CN217720703U

CN217720703U - Charging protection circuit and earphone charging bin

Info

Publication number: CN217720703U
Application number: CN202221159394.1U
Authority: CN
Inventors: 朱伟; 王丽
Original assignee: Shenzhen Horn Audio Co Ltd
Current assignee: Shenzhen Horn Audio Co Ltd
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2022-11-01
Anticipated expiration: 2032-05-13

Abstract

The application provides a protection circuit and earphone storehouse of charging. The charging protection circuit comprises a first protection circuit, a second protection circuit and a third protection circuit; the first protection circuit comprises a first electronic switching tube, a first resistor and a second resistor, and the first resistor is connected with the control end of the first electronic switching tube; the second protection circuit comprises a second electronic switching tube, a third resistor and a fourth resistor, wherein the third resistor is respectively connected with the control end of the second electronic switching tube and the first end of the first electronic switching tube; the third protection circuit comprises a third electronic switching tube and a fifth resistor, and the fifth resistor is respectively connected with the first end of the second electronic switching tube and the control end of the third electronic switching tube. Under the undervoltage, first electronic switch pipe, second electronic switch pipe and third electronic switch pipe all cut off, and under overpressure, first electronic switch pipe switches on, and second electronic switch pipe and third electronic switch pipe all cut off, have the function of excessive pressure and undervoltage protection concurrently.

Description

Charging protection circuit and earphone charging bin

Technical Field

The utility model relates to an earphone technical field especially relates to a charging protection circuit and earphone storehouse of charging.

Background

Currently, a TWS (True-Wireless-Stereo) headset is a new Wireless headset variety, and has become a mainstream in the development of Wireless headsets. The TWS headset is charged through the charging box, and in the charging process, protection of the charging voltage is generally realized by using a dedicated overvoltage protection chip or a charging management chip.

However, the conventional overvoltage protection chip or the charging management chip can only perform overvoltage protection, and cannot protect the undervoltage charging, which easily results in insufficient charging protection.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the weak point among the prior art, provide a have simultaneously excessive pressure and undervoltage protection's charging protection circuit and earphone charging bin concurrently.

The purpose of the utility model is realized through the following technical scheme:

a charge protection circuit, comprising: the protection circuit comprises a first protection circuit, a second protection circuit and a third protection circuit; the first protection circuit comprises a first electronic switching tube, a first resistor and a second resistor, wherein the first end of the first resistor is used for being connected with a power supply, the second end of the first resistor is grounded through the second resistor, the second end of the first resistor is also connected with the control end of the first electronic switching tube, and the second end of the first electronic switching tube is grounded; the second protection circuit comprises a second electronic switching tube, a third resistor and a fourth resistor, wherein the first end of the third resistor is connected with the first end of the first resistor, the second end of the third resistor is grounded through the fourth resistor, the second end of the third resistor is also respectively connected with the control end of the second electronic switching tube and the first end of the first electronic switching tube, and the second end of the second electronic switching tube is grounded; the third protection circuit comprises a third electronic switching tube and a fifth resistor, the first end of the fifth resistor is connected with the first end of the first resistor, the first end of the fifth resistor is further connected with the first end of the third electronic switching tube, the second end of the fifth resistor is respectively connected with the first end of the second electronic switching tube and the control end of the third electronic switching tube, and the second end of the third electronic switching tube is used for being connected with a battery to be charged.

In one embodiment, the first resistor has a resistance of 10K Ω to 100K Ω.

In one embodiment, the first resistor has a resistance of 22K Ω.

In one embodiment, the third resistor has a resistance of 22K Ω to 1M Ω.

In one embodiment, the third resistor has a resistance of 100K Ω.

In one embodiment, the first protection circuit further includes a first capacitor, a second end of the first resistor is connected to a first end of the first capacitor, and a second end of the first capacitor is grounded.

In one embodiment, the second protection circuit further includes a second capacitor, a second terminal of the third resistor is connected to a first terminal of the second capacitor, and a second terminal of the second capacitor is grounded.

In one embodiment, the third protection circuit further includes a third capacitor, a second terminal of the fifth resistor is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is grounded.

