CN217240917U - POP sound processing circuit and playing device - Google Patents

Abstract

The application is suitable for the field of audio processing, and provides a POP sound processing circuit and a playing device, wherein the POP sound processing circuit comprises a first charging and discharging unit, a second charging and discharging unit, a first logic unit and a second logic unit; the first logic unit is electrically connected with the first charge-discharge unit, the second charge-discharge unit and the second logic unit respectively, the second logic unit is used for being electrically connected with a control end of the power amplifier, the first charge-discharge unit and the second charge-discharge unit are both used for being electrically connected with a first power supply, and a power supply end of the power amplifier is electrically connected with a second power supply. The POP sound processing circuit provided by the embodiment of the application can solve the POP sound problem generated by products with power amplifiers at the moment of power-on or power-off.

Description

POP sound processing circuit and play device

Technical Field

The application belongs to the field of audio processing, and particularly relates to a POP audio processing circuit and a playing device.

Background

At present, POP sound generated at the moment of power-on or power-off of products with power amplifiers is always a problem which is addressed by hardware engineers.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a POP sound processing circuit, which can solve the problem of POP sound generated by products with power amplifiers at the moment of power-on or power-off.

In a first aspect, an embodiment of the present application provides a POP sound processing circuit, including a first charge and discharge unit, a second charge and discharge unit, a first logic unit, and a second logic unit;

the first logic unit is electrically connected with the first charge-discharge unit, the second charge-discharge unit and the second logic unit respectively, the second logic unit is used for being electrically connected with a control end of the power amplifier, the first charge-discharge unit and the second charge-discharge unit are both used for being electrically connected with a first power supply, and a power supply end of the power amplifier is electrically connected with a second power supply;

the first charging and discharging unit is used for outputting a first voltage, and the second charging and discharging unit is used for outputting a second voltage; in the process of starting up or shutting down, the first logic unit is used for outputting a first logic signal according to the first voltage and the second voltage; the second logic unit is used for outputting a second logic signal according to the first logic signal; and the power amplifier is used for delaying starting according to the second logic signal in the starting process, and is used for closing in advance according to the second logic signal in the shutdown process so as to eliminate POP sound generated by the playing device in the starting process or the shutdown process.

In one possible implementation manner of the first aspect, the first charge and discharge unit includes a first diode and a first capacitor;

the cathode of the first diode is electrically connected with the first end of the first capacitor and the first logic unit respectively, the second end of the first capacitor is grounded, and the anode of the first diode is used for being electrically connected with the first power supply.

In a possible implementation manner of the first aspect, the second charging and discharging unit includes a first resistor, a second capacitor, and a second diode;

the first end of the first resistor is electrically connected with the cathode of the second diode and the anode of the first diode respectively, the second end of the first resistor is electrically connected with the anode of the second diode, the first end of the second capacitor and the first logic unit respectively, and the second end of the second capacitor is grounded.

In one possible implementation manner of the first aspect, the first logic unit includes a first triode and a second resistor;

the emitter of the first triode is electrically connected with the cathode of the first diode, the base of the first triode is electrically connected with the second end of the first resistor, the collector of the first triode is electrically connected with the first end of the second resistor and the second logic unit respectively, and the second end of the second resistor is grounded.

In a possible implementation manner of the first aspect, the first transistor is a PNP transistor.

In a possible implementation manner of the first aspect, the second logic unit includes a second triode and a fourth resistor;

the base electrode of the second triode is electrically connected with the collector electrode of the first triode, the emitter electrode of the second triode is grounded, the collector electrode of the second triode is electrically connected with the first end of the fourth resistor, and the second end of the fourth resistor is used for being electrically connected with the control end of the power amplifier.

In one possible implementation manner of the first aspect, the second logic unit further includes a third resistor; the third resistor is connected in series between the collector of the first triode and the base of the second triode.

In a possible implementation manner of the first aspect, the second transistor is an NPN transistor.

In a second aspect, an embodiment of the present application provides a playback apparatus, including a power amplifier, a speaker, a first power supply, a second power supply, and the POP sound processing circuit;

the POP sound processing circuit is respectively and electrically connected with the first power supply and the control end of the power amplifier, the power end of the power amplifier is electrically connected with the second power supply, and the output end of the power amplifier is electrically connected with the loudspeaker;

the POP sound processing circuit is used for outputting a second logic signal in the process of starting up or shutting down; and the power amplifier is used for delaying starting according to the second logic signal in the starting process, and is used for closing in advance according to the second logic signal in the shutdown process so as to eliminate POP sound generated by the playing device in the starting process or the shutdown process.

