CN210840030U - Active noise reduction earphone and power management circuit thereof - Google Patents

Abstract

The utility model relates to an earphone of making an uproar falls in initiative and power management circuit thereof. A power management circuit is applied to an active noise reduction earphone with a noise reduction circuit and comprises a detection circuit, a control circuit and a switch circuit. When the power management circuit works, the detection circuit can acquire an audio detection signal and generate a first signal to be transmitted to the control circuit. The control circuit can output a second electric signal according to the first signal, and is used for controlling the on-off of the switch circuit, so that the power supply on-off of the noise reduction circuit is controlled. The power management circuit can control whether the power supply of the noise reduction circuit is controlled according to whether the detection circuit acquires the audio detection signal or not, so that when the active noise reduction earphone does not work, the power supply of the noise reduction circuit is automatically cut off, and the electric energy waste is reduced.

Description

Active noise reduction earphone and power management circuit thereof

Technical Field

The utility model relates to a power management technical field especially relates to the earphone of making an uproar and power management circuit fall in the initiative.

Background

The active noise reduction earphone is an earphone which can generate reverse sound waves equal to external noise through a noise reduction circuit in the working process of the earphone, so that the noise is neutralized to achieve the purpose of noise reduction.

In the conventional technology, a noise reduction circuit of an active noise reduction earphone is generally powered by an independent power supply, and the on/off of the noise reduction circuit is manually controlled by setting a noise reduction switch. When a user uses the active noise reduction earphone, the noise reduction switch is controlled to be closed, and the noise reduction circuit is electrified to work; on the contrary, when the user controls the noise reduction switch to be switched off, the noise reduction circuit is powered off and stops working.

The inventor finds out in the process of realizing the conventional technology that: the traditional active noise reduction earphone needs a user to manually cut off the power supply of a noise reduction circuit, and the hidden danger of electric energy waste exists.

SUMMERY OF THE UTILITY MODEL

Therefore, the active noise reduction earphone and the power management circuit thereof are needed to be provided for solving the problems that the active noise reduction earphone in the prior art needs a user to manually cut off the power supply of the noise reduction circuit and the hidden trouble of electric energy waste exists.

A power management circuit is applied to an active noise reduction earphone with a noise reduction circuit and comprises a detection circuit, a control circuit and a switch circuit;

the detection circuit is provided with a detection circuit input end and a detection circuit output end, the detection circuit input end is used for acquiring an audio detection signal, the detection circuit is used for outputting a first signal according to the audio detection signal, and the first signal is output from the detection circuit output end;

a first pin of the control circuit is connected with an output end of the detection circuit, a second pin of the control circuit is connected with a signal input end of the switch circuit, the control circuit is used for generating a second electric signal according to the first signal, and the second electric signal is output from the second pin;

the noise reduction circuit comprises a noise reduction circuit, a switching circuit and a control circuit, wherein the noise reduction circuit comprises a switching circuit input end and a switching circuit output end; the control circuit controls the on-off between the input end of the switch circuit and the output end of the switch circuit through the second electric signal so as to control the electrification of the noise reduction circuit.

The power management circuit is applied to an active noise reduction earphone with a noise reduction circuit and comprises a detection circuit, a control circuit and a switch circuit. When the power management circuit works, the detection circuit can acquire an audio detection signal and generate a first signal to be transmitted to the control circuit. The control circuit can output a second electric signal according to the first signal, and is used for controlling the on-off of the switch circuit, so that the power supply on-off of the noise reduction circuit is controlled. The power management circuit can control whether the power supply of the noise reduction circuit is controlled according to whether the detection circuit acquires the audio detection signal or not, so that when the active noise reduction earphone does not work, the power supply of the noise reduction circuit is automatically cut off, and the electric energy waste is reduced.

Drawings

Fig. 1 is a schematic block diagram of a power management circuit according to an embodiment of the present application.

Fig. 2 is a schematic circuit diagram of a power management circuit according to an embodiment of the present application.

Fig. 3 is a schematic block diagram of a power management circuit according to another embodiment of the present disclosure.

Fig. 4 is a schematic circuit diagram of a power management circuit according to another embodiment of the present application.

