TW201513564A - Electronic device with audio control circuit - Google Patents

Abstract

An electronic device with audio control circuit is provided. The audio control circuit includes a system decoding chip, a power amplifying chip, and an output port. The power amplifying chip is connected between the system decoding chip and the output port. The electronic device further includes a MCU and an audio control circuit. The audio control circuit is connected with the MCU and the power amplifying chip. The MCU generates a GPIO control signal when the electronic device is turned on/off to the audio control circuit. The audio control circuit generates a mute control signal to the MUTE port of the system decoding chip, thereby system decoding chip performs mute function.

Description

Electronic device with audio control circuit

The invention relates to an electronic device with an audio control circuit, in particular to an electronic device for preventing a switch machine from generating POP sound.

At present, the portable electronic device generates a popping sound, that is, a POP sound, at the output end of the audio signal when the machine is turned on and off, thereby affecting the normal use of the user.

In view of the above, it is desirable to provide an electronic device having an audio control circuit.

An electronic device includes a system decoder chip, a power amplifier chip and an output port, wherein the power amplifier chip is connected between the system decoding chip and the output port, the output port is used to connect the output device, and the system decodes the chip for generating the electronic device. The audio signal is decoded, and the power amplifier chip is used to amplify the decoded audio signal, and then output to the output device through the output port, and the power amplifier chip includes a MUTE. The electronic device further includes a micro control unit and an audio control circuit, the audio control circuit is connected to the micro control unit and the power amplifier chip, and the micro control unit generates a GPIO control signal to the audio control circuit when the machine is turned on and off, and the control station The audio control signal generates a mute control signal to the MUTE of the power amplifier chip, so that the power amplifier chip performs the mute function without outputting the audio signal to the output port.

The electronic device with the audio control circuit of the invention controls the decoding chip to output the mute output in the switch machine, thereby effectively avoiding the generation of POP sound.

1 is a circuit diagram of an audio control circuit in an electronic device in a preferred embodiment of the present invention.

Please refer to FIG. 1, which is a circuit diagram of an audio control circuit in an electronic device in a preferred embodiment of the present invention. The electronic device 1 includes a system decoder chip 10, a power amplifier chip 20, an output port 30, a micro control unit (MCU) 40, and an audio control circuit 50. The power amplifier chip 20 is connected between the system decoding chip 10 and the output port 30. The output port 30 is used to connect an output device such as a headphone or a speaker. The system decoding chip 10 is used to decode the audio signal generated by the electronic device 1, and the power amplifier chip 20 is used to amplify the decoded audio signal, and then output to the output device such as a headphone or a speaker through the output port 30. The power amplifier chip includes a MUTE.

The audio control circuit 50 connects the MCU 40 and the power amplifier chip 20. The MCU 40 generates a GPIO control signal to the audio control circuit 50 when the machine is turned on and off, and controls the audio control circuit 50 to generate a mute control signal to the MUTE of the power amplifier chip 20, so that the power amplifier chip 20 performs the mute function, that is, does not output the audio signal to the output port. 30, thereby effectively preventing the power amplifier chip 20 from generating POP sound.

Specifically, the audio control circuit 50 includes a mute control signal generating circuit 500. The mute control signal generating circuit 500 includes a first resistor 501, a second resistor 502, a transistor 505, a first diode 506, a second diode 507, a third resistor 508, and a fourth resistor. 509.

The emitter of the transistor 505 is connected to the voltage terminal Vcc, the collector is connected to the anode of the first diode 506 and the second diode 507, and the base is electrically connected to the MCU 40, and passes through the first resistor 501. The voltage terminal Vcc is connected and grounded through the second resistor 502. The cathode of the first diode 506 is grounded through the fourth resistor 509 while connecting the MUTE of the power amplifier chip. The cathode of the second diode 507 is grounded through a third resistor 508. The voltage terminal Vcc can be connected to a battery (not shown) of the electronic device 1 to obtain a high-level voltage, for example, a voltage of 5V.

In the present embodiment, the transistor 505 is a PNP transistor. In this embodiment, the GPIO control signal is a low level, and the mute control signal is a high level signal.

When the MCU 40 generates a low level GPIO control signal, the base of the transistor 505 receives the low level and the transistor 505 is turned on, and the collector of the transistor 505 outputs a high level, so that the first diode 506 is turned on. The cathode of a diode 506 outputs a high level mute control signal to the MUTE of the power amplifier chip 20, thereby causing the power amplifier chip 20 to perform a mute function, thereby effectively preventing the power amplifier chip 20 from generating POP sound when the machine is turned on and off.

The audio control circuit 50 also includes a left channel mute circuit 60a and a right channel mute circuit 60b. The input terminals of the left channel mute circuit 60a and the right channel mute circuit 60b are commonly connected to the cathode of the second diode 507, and the output terminals are respectively connected to the left and right channels 301, 302 of the output port 30. The left channel mute circuit 60a and the right channel mute circuit 60b have the same internal structure.

Specifically, the left channel mute circuit 60a includes a transistor 602 and a capacitor 603. The base of the transistor 602 is electrically connected to the input terminal and electrically connected to the cathode of the second diode 507. The emitter of the transistor 602 is grounded, and the collector is connected to the left channel 301 of the output port 30. A capacitor 603 is connected between the collector and the emitter of the transistor 602. The right channel mute circuit 60b includes a transistor 612 and a capacitor 613. The base of the transistor 612 is electrically connected to the input end of the right channel mute circuit 60b and is electrically connected to the cathode of the second diode 507. The emitter of the transistor 612 is grounded, and the collector is connected to the right channel 302 of the output port 30. A capacitor 613 is connected between the collector and the emitter of the transistor 612.