In a possible implementation manner of the second aspect, the playing apparatus further includes a pull-up unit, where the pull-up unit is electrically connected to the control end of the power amplifier;

when the playing device is normally powered on, the pull-up unit is configured to provide a pull-up voltage to the control terminal of the power amplifier, so that the power amplifier drives the speaker to operate.

Compared with the prior art, the embodiment of the application has the advantages that:

the POP sound processing circuit provided by the embodiment of the application is applied to a playing device, and in a starting process or a shutdown process, the first logic unit outputs a first logic signal according to a first voltage output by the first charge-discharge unit and a second voltage output by the second charge-discharge unit, and the second logic unit outputs a second logic signal according to the first logic signal. And the power amplifier is started in a delayed mode according to the second logic signal in the starting process, and the power amplifier does not drive the loudspeaker to work at the moment, so that POP sound generated by the playing device in the starting process is eliminated. And the power amplifier is closed in advance according to the second logic signal in the shutdown process, and the power amplifier does not drive the loudspeaker to work at the moment, so that POP sound generated by the playing device in the shutdown process is eliminated.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a POP sound processing circuit according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a POP sound processing circuit according to another embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a playing device according to another embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

As shown in fig. 1, the embodiment of the present application provides a POP sound processing circuit, which is applied to a playing device and can solve the problem of POP sound generated by products with power amplifiers at the moment of power-on or power-off. Includes a first charge and discharge unit 101, a second charge and discharge unit 102, a first logic unit 103, and a second logic unit 104. The first logic unit 103 is electrically connected to the first charge and discharge unit 101, the second charge and discharge unit 102 and the second logic unit 104, respectively, the second logic unit 104 is used for being electrically connected to a control terminal of the power amplifier 200, both the first charge and discharge unit 101 and the second charge and discharge unit 102 are used for being electrically connected to the first power supply 300, a power supply terminal of the power amplifier 200 is electrically connected to the second power supply 500, and an output terminal of the power amplifier 200 is electrically connected to the speaker 400.

Specifically, the first charge and discharge unit 101 outputs a first voltage, the second charge and discharge unit 102 outputs a second voltage, the first logic unit 103 outputs a first logic signal according to the first voltage and the second voltage, and the second logic unit 104 outputs a second logic signal according to the first logic signal during the power-on process or the power-off process.

During the power-on process, the power amplifier 200 is started according to the second logic signal delay, and at this time, the power amplifier 200 does not drive the speaker 400 to operate, so as to eliminate the POP sound generated during the power-on process of the playback apparatus.

During the shutdown process, the power amplifier 200 is turned off in advance according to the second logic signal, and at this time, the power amplifier 200 does not drive the speaker 400 to operate, so as to eliminate the POP sound generated by the playback apparatus during the shutdown process.

In normal power-on, the POP sound processing circuit does not operate, and at this time, a pull-up voltage is supplied to the control terminal of the power amplifier 200 through the pull-up unit 600, so that the power amplifier 200 drives the speaker 400 to operate. The pull-up unit 600 is prior art and will not be described herein.

It should be noted that the first power supply 300 and the second power supply 500 in the embodiment of the present application may be the same power supply or may be two different power supplies.

As shown in fig. 2, the first charge and discharge unit 101 includes a first diode D1 and a first capacitor C1, a cathode of the first diode D1 is electrically connected to a first terminal of the first capacitor C1 and the first logic unit 103, respectively, a second terminal of the first capacitor C1 is grounded, and an anode of the first diode D1 is electrically connected to the first power supply 300.

Specifically, during the power-on process, the first power supply 300 charges the first capacitor C1 through the first diode D1, and the voltage of the first terminal of the first capacitor C1 is the first voltage. Since the voltage of the first terminal of the first capacitor C1 gradually increases as the charging progresses, the first voltage output by the first charge and discharge unit 101 at this time gradually increases.