In one embodiment, a resistance ratio of the third resistor to the fourth resistor is smaller than a resistance ratio of the first resistor to the second resistor.

An earphone charging chamber comprises the charging protection circuit in any one of the above embodiments.

Compared with the prior art, the utility model discloses at least, following advantage has:

under the undervoltage, first electronic switch pipe, second electronic switch pipe and third electronic switch pipe all cut off for power supply with treat the rechargeable battery disconnection, and under the excessive pressure, first electronic switch pipe switches on, make second electronic switch pipe and third electronic switch pipe all cut off, thereby make power supply with treat that the rechargeable battery keeps the disconnection equally, and then make the protection circuit that charges have the function of excessive pressure and undervoltage protection simultaneously concurrently.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a circuit diagram of a charge protection circuit according to an embodiment.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The utility model relates to a charging protection circuit. In one embodiment, the charging protection circuit comprises a first protection circuit, a second protection circuit and a third protection circuit. The first protection circuit comprises a first electronic switching tube, a first resistor and a second resistor. The first end of the first resistor is used for being connected with a power supply, the second end of the first resistor is grounded through the second resistor, and the second end of the first resistor is further connected with the control end of the first electronic switch tube. The second end of the first electronic switch tube is grounded. The second protection circuit comprises a second electronic switching tube, a third resistor and a fourth resistor. The first end of the third resistor is connected with the first end of the first resistor, the second end of the third resistor is grounded through the fourth resistor, and the second end of the third resistor is further connected with the control end of the second electronic switch tube and the first end of the first electronic switch tube respectively. And the second end of the second electronic switching tube is grounded. The third protection circuit comprises a third electronic switching tube and a fifth resistor. The first end of the fifth resistor is connected with the first end of the first resistor, the first end of the fifth resistor is further connected with the first end of the third electronic switch tube, and the second end of the fifth resistor is respectively connected with the first end of the second electronic switch tube and the control end of the third electronic switch tube. And the second end of the third electronic switching tube is used for being connected with a battery to be charged. When undervoltage, the first electronic switch tube, the second electronic switch tube and the third electronic switch tube are all cut off, so that the power supply and the rechargeable battery are disconnected, and when the overvoltage occurs, the first electronic switch tube is switched on, so that the second electronic switch tube and the third electronic switch tube are all cut off, so that the power supply and the rechargeable battery are kept disconnected as well, and the charging protection circuit has functions of overvoltage protection and undervoltage protection.

Please refer to fig. 1, which is a circuit diagram of a charging protection circuit according to an embodiment of the present invention.

The charging protection circuit 10 of an embodiment includes a first protection circuit 100, a second protection circuit 200, and a third protection circuit 300. The first protection circuit 100 includes a first electronic switch Q1, a first resistor R1, and a second resistor R2. First resistance R1's first end is used for being connected with power supply TYPE-C-IN, first resistance R1's second end passes through second resistance R2 ground connection, first resistance R1's second end still with first electronic switch Q1's control end is connected. The second end of the first electronic switch tube Q1 is grounded. The second protection circuit 200 includes a second electronic switch Q2, a third resistor R3, and a fourth resistor R4. The first end of the third resistor R3 is connected with the first end of the first resistor R1, the second end of the third resistor R3 is grounded through the fourth resistor R4, and the second end of the third resistor R3 is also connected with the control end of the second electronic switch tube Q2 and the first end of the first electronic switch tube Q1 respectively. The second end of the second electronic switch tube Q2 is grounded. The third protection circuit 300 includes a third electronic switch Q3 and a fifth resistor R5. The first end of the fifth resistor R5 is connected with the first end of the first resistor R1, the first end of the fifth resistor R5 is further connected with the first end of the third electronic switch tube Q3, and the second end of the fifth resistor R5 is respectively connected with the first end of the second electronic switch tube Q2 and the control end of the third electronic switch tube Q3. And the second end of the third electronic switching tube Q3 is used for connecting with a battery to be charged.

