, the precharge P-channel MOS transistor MP1 is turned off, and the capacitance C2 is connected to the lower power supply (ground) via the N-channel transistors MN3 and MN2. To.
【0051】
At this time, depending on the potential (0V or 3V) of the input signal held in the capacitance C1, the terminal voltage of the capacitance C2 precharged to 10V is held as it is or discharged to 0V. .. That is, when the terminal voltage of the capacitance C1 is 3V, the N-channel MOS transistor MN2 that receives the terminal voltage of the capacitance C1 at the gate is turned on, the accumulated charge of the capacitance C2 is discharged, and the terminal voltage of the capacitance C2 is on the lower side. It becomes the power supply potential (0V: ground potential). The P-channel MOS transistor MP2 that receives the gate potential of 0V turns on, the N-channel MOS transistor MN4 turns off, and the output terminal OUT becomes High level (10V). In the process of discharging the accumulated charge of the capacitance C2, when the terminal voltage drops from 10V by the threshold voltage of the P-channel MOS transistor MP2, the P-channel MOS transistor MP2 turns on and the output signal (OUT). ) Starts rising.
【0052】
On the other hand, when the terminal voltage of the capacitance C1 is 0V, the N-channel MOS transistor MN2 is turned off, the accumulated charge of the capacitance C2 is retained, the terminal voltage of the capacitance C2 is 10V, and the P-channel MOS transistor receives the gate potential of 10V. MP2 is turned off, N-channel MOS transistor MN4 is turned on, and the signal voltage of the output terminal OUT becomes 0V. As a result, a signal of 10V or 0V can be obtained from the output terminal OUT depending on the input signal potential of the input terminal IN. The period during which the sampling pulse signal SMP is at the high level is also referred to as the "output period". In the process of precharging the accumulated charge of the capacitance C2, when the terminal voltage exceeds the threshold voltage of the N-channel MOS transistor MN4, the N-channel MOS transistor MN4 turns on and the output signal (OUT). Stands down.
【0053】
The power consumption of the sampling level conversion circuit shown in Fig. 1 was determined by simulation and found to be 859nW (nanowatt) (however, the signal SMP frequency is 62.5KHz). For example, 198 sampling level conversion circuits were arranged in parallel. Even in the case (see the sampling level shifter in FIG. 16), the power consumption is reduced to 172uW (microwatt).
【0054】
Next, a second embodiment of the present invention will be described. FIG. 3 is a diagram showing a configuration of a second embodiment of the present invention. Referring to FIG. 3, this circuit is obtained by connecting an inverter and a latch circuit to the sampling level conversion circuit shown in FIG. 1 to obtain an output signal synchronized with the sampling pulse signal SMP.
【0055】
As described in the above embodiment, the sampling level conversion circuit precharges the capacitance C2 to 10V when the sampling pulse signal SMP is at the low level, and charges the capacitance C1 with the input signal voltage during the setup period, the sampling pulse signal SMP. When is at High level, two types of operation mode periods, which are output periods for outputting a signal corresponding to the input signal voltage, are alternately repeated.
【0056】
The gate is commonly connected, the drain is commonly connected, and the gate is commonly connected to the first CMOS inverter consisting of the P-channel MOS transistor MP2 and the N-channel MOS transistor MN4, which are connected in series with the high-level power supply and the low-level power supply tube. The output of the first CMOS inverter is equipped with a second CMOS inverter consisting of a P-channel MOS transistor MP3 and an N-channel MOS transistor MN5, which are connected in common to the drain and connected in series with the high-level power supply and the low-level power supply tube. The terminal is connected to the input terminal of the second CMOS inverter, and the output terminal of the second CMOS inverter is a master slave that captures data at the rising edge of the sampling pulse signal SMP and outputs data at the falling edge of the sampling pulse signal SMP. It is connected to the input terminal of the type latch.
【0057】
This latch is input to the clocked inverter 11 that is turned on (activated) at the high level of the sampling pulse signal SMP input to the control terminal and turned off (deactivated) at the low level, and the output terminal of the clocked inverter 11. A clocked inverter with a terminal connected to the inverter 12 and an input terminal connected to the output terminal of the inverter 12 and input to the control terminal. Clocked inverter that turns on at the high level of the sampling pulse signal SMP inversion signal XSMP and turns off at the low level. 13 and the master latch part where the connection points of the output terminals of the clocked inverters 11 and 13 are connected to the input terminals of the clocked inverter 12, and the input terminals are connected to the output terminals of the clocked inverter 11 to be the control terminals. The input signal is a clocked inverter 14 that turns on at the high level of the XSMP and turns off at the low level, an inverter 15 with an input terminal connected to the output terminal of the clocked inverter 11, and an input terminal at the output terminal of the inverter 15. The signal SMP that is connected and input to the control terminal is equipped with a clocked inverter 16 that turns on at the high level of the SMP and turns off at the low level, and the connection points of the output terminals of the clocked inverters 14 and 16 are the input terminals of the inverter 15. It is equipped with a slave latch unit that is connected to.
【0058】
As shown in FIG. 3, the clocked inverter includes P-channel MOS transistors MP12 and MP11 and N-channel MOS transistors MN11 and MN12 connected between the high-level power supply (10V) and the low-level power supply (ground). The signal SMP is input to the gate of the N-channel MOS transistor MN12, the signal XSMP is input to the gate of the P-channel MOS transistor MP12, and when the MOS transistors MN12 and MP12 are in the conductive (ON) state, the MOS transistors MP11 and MN11 It functions as a CMOS inverter, and when the MOS transistors MN12 and MP12 are non-conducting (off), the output terminal is in a high impedance state. In each of the drawings attached to the specification of the present application, the signal name (for example, SMP or XSMP) under the clocked inverter is the clock whose signal name is turned on at the high level and turned off at the low level. It shows that it is a clock inverter.
【0059】
With reference to FIG. 3, the clocked inverter 11 conducts at the rising edge of the sampling pulse signal SMP, and the output signal of the second-stage CMOS inverter (MOS transistor MP3, MN5) is taken into the master latch section, and the sampling pulse signal is signaled. At the fall of the SMP, the clocked inverter 11 turns off, the clocked inverter 13 turns on, a flip-flop is configured with the inverter 12, data is stored in the master latch section, and the clocked inverter 14 turns on. Data is output from the output terminal OUT.
【0060】
When the clocked inverter 11 becomes conductive at the rising edge of the sampling pulse signal SMP in the next cycle, the clocked inverter 14 is turned off, and the slave latch portion stores and holds the data output to the output terminal OUT.
【0061】
FIG. 4 is a timing chart showing an example of the operation of the circuit of FIG. The operation of the circuit of FIG. 3 will be described with reference to FIG. When the sampling pulse signal SMP is at the low level, the setup period is set, the sampling pulse signal SMP rises, and the high voltage (10V) and low voltage (ground potential) corresponding to the input data (INDATA) are the sampling level conversion circuit. It is output from the second-stage CMOS inverter, taken into the master-slave type latch, and output at the falling edge of the sampling pulse signal SMP.
【0062】
In the example shown in FIG. 4, OUTDATA output in synchronization with the falling edge of the sampling pulse signal SMP (rising edge of XSMP) is the sampling pulse signal of the input data INDATA input to the input terminal IN of the sampling level conversion circuit. The timing of the rising edge of the SMP is the data of the data number included in the data cycle, and the even-order data D4, D6, D8, ..., D2n.