Wherein, the meanings represented by the reference numerals of the figures are respectively as follows:

10. a power management circuit;

110. a detection circuit;

112. an input terminal of the detection circuit;

114. an output end of the detection circuit;

c1, a first capacitance;

r1, a first resistor;

120. a control circuit;

122. a first pin;

124. a second pin;

126. a third pin;

121. a fourth pin;

123. a fifth pin;

130. a switching circuit;

132. a signal input terminal;

134. a switching circuit input;

136. a switching circuit output terminal;

q1, the first triode;

q2, the second triode;

r2, a second resistor;

r3, third resistor;

r4, fourth resistor;

k1, mechanical switch;

140. a wake-up circuit;

142. a wake-up circuit input;

144. a wake-up circuit output;

146. a wake-up signal output terminal;

c2, a second capacitor;

r5, fifth resistor;

VDD, power supply;

GND and ground wire;

21. a noise reduction circuit;

22. an audio circuit.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

Active noise reduction headsets are typically provided with noise reduction circuitry. The noise reduction circuit comprises a signal microphone, a controller and a loudspeaker which are arranged in the earphone. Wherein, the signal microphone is used for detecting low-frequency noise in the environment that human ears can hear. Low frequency noise herein generally refers to noise having a frequency of 100Hz to 1000 Hz. After the signal microphone detects the low-frequency noise, the low-frequency noise is converted into an electric signal and transmitted to the controller. The controller carries out real-time operation on the low-frequency noise and obtains sound waves with the same amplitude and opposite phases with the low-frequency noise. The sound wave with the same amplitude and the opposite phase with the low-frequency noise is played through a High-Fidelity (High-Fi) loudspeaker, so that the low-frequency noise can be counteracted, and the purpose of reducing the noise is achieved.

In the conventional technology, when a noise reduction circuit of an active noise reduction earphone works, an independent power supply is usually required to supply power to the noise reduction circuit, and an independent noise reduction switch is arranged to control whether the noise reduction circuit is powered on or not. When a user uses the noise reduction earphone, the noise reduction switch can be manually controlled to be closed, so that the noise reduction circuit is powered on; likewise, the de-energizing of the noise reduction circuit also requires the user to manually turn off the noise reduction switch. The inventor finds that after the user uses the noise reduction earphone, the user often forgets to turn off the noise reduction switch in the process of realizing the traditional technology.

Based on this, the application provides a power management circuit for carrying out power supply management to the noise reduction circuit of the active noise reduction earphone.

A power management circuit 10, as shown in FIG. 1, for an active noise reduction earphone with a noise reduction circuit 21 includes a detection circuit 110, a control circuit 120, and a switch circuit 130.

Specifically, the detection circuit 110 is configured to detect an audio signal generated when the active noise reduction earphone works, to obtain an audio detection signal, and to obtain a signal according to the audio signal. The detection circuit 110 has a detection circuit input 112 and a detection circuit output 114. The detection circuit input 112 is used to obtain an audio detection signal. The detection circuit 110 is configured to generate a first signal according to the audio detection signal. The first of the first signals is used only to distinguish it from other electrical signals and has no other meaning. Generally, the amplitude of the first signal may be higher than a preset signal amplitude threshold and equal to or lower than the preset signal amplitude threshold, where the preset signal amplitude threshold is an amplitude threshold for distinguishing whether the audio detection signal is acquired. When the audio detection signal is not acquired by the detection circuit input end 112, the amplitude of the first signal is equal to or lower than a preset signal amplitude threshold; when the audio detection signal is acquired by the detection circuit input terminal 112, the value of the first signal is higher than a preset signal amplitude threshold value. The detection circuit output 114 is configured to be coupled to the control circuit 120 to transmit the first signal to the control circuit 120.

