CN205179338U - A headphone control circuit compatible with various mobile phone systems - Google Patents

Abstract

The utility model discloses a headset control circuit compatible with multiple mobile phone systems, including a microprocessor U1, a plug, a microphone MIC, a left earphone L-earphone, a right earphone R-earphone, a play switch K1, a volume reduction switch K2, and a volume increase switch K3; the microprocessor U1 is provided with a microphone bias voltage pin MICBIAS, a left channel input pin Lin, a right channel input pin Lin, a left channel output pin Lout, a right channel output pin Lout, a volume reduction pin DOWN, a volume increase pin UP, and a ground pin GND. The utility model can be compatible with various existing mobile phone systems such as Android and ISO systems, and is suitable for wire-controlled headset volume control and other headset fields that require volume adjustment, with a simple structure, low cost, and easy use; through the play switch K1, the volume reduction switch K2, and the volume increase switch K3, and through the transistor Q1, the microphone and audio playback are switched, which is convenient and fast.

Description

A headphone control circuit compatible with various mobile phone systems

technical field

The utility model relates to an earphone volume control technology, in particular to an earphone control circuit compatible with various mobile phone systems.

Background technique

From the perspective of the development of the entire audio industry, wireless earphones are still a new thing, and the development time is not long. It is still in the rising period, user demand is constantly improving, and users' expectations for wireless earphones are also increasing. This is a proposal for the industry. new test. At present, the main points that users are most concerned about include sound quality, battery life and wireless transmission capability. From the data point of view, the wireless transmission capability can basically meet the needs of most users, and there is still great potential for improvement in sound quality and battery life. If we improve from these two points, I believe it will be easy to attract users' attention in the future.

Earphones are a pair of conversion units that receive electrical signals from a media player or receiver and convert them into audible sound waves using speakers close to the ears. Headphones are generally detachable from the media player and connected with a plug. The advantage is that you can listen to the audio alone without affecting others; it can also isolate the sound of the surrounding environment, which is very helpful for people who use it in noisy environments such as recording studios, DJs, travel, and sports. Earphones were originally used for telephones and radios, but with the popularity of portable electronic devices, earphones are mostly used for mobile phones, walkmans, and radios. Portable video games and digital audio players, etc. From the perspective of the development of the entire audio industry, wireless earphones are still a new thing, and the development time is not long. It is still in the rising period, user demand is constantly improving, and users' expectations for wireless earphones are also increasing. This is the proposal for the industry. new test.

Headphones are a symbol of people's portable audio. Mobile phone headsets are divided into two standards: OMTP standard is usually called the national standard, and CTIA is called the international standard. Earphones are classified according to their energy conversion methods, mainly including: moving coil, moving iron, electrostatic and equimagnetic. Classified from the structure and function, it can be divided into semi-open and closed; from the wearing form, there are earplugs, ear-hanging, in-ear and head-mounted; from the number of wearers, there are single earphones and earphones. Multiple people earphones; from the difference of sound source, it can be divided into active earphones and passive earphones; active earphones are also often called plug-in earphones.

To measure headphones, you can use some methods to evaluate speakers, but the sense of hearing of headphones is different from that of speakers. The sound waves emitted by speakers are attenuated and interfered in the air, and interact with the head and ears of people. The sound of headphones directly enters the ears. . The quality of the sound of the earphone is more important than its technical performance. Since the shapes of the human head and ears are different, a pair of earphones will have different hearing sensations for different people, so the recommendation can only be used as a reference. If you have the opportunity, you must listen to it yourself. Only then can you really feel the sound of the headphones.

However, in the prior art, the earphone compatibility of mobile phones of various brands is relatively poor, and when connected to another mobile phone, the sound quality is relatively poor, and the user experience is relatively poor.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art, and provide an earphone control circuit compatible with various mobile phone systems, compatible with various existing mobile phone systems such as Android and ISO systems, with a wide range of applications, simple structure, and low cost .