【0063】
When the signal voltage of the input terminal IN is high level, the sampling pulse SMP becomes the ground potential during the output period of the high level, and the node N1 (terminal voltage of the capacitance C2) of the sampling level conversion circuit becomes the ground potential, and the two-stage CMOS that receives this. The ground potential (Low level) is output from the inverter (forward rotation buffer), the High level (10V) is output via the clocked inverter 11 that receives it, and the clocked inverter 14 is output at the high level timing of the signal XSMP. The low level is output to the output terminal OUT via.
【0064】
When the signal voltage of the input terminal IN is low level, the sampling pulse signal SMP becomes 10V during the high level output period, and the high level (10V) is output from the two-stage CMOS inverter that receives this. The low level is output via the clocked inverter 11 that receives this, and the high level is output to the output terminal OUT via the clocked inverter 14 at the timing of the high level of the signal XSMP. The logic of the 0-10V output signal is inverted with the input data.
【0065】
At the high level of the sampling pulse signal SMP, the sampling level conversion circuit is set as the output period, and the output signal is output to the output terminal OUT at the falling edge of the sampling pulse signal SMP, that is, the rising edge of the signal XSMP, and the output timing is sampling. The pulse signal SMP is delayed by half a cycle.
【0066】
As shown in FIG. 5, a CMOS inverter is connected to node N1 of the sampling level conversion circuit shown in FIG. 1 in an even stage or 0 stage (10 in FIG. 5), and activated by a sampling pulse signal SMP in the subsequent stage. When a clocked inverter (on) is connected, this circuit does not malfunction due to the presence of clock skew in the sampling pulse signal SMP and its inverting signal XSMP. In FIG. 5, the clocked inverter includes P-channel MOS transistors MP12, MP11, and N-channel MOS transistors MN11, MN12 connected between the high-level power supply (10V) and the low-level power supply (ground), and is an N-channel MOS transistor. The signal SMP is input to the gate of the MN12, the signal XSMP is input to the gate of the P-channel MOS inverter MP12, and CMOS is input to the common gate (node N2) of the P-channel MOS transistor MP11 and the N-channel MOS inverter MN11. The output of the CMOS inverter circuit 10 in which the inverters are connected in even or 0 stages is input, and it corresponds to the clocked inverter 11 in FIG.
【0067】
The principle that the circuit shown in FIG. 5 does not malfunction due to clock skew will be described with reference to the timing diagram of FIG. Referring to FIG. 6 (a), the sampling pulse signal SMP is initially set to the high level, the inverted signal XSMP of the sampling pulse signal is set to the low level, and at this time, the node N1 of FIG. 5 is 0V and the node N2 is also 0V. It is assumed that the P-channel MOS transistor MP12 of the clocked inverter is turned on and the output terminal OUT is at high potential (10V).
【0068】
From this state, the P-channel MOS transistor MP1 is turned on at the same time as the sampling pulse signal SMP falls, precharging from the higher power supply (10V) to the capacitance C2 is started, the potential of node N1 rises, and even stages. Alternatively, the potential of the node N2 (in the case of the 0-stage inverter, the node N1 itself) rises and transitions to the High level (10V) with a delay of the propagation delay time of the 0-stage CMOS inverter circuit 10. The N-channel MOS transistor MN12 of the clocked inverter turns off (high impedance state) at the same time as the sampling pulse signal SMP falls, and then the N-channel MOS transistor MN11 turns on even if the node N2 becomes high potential (10V). However, the output of the output terminal OUT does not reach the Low level (0V). In this way, the output signal from the output terminal OUT does not reach the low level without depending on the timing variation (skew) of the rising edge of the signal XSMP. That is, even in the presence of clock skew, malfunctions are avoided and therefore clock skew free.
【0069】
On the other hand, when the circuit 10 of FIG. 5 is configured by connecting CMOS inverters in odd-numbered stages, the node N2 has the potential obtained by inverting the node N1. The sampling pulse signal SMP is initially set to High level (10V), the signal XSMP is set to Low level, node N1 is 0V, node N2 is 10V, at which time the clocked inverter's P-channel MOS transistor MP12 is turned on and It is assumed that the P-channel MOS transistors MN11 are turned off, the N-channel MOS transistors MN11 and MN12 are turned on, and the output signal from the output terminal OUT is at the low level (0V).
【0070】
From this state, the P-channel MOS transistor MP1 is turned on at the same time as the sampling pulse signal SMP falls, precharging from the higher power supply (10V) to the capacitance C2 is started, the potential of node N1 rises, and the odd stage With a delay of the propagation delay time of the CMOS inverter circuit 10 of the configuration, node N2 falls and transitions to the low level (0V). Simultaneously with the fall of the sampling pulse signal SMP, the N-channel MOS transistor MN12 of the clocked inverter is turned off (high impedance state), and then the node N2 is at the low level. At this time, the signal XSMP is still at the low level. , P-channel MOS transistors MP12 and MP11 are turned on, and the output signal of the output terminal OUT becomes High level (10V). As described above, when the circuit 10 of FIG. 5 is configured by connecting the CMOS inverters in odd-numbered stages, a malfunction occurs due to the delay of the rising edge of the inverting signal XSMP of the sampling pulse signal SMP. That is, if the inverted signal XSMP of the sampling pulse signal SMP is generated by inverting the sampling pulse signal SMP with the inverter and the delay due to the propagation delay time of the inverter is not adjusted, a malfunction occurs due to the delay of the rising edge of the signal XSMP.
【0071】
Next, a third embodiment of the present invention will be described. FIG. 7 is a diagram showing a configuration of a third embodiment of the present invention, and is a diagram showing a configuration of a circuit that expands serial data into two-phase data.
【0072】
Two circuits consisting of a sampling level conversion circuit, an inverter, and a master-slave type latch described with reference to FIG. 3 are connected in parallel to one data input terminal DATA, and one latch is set in one circuit. By adding, the even-th input data and the odd-th input data are synchronized with the rising edge of the sampling pulse signal SMP, and are output in parallel at a frequency obtained by dividing the frequency of the input data DATA by two. That is, referring to FIG. 7, the data input terminal DATA is provided with two sampling level conversion circuits of the above-described embodiment in parallel. As shown in FIG. 4, the first sampling level conversion circuit has two CMOS inverters connected to the output stage, a master latch and a slave latch, a one-stage latch, and an inverter. It is configured to output XDATAODD, and a CMOS inverter is connected to the output stage of the second sampling level conversion circuit in two stages, and a master latch, a slave latch, and an inverter are provided to output DATAEVEN / XDATAEVEN. ..
【0073】
More specifically, the circuit that outputs the odd-th signal is a first sampling level conversion circuit (MOS transistors MN1, MN2, MN3, MP1 and capacitance C1, which has the same configuration as that described with reference to FIG. When the C2), the CMOS inverters (MOS transistors MP2, MN4, MOS transistors MP3, MN5) connected in two stages and the sampling pulse signal SMP are at the high level, the data is taken into the master latch section and the inverting signal XSMP is generated. Master-slave latch (clocked inverter 11, inverter 12, clocked inverter 13, clocked inverter 11, clocked inverter 13, clocked inverter 11, clocked inverter 13, clocked inverter 13, clocked inverter 11, clocked inverter 13, clocked inverter 11, clocked inverter 13, clocked inverter 13, clocked inverter 11, clocked inverter 13, It consists of 14, an inverter 15, and a clocked inverter 16 and has the same configuration as the master-slave latch in Fig. 3) and outputs data at the high level of the sampling pulse signal SMP, and stores the output data when the signal XSMP is at the high level. It is equipped with a latch (consisting of a clocked inverter 17, an inverter 18, and a clocked inverter 19), an inverter 20 that reverses the output of the clocked inverter 17, and an inverter 21 that reverses the output of the inverter 18. The odd-th signal DATAODD and its complementary (inverted) signal XDATAODD are output from the output terminals 21 and 20.
