Mobile terminal and charging and discharging protection circuit of standby battery of mobile terminal

Abstract

The utility model relates to a mobile terminal and a charging and discharging protection circuit of a standby battery of the mobile terminal. The charging and discharging protection circuit comprises a first detection module and a second detection module, wherein the first detection module is used for detecting whether the voltage of a standby battery is lower than a first preset voltage value or not and inputting a corresponding turn-on or turn-off control signal to a first switching tube module, so that over-discharging prevention of the standby battery is realized through turn-on or turn-off of the first switching tube module; the second switching tube module is connected between the output end of the boosting module and the first switching tube module, and one end, connected with the output end of the boosting module, of the second switching tube module is also connected with a system power supply; and the second detection module is used for detecting whether the voltage of the standby battery is higher than a second preset voltage value and outputting a second detection signal to the main control module. And the main control module inputs a corresponding turn-on or turn-off control signal to the second switch tube module according to the second detection signal, so that the standby battery is prevented from being overcharged through turn-on or turn-off of the second switch tube module.

Description

Technical Field

[0001] The utility model relates to the field of charge and discharge protection circuits, in particular to a charge and discharge protection circuit of a mobile terminal and a backup battery thereof. Background Art

[0002] With the development of warehousing and express delivery, many application scenarios require hot swapping. The so-called hot swapping means that after the main battery of the mobile terminal device is unplugged, the backup battery continues to supply power to the system, keeping the mobile terminal time from being lost or some programs running continuously.

[0003] In the current related technology, a battery protection chip is usually used to protect the backup battery during charging and discharging to prevent it from being overcharged or overdischarged. However, this will increase the cost and cannot flexibly cope with backup batteries of various specifications. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a mobile terminal and a charge and discharge protection circuit of a backup battery thereof.

[0005] The utility model solves the technical problem by adopting a technical solution: a charging and discharging protection circuit of a backup battery of a mobile terminal, comprising a main control module and a boost module, wherein the input end of the boost module is connected to a system power supply, and further comprising:

[0006] A first switch tube module connected between the backup battery and the second switch tube module;

[0007] A first detection module connected to the backup battery and the control input end of the first switch tube module, used to detect whether the voltage of the backup battery is lower than a first preset voltage value and input a corresponding on or off control signal to the first switch tube module, thereby preventing over-discharge when the backup battery is discharged to the system power supply by turning on or off the first switch tube module;

[0008] A second switch tube module connected between the output end of the boost module and the first switch tube module, wherein one end of the second switch tube module connected to the output end of the boost module is also connected to the system power supply;

[0009] A second detection module connected to the backup battery and the main control module, used to detect whether the voltage of the backup battery is higher than a second preset voltage value and output a second detection signal to the main control module, wherein the second preset voltage value is greater than the first preset voltage value;

[0010] The control output end of the main control module is also connected to the control input end of the second switch tube module, and a corresponding on or off control signal is input to the second switch tube module according to the second detection signal, so that the on or off of the second switch tube module can prevent overcharging when the boost module charges the backup battery.

[0011] Further, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the charge and discharge protection circuit also includes:

[0012] A third switch tube module is connected between the input end of the boost module and the system power supply, and the control output end of the main control module is also connected to the control input end of the third switch tube module, and a corresponding on or off control signal is input to the third switch tube module according to the second detection signal.

[0013] Further, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the third switch tube module includes a MOS tube Q1 and a triode Q2, the base of the triode Q2 is connected to the control output end of the main control module via a resistor R14, and is grounded via a resistor R17, the emitter of the triode Q2 is grounded, the collector of the triode Q2 is connected to the gate of the MOS tube Q1, and is connected to the source of the MOS tube Q1 via a resistor R11, the source of the MOS tube Q1 is also connected to the system power supply, and the drain of the MOS tube Q1 is connected to the input end of the boost module, and is grounded via a capacitor C14.