During the shutdown process, the first capacitor C1 discharges through the first diode D1, and the voltage at the first end of the first capacitor C1 gradually decreases as the discharge progresses, at this time, the first voltage output by the first charging and discharging unit 101 gradually decreases.

In normal power-on, the first capacitor C1 is fully charged, and the voltage at the first terminal of the first capacitor C1 approaches the first power supply 300.

As shown in fig. 2, the second charge/discharge unit 102 includes a second diode D2, a first resistor R1, and a second capacitor C2, wherein a first terminal of the first resistor R1 is electrically connected to a cathode of the second diode D2 and an anode of the first diode D1, a second terminal of the first resistor R1 is electrically connected to an anode of the second diode D2, a first terminal of the second capacitor C2, and the first logic unit 103, and a second terminal of the second capacitor C2 is grounded.

Specifically, during the power-on process, the first power supply 300 charges the second capacitor C2 through the first resistor R1, and the voltage of the first end of the second capacitor C2 is the second voltage. Since the voltage of the first terminal of the second capacitor C2 gradually increases as the charging progresses, the second voltage output by the second charge and discharge unit 102 at this time gradually increases.

During the shutdown process, the second capacitor C2 discharges through the second diode D2, the voltage at the first end of the second capacitor C2 gradually decreases along with the discharge, and at this time, the second voltage output by the second charging and discharging unit 102 gradually decreases.

In normal power-on, the second capacitor C2 is fully charged, and the voltage at the first end of the second capacitor C2 approaches the first power supply 300.

According to the common knowledge: the capacitor charge-discharge time is proportional to RC. In the boot process, the first power supply 300 charges the first capacitor C1 through the first diode D1, the first diode D1 is turned on in the forward direction, and the forward resistance of the first diode D1 is very small, so that the charging speed of the first capacitor C1 is very fast.

The first power supply 300 charges the second capacitor C2 through the first resistor R1, and the resistance of the first resistor R1 is certainly greater than the forward resistance of the first diode D1, so that the charging speed of the second capacitor C2 is slower than that of the first capacitor C1, and therefore the voltage of the first end of the first capacitor C1 is always greater than the voltage of the first end of the second capacitor C2, that is, the first voltage output by the first charging and discharging unit 101 is always greater than the second voltage output by the second charging and discharging unit 102.

During the shutdown process, the first capacitor C1 discharges through the first diode D1, the first diode D1 turns off in reverse, and the reverse resistance of the first diode D1 is very large, so that the discharge speed of the first capacitor C1 is very slow.

The second capacitor C2 discharges through the second diode D2, the second diode D2 conducts in the forward direction, the forward resistance of the second diode D2 is very small and much smaller than the reverse resistance of the first diode D1, so that the discharging speed of the second capacitor C2 is faster than that of the first capacitor C1, and therefore the voltage of the first end of the first capacitor C1 is always greater than that of the first end of the second capacitor C2, that is, the first voltage output by the first charging and discharging unit 101 is always greater than the second voltage output by the second charging and discharging unit 102. During normal power on, since the charging speed of the first capacitor C1 is faster than that of the second capacitor C2, when the charging of the second capacitor C2 is completed, the first capacitor C1 is already charged, and therefore the voltage of the first end of the first capacitor C1 is close to the voltage of the first end of the second capacitor C2, that is, the first voltage output by the first charging and discharging unit 101 is close to the second voltage output by the second charging and discharging unit 102.

As shown in fig. 2, the first logic unit 103 includes a first transistor Q1 and a second resistor R2, an emitter of the first transistor Q1 is electrically connected to a cathode of the first diode D1, a base of the first transistor Q1 is electrically connected to a second end of the first resistor R1, a collector of the first transistor Q1 is electrically connected to a first end of the second resistor R2 and the second logic unit 104, a second end of the second resistor R2 is grounded, and the first transistor Q1 is a PNP type transistor.

Specifically, the voltage of the emitter of the first transistor Q1 is a first voltage, the voltage of the base of the first transistor Q1 is a second voltage, and the collector of the first transistor Q1 outputs a first logic signal.

In the process of starting up the electronic device, the first voltage output by the first charging and discharging unit 101 gradually increases, the second voltage output by the second charging and discharging unit 102 gradually increases, and the first voltage is always greater than the second voltage. When the first voltage reaches the saturation conduction condition of the first transistor Q1, the first transistor Q1 is in saturation conduction, and the collector of the first transistor Q1 outputs a first logic signal. As the charging progresses, the voltage of the emitter of the first transistor Q1 gradually increases, causing the first logic signal to gradually increase.