【0074】
In the first sampling level conversion circuit of the path that outputs the odd-th signal DATAODD, the inverted signal XSMP of the sampling pulse signal SMP is input to the gate of the MOS transistor MN1 as in FIG. 3, and the MOS transistors MP1 and MN3 A sampling pulse signal SMP is commonly input to the gate, the low level of the sampling pulse signal SMP is the precharge period, the high level is the output period, and the data from the first sampling level conversion circuit is the next sampling pulse signal. It is output as data (DATA ODD) at the start of SMP. The sampling pulse signal SMP has a clock rate that is 1/2 of the data rate. That is, the first sampling level conversion circuit and the latch unit take in data at the rising edge of the sampling pulse signal SMP and output the data in synchronization with the rising edge of the sampling pulse signal SMP in the next cycle.
【0075】
The circuit that outputs the even-th signal (DATAEVEN) is the second sampling level conversion circuit (MOS transistor MN6, MN7, MN8, MP4, capacitance C1, C2) and the CMOS inverter (MOS transistor MP5) that is connected in two stages. , MN9, MOS inverter MP6, MN10), a master latch that captures data at the high level of the signal XSMP, and a slave that outputs data at the high level of the signal SMP and stores the output value at the high level of the signal XSMP. An inverter that has a master-slave type latch (clocked inverter 22, inverter 23, clocked inverter 24, 25, inverter 26, clocked inverter 27) that latches with a latch part, and reverses the output of the clocked inverter 25. 28 and an inverter 29 that inverts the output of the inverter 26 are provided, and the even-th signal DATAEVEN and the inverted signal XDATAEVEN are output from the inverters 28 and 29 in synchronization with the rising edge of the sampling pulse signal SMP.
【0076】
In the second sampling level conversion circuit of the path that outputs the even-th signal, the sampling pulse signal SMP is input to the gate of the MOS transistor MN6 that constitutes the sampling circuit, and is inverted at the gate of the MOS transistors MP4 and MN8. The signal XSMP is input, the low level of the inverting signal XSMP is the precharge period, the high level period of the inverting signal XSMP is the output period, and data is output at the rising edge of the sampling pulse signal SMP in the master-slave system latch. That is, the second sampling level conversion circuit and latch of the path that outputs the even-th signal captures data at the falling edge of the next sampling pulse signal SMP (rising edge of the signal XSMP), and the sampling pulse signal SMP of the next cycle Data is output at the rising edge (falling edge of the signal XSMP). In the path that outputs the odd-numbered signal DATAODD, the master-slave type latch is further provided with latches (17, 18, 19), and the latch of the path that outputs the even-numbered signal DATAEVEN (master-slave type latch) is better than the latch (master-slave type latch). The data is output with a delay of half a clock of the sampling pulse signal SMP.
【0077】
As a result, as shown in FIG. 8, for the input serial data DATA1, 2, 3, 4, 5, 6, 7, ..., as the odd-numbered signal DATAODD, DATA1, 3, 5, 7 , ... and as even-numbered signals DATAEVEN, DATA2, 4, 6, 8, ... are synchronized with the rising edge of the sampling pulse signal SMP, (DATA1, 2), (DATA3, 4), ( It is output sequentially as a set of DATA5, 6), .... One cycle of DATAODD and DATAEVEN corresponds to two cycles of input data DATA.
【0078】
In this way, by expanding the input data into two phases by the two-phase expansion circuit, the operating frequency of the subsequent circuit is reduced to 1/2. The sampling pulse signal SMP and its inverting signal XSMP require an amplitude of 0-10V, but since they are commonly used on the liquid crystal display module, for example, for a sampling level conversion circuit for 198 inputs. As the level conversion circuit for creating the sampling pulse signal SMP and its inverting signal XSMP, the conventional level conversion circuit described with reference to FIG. 24 and the like may be used.
【0079】
When the two-phase expansion circuit shown in FIG. 7 is applied to a configuration in which the signal of the external signal processing circuit is level-shifted and two-phase expansion is performed, the interface with the controller IC 120 has a bit width of 198 bits, as shown in FIG. The frequency is 125KHz (8us), two phases are developed inside the panel 100, and a 396bits, 62.5KHz signal is passed to 66 6-bit DAC arrays 104.
【0080】
Next, as a specific example of the sampling level conversion circuit according to the embodiment of the present invention, FIG. 9 shows a specific design example of the sampling level conversion circuit when the polysilicon TFT on the insulating substrate is used as the transistor element. It will be explained with reference to. In FIG. 9, the sampling level conversion circuit (MOS transistors MN1, MN2, MN3, MP1, capacitance C1, C2) having the configuration shown in FIG. 1 is connected to a two-stage CMOS inverter (MOS transistors MP2, MP3, MN4, MN5). MOS transistors MP4, MN6) are connected. In the sampling level conversion circuit, when the sampling pulse signal SMP is at the low level, the capacitance C2 is precharged and the capacitance C1 is charged by the input voltage. The first-stage CMOS inverter in which four MOS transistors (MP2, MP3, MN4, MN5) are stacked vertically reduces the through current of the inverter. That is, the discharge time of the accumulated charge of the precharged capacitance C2 takes longer than that of a normal logic signal, and the transient time becomes longer. , It has been devised to reduce the through current. Further, due to charge redistribution described later, the terminal voltage (High level) of the capacitance C2 may drop from 10V to about 9.5V, and the penetration current at this time is reduced. In addition, the first stage inverter consisting of four vertical stages of transistors (MP2, MP3, MN4, MN5) is configured to double the gate length L of the MEMS and PMOS transistors of the CMOS inverter consisting of two stages of transistors. May be good.
【0081】
The discharge time of the capacitance C2 is such that the sampling pulse signal SMP is at a high level, the N-channel MOS transistors MN3, MN2, and the lower power supply (0V) pass, and the discharge occurs within a predetermined time (for example, 8us; one cycle of frequency 125KHz). If possible, the characteristics of the N-channel MOS transistor MN2 with a gate-source voltage VGS = 3V dominates. The gate-source voltage VGS is set to 3V at the terminal voltage of capacitance C1 when the input data is 3V.
【0082】
As the charge retention characteristic of the capacitance C2, when the sampling pulse signal SMP is at High level (10V) and the gate voltage of the N-channel MOS transistor MN2 is 0V, the terminal voltage of the capacitance C2 is held for a predetermined time (for example, 8us). Is required.
【0083】
When the gate voltage of the N-channel MOS transistor MN2 (also called "detection transistor") is 0V and the sampling pulse signal SMP is at High level, when the N-channel MOS transistor MN3 is turned on, it is added to the terminal node of capacitance C2. In addition to the stray capacitance (stray capacitance), that is, the capacitance (parastic capacitance) of the P-channel MOS transistor MP1 whose drain is connected to the terminal node of capacitance C2, the drain is connected to the terminal node of capacitance C2 and is on. The accumulated charge of the capacitance C2 is redistributed by the combined capacitance Cs of the capacitance of the channel MOS transistor MN3 and the capacitance of the N-channel MOS transistor MN2.