IN this embodiment, when undervoltage, first electronic switch tube Q1, second electronic switch tube Q2 and third electronic switch tube Q3 all end, make power supply TYPE-C-IN with wait that the rechargeable battery breaks off, and under excessive pressure, first electronic switch tube Q1 switches on, make second electronic switch tube Q2 and third electronic switch tube Q3 all end, thereby make power supply TYPE-C-IN and wait that the rechargeable battery keeps the disconnection equally, and then make the protection by charging circuit have overvoltage and undervoltage protection's function simultaneously concurrently. The power supply is a power supply input through a TYPE-C port.

In one embodiment, the resistance of the first resistor R1 is 10K Ω to 100K Ω. In this embodiment, the first resistor R1 is a variable resistor, and specifically, the first resistor R1 is a variable resistor with a variable resistance. Because the first resistance R1 with the second resistance R2 establishes ties, first electronic switch pipe Q1's control end with first resistance R1's second end is connected to form one with the bleeder circuit that first electronic switch pipe Q1 corresponds, through the adjustment first resistance R1's resistance, be convenient for change the turn-on voltage on first electronic switch pipe Q1's the control end, thereby be convenient for change first electronic switch pipe Q1 for power supply TYPE-C-IN's turn-on voltage, adjust promptly first electronic switch pipe Q1 is at the turn-on voltage under the output voltage of different power supply TYPE-C-IN, makes first electronic switch pipe Q1's turn-on voltage is variable, promptly through the thyristor of chooseing for use different models, so that the voltage that first electronic switch pipe Q1 switched on under the output voltage of different power supply TYPE-C-IN is different, thereby is applicable to different undervoltage or overvoltage protection. Like this, through the adjustment power supply TYPE-C-IN's that first electronic switch pipe Q1 corresponds when switching on output voltage, the adjustment of being convenient for charge protection circuit is to the voltage variation scope that undervoltage and overvoltage protection correspond, thereby is convenient for adjust charge protection circuit's charging voltage band-pass region, the voltage interval that corresponds between adjustment undervoltage protection and the overvoltage protection promptly. In another embodiment, the resistance of the first resistor R1 is 22K Ω.

In one embodiment, the third resistor R3 has a resistance of 22K Ω to 1M Ω. In this embodiment, the third resistor R3 is a variable resistor, and specifically, the third resistor R3 is a variable resistor with a variable resistance. Because the third resistance R3 with the fourth resistance R4 establishes ties, the control end of second electronic switch tube Q2 with the second end of third resistance R3 is connected, IN order to form one with the bleeder circuit that second electronic switch tube Q2 corresponds, through the adjustment third resistance R3's resistance, be convenient for change the turn-on voltage on second electronic switch tube Q2's the control end, thereby be convenient for change second electronic switch tube Q2 for the turn-on voltage of power supply TYPE-C-IN, adjust promptly the turn-on voltage of second electronic switch tube Q2 under the output voltage of different power supply TYPE-C-IN makes the turn-on voltage of second electronic switch tube Q2 is variable, promptly through choosing for use the thyristor of different models, so that the voltage that second electronic switch tube Q2 switched on under the output voltage of different power supply TYPE-C-IN is different, thereby be applicable to different under-voltage or overvoltage protection. Like this, through the adjustment the output voltage of the power supply TYPE-C-IN that second electronic switch pipe Q2 corresponds when switching on, the adjustment of being convenient for charge protection circuit is to the voltage variation scope that undervoltage and overvoltage protection correspond, thereby is convenient for adjust charge protection circuit's charging voltage band-pass region, the voltage interval that corresponds between adjustment undervoltage protection and the overvoltage protection promptly. In another embodiment, the third resistor R3 has a resistance of 100K Ω.