In the shutdown process, the first voltage output by the first charging and discharging unit 101 gradually decreases, the second voltage output by the second charging and discharging unit 102 gradually decreases, and the first voltage is always greater than the second voltage. When the second voltage reaches the conduction condition of the first transistor Q1, the first transistor Q1 is turned on and the collector of the first transistor Q1 outputs a first logic signal. The first logic signal varies with the voltage at the emitter of the first transistor Q1, and since the first voltage varies slowly, the voltage at the emitter of the first transistor Q1 also varies slowly, approaching the first power supply 300, so that the first logic signal output by the collector of the first transistor Q1 also approaches the first power supply 300.

In normal power-on, the voltage of the emitter of the first transistor Q1 is close to the voltage of the base, the first transistor Q1 is turned off, the collector of the first transistor Q1 is grounded, and the collector of the first transistor Q1 outputs a low level signal.

As shown in fig. 2, the second logic unit 104 includes a second transistor Q2 and a fourth resistor R4, a base of the second transistor Q2 is electrically connected to a collector of the first transistor Q1, an emitter of the second transistor Q2 is grounded, a collector of the second transistor Q2 is electrically connected to a first end of the fourth resistor R4, a second end of the fourth resistor R4 is configured to be electrically connected to a control terminal of the power amplifier 200, and the second transistor Q2 is an NPN-type triode.

Specifically, the base of the second transistor Q2 inputs the first logic signal, and the collector of the second transistor Q2 outputs the second logic signal.

During the boot process, the first logic signal gradually increases, when the first logic signal reaches the saturation conduction condition of the second triode Q2, the second triode Q2 is in saturation conduction, and since the emitter of the second triode Q2 is grounded, the collector of the second triode Q2 outputs a low level signal, and the low level signal output by the collector of the second triode Q2 is the second logic signal.

During the shutdown process, the first logic signal approaches the first power supply 300, the first logic signal triggers the second transistor Q2 to turn on, and since the emitter of the second transistor Q2 is grounded, the collector of the second transistor Q2 outputs a low level signal, and the low level signal output by the collector of the second transistor Q2 is the second logic signal.

In normal power-on, the first transistor Q1 is turned off, and the collector of the first transistor Q1 outputs a low level signal to turn off the second transistor Q2.

Illustratively, the fourth resistor R4 is a flying resistor.

As shown in fig. 2, the second logic unit 104 further includes a third resistor R3, and the third resistor R3 is connected in series between the collector of the first transistor Q1 and the base of the second transistor Q2.

Specifically, the third resistor R3 functions as a current limiter.

For the sake of clarity, the operation of the POP sound processing circuit is described in detail with reference to fig. 2.

Wherein, the parameters of each device are as follows: the power amplifier 200 is model OB 6228. Assuming that the first power supply 300 and the second power supply 500 are the same power supply, the first power supply 300 and the second power supply 500 are determined to be 19V according to the model of the power amplifier 200. The first diode D1 is model SN 4148. The first capacitor C1 is an electrolytic capacitor with the parameter of 220 u/35V. The second diode D2 is model SN 4148. The first resistor R1 has a resistance of 56K. The second capacitor C2 is an electrolytic capacitor with a parameter of 47 u/50V. The first transistor Q1 is model PMBT 3906. The resistance of the second resistor R2 is 100K. The second transistor Q2 is model PMBT 3904. The resistance of the resistor R3 is 100K.