【0084】
In this case, the parasitic capacitance Cn of the MOS transistor other than the P-channel MOS transistor MP1 connected to the capacitance C2 is the gate-to-channel capacitance of the N-channel MOS transistor MN3. Cgd (MN3) and gate-source capacitance Cgs (MN3) and gate-to-bulk capacitance It is defined by capacitance) Cgb (MN3) and gate-drain capacitance Cgd (MN2) of N-channel MOS transistor MN2 (0V is applied to the gate). Cgb (MN2) does not need to be considered because transistor MN2 is off. Also, Cgd (MN2) is considered to be almost 0, and in the end, the parasitic capacitance Cn is the capacitance Cox (MN3) of the unit area of the gate oxide film of the N-channel MOS transistor MN3, and the area A (= W) of the gate electrode. L: However, W is approximated by multiplying the gate width and L by the gate length). As is well known, in a MOS transistor on single crystal silicon, the gate-bulk capacitance Cgb at the cutoff when the gate-source voltage is below the threshold voltage is constant, but SOI (Silicon On Insulator) In the case of an N-channel TFT element with a structure of), there is no bulk, the Cgb at cutoff is not constant, and it has frequency dependence.
【0085】
Due to the redistribution of charges by the stray capacitance Cs applied to the terminals of capacitance C2, the terminal voltage of capacitance C2 drops below the power supply voltage of 10V precharged during the setup period. That is, when the input signal voltage is 0V, the terminal voltage of the capacitance C1 is set to 0V during the setup period, and 0V is applied to the gate during the output period when the sampling pulse signal SMP is set to the high level. Is turned off and the discharge path of capacitance C2 is closed, so the terminal voltage of capacitance C2 should be held at the power supply voltage of 10V, but due to charge redistribution, the terminal voltage of capacitance C2 becomes It drops below the precharged power supply voltage of 10V.
【0086】
The combined capacitance of the parasitic capacitances of the MOS transistors MN3, MP1 and MN2 connected to the terminal of the capacitance C2 is Cs, the terminal voltage of the initial capacitance C2 (before charge redistribution) is V (= 10V), and after the charge is redistributed. Assuming that the terminal voltage of capacitance C2 is V', C2 V = (Cs + C2) V' From V'= V C2 / (Cs + C2) <V (= 10V) ... (1) Will be.
【0087】
That is, when the input is 0V (terminal voltage of C1 is 0V), the voltage drop ΔV after charge redistribution is ΔV = V-V'= V Cs / (Cs + C2) ... (2) Given in.
【0088】
If this voltage drop ΔV is large, the leakage current will increase, and in the worst case, the logic will be inverted. That is, although the terminal voltage of the capacitance C2 should originally be the High level (10V), there may be a case where the voltage drop ΔV causes the terminal voltage to become the Low level below the logical threshold. When the capacitance value of C2 is large with respect to Cs having the same value, ΔV becomes small, and the element value of the capacitance C2 is determined in consideration of the above-mentioned charge redistribution.
【0089】
In this embodiment, the gate width (W) / gate length (L) of the N-channel MOS transistor MN2 forming the detection element is 40/4 (unit is um), and the capacitance value of the capacitance C2 is 150 fF.
【0090】
In addition, considering the voltage drop due to the field through of the capacitance C1 and the charge / discharge time of the capacitance C1, the N-channel MOS transistor MN1 has a double-sided LDD (Lightly Doped Drain) structure, and its W / L is 8/4 (unit). um).
【0091】
The W / L of the N-channel MOS transistor MN3 and the P-channel MOS transistor MP1 was set to 4/4 (unit: um).
【0092】
The specifications of the N-channel MOS transistor MN2 will be described with reference to the characteristic diagram of FIG. FIG. 10 is a diagram showing the characteristics of the drain voltage VD and the drain current ID of the N-channel MOS transistor MN2 at the gate voltage VG = 3V. Even if the transistor has a drain voltage of VD = 10V and a gate voltage of VG = 3V and the drain current ID is the same, the drain source is shown in the characteristic curves A and B depending on the threshold VTH, transconductance, and channel conductance. The behavior at the inter-voltage VDS <10V is different, and therefore the time required to discharge the capacitance C2 also changes. In FIG. 10, the discharge time of the capacitance C2 is R> B> A.
【0093】
R in FIG. 10 is an equivalent resistance value for defining the relationship between the drain voltage VD and the drain current ID (Kirchhoff's voltage law), and the relationship is VD = R · ID. When the N-channel MOS transistor MN2 in the ON state is replaced with this resistor R (ON resistor), the discharge characteristics of the capacitance C2 are as shown in FIG.
【0094】
That is, for example, in FIG. 9, when the N-channel MOS transistor MN2 is replaced with the on-resistance R, it operates as a logic circuit, that is, in order to correspond to an operating frequency of 125 KHz and have a discharge time of 8 us, the capacitance C2 Due to the discharge characteristics, the upper limit is R = 10 MegaOhm. That is, if it is larger than R = 10MegaOhm, it cannot be discharged within 8us.
【0095】
Therefore, if R = 10MegaOhm, W / L = 40/4 of N-channel MOS transistor MN2, drain-source voltage VDS = 10V, gate voltage VG = 3V, and drain current ID> 1uA in the case of one-sided LDD structure. Will be done.
【0096】
In the case of N-channel MOS transistor MN2, W / L = 4/4, drain-source voltage VDS = 10V, gate voltage VG = 3V, and one-sided LDD structure, drain current ID> 100nA.
【0097】
To reduce the voltage drop due to leakage to 0.5V or less, the drain current ID is <940nA in the case of W / L = 40/4, VDS = 10V, VG = 0V, and one-sided LDD structure of the N-channel MOS transistor MN2. ..
【0098】
In the case of the N-channel MOS transistor MN2 with W / L = 4/4, VDS = 10V, VG = 0V, and one-sided LDD structure, ID <940pA.
【0099】
Therefore, the transistor specifications required for the N-channel MOS transistor MN2 are based on the discharge time of the capacitance C2 (150fF). ID> 100nA (one side LDD W / L = 4/4 VDS = 10V VGS = 3V) From the holding time of C2 ID <940pA (one side LDD W / L = 4/4 VDS = 10V VGS = 0V) Will be.
【0100】
The threshold VTH of the N-channel MOS transistor MN2 that inputs the terminal voltage of the capacitance C1 to the gate is set to 3V or less.
【0101】
FIG. 12 is a diagram showing a simulation result using a TFT with typical characteristics in the sampling level conversion circuit shown in FIG. The N-channel MOS transistor MN1 has W / L = 8/4 and LDD structure on both sides, and the N-channel MOS transistor MN2 has W / L = 40/4. The N-channel MOS transistors MN3, MN4, MN5, and MN6 have W / L = 4/4, C1 = 500fF, and C2 = 150fF. It can be confirmed from FIG. 12 that the desired operation is performed.
【0102】
That is, during the initial setup (precharge) period [8us of 37 to 45us], the capacity C2 is precharged to 10V (see "C2 precharge state" in Fig. 12). Following the input data DATA (0.2 to 2.8V), the data writing to the capacitance C1 is completed in about 1us (see the signal marked with a circle indicated by the arrow line "C1" in Fig. 12).
【0103】
In the subsequent evaluation period [45 to 53us], the discharge is completed when the capacity C2 is 0.5us.
【0104】
In the subsequent setup (precharge) period [53 ~ 61us], the capacity C2 is precharged to 10V again.
【0105】
In the subsequent evaluation period [61 to 69us], since the input data DATA was 0, the capacitance C2 was not discharged and maintained the high level (10V).
【0106】
However, when the N-channel MOS transistor MN3 is turned on, the charge of the capacitance C2 is redistributed to the channels of the N-channel MOS transistor MN3, etc., resulting in a decrease of about 0.5V (0.5V due to C2 charge redistribution). Indicated by "decrease").