In the present embodiment, the transistors 602 and 612 are both NPN transistors.

When the MCU 40 generates a low level GPIO control signal, the transistor 505 is turned on, and the emitter of the transistor 505 outputs a high level, so that the second diode 507 is turned on, and the cathode of the second diode 507 outputs a high level to The common input terminal of the left channel mute circuit 60a and the right channel mute circuit 60b.

The base of the transistor 602 receives the high level, causing the transistor 602 to conduct, and the left channel 301 of the output port 30 is grounded through the turned-on transistor 602. At the same time, the base of the transistor 612 receives the high level to turn on the transistor 612, and the right channel of the output port 30 is also grounded through the turned-on transistor 612, thereby grounding the signals transmitted to the left and right channels of the output port 30, again It effectively avoids the POP sound generated when the external device is connected to the output port 30, such as when the external device is plugged or unplugged.

1‧‧‧Electronic device

10‧‧‧System Decoding Chip

20‧‧‧Amplifier chip

30‧‧‧ Output埠

301‧‧‧left channel

302‧‧‧right channel

40‧‧‧MCU

50‧‧‧Audio control circuit

500‧‧‧Mute control signal generation circuit

501‧‧‧First resistance

502‧‧‧second resistance

503,504,601,611‧‧‧resistance

505‧‧‧ triode

506‧‧‧First Diode

507‧‧‧Secondary

508‧‧‧ Third resistor

509‧‧‧fourth resistor

60a‧‧‧left channel mute circuit

60b‧‧‧Right channel mute circuit

602, 612‧‧‧ triode

603,613‧‧‧ capacitor

no

1‧‧‧Electronic device

10‧‧‧System Decoding Chip

20‧‧‧Amplifier chip

30‧‧‧ Output埠

301‧‧‧left channel

302‧‧‧right channel

40‧‧‧MCU

50‧‧‧Audio control circuit

500‧‧‧Mute control signal generation circuit

501‧‧‧First resistance

502‧‧‧second resistance

503,504,601,611‧‧‧resistance

505‧‧‧ triode

506‧‧‧First Diode

507‧‧‧Secondary

508‧‧‧ Third resistor

509‧‧‧fourth resistor

60a‧‧‧left channel mute circuit

60b‧‧‧Right channel mute circuit

602, 612‧‧‧ triode

603,613‧‧‧ capacitor

Claims (5)

An electronic device includes a system decoder chip, a power amplifier chip and an output port, wherein the power amplifier chip is connected between the system decoding chip and the output port, the output port is used to connect the output device, and the system decodes the chip for generating the electronic device. The audio signal is decoded, and the power amplifier chip is used to amplify the decoded audio signal, and then output to the output device through the output port, and the power amplifier chip includes a MUTE, and the improvement is that
The electronic device further includes a micro control unit and an audio control circuit, the audio control circuit is connected to the micro control unit and the power amplifier chip, and the micro control unit generates a GPIO control signal to the audio control circuit when the machine is turned on and off, and the control station The audio control signal generates a mute control signal to the MUTE of the power amplifier chip, so that the power amplifier chip performs the mute function without outputting the audio signal to the output port. The electronic device of claim 1, wherein the audio control circuit comprises a mute control signal generating circuit, the mute control signal generating circuit comprising a first resistor, a second resistor, and a first triode a first diode, a second diode, a third resistor, and a fourth resistor, wherein an emitter of the first transistor is connected to the voltage terminal Vcc, and a collector is connected to the first two An anode of the pole body and the second diode, the base is electrically connected to the micro control unit, and the voltage terminal Vcc is connected through the first resistor and grounded through the second resistor, and the cathode of the first diode passes through the fourth The resistor is grounded and connected to the MUTE埠 of the power amplifier chip, and the cathode of the second diode is grounded through the third resistor. The electronic device of claim 2, wherein the GPIO control signal generated by the micro control unit is a low level signal, the first triode is a PNP triode; and when the micro control unit generates a low level When the GPIO control signal, the base of the first triode receives the low level and the triode is turned on, and the collector of the first triode outputs a high level, so that the first diode is turned on, the first two The cathode of the polar body outputs a high level to the MUTE of the power amplifier chip, thereby performing a mute function on the power amplifier chip, thereby effectively preventing the power amplifier chip from generating POP sound when the power is turned on and off. The electronic device of claim 2, wherein the left channel mute circuit comprises a second transistor and a first capacitor, and a base of the second transistor is electrically connected to the input terminal Electrically connected to the cathode of the diode, the emitter of the second transistor is grounded, the collector is connected to the left channel pin of the output port, and the first capacitor is connected between the collector and the emitter of the second transistor The right channel mute circuit includes a third triode and a second capacitor, the base of the third triode being electrically connected to the input end of the right channel mute circuit and electrically connected to the cathode of the diode The emitter of the triode is grounded, the collector is connected to the right channel pin of the output ,, and the second capacitor is connected between the collector and the emitter of the third transistor. The electronic device of claim 4, wherein the GPIO control signal generated by the micro control unit is a low level signal, and the second triode and the third triode are NPN transistors, when the MCU generates When the GPIO control signal of the low level is used, the first transistor of the mute control signal generating circuit is turned on, and the emitter outputs a high level, so that the second diode of the mute control signal generating circuit turns on the cathode output to a high level to a common input end of the left channel mute circuit and the right channel mute circuit; the base of the second transistor of the left channel mute circuit receives the high level, the second triode is turned on, and the left channel of the output is output The pin is grounded through the turned-on second transistor; at the same time, the base of the third transistor of the right channel mute circuit receives the high level, the third transistor is turned on, and the right channel of the output port passes The turned-on third transistor is also grounded to ground the signals transmitted to the left and right channels of the output port.