[0014] Furthermore, in the charging and discharging protection circuit of the mobile terminal backup battery described in the utility model, the first switch tube module includes a MOS tube Q3 and a triode Q5, the base of the triode Q5 is connected to the first detection module via a resistor R29, and is connected to the emitter of the triode Q5 via a resistor R31 and grounded, the collector of the triode Q5 is connected to the gate of the MOS tube Q3, and is connected to the source of the MOS tube Q3 via a resistor R23, the source of the MOS tube Q3 is also connected to the backup battery, and the drain of the MOS tube Q3 is connected to the second switch tube module.

[0015] Furthermore, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the second switch tube module includes a MOS tube Q4 and a transistor Q6, the base of the transistor Q6 is connected to the control output end of the main control module via a resistor R30, and is connected to the emitter of the transistor Q6 via a resistor R32 and grounded, the collector of the transistor Q6 is connected to the gate of the MOS tube Q4, and is connected to the source of the MOS tube Q4 via a resistor R79, the source of the MOS tube Q4 is also respectively connected to the output end of the boost module and the system power supply, and the drain of the MOS tube Q4 is connected to the first switch tube module.

[0016] Further, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the first detection module includes a first detection chip U2, the first pin of the first detection chip U2 is connected to the first switch tube module, and is connected to the working power supply via a resistor R78, the third pin and the fourth pin of the first detection chip U2 are connected to the backup battery and are grounded via a capacitor C4, and the fifth pin of the first detection chip U2 is grounded via a capacitor C12; and / or

[0017] The second detection module includes a second detection chip U11, a first pin of the second detection chip U11 is connected to the main control module and is connected to the working power supply via a resistor R28, a third pin and a fourth pin of the second detection chip U11 are connected to the backup battery and are grounded via a capacitor C28, and a fifth pin of the second detection chip U11 is grounded via a capacitor C31.

[0018] Further, in the charging and discharging protection circuit of the backup battery of the mobile terminal described in the utility model, the first detection module is used to input a low level signal to the first switch tube module when detecting that the voltage of the backup battery is lower than the first preset voltage value during the discharge process of the backup battery, and the first switch tube module is turned off at this time, and the backup battery stops discharging;

[0019] The second detection module is used to input a high-level signal to the main control module when it detects that the voltage of the backup battery is higher than a second preset voltage value during the backup battery charging process, and the main control module inputs a corresponding shutdown control signal to the second switch tube module to turn off the second switch tube module and stop charging the backup battery.

[0020] Furthermore, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the boost module includes a boost chip U15, the first pin and the eleventh pin of the boost chip U15 are connected to each other, and connected to the system power supply, and are grounded via capacitors C26 and C14 respectively, the seventh pin of the boost chip U15 is connected to the second switch tube module via resistor R22, and is grounded via capacitors C21 and C24 respectively, the sixth pin of the boost chip U15 is connected to the seventh pin of the boost chip U15 via resistor R24, and is grounded via resistor R27.

[0021] Furthermore, in the charge and discharge protection circuit of the mobile terminal backup battery described in the utility model, the backup battery is a lithium-ion supercapacitor; and / or

[0022] The first preset voltage value is 2.5V, and the second preset voltage value is 3.8V.

[0023] In addition, the utility model also provides a mobile terminal, including a main battery and a backup battery, wherein the backup battery is used to continue to supply power to the system when the main battery loses power, and the mobile terminal also includes a charge and discharge protection circuit for the mobile terminal backup battery as described above.

[0024] The implementation of the mobile terminal and the charging and discharging protection circuit of the backup battery of the utility model has the following beneficial effects: the charging and discharging protection circuit of the backup battery of the mobile terminal of the utility model no longer needs to use a battery protection chip, and only two battery detection modules and a switch tube module are required to realize the protection of the backup battery, so that it will not be overcharged during charging and over-discharged during discharging, which reduces costs, improves efficiency, and can flexibly cope with backup batteries of various specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 It is a structural schematic diagram of a charge and discharge protection circuit of a backup battery of a mobile terminal according to an embodiment of the present application;

[0027] Figure 2 It is a structural schematic diagram of a charge and discharge protection circuit of a backup battery of a mobile terminal in some embodiments of the present application;

[0028] Figure 3 is a circuit diagram of a charge and discharge protection circuit of a mobile terminal backup battery in some embodiments of the present application;

[0029] Figure 4 yes Figure 3 The circuit diagram of two detection modules and a main control module in the charge and discharge protection circuit of the mobile terminal backup battery is shown.