【0107】
FIG. 13 (a) shows the discharge characteristics of the capacitance C2 at the rising edge of the sampling pulse signal SMP when the characteristics of the N-channel MOS transistor MN2 (slow (low speed), typ (standard), fast (high speed)) are used as parameters. Is shown.
【0108】
As can be seen from FIG. 13, even in the case of the worst case (sLow) model, the discharge is completed within 1 us. Fig. 13 (b) shows the charge / discharge characteristics of the capacitance C1 of the sampling circuit at the fall and rise of the sampling pulse signal SMP due to the characteristics of the transistor MN2 (slow (low speed), typ (standard), fast (high speed)). Shown. It can be seen that the writing is completed within 1us for the capacity C1.
【0109】
An example of the specifications of the sampling level conversion circuit and the two-phase expansion circuit according to the embodiment of the present invention described above is as follows.
【0110】
Input data amplitude is 0-3V, Output data amplitude is 0-10V, Input data frequency is 125KHz, Output data frequency is 62.5KHz, Setup time is 1us, -Control signals are SMP and its inverted signal XSMP, Power supply is 10V power supply and GND, Power consumption (total for 198 input circuits) is 0.006mW (all data is 0), 0.36mW (data 0, 1 same ratio), 0.69mW (all data 1) The power consumption varies depending on the input data, and the maximum is 0.69 mW (excluding the total power consumption of 198 input circuits, SMP, and power consumption of the inverted signal XSMP of 0.17 mW).
【0111】
About half of the above-mentioned power consumption is due to charging / discharging of the capacity C2 for precharging. That is, most of the power consumption is associated with the charging and discharging of the capacitance C2, and in the sampling level conversion circuit, the redistribution of the charge of the capacitance C2 and the leakage dominate the lower limit of the operating frequency.
【0112】
In the design of the sampling level conversion circuit according to this example, the capacitance value of the capacitance C2 is set to be slightly large in order to take a large operating margin. When reducing power consumption, the capacity value of capacity C2 is set small.
【0113】
14 and 15 are diagrams showing simulation results regarding clock skew free of the two-phase expansion circuit of the embodiment of the present invention shown in FIG. 7. FIG. 14 (a) is a diagram showing the signal waveforms of the test vectors (DATA, SMP, XSMP, DATAODD, DATAEVEN), and FIG. 14 (b) shows the simulation results during normal operation without clock skew. Shown.
【0114】
In FIG. 15 (a), when the transition timing of the inverted signal XSMP is delayed by 2 us with respect to the sampling pulse signal SMP, in FIG. The simulation result of the operation of the two-phase expansion circuit of the embodiment of the present invention is shown.
【0115】
From Fig. 15, even if the transition timing of the inverted signal XSMP deviates by ± 2us from the sampling pulse signal SMP, no logic error occurs and the same data as the data output in Fig. 14 (b) is output, which is normal. It can be confirmed that it works.
【0116】
Next, an example of the display device according to the present invention will be described. FIG. 16 is a diagram showing a configuration of a liquid crystal display device including a sampling shift circuit and a two-phase expansion circuit according to the present invention. The purpose is to reduce the cost and power consumption of the LCD (Liquid Crystal Display) module, and since the digital-to-analog converter DAC104 is mounted on the panel, the external controller IC120 with built-in memory has only a logic circuit. Become. Therefore, a fine process can be applied to the manufacture of the controller IC 120, the power supply voltage can be lowered, the chip size can be reduced, and the power consumption and cost can be reduced.
【0117】
Further, as shown in FIG. 16, the width of the data bus between the controller IC 120 and the liquid crystal display panel 100 is increased to 198 bits, and the video digital data from the frame memory 120 is transferred to the liquid crystal display panel 100 via the data bus. Transferring to the side. In this way, the precharge frequency of the frame memory 120 is slowed down, and the power consumption of the controller IC 120 can be reduced.
【0118】
Referring to FIG. 16, a controller IC 120 having a controller 122 having a bus interface with a host (CPU) (not shown), a frame memory 121 for accumulating video information for one frame, and a DC-DC converter / gradation It is equipped with a power supply circuit 130. The liquid crystal display panel (also referred to as "display device board") 100 contains 198-bit data (0-3V) transferred in parallel from the frame memory 121 (for example, 6-bit gradation, image data for 33 pixels). A sampling level conversion circuit 101 that inputs and converts the level to a signal with an amplitude of 0-10V, a two-phase expansion circuit 102 that serially inputs the output of the sampling level conversion circuit 101 and expands it into 2-bit parallel bits, and a two-phase expansion. Latch circuit 103 that latches 396 bits, which is the output of circuit 102, DAC 104 (66 circuits) that inputs 6-bit (gradation 6-bit) signals output from 6 latch circuits 103, and DAC 104 (66 circuits). The data lines are selected in sequence according to the selector control signal output from the timing system signal level shifter 106, having the same number of outputs as the number of inputs (N columns) on the column side of the liquid crystal pixel array 110. It is equipped with a selector 105 that outputs a video signal. The timing system signal level conversion circuit 106 outputs 0-10V sampling pulse signals SMP, XSMP, latch clock, and selector control signal. The shift register 108A and the output buffer 108B constitute a vertical driver 108 (scanning line driving circuit) that drives the scanning lines of the liquid crystal pixel array 110. The DC-DC converter / gradation power supply circuit 130 supplies power to the sampling level conversion circuit 101 and the timing system signal level conversion circuit 106. For example, in the case of an AM (active matrix method) LCD, the pixel 111 of the liquid crystal pixel array 110 of M rows and N columns has a gate connected to the word line, a drain (source) connected to the data line, and a source (drain). A transistor (TFT) that is connected to a pixel electrode to form a switch, and a holding (auxiliary) capacitance
【0119】
FIG. 17 is a partially enlarged view of FIG. 16, showing the connection relationship between the sampling level conversion circuit, the two-phase expansion circuit, and the sampling pulse signals SMP and XSMP. In FIG. 17, 102A does not use odd and even inverted signals XDATAODD and XDATAEVEN as output signals in the configuration including the sampling level conversion circuit and the two-phase expansion circuit shown in FIG. 7, and is odd and even positive. Only the inversion signals DATAODD and DATAEVEN are used, and in the configuration shown in FIG. 7, the inverter 20 for outputting the inverted signal XDATAODD and the inverter 29 for outputting the XDATAEVEN may be deleted.
【0120】
Since the sampling pulse signal SMP and its inverting signal XSMP are common to the sampling level conversion circuit and the two-phase expansion circuit, the circuit 106 (Fig. 16) that level-shifts the timing signal from the controller is shown in Fig. 23, Fig. 24, etc. The conventional circuit configuration shown may be used.
【0121】
The output from the three sets of sampling level shift / two-phase expansion circuit 102A (the sampling level shift / two-phase expansion circuit 102A has the latch circuit 103 in FIG. 16 in the output stage) is input to the 6-bit DAC104 and is input to the DAC104. The output voltage of is sequentially (with time) selected by the selector (MPX) 105 and output to the data line.
【0122】
Next, as yet another embodiment of the present invention, refer to FIGS. 18 and 19 for an example in which a 6-phase expansion circuit is configured by using the sampling level conversion circuit, the inverter, and the latch according to the present invention. explain. Note that FIGS. 18 and 19 are simply segmented for the convenience of drawing.