In one embodiment, referring to fig. 1, the first protection circuit 100 further includes a first capacitor C1, a second end of the first resistor R1 is connected to a first end of the first capacitor C1, and a second end of the first capacitor C1 is grounded. In this embodiment, the first end of the first capacitor C1 is connected to the second end of the first resistor R1, the second end of the first resistor R1 is connected to the control end of the first electronic switch Q1, so that the first capacitor C1 is located at the control end of the first electronic switch Q1, that is, the first end of the first capacitor C1 is connected to the control end of the first electronic switch Q1, the second end of the first capacitor C1 and the second end of the first electronic switch Q1 are both grounded, so that the first capacitor C1 is connected in parallel between the control end and the second end of the first electronic switch Q1. The first capacitor C1 carries out filtering processing on the voltage at the control end of the first electronic switch tube Q1, that is, the first capacitor C1 carries out interference filtering on an electric signal led into the control end of the first electronic switch tube Q1, specifically, the first capacitor C1 filters an interference signal, so that the control end of the first electronic switch tube Q1 receives an accurate and stable direct current signal, correct opening and closing of the first electronic switch tube Q1 are ensured, and normal operation of the first electronic switch tube Q1 is ensured. The first electronic switching tube Q1 is an NPN-type triode, the control end of the first electronic switching tube Q1 is a base electrode of the NPN-type triode, the first end of the first electronic switching tube Q1 is a collector electrode of the NPN-type triode, and the second end of the first electronic switching tube Q1 is an emitter electrode of the NPN-type triode. In another embodiment, the first electronic switching tube Q1 may also be an N-type field effect transistor, the control terminal of the first electronic switching tube Q1 is a gate of the N-type field effect transistor, the first terminal of the first electronic switching tube Q1 is a drain of the N-type field effect transistor, and the second terminal of the first electronic switching tube Q1 is a source of the N-type field effect transistor.

In one embodiment, referring to fig. 1, the second protection circuit 200 further includes a second capacitor C2, a second end of the third resistor R3 is connected to a first end of the second capacitor C2, and a second end of the second capacitor C2 is grounded. In this embodiment, the first end of the second capacitor C2 is connected to the second end of the third resistor R3, the second end of the third resistor R3 is connected to the control end of the second electronic switch Q2, so that the second capacitor C2 is located at the control end of the second electronic switch Q2, that is, the first end of the second capacitor C2 is connected to the control end of the second electronic switch Q2, and the second end of the second capacitor C2 and the second end of the second electronic switch Q2 are both grounded, so that the second capacitor C2 is connected in parallel between the control end and the second end of the second electronic switch Q2. The second capacitor C2 performs filtering processing on the voltage at the control end of the second electronic switch tube Q2, that is, the second capacitor C2 filters an electric signal led into the control end of the second electronic switch tube Q2, specifically, the second capacitor C2 filters an interference signal, so that the control end of the second electronic switch tube Q2 receives an accurate and stable direct current signal, and the second electronic switch tube Q2 is ensured to be correctly opened and closed, thereby ensuring the normal operation of the second electronic switch tube Q2. The second electronic switching tube Q2 is an NPN-type triode, the control end of the second electronic switching tube Q2 is a base electrode of the NPN-type triode, the first end of the second electronic switching tube Q2 is a collector electrode of the NPN-type triode, and the second end of the second electronic switching tube Q2 is an emitter electrode of the NPN-type triode. In another embodiment, the second electronic switching tube Q2 may also be an N-type field effect transistor, the control terminal of the second electronic switching tube Q2 is a gate of the N-type field effect transistor, the first terminal of the second electronic switching tube Q2 is a drain of the N-type field effect transistor, and the second terminal of the second electronic switching tube Q2 is a source of the N-type field effect transistor.

