Mobile terminal

0001The present invention relates to the field of communication technology, and particularly to mobile terminals.

0002With the rapid development of science and technology, playing music and movies using mobile terminals has already become a very important recreational form of people's daily lives. The demands on the user's mobile terminal function, especially on the volume and sound quality of the reproduced sound to the outside, are becoming higher and higher.

0003For mobile terminals, the main factors that affect the playback volume and sound quality are the performance of the horn unit and the size of the speaker sound chamber. Since the acoustic power radiated by the speaker of the mobile terminal is relatively large, the volume of the horn unit cannot be made very small, and at the same time, the volume of the horn cavity has a great influence on the loudness and sound quality of the reproduced sound to the outside. The more regular the horn cavity, the larger the rear cavity, the richer the sound of the low frequency part reproduced by the horn, the better the sound quality, and conversely, the smaller the rear cavity of the horn, the better. The low frequency component of the reproduced sound is reduced, and the sound is relatively dry, monotonous, and powerless.

0004Contradictory to that, the current intelligent mobile terminal market is delighted with the increasingly thin type, there is less space in the horn cavity, and there is little space for the sound quality to be completely improved by the algorithm. A large speaker SPK acoustic chamber volume and a high-performance horn unit are required in order to obtain good external reproduction sound quality. Traditionally, the thickness of commonly used horn units in mobile terminals is generally 3.5 mm, and horn unit manufacturers constantly optimize the thickness of the horn, but so far this thickness has been at least 2.5 mm or more. .. In order to put such a thick horn in the case of a mobile terminal, a certain volume of front and rear cavities is required, and it is always very difficult to add the thickness of the screen and the motherboard to make it ultra-thin.

<p num="0005"> An embodiment of the present invention provides a mobile terminal for solving the problem that the reproduced sound quality to the outside is relatively poor due to the small horn cavity of the conventional mobile terminal.</p>

<p num="0006"> In order to achieve the above object, an embodiment of the present invention provides a mobile terminal, includes a case, the case is provided with a headphone jack, and a compatible circuit connected to the headphone jack, the compatibility. Circuits include audio codecs, analog switches, application processors, and the headphone jack. The headphone jack has an input pin and an output pin. The audio codec is connected to the input pin of the headphone jack, and the external device inserted from the headphone jack is determined based on the impedance value measured from the input pin of the headphone jack, and the external device connects the external speaker and the headphone. Including The output pin of the analog switch is connected to the output pin of the headphone jack, and the input pin of the analog switch is connected to the speaker signal output pin and the headphone signal output pin of the audio codec, respectively. The application processor is connected to the audio codec and the analog switch so that when the external device is an external speaker, the input signal from the speaker signal output pin of the audio codec is output from the output pin of the analog switch. The analog switch is controlled so as to output an input signal from the headphone signal output pin of the audio codec from the output pin of the analog switch when the external device is a headphone.</p><p num="0007"> The input pin of the headphone jack includes a MIC pin and a DET pin. The audio codec includes an HPdet pin and an HPmic pin. The DET pin is connected to the HPdet pin, the impedance value of the input pin of the headphone jack is measured, an external device inserted from the headphone jack is determined, and the MIC pin is connected to the HPmic pin.</p><p num="0008"> The output pin of the headphone jack includes a right sound channel pin and a left sound channel pin. The output pins of the analog switch include a first output pin and a second output pin. The first output pin is connected to the right sound channel pin, and the second output pin is connected to the left sound channel pin.</p><p num="0009"> The analog switch includes a control line pin. The control line pin is connected to the GPIO pin of the application processor and When the external device is an external speaker, the application processor uses control line pins to connect the input signals of the first analog signal input port and the second analog signal input port of the analog switch to the first analog signal output port, respectively. Control to output from the 2nd analog signal output port, When the external device is a headphone, the application processor uses a control line pin to transmit the input signals of the third analog signal input port and the fourth analog signal input port of the analog switch to the first analog signal output port and the second analog signal output port, respectively. Control to output from the analog signal output port.</p><p num="0010"> The first analog signal input port and the second analog signal input port of the analog switch are connected to the SPKN pin and SPKP pin of the audio codec, respectively. The third analog signal input port and the fourth analog signal input port of the analog switch are connected to the HPR pin and HPL pin of the audio codec, respectively.</p><p num="0011"> The mobile terminal further includes a power amplifier, the two input ends of the power amplifier are connected to the SPKN pin and the SPKP pin of the audio codec, respectively, and the two output ends of the power amplifier are each the first analog of the analog switch. Connected to the input port and the second analog input port.</p><p num="0012"> The headphone jack, the audio codec, and the analog switch all have one ground pin.</p><p num="0013"> The external speaker is External horn sound box, The external horn sound box and the sound box plug connected to the headphone insertion hole in the case are provided.</p><p num="0014"> The sound box plug includes a first contact and a second contact, the first contact is connected to the left sound channel pin and the DET pin of the headphone jack, respectively, and the second contact is the right sound channel pin and the MIC pin of the headphone jack, respectively. And connected to the ground pin.</p><p num="0015"> The first contact and the second contact are connected to two connection pins of the external horn sound box by a conducting wire.</p><p num="0016"> The sound box plug is a two-stage plug, the first contact is in the first stage near the headphone jack port of the sound box plug, and the second contact is in the second stage far from the headphone jack port of the sound box plug. is there.</p>

