Circuit arrangement for voltage reversal in a mobile radio apparatus

The invention relates to a circuit arrangement for voltage reversal in a mobile device for generating a relative to an operating voltage reverse-polarity output voltage.

It relates in particular to a circuit arrangement, which generates in a battery voltage supplied to a mobile device (eg., Mobile phone) from a versus a Bzugspotential positive or negative voltage, a negative or positive voltage.

In a positive battery voltage supplied mobile devices, which are generally one or more MMIC (<u>M</u>onolithic <u>M</u>icrowave <u>I</u>ntegrated <u>C</u>ircuit) chips (z. B. have a MMIC power amplifiers) MESFET base such. as is the operation of the MESFET requires a negative gate bias. In a known circuit variant with which a negative voltage in a battery operated electronic device may be generated an alternating voltage with positive and negative Spannungsamplitugen is generated and subsequently rectified by means of an oscillator or multivibrator. In another circuit variant is to be generated by rectifying an applied to the input of a MMIC power amplifier received radio frequency signal is a negative voltage.

These two methods, however, have drawbacks. Thus, in the first-mentioned possibility of a supplemental AC voltage signal generated by the oscillator in the mobile station, which may impair the characteristics of the appliance. It may be affected and consequently impaired example are modulated onto signals interference spectra or adjacent components in their phones such as microprocessors.

In the latter method, has a particularly disadvantageous that the MMIC power amplifier is switched on only after concern the high frequency signal and is functional only at relatively high signal levels.

The present invention is therefore based on the object to develop a low-noise circuitry of the type mentioned.

This object is achieved by a circuit arrangement having the features of claim 1. Advantageous developments of the circuit arrangements according to the invention are subject of the claims 2 to 11th

According to the invention of the circuitry for generating an output voltage with a respect to a fixed reference potential first polarity in one with an operating voltage supplied with respect to the reference potential second polarity mobile device during operation of the mobile device via a circuit input terminal with a ringing signal generator supply voltage in the form of an alternating voltage or clocked voltage , with an intended in the mobile radio call signal generator is driven at an incoming call, applied.

The inventive circuit arrangement is particularly low interference, since it requires no additional oscillator but existing in their phones ringing signal generator supply voltage, the so-called clock voltage used. The ringing signal generator supply voltage is an AC voltage or a pulsed voltage with the present in a mobile phone call signal generator is driven at an incoming call.

Moreover, the circuit of the invention has the further particular advantage that they permanently provides with respect to the operating voltage umpoled output voltage, because the ringing signal generator supply voltage is permanently present in a mobile device.

The inventive circuit arrangement has the particular advantage that it is possible without great expense for components and therefore little space effort. all components can be easily integrated on a single MMIC chip except for the coil and the capacitors.

For the operation of the circuit arrangement, no additional oscillator is necessary. The operating voltage and the ringing signal generator supply voltage available in a mobile device usually already available and must not be created specifically for the circuitry

A first preferred embodiment of the inventive circuit arrangement has the following features: Between a first terminal of a load path of a transistor, in particular a source-drain path of a field effect transistor, and a first circuit input terminal, a coil is coupled and a second terminal of the load path of the transistor is electrically conductively connected to a fixed reference potential. In operation of the mobile device, an operating voltage having an opposite polarity to the reference potential is the second to the first circuit input terminal (z. B. positive) can be applied. Further, a control terminal of the transistor via a control line to a second circuit input terminal coupled to the call signal a supply voltage can be applied during operation of the mobile device. Between the first terminal of the load path of the transistor and a cathode of a first diode, a first capacitor is coupled, and the cathode of the first diode is coupled to an anode of a second diode. A cathode of the second diode is coupled to the fixed reference potential, while between the fixed reference potential and an anode of the first diode, a second capacitor is coupled. The anode of the first diode is connected to a circuit output terminal at which an output voltage with a respect to the fixed reference potential is the first polarity (eg. As negative) can be tapped off.

This embodiment of the circuit arrangement according to the invention operates according to the basic principle of operation, that by means of a voltage peak across the coil for a Sperrendschalten of the transistor, the first capacitor is charged to a potential with respect to the fixed reference positive voltage. During an on-phase of the transistor, the first capacitor then charges the second capacitor to a fixed reference potential relative to the negative voltage which can be tapped off from the outside.

The ringing signal generator supply voltage consists for example of voltage pulses with a relative to the fixed reference potential second polarity, in particular from a square-wave voltage.