【0123】
The configuration shown in FIG. 18 consists of the two-phase expansion circuit shown in FIG. 7. This two-phase expansion circuit synchronizes odd and even forward rotation signals DATAODD and DATAEVEN with the rising edge of the sampling pulse signal SMP from the input signal. It is configured to output in parallel. In the sampling level conversion circuit of the two-phase expansion circuit shown in FIG. 18, the capacitances C1 and C2 are composed of MOS capacitors.
【0124】
In the configuration shown in FIG. 19, in the two-phase expansion circuit of FIG. 18, the DATAODD system delays the node (A) to which the DATAODD is transmitted by the inverters 82 and 83, and divides the frequency of the input data (DATA) by 6. It is equipped with a latch (clocked inverter 52, inverter 53, clocked inverter 54) that outputs at the rising edge of the signal DCL, and an inverter 55 that outputs a signal in which the output of the latch is inverted as D1.
【0125】
The first master-slave type latch (clocked inverter 30, clocked inverter 32, clocked inverter 32, clocked inverter 33, inverter 34) that captures the potential of node A at the falling edge of the signal XSMP and outputs it at the rising edge of the signal SMP. , Clocked inverter 35) and the output (node C) of the clocked inverter 33 are captured at the falling edge of the signal XSMP and output at the rising edge of the signal SMP. , Clocked Inverter 38, Clocked Inverter 39 (Output is Node E), Inverter 40, Clocked Inverter 41), and the signal obtained by inverting the output of Inverter 34 of the first master-slave type latch by Inverter 42. It is equipped with a latch (clocked inverter 48, inverter 49, clocked inverter 50) that outputs at the rising edge of the signal DCL, and an inverter 51 that outputs a signal obtained by inverting the output of this latch as D2. A latch (clocked inverter 44, inverter 45, clocked inverter 46) that outputs a signal obtained by inverting the output of the inverter 40 of the inverter 40 of the second master-slave type latch by the inverter 43 at the rising edge of the signal DCL, and the output of this latch. It is equipped with an inverter 47 that outputs the inverted signal as D3.
【0126】
The DATAEVEN system delays the node (F) to which the DATAEVEN signal is transmitted by inverters 84 and 85 in the two-phase expansion circuit, and outputs the input data at the rising edge of the signal DCL divided by 6 (clocked inverter 78, It is equipped with an inverter 79, a clocked inverter 80), and an inverter 81 that outputs a signal in which the output of the latch is inverted as D0.
【0127】
A third master-slave type latch (clocked inverter 56, inverter 57, clocked inverter 58, clocked inverter 59, clocked inverter 60) that captures the potential of node F at the falling edge of the signal XSMP and outputs it at the rising edge of the signal SMP. , Clocked inverter 61) and the output (node H) of the clocked inverter 59 are taken in at the falling edge of the signal XSMP and output at the rising edge of the signal SMP. , Clocked Inverter 64, Clocked Inverter 65 (Output is Node J), Inverter 66, Clocked Inverter 67), and the signal obtained by inverting the output of Inverter 60 of the third master-slave type latch by Inverter 68. It is equipped with a latch (clocked inverter 74, inverter 75, clocked inverter 76) that outputs at the rising edge of the signal DCL, and an inverter 77 that outputs a signal obtained by inverting the output of this latch as D2. A latch (clocked inverter 70, inverter 71, clocked inverter 72) that outputs a signal obtained by inverting the output of the inverter 66 of the fourth master-slave type latch inverter 66 at the rising edge of the signal DCL, and the output of this latch. It is equipped with an inverter 73 that outputs a signal in which the above is inverted as D4.
【0128】
FIG. 20 is a timing diagram showing the operation of the 6-phase expansion circuit shown in FIGS. 18 and 19. DATAODD (node A) and DATAEVEN (F) are generated from the input data DATA. At nodes C and E of the DATAODD path, the signal of node F is delayed by one or two cycles of the sampling pulse signal SMP, and the rising edge of DCL, which is the 6-division clock of the input data DATA (7 of the input data DATA is input). The data of nodes A, C, and E are output as D1, D3, and D5. At nodes H and J of the DATAEVEN path, the signal of node F is delayed by one or two cycles of the sampling pulse signal SMP, and the rising edge of DCL, which is the 6-division clock of the input data DATA (7 of the input data DATA is input). The data of nodes F, H, and J are output as D0, D2, and D4.
【0129】
FIG. 21 is a diagram showing a configuration of a sampling level conversion circuit according to another embodiment of the present invention. Referring to FIG. 21, the sampling level conversion circuit of this embodiment is obtained by exchanging the connection positions of the evaluation element and the detection element in the embodiment shown in FIG. 1, and the sampling pulse signal SMP is High. The N-channel MOS transistor MN2 for evaluation, which is turned on at the level, is placed on the lower side (ground side), and the N-channel MOS transistor MN3, which inputs the terminal voltage of the capacitance C1 forming the sampling circuit to the gate, is supplied by the source on the higher side. It is inserted between the drain of the P-channel MOS transistor MP1 for precharge control connected to (10V) and the drain of the N-channel MOS transistor MN2 whose source is connected to the lower power supply.
【0130】
The sampling level conversion circuit of the above embodiment shown in FIG. 1 is suitable for use when the amplitude voltage (High level voltage) of the signal (DATA) input to the input terminal is close to the threshold VTH of the N-channel MOS transistor MN2. It is said that. That is, the source of the N-channel MOS transistor MN2 that inputs the terminal voltage (input signal voltage) of capacitance C1 to the gate is connected to the lower power supply (ground voltage), and the amplitude voltage of the signal input to the input terminal (input signal voltage). The terminal voltage of capacitance C1) is the gate-source voltage Vgs.
【0131】
On the other hand, in the circuit configuration of this embodiment shown in FIG. 21, the source of the N-channel MOS transistor MN3 that inputs the amplitude voltage of the signal input to the input terminal (terminal voltage of capacitance C1) to the gate is , It is connected to the lower power supply (ground potential) via the N-channel MOS transistor MN2, so that the gate-source voltage Vgs of the N-channel MOS transistor MN3 is lower than the voltage of the input signal (DATA). .. For example, when the sampling pulse signal SMP is in the output period of the high level period and the input signal voltage sampled during the setup period is at the high level, the MOS transistor MN3 is turned on and the N channel MOS transistor MN2 (on resistance ron) in the on state is turned on. The accumulated charge of the capacitance C2 is discharged through, but the gate-source voltage Vgs of this MOS transistor MN3 is changed from the input signal voltage (terminal voltage of the capacitance C1) to the drain current I of the N-channel MOS transistor MN2. It is the value obtained by subtracting the voltage drop due to ron. Therefore, this embodiment is applied when the amplitude voltage (High level voltage VIH) of the input signal is sufficiently higher than the threshold voltage VTH of the transistor MN3.
【0132】
Further, in this embodiment, by exchanging the connection positions of the N-channel MOS transistor MN2, which is the detection element in FIG. 1, and the N-channel MOS transistor MN3, which is the evaluation element, the accumulated charge of the capacitance C2 during the output period is The voltage fluctuation due to charge redistribution is reduced, and the capacitance value of the capacitance C2 is further reduced. That is, when the gate potential of the N-channel MOS transistor MN3 is 0V (input signal voltage = Low level) and the sampling pulse signal SMP is High level (10V), the N-channel MOS transistor MN3 is turned off and the terminal of capacitance C2 is connected. Of the added stray capacitance Cs, the parasitic capacitance Cn of MOS transistors other than the P-channel MOS transistor MP1 is the gate-drain capacitance Cgd (MN3) of the N-channel MOS transistor MN3 in the off state when 0V is applied to the gate. Only (Cgb (MN3) does not need to be considered because the transistor MN3 is off), Cgd (MN3) is approximated by almost 0, and N in the above-described embodiment described with reference to FIGS. 1, 9 and the like. The parasitic capacitance of the channel MOS device is smaller than Cn = (W · L) Cox. Therefore, the combined value Cs of the stray capacitance added to the terminal of the capacitance C2 is smaller than the capacitance of the above-described embodiment described with reference to FIG.