<p num="0017"> The examples of the present invention have the following beneficial effects, The mobile terminal of the embodiment of the present invention determines whether the external device inserted into the headphone insertion hole is a headphone or an external speaker based on the impedance value of the input pin of the headphone jack, thereby setting the headphone playback mode. By performing handover with the external speaker playback mode, a high-performance external playback effect is realized, and the external playback volume and user experience are improved.</p>

0018<figref num="1">FIG. 1 is a compatible circuit diagram according to an embodiment of the present invention.</figref><figref num="2">FIG. 2 is a structural diagram of an external speaker according to an embodiment of the present invention.</figref><figref num="3">FIG. 3 is an operation flowchart according to an embodiment of the present invention. Code Description 1-External Speaker, 2-Sound Box Plug, 3-External Horn Sound Box.</figref>

0019In order to further clarify the technical problems, technical solutions, and advantages to be solved by the embodiments of the present invention, the following will be described in detail with reference to specific examples and drawings.

0020The embodiment of the present invention solves the problem that the reproduced sound quality to the outside is relatively poor due to the small horn cavity of the conventional mobile terminal, and the embodiment of the present invention provides the mobile terminal, includes a case, and a case. The mobile terminal is provided with a headphone insertion hole. It also has a compatible circuit connected to the headphone jack, and as shown in Figure 1, the compatible circuit is a headphone jack with input and output pins, an audio codec connected to the input pin of the headphone jack. It has an (CODEC) chip, an application processor (AP) chip connected to an audio codec chip, and an analog switch chip connected to an application processor chip. The input pin of the headphone jack includes the MIC pin and the DET pin, the output pin of the headphone jack includes the right sound channel RIGHT pin and the left sound channel LEFT pin, and the headphone jack further includes one ground pin GND. The audio codec chip determines the external device inserted in the headphone jack based on the impedance value of the input pin of the headphone jack, the external device is an external speaker or headphone, and the audio codec chip is HPdet pin, HPmic pin, HPL pin, Including HPR pin, SPKP pin and SPKN pin, In a specific embodiment of the present invention, the DET pin of the headphone jack measures the impedance value of the input pin of the headphone jack, determines the external device inserted in the headphone jack, and is connected to the HPdet pin of the audio codec chip. The MIC pin on the headphone jack is connected to the HPmic pin on the audio codec chip.

0021The application processor (AP) chip connected to the audio codec chip is specifically connected by a bus between the audio codec and the application processor chip and can transmit control signals and data flows to each other. The input pins of the analog switch chip include four analog signal input ports IN1 to IN4, and the first analog signal input port IN1 and the second analog signal input port IN2 are connected to the speaker signal output terminals SPKN and SPKP of the audio codec chip, respectively. The 3rd analog signal input port IN3 and the 4th analog signal input port IN4 are connected to the headphone signal output terminals HPR and HPL of the audio codec chip, respectively, and the output pins of the analog switch chip are the 1st output pin OUT1 and the 2nd. Includes output pin OUT2, each connected to the output pin of the headphone jack, selectively the first output pin OUT1 is connected to the right sound channel RIGHT pin of the headphone jack, and the second output pin OUT2 is the left sound channel of the headphone jack. Connected to the LEFT pin.

0022In a specific embodiment of the present invention, the analog switch chip further comprises a control line SELECT pin and is connected to the GPIO pin of the application processor chip by the SELECT pin. When the external device is an external speaker, the application processor chip controls IN1 and IN2 of the analog switch chip to communicate with OUT1 and OUT2, respectively, by the SELECT pin. When the external device is a headphone, the application processor chip controls IN3 and IN4 of the analog switch chip to communicate with OUT1 and OUT2, respectively, by the SELECT pin.

0023Further, in a specific embodiment of the present invention, one power amplifier, for example, a high-performance class D speaker amplifier may be added between the IN1 and IN2 of the analog switch and the SPKP pin and the SPKN pin of the audio codec chip.

0024The compatible circuit according to the embodiment of the present invention determines whether the external device inserted into the headphone insertion hole is a headphone or an external speaker by inspecting the impedance value of the external device, thereby playing back the headphones. A handover is performed between the mode and the external speaker reproduction mode to realize a high-performance external reproduction effect.

0025Hereinafter, the operating principle of the embodiment of the present invention will be described with reference to an example.

0026In a specific embodiment of the present invention, as shown in FIG. 2, the external speaker 1 is a sound connected to an external horn sound box 3, an external horn sound box 3, and a headphone insertion hole in the case of a mobile terminal. Equipped with a box plug 2, optionally the sound box plug 2 is a two-stage plug, and the sound box plug 2 contains two contacts, a first contact and a second contact, the first contact is the sound box plug 2. The second contact is in the first stage near the headphone jack of the sound box plug 2, the second contact is in the second stage far from the headphone jack of the sound box plug 2, and the two contacts are connected to the two connection pins of the external horn sound box 3 by a lead wire. , Thereby pulling the sound analog electrical signal into the two connecting pins of the external horn sound box, driving the operation of the horn to produce sound.