[0030] Description of reference numerals:

[0031] 10. Main control module; 20. Boost module; 30. First detection module; 40. Second detection module; 50. First switch tube module; 60. Second switch tube module; 70. Third switch tube module; 80. Backup battery; 90. System power supply. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0033] In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details that hinder the description of the present invention.

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0035] It should be understood that although the terms first, second, third, etc. may be used to describe various information in the present embodiment, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. It is not necessarily required or implied that there is any such actual relationship or order between these entities or operations.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0037] refer to Figure 1 An embodiment of the present application discloses a charge and discharge protection circuit of a mobile terminal backup battery 80, including a main control module 10 and a boost module 20, wherein the input end of the boost module 20 is connected to a system power supply 90, and further includes:

[0038] The first switch tube module 50 is connected between the backup battery 80 and the second switch tube module 60 .

[0039] A first detection module 30 is connected to the control input end of the backup battery 80 and the first switch tube module 50, and is used to detect whether the voltage of the backup battery 80 is lower than a first preset voltage value and input a corresponding on or off control signal to the first switch tube module 50, thereby preventing over-discharge when the backup battery 80 discharges to the system power supply 90 by turning on or off the first switch tube module 50.

[0040] The second switch tube module 60 is connected between the output end of the boost module 20 and the first switch tube module 50 , and one end of the second switch tube module 60 connected to the output end of the boost module 20 is also connected to the system power supply 90 .

[0041] A second detection module 40 connected to the backup battery 80 and the main control module 10, for detecting whether the voltage of the backup battery 80 is higher than a second preset voltage value and outputting a second detection signal to the main control module 10, wherein the second preset voltage value is greater than the first preset voltage value. Specifically, the first preset voltage value is 2.5V, and the second preset voltage value is 3.8V. Of course, the present application may also make different specific limitations on the preset voltage values ​​according to different system voltage requirements of different mobile terminals, for example, the second preset voltage value may also be 2.9V, 3.6V, and the first preset voltage value may be 2.6V, 2.7V, and so on.

[0042] The control output end of the main control module 10 is also connected to the control input end of the second switch tube module 60, and inputs a corresponding on or off control signal to the second switch tube module 60 according to the second detection signal, thereby preventing overcharging when the boost module 20 charges the backup battery 80 by turning on or off the second switch tube module 60.

[0043] It can be understood that the first detection module 30 is used to input a low-level signal to the first switch module 50 when it is detected that the voltage of the backup battery 80 is lower than the first preset voltage value during the discharge process of the backup battery 80, and the first switch module 50 is turned off, and the backup battery 80 stops discharging. The second detection module 40 is used to input a high-level signal to the main control module 10 when it is detected that the voltage of the backup battery 80 is higher than the second preset voltage value during the charging process of the backup battery 80, and the main control module 10 inputs a corresponding shutdown control signal to the second switch module 60, so that the second switch module 60 is turned off and the backup battery 80 stops charging.

[0044] The charge and discharge protection circuit of the mobile terminal backup battery 80 of this embodiment no longer needs to use a battery protection chip. Only two battery detection modules and a switch tube module are needed to realize the backup battery protection, so that it will not be overcharged during charging and over-discharged during discharging, which reduces costs, improves efficiency, and can flexibly cope with backup batteries of various specifications.

[0045] In a specific embodiment, Figure 3 As shown, the first switch tube module 50 includes a MOS tube Q3 and a transistor Q5. The base of the transistor Q5 is connected to the first detection module 30 via a resistor R29, and is connected to the emitter of the transistor Q5 via a resistor R31 and grounded. The collector of the transistor Q5 is connected to the gate of the MOS tube Q3, and is connected to the source of the MOS tube Q3 via a resistor R23. The source of the MOS tube Q3 is also connected to a backup battery 80, and the drain of the MOS tube Q3 is connected to the second switch tube module 60.