【0133】
When the sampling pulse signal SMP is at High level (10V), the voltage drop ΔV after charge redistribution is, as described above. ΔV = V-V'= V Cs / (Cs + C2) Given in. That is, in this embodiment, since the combined value Cs of the stray capacity is small, the capacity value of the capacity C2 required to set a certain value ΔV can be made smaller than the configuration shown in FIG. it can.
【0134】
Since the basic operation of the sampling level conversion circuit shown in FIG. 21 is the same as that of the above-described embodiment described with reference to FIG. 1, the description thereof will be omitted.
【0135】
FIG. 22 is a diagram showing a configuration of a polyphase (n-phase) expansion circuit according to still another embodiment of the present invention. Referring to FIG. 22, this embodiment expands the serial data of a low voltage amplitude logic signal (0-3V) into n phases, with the two outputs of the shift register 1010 as the sampling pulse signals XSMP and SMP. It is equipped with n sampling level conversion circuits that input and the input terminal of the sampling circuit is connected to the data line (DATA), and the output of the n sampling level conversion circuits is output signals A2, A3, of the shift register 1010. Based on A4, ..., it has a first latch circuit that latches each, and n second latch circuits that latch the output of the first latch circuit with a latch timing signal DCL that divides the data signal by n. It is configured.
【0136】
More specifically, the shift register 1010 has parallel outputs A1 to An + 1 (up to A4 is shown in FIG. 22), of which signal A1 samples the data signal into capacitance C101. The signal A2 is input to the gate of the N-channel MOS transistor MN101 of the sampling circuit, the signal A2 is input to the gate of the P-channel MOS transistor MP101 and the N-channel MOS transistor MN103, the source is connected to the ground potential, and the drain is the N-channel MOS transistor. With N-channel MOS transistor MN102 connected to the source of MN103 and the gate connected to the terminal voltage (voltage of node B) of capacitance C101 of the sampling circuit, the source of P-channel MOS transistor MP101 is connected to a 10V power supply, The capacitance C102 is connected to the drain connection point of the P-channel MOS transistor MP101 and the N-channel MOS transistor MN103 to form a sampling level conversion circuit. This sampling level conversion circuit has the same circuit configuration as the configuration shown in FIG. 1, but the control of the supplied sampling pulse signal is different, and the signal A2 corresponding to the sampling pulse signal SMP is a signal. It is delayed by one clock of the shift register 1010 with respect to A1 (corresponding to the sampling pulse signal XSMP), and the signal A1 is not an inverted signal of the signal A2.
【0137】
Input the terminal voltage (voltage of node C) of the capacitance C102 of the sampling level conversion circuit, turn it on at the high level of the signal A2, and input the output of the clocked inverter 211 and the clocked inverter 211 that invert and output the input signal. A clocked inverter 213 that takes the output of the inverter 212 as an input and turns on when the signal A2 is at a low level and inverting the output of the input signal constitutes a first latch circuit. , The input data (inverted signal of node C) is output when the signal A2 rises to the high level, and the data is stored when the signal A2 is at the low level. The output (node D) of the first latch circuit is connected to the input terminal, and the clocked inverter 214 that turns on at the high level of the n-divided clock DCL of the data signal and inverting the output of the input signal, and the clocked inverter 214 The inverter 215 that takes the output as an input and the clocked inverter 216 that takes the output of the inverter 215 as an input and turns on when the signal DCL is at the low level and outputs the input signal in reverse form a second latch circuit. The latch circuit of is output the inversion of the input data (state of node D) at the rising edge of the signal DCL to the high level, and stores the output data when the signal DCL is at the low level.
【0138】
Sampling level conversion circuit (consisting of N-channel MOS transistors MN201, MN202, MN203, P-channel MOS transistors MP201, capacitances C201, and C202) that input the output signals A2 and A3 of the shift register 1010, and the first latch circuit (311, 312, 313) and the second latch circuit (314, 315, 316) are also the same as the above-mentioned circuit.
【0139】
Sampling level conversion circuit (consisting of N-channel MOS transistors MN301, MN302, MN303, P-channel MOS transistors MP301 and capacitances C301, C302) that input the output signals A3 and A4 of the shift register 1010, the first latch circuit (411, 412, 413) and the second latch circuit (414, 415, 416) are the same as the above-mentioned circuit.
【0140】
As described above, in this embodiment, of the n + 1 phase signals output from the shift register, which are out of phase by one data cycle, two adjacent phase signals are sampled pulse signals XSMP and SMP. By inputting to the sampling level conversion circuit, latching with the first latch circuit with the sampling pulse with the delayed phase, and latching and outputting this in synchronization with the clock DCL obtained by dividing the frequency of the data signal by n. , N-phase parallel signal is output. The shift register 1010 is composed of n + 1-stage D-type flip-flops, the output of the i-th stage D-type flip-flops is Ai, and sampling pulse signals (Ai, Ai +) are applied to n sampling level conversion circuits. 1) may be supplied respectively. The signal Ai generation circuit is not limited to the shift register, and any circuit that generates a multiphase clock that is out of phase by one data cycle is used.
【0141】
FIG. 23 is a diagram showing a part of the transition of the signal waveform of each node in the circuit of FIG. 22. Looking at the sampling level conversion circuit of the second stage, the MOS transistor MN201 is turned on at the rising timing of the signal A2 of the shift register 1010. At this time, since the signal A3 is at the low level, the MOS transistor MP201 is turned on and the MOS transistor. The MN203 is turned off, the node G is precharged to 10V, and the high level (3V) of the data signal (2) is sampled at the node F of the sampling circuit (setup period).
【0142】
Next, one data cycle period is delayed from the rising edge of the signal A2, the signal A3 rises, the MOS transistor MP201 of the sampling level conversion circuit is turned off, the MOS transistor MN203 is turned on, the output period is reached, and the gate potential of the MOS transistor MN202 is set. It is set to 3V, the MOS transistor MN202 is turned on, the accumulated charge of the capacitance C202 (the charge charged during the setup period) is discharged to the ground via the MOS transistors MN203 and 202, and the node G becomes 0V. Then, at the rising edge of the signal A3, the clocked inverter 311 is turned on, and the high level, which is a logical value obtained by inverting the terminal voltage of the capacitance C202, is output to the node H.
【0143】
Subsequently, the signal A3 becomes the Low level, and the state (High level) of the node H is stored in the flip-flop composed of the inverters 312 and 313. At the same time, the capacity C202 of node G is precharged to the power supply voltage (10V) to prepare for the next operation.
【0144】
According to the outputs A2, A3, A4, ... of the shift register 1010, the sampled data is sequentially latched in the nodes D, H, L, ... And supplied serially to the data line (DATA). When the latching of n data to be performed is completed, the latch timing signal DCL is commonly input to the n second latch circuits, and the n second latches are synchronized with the rising edge of this signal DCL. An n-bit parallel signal is output from the circuit. That is, in the example shown in FIG. 23, the output nodes E, I, and M of the second latch circuit become High, Low, and High at the rising edge of the latch timing signal DCL.
【0145】
In the example shown in FIG. 22, the n-bit parallel outputs from the n second latch circuits are input to the DAC circuit 1020, but the output destination of the n-phase expansion circuit is not limited to the DAC circuit. Of course.