0027Conventionally, the impedance value of a horn that is often used in mobile terminals is generally 8 ohms or less, and after inserting the sound box plug 2 of the external speaker 1 into the headphone insertion hole, the contact point at the tip of the sound box plug 2 is It is connected to the DET pin of the headphone jack and the LEFT pin of the left sound channel, and the other contacts of the sound box plug 2 are connected to the MIC pin of the headphone jack, the RIGHT pin of the right sound channel, and the ground GND pin. Since the DET pin of the headphone jack is connected to the HPdet pin of the audio codec chip, the resistance value measured by the HPdet pin of the CODEC chip is the resistance value between the two connection pins of the horn unit in the external horn sound box or the headphones. It is the impedance of the left sound channel, and in the case of an external horn sound box, it is the resistance value between the two connection pins of the horn unit, that is, the impedance value to the ground of the horn unit, and the impedance value is 8 ohms or less. For headphones, the impedance of the left and right sound channels to ground is generally 32 ohms, the smallest of 16 ohms or more, so the CODEC chip is based on the impedance value measured by the HPdet pin into the headphone insertion hole. It is possible to distinguish whether the inserted external device is an external speaker or headphones.

0028As shown in FIG. 3, the operation flow of the embodiment of the present invention is that the user inserts an external speaker or headphones into the headphone insertion hole. The CODEC chip detects the insertion of the plug by the insertion and removal operation, and the HPdet pin detects the impedance value of the headphone jack input pin DET pin to the ground. The CODEC chip compares the impedance value measured by the HPdet pin with the preset threshold value to obtain one comparison result, and if the preset threshold value is 10 ohms, If the comparison result is that the impedance value is less than 10 ohms, it is determined that the external device inserted in the headphone insertion hole is an external speaker, and if the measured impedance value is larger than 10 ohms, the headphone insertion hole is determined. It is determined that the external device inserted in is a headphone, When the external device inserted in the headphone insertion hole is an external speaker, the CODEC chip decodes the sound signal to the speaker channel, that is, outputs the sound signal from the SPKP pin and SPKN pin of the CODEC chip, and at the same time outputs the judgment result to the AP chip. When the external device inserted into the headphone insertion hole is a headphone, the CODEC chip decodes the sound signal to the headphone channel, that is, outputs the sound signal from the HPL pin and HPR pin of the CODEC chip, and simultaneously outputs the judgment result. Feed back to the AP chip The judgment result fed back by the CODEC chip is that when the external device inserted in the headphone insertion hole is an external speaker, the AP chip connects OUT1 and OUT2 of the analog switch chip via the SELECT pin of the analog switch by the GPIO control line, respectively. It is controlled so that it is connected to IN1 and IN2, and at this time, the sound signal is converted by the analog switch chip and played back by the external speaker, and the judgment result fed back by the CODEC chip is determined by the external device inserted in the headphone insertion hole. In the case of headphones, the AP chip controls OUT1 and OUT2 of the analog switch chip to be connected to IN3 and IN4, respectively, via the SELECT pin of the analog switch by the GPIO control line, and at this time, the sound signal is analog. Converted by a switch chip and played by headphones.

0029The mobile terminal according to the embodiment of the present invention determines that the external device inserted into the headphone insertion hole is a headphone or an external speaker by measuring the impedance value of the external device inserted into the headphone insertion hole, thereby determining that the external device is a headphone or an external speaker. It realizes handover between the headphone playback mode and the external speaker playback mode, realizes a high-performance external playback effect, and improves the external playback volume.

0030In a specific embodiment of the present invention, various horn sound box cavities can be designed based on the outer shape of different mobile terminals, giving the user more choice. At the same time, the horn sound box unit can be rotated freely and removed freely, and the sound propagation direction can be freely selected, enhancing the user experience.

0031When the mobile terminal according to the embodiment of the present invention requires an external playback mode, an external speaker may be inserted into the headphone insertion hole, and when the external playback mode is not required, the mobile terminal automatically vibrates. Hand over to mode.

0032The mobile terminal according to the embodiment of the present invention realizes a high-performance external reproduction effect by utilizing the existing headphone insertion hole, and at the same time effectively limits the layout of the horn and its cavity in the mobile terminal. Avoid, have high value in use, and improve the user experience.

0033The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made, as long as they do not deviate from the spirit and principles of the invention, should be included in the scope of protection of the invention.

0034The mobile terminal according to the embodiment of the present invention determines that the external device inserted into the headphone insertion hole is a headphone or an external speaker by measuring the impedance value of the external device inserted into the headphone insertion hole, thereby determining that the external device is a headphone or an external speaker. It realizes handover between the headphone playback mode and the external speaker playback mode, realizes a high-performance external playback effect, and improves the external playback volume.