In a preferred development of the above-mentioned first embodiment of the inventive circuit arrangement is as ringing signal generator supply voltage a square wave voltage used. This advantageously very high voltage spikes may be generated at the coil, thereby increasing the efficiency of the circuit can be improved.

Furthermore, in a preferred further development of this embodiment of the inventive circuit arrangement is connected to the control terminal lead (connection between the second circuit input terminal and the control terminal) of the transistor a current limiting resistor that prevents the ringing signal supply voltage in operation, greatly collapses.

Moreover, be connected to the control line advantageously a third capacitor, the DC-decoupled a the ringing signal generator supply voltage generating power source of the circuit arrangement.

In a further advantageous embodiment of the first embodiment of the inventive circuitry a fourth capacitor is coupled between the first circuit input terminal and the fixed reference potential. This ensures that a positive operating voltage supplying voltage source is AC decoupled from the circuit arrangement.

In a particularly preferred embodiment of the first embodiment of the inventive circuit arrangement, a feedback resistor connected between the circuit output terminal and the control input of the transistor, via which the control terminal of the transistor T is supplied with a negative voltage and the transistor can thereby work more power efficient.

In addition, may also be connected between the second circuit input terminal and the third capacitor and the fixed reference potential, an additional electrical resistance. This advantageously causes a stabilization of the potential at the control terminal of the transistor relative to the fixed reference potential.

As transistor may be used advantageously both a field effect transistor and a bipolar transistor.

In a simplified second preferred embodiment of a circuit arrangement according to the invention compared to the above first preferred embodiment of the circuit arrangement of the transistor and the inductor and the first circuit input terminal is omitted with the operating voltage. One the ringing signal generator supply voltage supplying voltage source is here directly connected to a first terminal of the first capacitor. This is charged in operation at a voltage having a potential relative to the fixed second polarity, the value of which corresponds at most to the maximum of the ringing signal supply voltage. This simplified embodiment has the beonderen advantage that it can be produced with a very low component cost.

The term mobile station is to be interpreted broadly in the context of the present invention. Among all mobile electronic devices are to be understood, which are suitable for receiving messages via electromagnetic waves.

Further advantages of the inventive circuit arrangement are evident from the dependent claims and described in the following exemplary embodiments in conjunction with Figures 1 to 6. In the drawings:<ul><li>Figure 1 is a diagram of a first embodiment of an inventive circuitry,</li><li>Figure 2 is a schematic diagram of a voltage-time diagram of a ringing signal supply voltage for driving the transistor,</li><li>Figure 3 is a schematic diagram of a voltage-time diagram of the voltage curve at the marked in Figure 1 with I node of the circuit of Figure 1,</li><li>Figure 4 is a schematic diagram of a voltage-time diagram of the voltage profile at the marked in Figure 1 with K nodes of the circuit of Figure 1, </li><li>Figure 5 is a block diagram of the inventive circuit arrangement in connection with an MMIC power amplifier and</li><li>Figure 6 is a circuit diagram of a second embodiment of an inventive circuitry.</li></ul>

In the circuit of Figure 1, a transistor T is realized as field effect transistor. Between a drain D (corresponding to the aforementioned first terminal of the load path) of the transistor T and a first circuit input terminal E1, in which a positive operating voltage V + (z. B. + 3V) is applied, a coil L (z. B. with an inductance connected from 10μH). A source S (corresponding to the above-mentioned second terminal of the load path) of the transistor T is connected to a fixed reference potential P (z., Ground) and a gate terminal G (corresponding to the above-mentioned control terminal) of the transistor T is connected to a second circuit input terminal E2 at which a ringing signal generator supply voltage V_clk (Z. B. a square-wave voltage with rectangular pulses of + 3V, one see FIG. 2). Between the drain terminal D and a cathode K1 of a first diode D1, a first capacitor C1 (for. Example, with a capacity of about 1 nF) is connected. Simultaneously, the cathode K1 of the first diode D1 having an anode A2 of the second diode D2 and a cathode K2 of the second diode D2 to the fixed reference potential P is connected. Between the fixed reference potential P and an anode A1 of the first diode D1, a second capacitor C2 (z. B. with a capacity of about 1 nF) is connected. The anode A1 of the first diode D1 is connected to a circuit output terminal A, to which a negative voltage V- (at the indicated inductance and Kabazitätswerten approximately -6 to -9V) can be tapped.