The control circuit 120 is configured to generate a second electrical signal according to the first signal, and control the on/off of the switch circuit 130 through the second electrical signal. The control circuit 120 may have a first pin 122 and a second pin 124. Wherein the first pin 122 is configured to be connected to the detection circuit output 114, so as to obtain the first signal. The control circuit 120 is configured to generate a second electrical signal according to the first signal, and the second electrical signal is output from the second pin 124. Generally, the second electrical signal may be a high level signal or a low level signal. When the amplitude of the first signal is equal to or lower than a preset signal amplitude threshold, the second electrical signal may be a low-level signal; correspondingly, when the amplitude of the first signal is higher than a preset signal amplitude threshold value, the second electrical signal may be a high-level signal.

The switch circuit 130 is connected between the noise reduction circuit 21 and the power supply VDD, and is used for controlling whether the noise reduction circuit 21 is powered on or not. The switching circuit 130 may have a signal input 132, a switching circuit input 134, and a switching circuit output 136. Wherein the signal input terminal 132 is configured to be connected to the second pin 124 of the control circuit 120, so as to obtain the second electrical signal. The second electrical signal may control the on/off of the circuit between the switch circuit input 134 and the switch circuit output 136. The switch circuit input end 134 is used for being connected with the power supply VDD to obtain electric energy of the power supply VDD; the switching circuit output 136 is used for connecting with the noise reduction circuit 21. The noise reduction circuit 21 is connected between the switching circuit output terminal 136 and the ground GND.

More specifically, when the power management circuit 10 of the present application is in operation, the detection circuit 110 may be configured to obtain whether the active noise reduction earphone generates an audio signal, that is, detect whether the active noise reduction earphone operates. If the active noise reduction earphone works, the detection circuit 110 obtains an audio detection signal, generates a first signal according to the audio detection signal, and transmits the first signal to the control circuit 120, where the amplitude of the first signal is higher than a preset signal amplitude threshold. After acquiring the first signal, the control circuit 120 outputs a second electrical signal with a high level according to the first signal. The second electrical signal is output from the second pin 124 of the control circuit 120 and input to the signal input 132 of the switch circuit 130. The second electrical signal controls whether the switch circuit input 134 and the switch circuit output 136 are connected or not.

For example, when the control circuit 120 acquires the first signal and the amplitude of the first signal is higher than a preset signal amplitude threshold, the second electrical signal output by the control circuit 120 is a high-level second electrical signal, so as to control conduction between the switch circuit input end 134 and the switch circuit output end 136. When the control circuit 120 obtains the first signal and the amplitude of the first signal is equal to or lower than a preset signal amplitude threshold, the second level signal output by the control circuit 120 is a low level signal, so as to control the switch circuit input end 134 and the switch circuit output end 136 to be disconnected. When the switch circuit input end 134 and the switch circuit output end 136 are conducted, the noise reduction circuit 21 is powered on to work; on the contrary, when the switch circuit input end 134 and the switch circuit output end 136 are disconnected, the noise reduction circuit 21 is powered off and stops working. Therefore, in the power management circuit 10 of the present application, the control circuit 120 can control whether the noise reduction circuit 21 is powered on to work according to whether the active noise reduction earphone has an audio signal generated, so that when the active noise reduction earphone does not work, the power supply of the noise reduction circuit 21 is automatically cut off, and the electric energy waste is reduced.

In one embodiment, as shown in fig. 2, the detection circuit 110 of the power management circuit 10 includes a first capacitor C1 and a first resistor R1.

Specifically, the first capacitor C1 has a first plate and a second plate disposed opposite to each other. The first polar plate is used for acquiring the audio detection signal. In this case, the first plate constitutes a detection circuit input terminal 112 of the detection circuit 110. The second plate is connected to the first pin 122.

The first resistor R1 is connected between the second plate and the ground GND. In other words, one end of the first resistor R1 is connected to the second plate, and the other end of the first resistor R1 is connected to the ground GND.

More specifically, the first capacitor C1 is an isolation capacitor to isolate the circuits on both sides of the first and second plates. When the detection circuit 110 obtains an audio detection signal, the amount of charge on the first plate and the second plate changes, so that the voltage across the first resistor R1 changes, that is, a first signal with an amplitude equal to or lower than a preset signal amplitude threshold is generated. At this time, the control circuit 120 may output a second electrical signal with a high level according to the first signal, thereby controlling the switch circuit 130 to be closed. On the contrary, when the detection circuit 110 does not obtain the detection signal, the amount of charge on the first substrate and the second substrate does not change, the voltage across the first resistor R1 does not change, that is, the signal amplitude of the first signal is equal to the preset signal amplitude threshold. At this time, the control circuit may output a second electrical signal of a low level according to the first signal.