[0046] The second switch tube module 60 includes a MOS tube Q4 and a transistor Q6. The base of the transistor Q6 is connected to the control output end of the main control module 10 via a resistor R30, and is connected to the emitter of the transistor Q6 via a resistor R32 and grounded. The collector of the transistor Q6 is connected to the gate of the MOS tube Q4, and is connected to the source of the MOS tube Q4 via a resistor R79. The source of the MOS tube Q4 is also connected to the output end of the boost module 20 and the system power supply 90 respectively. The drain of the MOS tube Q4 is connected to the first switch tube module 50.

[0047] Specifically, the drain of the MOS transistor Q3 is connected to the drain of the MOS transistor Q4.

[0048] In some embodiments, reference Figure 2 The charge and discharge protection circuit also includes: a third switch tube module 70 connected between the input end of the boost module 20 and the system power supply 90. The control output end of the main control module 10 is also connected to the control input end of the third switch tube module 70, and a corresponding on or off control signal is input to the third switch tube module 70 according to the second detection signal.

[0049] In a specific embodiment, Figure 3 As shown, the third switch tube module 70 includes a MOS tube Q1 and a transistor Q2. The base of the transistor Q2 is connected to the control output end of the main control module 10 via a resistor R14 and is grounded via a resistor R17. The emitter of the transistor Q2 is grounded. The collector of the transistor Q2 is connected to the gate of the MOS tube Q1 and is connected to the source of the MOS tube Q1 via a resistor R11. The source of the MOS tube Q1 is also connected to the system power supply 90. The drain of the MOS tube Q1 is connected to the input end of the boost module 20 and is grounded via a capacitor C14.

[0050] The boost module 20 includes a boost chip U15, wherein the first pin and the eleventh pin of the boost chip U15 are connected to each other, and are connected to the system power supply 90, and are grounded via capacitors C26 and C14, respectively; the seventh pin of the boost chip U15 is connected to the second switch tube module 60 via resistor R22, and is grounded via capacitors C21 and C24, respectively; the sixth pin of the boost chip U15 is connected to the seventh pin of the boost chip U15 via resistor R24, and is grounded via resistor R27. The fifth pin and the ninth pin of the boost chip U15 are connected to each other and are grounded, the second pin of the boost chip U15 is grounded, and the fourth pin of the boost chip U15 is grounded via capacitor C27.

[0051] Specifically, the eleventh pin of the boost chip U15 is connected to the drain of the MOS tube Q1 , and the seventh pin of the boost chip U15 is connected to the source of the MOS tube Q4 via the resistor R22 .

[0052] Combination Figure 3 and Figure 4 , the working principle of the utility model is further explained.

[0053] When the main battery is in place, when 2.5V<the voltage of the backup battery 80<3.8V, INT1_2.5V outputs a high-level signal, INT4_3.8V outputs a low-level signal, and GPIO1 outputs a high-level signal. At this time, transistor Q2 is turned on, MOS transistor Q1 is turned on, and the voltage of the system power supply 90 is boosted by the boost module 20. Since transistors Q5 and Q6 are turned on, MOS transistors Q3 and Q4 are also turned on, so the backup battery 80 is in a charging state at this time.

[0054] When the backup battery 80 is charged until the voltage of the backup battery 80 is detected to be ≥3.8V, INT1_2.5V outputs a high level signal, INT4_3.8V outputs a high level signal, and GPIO1 outputs a low level signal. At this time, the transistor Q2 is turned off, the MOS transistor Q1 is turned off, the transistor Q6 is turned off, and the MOS transistor Q4 is turned off, so that the voltage output by the boost module 20 cannot charge the backup battery 80 through the MOS transistor Q4, and the backup battery 80 stops charging.