Optionally, in the circuit of Figure 1 in the gate wire (connection between the gate terminal G and the second circuit input terminal E2) a gate resistor R1 (current limiting resistor) with, for example, R = 1 kOhm connected his (shown in dashed lines in Figure 1). This possibly prevents a strong collapse of the ringing signal generator supply voltage V_clk,

Furthermore, can be between the fixed reference potential P and the second circuit input terminal E2, an additional electrical resistance R2 (z. B. R = 20 ohms) to be coupled (shown in dashed lines in Figure 1), the stabilization of the gate (G) -source (S) potential for development of the transistor T causes.

For DC moderate decoupling the ringing signal generator supply voltage (V_clk) Supply of the circuitry may be between the second circuit input terminal E2 and the gate terminal G and the gate resistor R1, a third capacitor C3 (to be shown also in dashed lines in Fig. 1) connected with a capacity of for example 1 nF.

Furthermore, for the uncoupling of the coil L from an operating voltage (V +) - supply between the first circuit input terminal E1, and the fixed reference potential P a fourth capacitor C4 (in Fig 1, in turn, shown in dashed lines.) May be connected with a capacity of for example 2 nF.

In addition, R1 is a feedback resistor (shown in dashed lines in Figure 1) be connected R3 for supplying the transistor T with a negative gate voltage between the circuit output terminal A and the gate terminal G and the gate resistor. This enables a particularly energy-efficient operation of the circuit can be achieved.

In figure 2 is a voltage-time diagram for an exemplary ringing signal supply voltage V_clk shown as they can be used for driving the transistor T and in a mobile radio device (for. example, mobile telephone) is available. On the abscissa is the time and the ordinate represents a voltage V is applied. The ringing signal generator supply voltage V_clk is a square-wave voltage with a pulse height of for example + 3V with respect to the fixed reference potential P (z. B. mass) and a frequency of z. B. 5-15 Mhz and is applied to the second circuit input terminal E2.

The illustrated in Figure 3 voltage-time diagram schematically illustrates the voltage profile at the designated I node of the circuit arrangement shown in Figure 1. On the abscissa is time and the ordinate a voltage V is analogous to Figure 2 applied. Accordingly, lies at the junction I within the pulse intervals of the ringing signal generator supply voltage V_clk a P against the reference potential in comparison with the operating voltage V + voltage to increase to a maximum of about +6 to + 9V. During the pulses of the node I is due to the through-connected transistor T to the fixed reference potential P. The + increased in comparison with the operating voltage V voltage is effected from one occurring during the de-energizing of the coil L voltage overshoot, which charges the first capacitor C1. The ideal voltage waveform is shown in dashed lines in Fig. 3

This illustrated in Figure 4 voltage-time diagram schematically illustrates the voltage waveform at the node designated in Figure 1 with K. On the abscissa is time and the ordinate a voltage V is again analogous to Figure 2 applied. Within the pulse intervals of the ringing signal generator supply voltage V_clk is here relative to the fixed reference potential at a voltage with a maximum of about -6 to -9V. This is produced that is loaded when the transistor T and thus switched to the fixed reference potential positive pole of the first capacitor C1, the second capacitor C2 to a relative to the fixed reference potential negative voltage V-. The ideal voltage waveform is shown in dashed lines in Figure 3 again.

At the circuit output terminal A a pure DC voltage of about -6 to -9 V can be tapped in the unloaded state.

In the illustrated in Figure 5. Block diagram of the inventive circuit arrangement in connection with an MMIC power amplifier chip MMIC having three amplifier stages V1, V2, V3 can be seen that the transistor T, the diodes D1 and D2, and optionally the first, second and / or the third electrical resistor R1, R2, R3 are integrated on the power amplifier MMIC chip MMIC. The coil L, the first and second capacitors C1, C2 as well as possibly the third and the fourth capacitor C3, C4 are arranged outside the MMIC power amplifier chips MMIC.

The circuit arrangement shown in figure 6 differs in that the coil L and the transistor T and the positive operating voltage V + are omitted, and a terminal E of the first capacitor C1 to the ringing signal supply voltage V of the above-described in reference to Figure 1_clk is coupled. The voltage waveforms at the terminal E of the first capacitor and the node K correspond in principle to the above-discussed with respect to Figures 3 and 4 voltage waveforms at nodes I and K, but with magnitude lower voltage values.

This circuit of Figure 6 is particularly suitable for use in a mobile device (mobile phone), if any is needed compared to the positive operating voltage V + magnitude increased negative voltage V-.