Further, the active noise reduction earphone may have an audio circuit 22, and the audio circuit 22 is a connection circuit between the controller of the active noise reduction earphone and the player. When the audio circuit 22 has an audio signal therein, the active noise reduction earphone is operated to play audio.

At this time, the detection circuit input terminal 112 is connected to the audio circuit 22 for obtaining an audio detection signal. That is, when the detection circuit 110 includes the first capacitor C1 and the first resistor R1, the first plate of the first capacitor C1 is connected to the audio circuit 22 for obtaining the audio detection signal.

In one embodiment, the control circuit 120 may be a controller. When the controller obtains the first signal, the controller outputs a high second level signal from the second pin 124 for a continuous period of time, and controls the switch circuit 130 to close. After the duration is over, the second pin 124 no longer outputs a high signal until the first signal is detected next time.

The control circuit 120 may also be a comparison circuit to compare the value of the first signal with a fixed value when the control circuit 120 obtains the first signal. When the value of the first signal is higher than the fixed value, the control circuit 120 outputs a second electric signal of a high level; on the contrary, when the value of the first electrical signal is less than or equal to the fixed value, the control circuit 120 outputs the second electrical signal of low level. Wherein the fixed value is an amplitude threshold value for distinguishing whether the audio detection signal is acquired.

For example, the fixed value may be 0, and when the control circuit 120 acquires the first signal, the value of the first signal is compared with 0. If the signal value of the first signal is higher than 0, the control circuit 120 outputs a second electrical signal of a high level. On the contrary, when the value of the first signal is 0, the control circuit 120 outputs a second electrical signal of a low level. The comparison circuit may be implemented by an operational amplifier. When the first signal is an electrical signal, the fixed value may be a fixed level signal.

In one embodiment, as shown in fig. 2, the switching circuit 130 of the power management circuit 10 of the present application includes a first transistor Q1 and a second transistor Q2.

Specifically, the base of the first transistor Q1 is connected to the second pin 124, so that the second electrical signal can be obtained. At this time, the base of the first transistor Q1 is the signal input terminal 132 of the switch circuit 130. The emitter of the first triode Q1 is connected to the ground GND.

The base of the second transistor Q2 is connected to the collector of the first transistor Q1. The emitter of the second transistor Q2 is connected to the power supply VDD, so that the power of the power supply VDD can be obtained. At this time, the emitter of the second transistor Q2 is the switching circuit input end 134 of the switching circuit 130. The collector of the second transistor Q2 is connected to the noise reduction circuit 21 such that the noise reduction circuit 21 is connected between the collector of the second transistor Q2 and the ground GND to supply power to the noise reduction circuit 21. The collector of the second transistor Q2 is the switching circuit output 136 of the switching circuit 130.

More specifically, the first transistor Q1 may be a high-conduction NPN transistor, and the second transistor Q2 may be a low-conduction PNP transistor. When the power management circuit 10 is operated and the second pin 124 outputs a high level, the base of the first transistor Q1 inputs a high level signal, and the first transistor Q1 is turned on. At this time, the base of the second transistor Q2 is connected to the ground GND, the second transistor Q2 is turned on at a low level, and the switching circuit input end 134 and the switching circuit output end 136 of the switching circuit 130 are turned on.

Further, the switch circuit 130 further includes a second resistor R2, a third resistor R3, and a fourth resistor R4.

Specifically, the second resistor R2 is a pull-up resistor at the base of the first transistor Q1. The second resistor R2 is connected between the base of the first transistor Q1 and the second pin 124. In other words, one end of the second resistor R2 is connected to the base of the first transistor Q1, and the other end of the second resistor R2 is connected to the second pin 124.

The third resistor R3 is connected between the base of the second transistor Q2 and the collector of the first transistor Q1. In other words, one end of the third resistor R3 is connected to the base of the second transistor Q2, and the other end of the third resistor R3 is connected to the collector of the first transistor Q1.