In order to achieve the above object, the technical scheme that the utility model adopts is:

A headphone control circuit compatible with various mobile phone systems,

Including microprocessor U1, plug, microphone MIC, left earphone L-earphone, right earphone R-earphone, playback switch K1, volume down switch K2, volume up switch K3;

The microprocessor U1 is provided with a microphone bias voltage pin MICBIAS, a left channel input pin Lin, a right channel input pin Lin, a left channel output pin Lout, a right channel output pin Lout, and a volume reduction pin DOWN , volume increase pin UP and ground pin GND;

The microphone bias voltage pin MICBIAS is respectively connected to the microphone MIC and the playback switch K1; the left channel input pin Lin and the right channel input pin Lin are connected to a plug; the volume reduction pin DOWN is connected to the volume reduction switch K2 The volume increase pin UP is connected to the volume increase switch K3; the left channel output pin Lout is connected to the left earphone L-earphone of the earphone; the right channel output pin Lout is connected to the right earphone R-earphone of the earphone; The pin GND is connected to the ground terminal.

As the best embodiment of the present utility model, a transistor Q1 is arranged at the output end of the microphone bias voltage pin MICBIAS described in the utility model, and the gate of the transistor Q1 is connected to the microphone bias voltage pin MICBIAS, and the source electrode of the transistor Q1 is one way Ground, the other channel is connected to the playback switch K1, the drain of the transistor Q1 is connected to one end of the microphone MIC, and the drain of the transistor Q1 is connected in series with a resistor R3 to the other end of the microphone MIC.

As a preferred embodiment of the present invention, the transistor Q1 described in the present invention is an NMOS transistor.

As the best embodiment of the present utility model, a diode D1 is arranged between the microphone MIC and the microphone bias voltage pin MICBIAS of the utility model, the anode of the diode D1 is connected to the microphone MIC, and the cathode of the diode D1 is connected to the microphone bias voltage pin Foot MICBIAS.

As a preferred embodiment of the utility model, the microphone bias voltage pin MICBIAS of the utility model is connected in series with a capacitor C1 and grounded.

As the best embodiment of the present utility model, the plug described in the utility model is provided with a left channel input pin Lin interface, a right channel input pin Lin interface, a microphone MIC interface and a GND interface; the left channel input pin Lin interface is connected to the left channel The input pin Lin is connected, the right channel input pin Lin interface is connected to the right channel input pin Lin, the microphone MIC interface is connected to the microphone MIC, and the GND interface is grounded.

As a preferred embodiment of the present invention, the Lin interface of the left channel input pin of the present invention is grounded after being connected in series with a resistor R1, and the Lin interface of the right channel input pin is connected in series with a resistor R2 and then grounded.

As the best embodiment of the present utility model, the microprocessor U1 described in the present utility model includes a button detection module, a counting control module, a level conversion module, an attenuation output module and a charge pump module; wherein,

The button detection module is used to output the control signal after detecting the volume up signal or the volume down signal input by the button;

The counting control module is used to receive the control signal and output the count value signal. If the control signal is the volume increase control signal sent by pressing the volume increase switch K3, the counting will be performed. If the control signal is the volume decrease signal sent by the volume decrease switch K2 The control signal is counted down;

The level conversion module is used to convert the count value signal to a level and then output the converted count value signal;

The attenuation output module is used to output the audio signal from the left channel output pin Lout and the right channel output pin Lout after the received converted count value signal, the input left channel audio signal, and the right channel audio signal are attenuated;

The charge pump module is used to generate a negative power supply and output it to the level conversion module and the attenuation output module, so that the level conversion module and the attenuation output module work between the negative power supply and the positive power supply.

As the best embodiment of the utility model, the attenuation output module of the utility model includes 1st to n resistors, 1st to n switches, n+1 to 2n resistors and n+1 to 2n switches; wherein, the One end of the 1 to n resistors is connected to the right channel input pin Lin, the other end of the 1st to n resistors is respectively connected to one end of the 1st to n switches, and the other end of the 1st to n switches is connected to the right channel output pin Lout connection; one end of the n+1 to 2n resistors is connected to the left channel input pin Lin, and the other end of the n+1 to 2n resistors are respectively connected to one end of the n+1 to 2n switches one by one, and the n+1 The other end of the 2n switch is connected to the left channel output pin Lout, and n is an integer greater than 1.