During the start-up process, the first charging and discharging unit 101 and the second charging and discharging unit 102 are both in a charging state. When the first diode D1 rises from 0V to 19V, the forward resistance is very small, so that the first capacitor C1 charges very fast. The resistance of the first resistor R1 reaches 56K, so that the charging speed of the second capacitor C2 is slower than that of the first capacitor C1, and therefore the voltage of the first end of the first capacitor C1 is always greater than the voltage of the first end of the second capacitor C2, i.e. the first voltage output by the first charging and discharging unit 101 is always greater than the second voltage output by the second charging and discharging unit 102. When the first voltage reaches about 0.7V, the first transistor Q1 is turned on in saturation, and the collector of the first transistor Q1 outputs a first logic signal. As the charging progresses, the voltage of the emitter of the first transistor Q1 gradually increases, causing the first logic signal to gradually increase. When the first logic signal reaches about 0.7V +0.3V, the second triode Q2 is in saturation conduction, and since the emitter of the second triode Q2 is grounded, the collector of the second triode Q2 outputs a low level signal, and the low level signal output by the collector of the second triode Q2 is the second logic signal. The control terminal of the power amplifier 200 is pulled low by the second logic signal, so that the power amplifier 200 is started in a delayed manner, and at this time, the power amplifier 200 does not drive the speaker 400 to work, thereby eliminating the POP sound generated by the playing apparatus during the startup process.

During shutdown, both the first charge and discharge unit 101 and the second charge and discharge unit 102 are in a discharged state. When the first diode D1 drops from 19V to 0V, the reverse resistance is very large, so that the discharge speed of the first capacitor C1 is very slow. When the second diode D2 decreases from 19V to 0V, the forward resistance is very small, so that the discharging speed of the second capacitor C2 is faster than that of the first capacitor C1, and therefore the voltage of the first end of the first capacitor C1 is always greater than the voltage of the first end of the second capacitor C2, i.e. the first voltage output by the first charging and discharging unit 101 is always greater than the second voltage output by the second charging and discharging unit 102. When the second voltage is less than about 4.3V, the first transistor Q1 is turned on, and the collector of the first transistor Q1 outputs a first logic signal. The first logic signal varies with the voltage at the emitter of the first transistor Q1, and since the voltage at the emitter of the first transistor Q1 varies slowly, approaching 19V, the first logic signal output by the collector of the first transistor Q1 also approaches 19V. Since the voltage of the first logic signal is high, the second transistor Q2 is turned on accordingly, and since the emitter of the second transistor Q2 is grounded, the collector of the second transistor Q2 outputs a low level signal, and the low level signal output by the collector of the second transistor Q2 is the second logic signal. The control terminal of the power amplifier 200 is pulled low by the second logic signal, so that the power amplifier 200 is turned off in advance, and at this time, the power amplifier 200 does not drive the speaker 400 to operate, thereby eliminating POP sound generated by the playback apparatus during the shutdown process.

In normal power-on, when the second charging and discharging unit 102 is charged completely, the first charging and discharging unit 101 is charged completely, the voltage of the first end of the first capacitor C1 is similar to the voltage of the first end of the second capacitor C2, that is, the first voltage output by the first charging and discharging unit 101 is similar to the second voltage output by the second charging and discharging unit 102, so that the voltage of the emitter of the first transistor Q1 is similar to the voltage of the base, and the first transistor Q1 is turned off. Since the collector of the first transistor Q1 is grounded, the collector of the first transistor Q1 outputs a low signal, so that the second transistor Q2 is also turned off. The control terminal of the power amplifier 200 is not pulled down by the POP tone processing circuit. The control terminal of the power amplifier 200 is supplied with a pull-up voltage through the pull-up unit 600 so that the power amplifier 200 drives the speaker 400 to operate.

As shown in fig. 3, an embodiment of the present application further provides a playing device 10, which includes a power amplifier 200, a speaker 400, a first power supply 300, a second power supply 500, and the POP sound processing circuit 100, where the POP sound processing circuit 100 is electrically connected to the first power supply 300 and the control terminal of the power amplifier 200, the power terminal of the power amplifier 200 is electrically connected to the second power supply 500, and the output terminal of the power amplifier 200 is electrically connected to the speaker 400.

Specifically, during the boot process, the POP sound processing circuit 100 outputs the second logic signal. The power amplifier 200 is started up according to the second logic signal delay, and the power amplifier 200 does not drive the speaker 400 to operate, so as to eliminate the POP sound generated by the playing apparatus 10 during the power-on process.

During the shutdown process, the POP sound processing circuit 100 outputs a second logic signal. The power amplifier 200 is turned off in advance according to the second logic signal, and the power amplifier 200 does not drive the speaker 400 to operate, so as to eliminate the POP sound generated by the playing apparatus 10 during the shutdown process.

In the embodiment of the present application, the first power supply 300 and the second power supply 500 may be the same power supply or may be two different power supplies.