The fourth resistor R4 is connected between the base of the second transistor Q2 and the emitter of the second transistor Q2. In other words, one end of the fourth resistor R4 is connected to the base of the second transistor Q2, and the other end of the fourth resistor R4 is connected to the emitter of the second transistor Q2.

In one embodiment, as shown in FIG. 3, the power management circuit 10 further includes a mechanical switch K1.

Specifically, the mechanical switch K1 is a manual switch. The mechanical switch K1 is connected between the power supply VDD and the input end 134 of the switch circuit, and is used for controlling the on/off of the circuit between the power supply VDD and the input end 134 of the switch circuit. When the mechanical switch K1 is closed, the power within the power supply VDD can reach the switch circuit input 134 through the mechanical switch K1, thereby powering the noise reduction circuit 21 when the switch circuit 130 is closed. When the mechanical switch K1 is turned off, the power supply VDD cannot supply power to the noise reduction circuit 21.

In one embodiment, when the power management circuit 10 includes the mechanical switch K1, as shown in fig. 3, the power management circuit 10 may further include a wake-up circuit 140.

Specifically, the wake-up circuit 140 is configured to wake up the control circuit 120, and enable the control circuit 120 to control the switch circuit 130 to be turned on and off. The wake-up circuit 140 may have a wake-up circuit input 142, a wake-up circuit output 144, and a wake-up signal output 146. The wake-up circuit input 142 is connected to the switch circuit input 134, and the wake-up circuit output 144 is connected to the ground GND, so that when the mechanical switch K1 is closed, an electrical signal is formed in the wake-up circuit 140. The wake-up signal output terminal 146 is connected to the third pin 126 of the control circuit 120, and is configured to output a wake-up signal to the control circuit 120.

When the mechanical switch K1 is closed, the power supply VDD to the ground GND forms a loop through the mechanical switch K1 and the wake-up circuit 140. At this time, the wake-up circuit 140 has an electrical signal therein. The electrical signal may be used to wake up the control circuit 120 to cause the control circuit 120 to react in accordance with the electrical signal. Therefore, this electrical signal is named wake-up signal in this application. When the control circuit 120 obtains the wake-up signal, a second electrical signal is output from the second pin 124 according to the wake-up signal, so as to control the switch circuit 130 to be turned on and off.

The power management circuit 10 in this embodiment can control the switch circuit 130 to be turned on even if the control circuit 120 outputs the second electrical signal when the mechanical switch K1 is turned on, so as to energize the noise reduction circuit 21. Therefore, the power management circuit 10 can perform noise reduction processing when the mechanical switch K1 is closed, so that the noise reduction module works in advance, and the user experience effect is improved.

In this embodiment, the control circuit 120 may also be a controller. When the controller acquires the wake-up signal, the controller continuously outputs a second high-level electric signal within a time period; after the time period is over, the control circuit 120 outputs the second electrical signal according to whether the detection circuit 110 obtains the audio detection signal.

Further, as shown in fig. 4, the wake-up circuit 140 may include a second capacitor C2 and a fifth resistor R5.

Specifically, the second capacitor C2 has a third plate and a fourth plate disposed opposite to each other. The third plate is connected to the switching circuit input 134. At this time, the third plate is the input end 142 of the wake-up circuit 140. The fourth plate is connected to the third pin 126, and is configured to output a wake-up signal to the control circuit 120. At this time, the fourth plate is the wake-up signal output end 146.

The fifth resistor R5 is connected between the fourth plate and the ground GND. In other words, one end of the fifth resistor R5 is connected to the fourth plate. The other end of the fifth resistor R5 is connected to the ground GND.

In one embodiment, as shown in fig. 4, the control circuit 120 further has a fourth pin 121 and a fifth pin 123. The fourth pin 121 is used for connecting with the power supply VDD; the fifth pin 123 is used for connecting with the ground GND. The fourth pin 121 and the fifth pin 123 are used for supplying power to the control circuit 120, so that the control circuit 120 is powered on to operate.