In one embodiment, referring to fig. 1, the third protection circuit 300 further includes a third capacitor C3, a second end of the fifth resistor R5 is connected to a first end of the third capacitor C3, and a second end of the third capacitor C3 is grounded. In this embodiment, the first end of the third capacitor C3 is connected to the second end of the fifth resistor R5, the second end of the fifth resistor R5 is further connected to the control end of the third electronic switch Q3, so that the third capacitor C3 is located at the control end of the third electronic switch Q3, that is, the first end of the third capacitor C3 is connected to the control end of the third electronic switch Q3, and the second end of the third capacitor C3 is grounded, so that the third capacitor C3 can filter the voltage at the control end of the third electronic switch Q3, that is, the third capacitor C3 can filter the electric signal led into the control end of the third electronic switch Q3, specifically, the third capacitor C3 can filter the interference signal, so that the control end of the third electronic switch Q3 can receive an accurate and stable direct current signal, and the third electronic switch Q3 can be enabled to be switched correctly, and the normal operation of the third electronic switch Q3 can be ensured. The third electronic switch tube Q3 is an N-type field effect transistor, the control end of the third electronic switch tube Q3 is a gate electrode of the N-type field effect transistor, the first end of the third electronic switch tube Q3 is a drain electrode of the N-type field effect transistor, and the second end of the third electronic switch tube Q3 is a source electrode of the N-type field effect transistor. In another embodiment, the third electronic switching tube Q3 is an NPN type triode, the control terminal of the third electronic switching tube Q3 is a base of the NPN type triode, the first terminal of the third electronic switching tube Q3 is a collector of the NPN type triode, and the second terminal of the third electronic switching tube Q3 is an emitter of the NPN type triode.

In one embodiment, a resistance ratio of the third resistor R3 to the fourth resistor R4 is smaller than a resistance ratio of the first resistor R1 to the second resistor R2. IN this embodiment, the resistance ratio of the first resistor R1 to the second resistor R2 corresponds to the first electronic switch tube Q1, the resistance ratio of the third resistor R3 to the fourth resistor R4 corresponds to the second electronic switch tube Q2, that is, the resistance ratio of the first resistor R1 to the second resistor R2 determines the voltage of the power supply TYPE-C-IN corresponding to the first electronic switch tube Q1 when the first electronic switch tube Q1 is turned on, and the resistance ratio of the third resistor R3 to the fourth resistor R4 determines the voltage of the power supply TYPE-C-IN corresponding to the first electronic switch tube Q1 when the first electronic switch tube Q1 is turned on. The resistance ratio of the first resistor R1 to the second resistor R2 is used to determine a voltage division ratio at the control end of the first electronic switching tube Q1, and the resistance ratio of the third resistor R3 to the fourth resistor R4 is used to determine a voltage division ratio at the control end of the second electronic switching tube Q2. Like this, will third resistance R3 with fourth resistance R4's resistance ratio sets up to be less than first resistance R1 with second resistance R2's resistance ratio makes first electronic switch tube Q1 with the corresponding power supply TYPE-C-IN's of second electronic switch tube Q2 voltage when switching on is different, is convenient for form the band-pass area of protection voltage of charging protection circuit.

Specifically, when the output voltage of the power supply TYPE-C-IN is less than or equal to a first preset voltage, the first electronic switch tube Q1, the second electronic switch tube Q2, and the third electronic switch tube Q3 are all turned off, and at this time, the charging protection circuit is IN an under-voltage protection state, so as to implement under-voltage protection; when the output voltage of the power supply TYPE-C-IN is greater than a first preset voltage and less than a second preset voltage, because the resistance ratio of the third resistor R3 to the fourth resistor R4 is less than the resistance ratio of the first resistor R1 to the second resistor R2, the voltage of the control end of the first electronic switching tube Q1 is less than the voltage of the control end of the second electronic switching tube Q2, so that the second electronic switching tube Q2 is turned on, the first electronic switching tube Q1 is turned off, and the third electronic switching tube Q3 is turned on, thereby charging the battery is realized, and at this time, the first preset voltage and the second preset voltage are voltage range end values corresponding to the band-pass region of the charging protection circuit; when power supply TYPE-C-IN's output voltage is greater than the second and predetermines voltage, first electronic switch pipe Q1 with second electronic switch pipe Q2 all switches on, makes the level of third electronic switch pipe Q3's control end reduces, thereby makes third electronic switch pipe Q3 ends, stops to charge for the battery, realizes overvoltage protection. The first electronic switching tube Q1 and the second electronic switching tube Q2 have the same model, that is, the conduction voltages of the first electronic switching tube Q1 and the second electronic switching tube Q2 are the same.