As shown in fig. 3, the playing apparatus 10 further includes a pull-up unit 600, and the pull-up unit 600 is electrically connected to the control terminal of the power amplifier 200.

Specifically, during normal power-on, the POP sound processing circuit 100 does not operate, and the pull-up unit 600 provides a pull-up voltage to the control terminal of the power amplifier 200, so that the power amplifier 200 drives the speaker 400 to operate, thereby enabling the playback device 10 to operate normally.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (10)

1. A POP sound processing circuit is applied to a playing device and is characterized by comprising a first charging and discharging unit, a second charging and discharging unit, a first logic unit and a second logic unit;

the first logic unit is electrically connected with the first charge and discharge unit, the second charge and discharge unit and the second logic unit respectively, the second logic unit is used for being electrically connected with a control end of a power amplifier, the first charge and discharge unit and the second charge and discharge unit are both used for being electrically connected with a first power supply, and a power supply end of the power amplifier is electrically connected with a second power supply;

the first charging and discharging unit is used for outputting a first voltage, and the second charging and discharging unit is used for outputting a second voltage; in the process of starting up or shutting down, the first logic unit is used for outputting a first logic signal according to the first voltage and the second voltage; the second logic unit is used for outputting a second logic signal according to the first logic signal; and the power amplifier is used for delaying starting according to the second logic signal in the starting process, and is used for closing in advance according to the second logic signal in the shutdown process so as to eliminate POP sound generated by the playing device in the starting process or the shutdown process.

2. The POP sound processing circuit of claim 1, wherein the first charge and discharge unit comprises a first diode and a first capacitor;

the cathode of the first diode is electrically connected with the first end of the first capacitor and the first logic unit respectively, the second end of the first capacitor is grounded, and the anode of the first diode is used for being electrically connected with the first power supply.

3. The POP sound processing circuit of claim 2, wherein the second charge and discharge unit comprises a first resistor, a second capacitor and a second diode;

the first end of the first resistor is electrically connected with the cathode of the second diode and the anode of the first diode respectively, the second end of the first resistor is electrically connected with the anode of the second diode, the first end of the second capacitor and the first logic unit respectively, and the second end of the second capacitor is grounded.

4. The POP tone processing circuit of claim 3, wherein the first logic unit comprises a first transistor and a second resistor;

the emitter of the first triode is electrically connected with the cathode of the first diode, the base of the first triode is electrically connected with the second end of the first resistor, the collector of the first triode is electrically connected with the first end of the second resistor and the second logic unit respectively, and the second end of the second resistor is grounded.

5. The POP sound processing circuit of claim 4, wherein the first transistor is a PNP type transistor.

6. The POP tone processing circuit of claim 4, wherein the second logic unit includes a second transistor and a fourth resistor;

the base electrode of the second triode is electrically connected with the collector electrode of the first triode, the emitter electrode of the second triode is grounded, the collector electrode of the second triode is electrically connected with the first end of the fourth resistor, and the second end of the fourth resistor is used for being electrically connected with the control end of the power amplifier.

7. The POP sound processing circuit of claim 6, wherein the second logic unit further includes a third resistor;

the third resistor is connected in series between the collector of the first triode and the base of the second triode.

8. The POP sound processing circuit of claim 6, wherein the second transistor is an NPN transistor.

9. A playback apparatus, comprising a power amplifier, a speaker, a first power supply, a second power supply, and the POP sound processing circuit of any one of claims 1 to 8;

the POP sound processing circuit is respectively and electrically connected with the first power supply and the control end of the power amplifier, the power end of the power amplifier is electrically connected with the second power supply, and the output end of the power amplifier is electrically connected with the loudspeaker;

the POP sound processing circuit is used for outputting a second logic signal in the starting process or the shutdown process; and the power amplifier is used for delaying starting according to the second logic signal in the starting process, and is used for closing in advance according to the second logic signal in the shutdown process so as to eliminate POP sound generated by the playing device in the starting process or the shutdown process.

10. The playback apparatus according to claim 9, further comprising a pull-up unit, wherein the pull-up unit is electrically connected to the control terminal of the power amplifier;

when the playing device is normally powered on, the pull-up unit is configured to provide a pull-up voltage to the control terminal of the power amplifier, so that the power amplifier drives the speaker to operate.

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