As the best embodiment of the utility model, the charge pump module of the utility model provides a negative power supply for the circuit.

Compared with the prior art, the utility model has the beneficial effects as follows: first, it is compatible with various existing mobile phone systems such as Android and ISO systems, and is suitable for volume control of wire-controlled earphones and other earphone fields that require volume adjustment, and has a simple structure 1. Low cost and easy to use; Second, through the playback switch K1, the volume down switch K2 and the volume up switch K3, and the switching of the microphone and audio playback through the transistor Q1, it is convenient and quick.

Description of drawings

Fig. 1 is the overall structural representation of the utility model;

Fig. 2 is a schematic diagram of the internal structure of the microprocessor of the present invention.

detailed description

The gist of the utility model is to overcome the deficiencies of the prior art and provide an earphone control circuit compatible with various mobile phone systems, which can adapt to different mobile phones, such as compatible with various existing mobile phone systems such as Android and ISO systems, and can receive Better sound quality effect. The following will be described in detail with reference to the accompanying drawings in conjunction with the embodiments, so as to further explain the technical features and advantages of the present utility model.

The overall structural diagram of the utility model is shown in Figure 1, a kind of earphone control circuit compatible with various mobile phone systems, including microprocessor U1, plug, microphone MIC, earphone left earphone L-earphone, earphone right earphone R-earphone and Play switch K1, volume down switch K2, volume up switch K3.

Preferably, the microprocessor U1 of the present invention adopts the chip ST2618. ST2618 is a button-controlled general headphone volume control circuit (the maximum attenuation is MUTE), which includes a button detection module, a counting control module, an attenuation output module, a level conversion module, and a charge pump module. The key input will be detected by the key detection module, and the count value of the count control module will be adjusted to control the attenuation output module to select different attenuation resistance values, so that the audio signal externally input to the attenuation output module will be output to the earphone after being attenuated by the attenuation resistance. controls the volume of the headphones. The high-impedance output is realized through the attenuation output module, and the mute function is realized, and the mute effect can be obtained on the earphone; fifth, the built-in charge pump module greatly reduces the peripheral components while realizing the analog ground of the output audio signal to 0V.

The circuit detects the input of buttons UP and DOWN through the button detection module, controls the addition or subtraction of the internal counter, and then controls the attenuation output module to select different attenuation resistors through the count value to attenuate the audio signal and output it to the earphone. ST2618 is suitable for wire-controlled earphone volume and other earphone fields that need to adjust the volume. A built-in charge pump circuit is used to provide negative voltage. UP: UP is used to increase the output volume and reduce the output resistance through switch selection. DOWN: DOWN is used to reduce the output volume, and increase the output resistance through switch selection. The UP and DOWN pins have built-in pull-up resistors, and the circuit will change the switch to adjust the output resistance only when the button is pulled down for more than 40ms from the anti-shake time. When the button is continuously pulled low, adjust the switch every 200ms to change the output resistance. The maximum working current of ST2618 is lower than 10uA.

As shown in Figure 2, the microphone bias voltage pin MICBIAS, the left channel input pin Lin, the right channel input pin Lin, the left channel output pin Lout, the right channel output pin Lout, are set on the microprocessor U1. Volume down pin DOWN, volume up pin UP and ground pin GND. The microphone bias voltage pin MICBIAS is respectively connected to the microphone MIC and the playback switch K1; the left channel input pin Lin and the right channel input pin Lin are connected to a plug; the volume reduction pin DOWN is connected to the volume reduction switch K2 The volume increase pin UP is connected to the volume increase switch K3; the left channel output pin Lout is connected to the left earphone L-earphone of the earphone; the right channel output pin Lout is connected to the right earphone R-earphone of the earphone; The pin GND is connected to the ground terminal.