In one embodiment, the present application further provides an earphone charging chamber, including the charging protection circuit described in any of the above embodiments. In this embodiment, the charging protection circuit includes a first protection circuit, a second protection circuit, and a third protection circuit. The first protection circuit comprises a first electronic switching tube, a first resistor and a second resistor. The first end of the first resistor is used for being connected with a power supply, the second end of the first resistor is grounded through the second resistor, and the second end of the first resistor is further connected with the control end of the first electronic switch tube. The second end of the first electronic switch tube is grounded. The second protection circuit comprises a second electronic switching tube, a third resistor and a fourth resistor. The first end of the third resistor is connected with the first end of the first resistor, the second end of the third resistor is grounded through the fourth resistor, and the second end of the third resistor is further connected with the control end of the second electronic switch tube and the first end of the first electronic switch tube respectively. And the second end of the second electronic switching tube is grounded. The third protection circuit comprises a third electronic switching tube and a fifth resistor. The first end of the fifth resistor is connected with the first end of the first resistor, the first end of the fifth resistor is further connected with the first end of the third electronic switching tube, and the second end of the fifth resistor is respectively connected with the first end of the second electronic switching tube and the control end of the third electronic switching tube. And the second end of the third electronic switching tube is used for being connected with a battery to be charged. When under-voltage, the first electronic switch tube, the second electronic switch tube and the third electronic switch tube are all cut off, so that the power supply and the rechargeable battery are disconnected, and when over-voltage occurs, the first electronic switch tube is switched on, so that the second electronic switch tube and the third electronic switch tube are all cut off, so that the power supply and the rechargeable battery are also kept disconnected, and further the charging protection circuit has functions of over-voltage and under-voltage protection.

The above-mentioned embodiments only represent several embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the 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

1. A charge protection circuit, comprising:

the protection circuit comprises a first electronic switching tube, a first resistor and a second resistor, wherein a first end of the first resistor is connected with a power supply, a second end of the first resistor is grounded through the second resistor, a second end of the first resistor is also connected with a control end of the first electronic switching tube, and a second end of the first electronic switching tube is grounded;

the second protection circuit comprises a second electronic switching tube, a third resistor and a fourth resistor, wherein the first end of the third resistor is connected with the first end of the first resistor, the second end of the third resistor is grounded through the fourth resistor, the second end of the third resistor is also respectively connected with the control end of the second electronic switching tube and the first end of the first electronic switching tube, and the second end of the second electronic switching tube is grounded;

the third protection circuit comprises a third electronic switch tube and a fifth resistor, the first end of the fifth resistor is connected with the first end of the first resistor, the first end of the fifth resistor is further connected with the first end of the third electronic switch tube, the second end of the fifth resistor is respectively connected with the first end of the second electronic switch tube and the control end of the third electronic switch tube, and the second end of the third electronic switch tube is used for being connected with a battery to be charged.

2. The charging protection circuit of claim 1, wherein the first resistor has a resistance of 10K Ω to 100K Ω.

3. The charge protection circuit of claim 2, wherein the first resistor has a resistance of 22K Ω.

4. The charging protection circuit of claim 1, wherein the third resistor has a resistance of 22K Ω to 1M Ω.

5. The charging protection circuit of claim 4, wherein the third resistor has a resistance of 100K Ω.

6. The charging protection circuit of claim 1, wherein the first protection circuit further comprises a first capacitor, wherein a second terminal of the first resistor is connected to a first terminal of the first capacitor, and wherein a second terminal of the first capacitor is connected to ground.

7. The charging protection circuit of claim 1, wherein the second protection circuit further comprises a second capacitor, wherein a second terminal of the third resistor is connected to a first terminal of the second capacitor, and a second terminal of the second capacitor is grounded.

8. The charging protection circuit of claim 1, wherein the third protection circuit further comprises a third capacitor, wherein a second terminal of the fifth resistor is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to ground.

9. The charge protection circuit of claim 1, wherein a resistance ratio of the third resistor to the fourth resistor is smaller than a resistance ratio of the first resistor to the second resistor.

10. An earphone charging chamber, characterized by comprising a charging protection circuit according to any one of claims 1 to 9.