The operation of the power management circuit 10 of the present application is explained below with reference to fig. 4 from a specific embodiment.

When a user uses the active noise reduction earphone with the power management circuit 10 of the present application, the mechanical switch K1 may be manually turned off first. At this time, a loop from the power supply VDD through the mechanical switch K1, the second capacitor C2, and the fifth resistor R5 to the ground GND is formed. The electrical signal in the loop may be transmitted to the control circuit 120 through the third pin 126 of the control circuit 120 as a wake-up signal. After acquiring the wake-up signal, the control circuit 120 outputs a second electrical signal with a high level from the second pin 124 for three minutes.

At this time, when the second pin 124 of the control circuit 120 outputs a high signal, the base of the first transistor Q1 is at a high level. The first transistor Q1 is turned on high. When the first triode Q1 is turned on, the base of the second triode Q2 is turned on with the ground GND, and at this time, the level of the base of the second triode Q2 is the same as the ground GND, that is, the base of the second triode Q2 is at a low level, and the second triode Q2 is turned on.

When the second transistor Q2 is turned on and the mechanical switch K1 is closed, a loop is formed from the power supply VDD through the mechanical switch K1, the emitter of the second transistor Q2, the collector of the second transistor Q2 and the noise reduction circuit 21 to the ground GND. At this time, the noise reduction circuit 21 is energized.

In the process, before the user wears the active noise reduction earphone, the mechanical switch K1 can be closed, so that the noise reduction circuit 21 works in advance, and the user experience effect is improved.

After the three minutes, the control circuit 120 controls the on/off of the switch circuit 130 according to the audio detection signal obtained by the detection circuit 110. The method specifically comprises the following steps: after the three minutes, if the current passes through the audio circuit 22, the two plates of the capacitor C1 have charges, and the detection circuit 110 can output a first signal to the control circuit 120, where the amplitude of the first signal is higher than a preset signal amplitude threshold. At this time, after the control circuit 120 acquires the first signal through the first pin 122, the second pin 124 outputs a high-level second electrical signal for three minutes, so that the switch circuit 130 is closed, and the noise reduction circuit 21 is powered on.

After the three minutes of advanced operation of the noise reduction circuit 21, if no current passes through the audio circuit 22, there is no charge on the two plates of the capacitor C1, and the detection circuit 110 outputs a first signal with a signal value equal to a preset signal amplitude threshold value to the control circuit 120. At this time, after the control circuit 120 obtains the first signal through the first pin 122, the second pin 124 outputs a low-level second electrical signal to turn off the switch circuit 130, so that the noise reduction circuit 21 is powered off and does not operate.

The present application also provides an active noise reduction earphone comprising a noise reduction circuit 21, an audio circuit 22 and a power management circuit 10 as described in any of the above embodiments.

Specifically, the power management circuit 10 includes a detection circuit 110, a control circuit 120, and a switch circuit 130.

The detection circuit 110 has a detection circuit input 112 and a detection circuit output 114, and the detection circuit input 112 is connected to the audio circuit 22 for obtaining an audio detection signal. The detection circuit 110 is configured to output a first signal according to the audio detection signal, and the first signal is output from the detection circuit output terminal 114.

The first pin 122 of the control circuit 120 is connected to the detection circuit output 114. The second pin 124 of the control circuit 120 is connected to the signal input 132 of the switching circuit 130. The control circuit 120 is configured to generate a second electrical signal according to the first signal, and the second electrical signal is output from the second pin 124.

The switching circuit 130 further comprises a switching circuit input 134 and a switching circuit output 136. The switch circuit input end 134 is connected to a power supply VDD, and the noise reduction circuit 21 is connected between the switch circuit output end 136 and the ground GND. The control circuit 120 controls the on/off between the input end 134 and the output end 136 of the switch circuit through the second electrical signal, so as to control the energization of the noise reduction circuit 21.