Preferably, a transistor Q1 is provided at the output end of the microphone bias voltage pin MICBIAS described in the present invention, the gate of the transistor Q1 is connected to the microphone bias voltage pin MICBIAS, one source of the transistor Q1 is grounded, and the other is connected to the playback switch K1, the drain of the transistor Q1 is connected to one end of the microphone MIC, and the drain of the transistor Q1 is connected in series with a resistor R3 to the other end of the microphone MIC.

In order to achieve a better switching effect, the transistor Q1 described in the utility model is an NMOS transistor, VT=1V. Of course, the present invention is not limited to NMOS transistors, and other transistors may also be used.

In order to prevent reverse voltage and current in the utility model, a diode D1 is arranged between the microphone MIC and the microphone bias voltage pin MICBIAS, the anode of the diode D1 is connected to the microphone MIC, and the cathode of the diode D1 is connected to the microphone bias voltage pin MICBIAS . A diode D1 is arranged between the microphone MIC and the microphone bias voltage pin MICBIAS to form a reverse cut-off circuit to prevent circuit damage caused by reverse current and improve safety performance.

As a preferred embodiment of the utility model, the microphone bias voltage pin MICBIAS of the utility model is connected in series with a capacitor C1 and then grounded to be isolated from the ground to form a protection.

The plug of the utility model is provided with a left channel input pin Lin interface, a right channel input pin Lin interface, a microphone MIC interface and a GND interface; the left channel input pin Lin interface is connected with the left channel input pin Lin, and the right channel input pin The pin Lin interface is connected to the right channel input pin Lin, the microphone MIC interface is connected to the microphone MIC, and the GND interface is grounded. In addition, the other channel of the left channel input pin Lin interface of the utility model is connected in series with a resistor R1 and then grounded, and the other channel of the right channel input pin Lin interface is connected in series with a resistor R2 and then grounded.

The microprocessor U1 described in the utility model includes a button detection module, a counting control module, a level conversion module, an attenuation output module and a charge pump module; wherein, the button detection module is used to perform a volume up signal or a volume down signal input by a button Output the control signal after detection; the counting control module is used to receive the control signal and output the count value signal. If the control signal is the volume increase control signal sent by pressing the volume increase switch K3, the counting will be performed. If the control signal is the volume decrease switch K2 Press the volume reduction control signal sent to perform subtraction counting; the level conversion module is used to convert the count value signal to the level and output the converted count value signal; the attenuation output module is used to convert the received count value signal, The input left channel audio signal and right channel audio signal are attenuated and output audio signals from the left channel output pin Lout and the right channel output pin Lout; the charge pump module is used to generate a negative power supply and output it to the level conversion module and the attenuation output module, so that the level conversion module and the attenuation output module work between the negative power supply and the positive power supply. The charge pump module of the utility model provides a negative power supply for the circuit without additional peripheral devices.

As the best embodiment of the utility model, the attenuation output module of the utility model includes 1st to n resistors, 1st to n switches, n+1 to 2n resistors and n+1 to 2n switches; wherein, the One end of the 1 to n resistors is connected to the right channel input pin Lin, the other end of the 1st to n resistors is respectively connected to one end of the 1st to n switches, and the other end of the 1st to n switches is connected to the right channel output pin Lout connection; one end of the n+1 to 2n resistors is connected to the left channel input pin Lin, and the other end of the n+1 to 2n resistors are respectively connected to one end of the n+1 to 2n switches one by one, and the n+1 The other end of the 2n switch is connected to the left channel output pin Lout, and n is an integer greater than 1. Preferably, the value of n is set according to the number of levels that the earphone needs to adjust the volume, and n is an integer ranging from 2 to 99, as shown in FIG. 2 , n is 11.