【0146】
In each of the above embodiments, a level conversion circuit using a polycrystalline silicon TFT as a transistor, a 2-phase expansion circuit, and a 6-phase expansion circuit have been described, but a CMOS circuit formed on a single crystal silicon substrate may also be used. Of course, it's good. Of course, it can also be applied to a configuration in which discrete electronic components such as individual semiconductor elements and capacitors are mounted on a circuit board instead of an integrated circuit.
【0147】
Further, in FIGS. 16 and 17, the liquid crystal display device and its data line drive circuit have been described as an example, but the same can be applied to an AM (active matrix method) organic EL display device.
【0148】
Further, an example in which the amplitude voltage of the input signal is 0-3V and the output amplitude is 0-10V has been described, but the present invention is not limited to this configuration.
【0149】
In addition to the 2-phase and 6-phase expansion circuits, a circuit that expands to 2N phases can be configured in the same manner, and according to the n-phase expansion circuit, it can be expanded to any number of phases.
【0150】
Furthermore, the clocked inverters (for example, 13 and 16 in Fig. 3) that make up the flip-flops of the master-slave latch (two inverters in which the input and output are interconnected) are turned on by the sampling pulse signal SMP and the inverting signal XSMP. , The off-controlled transfer switch and the inverter may be replaced, or the clocked inverter (for example, 11 and 14 in FIG. 3) that controls the signal transmission in the latch on and off may be configured by the transfer gate.
【0151】
Although the present invention has been described above in accordance with each of the above examples, the present invention is not limited to the above examples, and can be made by those skilled in the art within the scope of the claimed invention. It goes without saying that it includes various modifications and modifications that may be made.
【0152】
[Effect of the invention]
As described above, according to the sampling level conversion circuit according to the present invention, steady current does not flow, power consumption can be reduced, and the number of connection terminals is reduced by using a single-phase signal input. doing.
【0153】
Further, according to the sampling level conversion circuit, the two-phase expansion circuit, and the multi-phase expansion circuit according to the present invention, the drive is simplified and an extra power supply is not required. For example, a 3V interface with an external controller circuit, an LCD module, etc. It is suitable for use as an interface with a DAC array mounted on a display panel.
[Simple explanation of drawings]
[Figure 1]
It is a figure which shows the structure of the sampling level conversion circuit of one Example of this invention.
[Figure 2]
(a) and (b) are diagrams for explaining the operation of the sampling level conversion circuit according to the embodiment of the present invention.
[Fig. 3]
It is a figure which shows the structure which provided the sampling level conversion circuit and the latch circuit of the 2nd Example of this invention.
[Fig. 4]
It is a figure for demonstrating the operation of the sampling level conversion circuit and the inverter of the 2nd Example of this invention.
[Fig. 5]
It is a figure which shows the structure which provided the sampling level conversion circuit and the inverter of the 2nd Example of this invention. [Fig. 6]
(a) and (b) are diagrams for explaining the presence or absence of malfunction due to clock skew in the configuration including the sampling level conversion circuit and the inverter of the second embodiment of the present invention.
[Fig. 7]
It is a figure which shows the structure of the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 8]
It is a figure for demonstrating operation of the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 9]
It is a figure for demonstrating the design of the sampling level conversion circuit of one Example of this invention.
[Fig. 10]
It is a figure for demonstrating the design of the sampling level conversion circuit of one Example of this invention, and is the figure which shows the characteristic of the detection transistor.
[Fig. 11]
It is a figure for demonstrating the design of the sampling level conversion circuit of one Example of this invention, and is the figure which shows the discharge characteristic of the precharge capacitance and the characteristic of a detection transistor.
[Fig. 12]
It is a figure which shows the simulation result of the operation of the sampling level conversion circuit of one Example of this invention.
[Fig. 13]
It is a figure for demonstrating the design of the sampling level conversion circuit of one Example of this invention, and is the figure which shows the simulation result of the discharge characteristic of a precharge capacity and the charge discharge characteristic of a sampling capacity.
[Fig. 14]
It is a figure which shows the simulation result which confirmed the clock skew-free operation in the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 15]
It is a figure which shows the simulation result which confirmed the clock skew-free operation in the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 16]
It is a figure which shows an example of the structure of the LCD with built-in DAC.
[Fig. 17]
It is a figure which shows the structure around the two-phase expansion circuit of the structure of the LCD with built-in DAC.
[Fig. 18]
It is a figure which shows the structure of the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 19]
It is a figure which shows the structure of the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 20]
It is a figure for demonstrating operation of the two-phase expansion circuit of the 3rd Example of this invention.
[Fig. 21]
It is a figure which shows the structure of the sampling level conversion circuit of another Example of this invention.
[Fig. 22]
It is a figure which shows the structure of the n-phase expansion circuit of another Example of this invention.
[Fig. 23]
It is a figure for demonstrating operation of the n-phase expansion circuit of another Example of this invention.
[Fig. 24]
It is a figure which shows the structure of the conventional level conversion circuit.
[Fig. 25]
It is a figure which shows the structure of the conventional level conversion circuit.
[Fig. 26]
It is a figure which shows the structure of the conventional level conversion circuit.
[Explanation of symbols]
10 CMOS inverter circuit (buffer circuit) 11, 13, 14, 16, 17, 19 Clocked inverter 12, 15, 18 inverter 20, 21, 23, 26, 28, 29 Inverters 22, 24, 25, 27 clocked inverter 30, 32, 33, 35, 36, 38, 39 Clocked inverter 31, 34, 37 Inverters 40, 42, 43, 45, 47, 49 Inverters 41, 44, 46, 48 Clocked inverter 50, 52, 54, 56, 58, 59 Clocked inverter 51, 53, 55, 57 Inverters 60, 63, 66, 68, 69 Inverters 61, 62, 64, 65, 67 Clocked inverter 70, 72, 74, 76, 78, 80 Clocked inverter 71, 73, 75, 77, 79, 81, 82, 83, 84, 85 Inverters 100 LCD module (liquid crystal display panel) 101 Sampling level conversion circuit 102 2-phase expansion circuit 103 latch 104 DAC 105 Selector 106 Timing system level conversion circuit 108 Scan line drive circuit 108A shift register 108B output buffer 110 LCD pixel array 111 pixels 120 controller IC 121 Frame memory (display memory) 122 controller 130 DC-DC converter / gradation power supply circuit 211,213,214,216,311,313,314,316,411,413,414,416 Clocked inverters 212, 215, 312, 315, 412, 415 Inverters 1010 shift register 1020 DAC circuit MN1 ~ 12, MN101 ~ 103, MN201 ~ 203, MN301 ~ 303 N-channel MOS transistor (N-channel TFT) MP1 to MP6, MP11, MP12, MP101, MP201, MP301 P-channel MOS transistor (P-channel TFT) C1, C2, C101, C102, C201, C202, C301, C302 Capacitor (capacitor)
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Numbers
- Publication
- 2003-115758
- Application
- 307397
Titles2
- Japanese
- 【発明の名称】サンプリングレベル変換回路と2相及び多相展開回路並びに表示装置
- English
- Description: Sampling level conversion circuit, two-phase and multi-phase expansion circuit, and display device.
Classification
- CPC, 6
- G09G3/3688
- G09G2310/027
- G09G2310/0289
- G11C19/184
- G11C27/024
- H03K19/01855
- IPC, 6
- G09G3 20
- G09G3 30
- G09G3 36
- G11C19 18
- G11C27 02
- H03K19 0185