The active noise reduction earphone can control whether the noise reduction circuit 21 is powered or not according to whether the audio circuit 22 has good audio information, so that when the active noise reduction earphone does not work, the power supply of the noise reduction circuit 21 is automatically cut off, and the electric energy waste is reduced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. A power management circuit applied to an active noise reduction earphone with a noise reduction circuit (21) is characterized by comprising a detection circuit (110), a control circuit (120) and a switch circuit (130);

the detection circuit (110) is provided with a detection circuit input end (112) and a detection circuit output end (114), the detection circuit input end (112) is used for obtaining an audio detection signal, the detection circuit (110) is used for outputting a first signal according to the audio detection signal, and the first signal is output from the detection circuit output end (114);

a first pin (122) of the control circuit (120) is connected with the detection circuit output end (114), a second pin (124) of the control circuit (120) is connected with a signal input end (132) of the switch circuit (130), the control circuit (120) is used for generating a second electric signal according to the first signal, and the second electric signal is output from the second pin (124);

the switch circuit (130) comprises a switch circuit input end (134) and a switch circuit output end (136), the switch circuit input end (134) is connected with a power supply (VDD), and the noise reduction circuit (21) is connected between the switch circuit output end (136) and a ground wire (GND); the control circuit (120) controls the on-off between the input end (134) of the switch circuit and the output end (136) of the switch circuit through the second electric signal so as to control the electrification or nonexistence of the noise reduction circuit (21).

2. The power management circuit of claim 1, wherein the detection circuit (110) comprises:

a first capacitor (C1), a first plate of the first capacitor (C1) is used for acquiring the audio detection signal, and a second plate of the first capacitor (C1) is connected with the first pin (122);

and the first resistor (R1) is connected between the second plate of the first capacitor (C1) and the Ground (GND).

3. The power management circuit according to claim 1 or 2, wherein the active noise reduction earphone comprises an audio circuit (22), and wherein the detection circuit input (112) is connected to the audio circuit (22) for obtaining the audio detection signal.

4. The power management circuit of claim 1, wherein the switching circuit (130) comprises:

a first transistor (Q1), wherein the base of the first transistor (Q1) is connected with the second pin (124), and the emitter of the first transistor (Q1) is connected with the Ground (GND);

a second transistor (Q2), wherein the base of the second transistor (Q2) is connected with the collector of the first transistor (Q1), the emitter of the second transistor (Q2) is connected with the power supply (VDD), and the noise reduction circuit (21) is connected between the collector of the second transistor (Q2) and the Ground (GND).

5. The power management circuit of claim 4, wherein the switching circuit (130) further comprises:

a second resistor (R2) connected between the base of the first transistor (Q1) and the second pin (124);

a third resistor (R3) connected between the base of the second transistor (Q2) and the collector of the first transistor (Q1);

a fourth resistor (R4) connected between the base of the second transistor (Q2) and the emitter of the second transistor (Q2).

6. The power management circuit of claim 1, further comprising:

and the mechanical switch (K1) is connected between the power supply (VDD) and the switch circuit input end (134) to control the on-off of the circuit between the power supply (VDD) and the switch circuit (130).

7. The power management circuit of claim 6, further comprising:

a wake-up circuit (140) having a wake-up circuit input (142), a wake-up circuit output (144), and a wake-up signal output (146); the wake-up circuit input end (142) is connected with the switch circuit input end (134), the wake-up circuit output end (144) is connected with the Ground (GND), and the wake-up signal output end (146) is connected with a third pin (126) of the control circuit (120); the wake-up circuit (140) is configured to output a wake-up signal from the wake-up signal output (146) when the mechanical switch (K1) is closed, and the control circuit (120) controls the switch circuit (130) to be closed according to the wake-up signal.

8. The power management circuit of claim 7, wherein the wake-up circuit (140) comprises:

a second capacitor (C2), a third plate of the second capacitor (C2) being connected to the switch circuit input (134), a fourth plate of the second capacitor (C2) being connected to the third pin (126);

and a fifth resistor (R5) connected between the fourth plate and the Ground (GND).

9. The power management circuit according to claim 1, wherein the control circuit (120) further has a fourth pin (121) and a fifth pin (123), the fourth pin (121) being connected to the power supply (VDD), the fifth pin (123) being connected to the Ground (GND).

10. An active noise reducing headphone, characterized by comprising a power management circuit (10) according to any one of claims 1 to 9.

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