In a specific embodiment, the attenuation output module includes 1st to nth resistors R1, R2, R3...Rn, 1st to nth switches K1, K2, K3...Kn, n+1 to 2nth resistors R(n+ 1), R(n+2)...R(2n) and n+1 to 2nth switches K(n+1), K(n+2)...K(2n); among them, the 1st to nth resistors One end of R1, R2, R3...Rn is connected to the right channel input pin Lin, and the other end of the 1st to nth resistors R1, R2, R3...Rn is respectively connected to the 1st to nth switch K1, K2, K3... One end of Kn is connected one by one, the other end of the first to n switches K1, K2, K3... Kn is connected to the right channel output pin Lout; the n+1 to 2n resistors R(n+1), R(n+2 )... One end of R(2n) is connected to the left channel input pin Lin, and the other end of n+1 to 2n resistors R(n+1), R(n+2)...R(2n) are respectively connected to The n+1 to 2n switches K(n+1), K(n+2)...K(2n) are connected one by one, and the n+1 to 2n switches K(n+1), K(n+2 )... The other end of K (2n) is connected to the left channel output pin Lout.

The utility model is clearly and completely described through the technical solutions in the above embodiments, and it is obvious that the described embodiments are a part of the embodiments of the utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Claims (7)

1. The utility model provides a compatible multiple cell-phone system's earphone control circuit which characterized in that:

the earphone comprises a microprocessor U1, a plug, a microphone MIC, an earphone left receiver L-earphone, an earphone right receiver R-earphone, a play switch K1, a volume reduction switch K2 and a volume increase switch K3;

a microphone bias voltage pin MICBIAS, a left channel input pin Lin, a right channel input pin Lin, a left channel output pin Lout, a right channel output pin Lout, a volume reduction pin DOWN, a volume increase pin UP and a ground pin GND are arranged on the microprocessor U1;

the microphone bias voltage pin MICBIAS is respectively connected with a microphone MIC and a play switch K1; the left channel input pin Lin and the right channel input pin Lin are connected with a plug; the volume reduction pin DOWN is connected with a volume reduction switch K2; the volume increasing pin UP is connected with a volume increasing switch K3; the left channel output pin Lout is connected with an earphone left receiver L-earphone; the right channel output pin Lout is connected with an earphone right receiver R-ear phone; the ground pin GND is connected with a ground terminal.

2. The headset control circuit compatible with multiple cellular phone systems of claim 1, wherein: the output end of the microphone bias voltage pin MICBIAS is provided with a transistor Q1, the grid electrode of the transistor Q1 is connected with the microphone bias voltage pin MICBIAS, one path of the source electrode of the transistor Q1 is grounded, the other path of the source electrode of the transistor Q1 is connected with the play switch K1, the drain electrode of the transistor Q1 is connected with one end of the microphone MIC, and the drain electrode of the transistor Q1 is connected with a resistor R3 in series and is connected with the other end of the microphone MIC.

3. The headset control circuit of claim 2, further comprising: the transistor Q1 is an NMOS transistor.

4. The headset control circuit of claim 2, further comprising: a diode D1 is arranged between the microphone MIC and the microphone bias voltage pin MICBIAS, the anode of the diode D1 is connected with the microphone MIC, and the cathode of the diode D1 is connected with the microphone bias voltage pin MICBIAS.

5. The headset control circuit of claim 2, further comprising: the mic bias voltage pin MICBIAS is connected in series with a capacitor C1 and then to ground.

6. The headset control circuit compatible with multiple cellular phone systems of claim 1, wherein: the plug is provided with a left channel input pin Lin interface, a right channel input pin Lin interface, a microphone MIC interface and a GND interface; the left channel input pin Lin interface is connected with the left channel input pin Lin, the right channel input pin Lin interface is connected with the right channel input pin Lin, the microphone MIC interface is connected with the microphone MIC, and the GND interface is grounded.

7. The headset control circuit of claim 6, further comprising: the interface of the left channel input pin Lin is connected with a resistor R1 in series and then grounded, and the interface of the right channel input pin Lin is connected with a resistor R2 in series and then grounded.