[0055] When the main battery loses power, when 2.5V<the voltage of the backup battery 80<3.8V, INT1_2.5V outputs a high-level signal, INT4_3.8V outputs a low-level signal, and GPIO1 outputs a high-level signal. At this time, transistor Q5 is turned on, transistor Q6 is turned on, so that MOS transistors Q3 and MOS transistors Q4 are turned on. At this time, the backup battery 80 is discharged through MOS transistors Q3 and MOS transistors Q4 to support the system power supply 90 from losing power.

[0056] When the backup battery 80 is continuously discharged, until the voltage of the backup battery 80 is detected to be ≤2.5V, INT1_2.5V outputs a low level signal, INT4_3.8V outputs a low level signal, and GPIO1 outputs a high level signal. At this time, the transistor Q5 is turned off, so that the MOS tube Q3 is turned off, and the backup battery 80 stops discharging.

[0057] It should be noted that the mobile terminal supplies power to the system through a main battery and a backup battery 80 in parallel. Since the main battery voltage is higher, it is usually powered by the main battery. When the main battery is unplugged (or the main battery loses power), due to the voltage difference, as long as it detects that the voltage of the backup battery 80 is not lower than the first preset voltage value, it will continue to support the system directly.

[0058] like Figure 4 As shown, the first detection module 30 includes a first detection chip U2, a first pin of the first detection chip U2 is connected to the first switch tube module 50, and is connected to the working power supply via a resistor R78, a third pin and a fourth pin of the first detection chip U2 are connected to a backup battery 80, and are grounded via a capacitor C4, and a fifth pin of the first detection chip U2 is grounded via a capacitor C12. A second pin of the first detection chip U2 is grounded.

[0059] Specifically, the first pin of the first detection chip U2 is connected to the base of the transistor Q5 via the resistor R29.

[0060] The second detection module 40 includes a second detection chip U11, a first pin of the second detection chip U11 is connected to the main control module 10, and is connected to the working power supply via a resistor R28, a third pin and a fourth pin of the second detection chip U11 are connected to the backup battery 80, and are grounded via a capacitor C28, and a fifth pin of the second detection chip U11 is grounded via a capacitor C31. The second pin of the second detection chip U11 is grounded. Alternatively, the voltage detection chip can be a detection chip of model SGM803-SXN3L-TR.

[0061] This embodiment uses two voltage detection chips U2 and U11 to monitor the voltage of the backup battery 80 in real time, and uses two PMOS tubes Q3 and Q4 to control the on and off of the charging and discharging path of the backup battery 80.

[0062] like Figure 4 As shown, the main control module 10 includes a fourth chip U4 , a first pin of the second detection chip U11 is connected to a detection signal input terminal of the fourth chip, and a first pin of the fourth chip U4 is connected to a system power supply 90 .

[0063] In another preferred embodiment, the mobile terminal of this embodiment includes a main battery and a backup battery 80, the backup battery 80 is used to continue to supply power to the system power supply 90 when the main battery loses power, and the mobile terminal also includes the charging and discharging protection circuit of the mobile terminal backup battery 80 of the above embodiment. The backup battery 80 is a lithium-ion supercapacitor.

[0064] It should be noted that the mobile terminal of this embodiment may be a broad range of mobile terminals including POS machines, vehicle-mounted computers, notebooks, mobile phones, etc.

[0065] The mobile terminal of this embodiment no longer needs to use a battery protection chip. Only two battery detection modules and a switch tube module are needed to realize backup battery protection, so that it will not be overcharged during charging and over-discharged during discharging, which reduces costs, improves efficiency, and can flexibly cope with backup batteries of various specifications.

[0066] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should belong to the scope covered by the claims of the utility model.

Claims

1. A charge and discharge protection circuit for a mobile terminal backup battery, comprising a main control module (10) and a boost module (20), wherein an input end of the boost module (20) is connected to a system power supply (90), characterized in that: Also includes: A first switch tube module (50) connected between the backup battery (80) and the second switch tube module (60); A first detection module (30) connected to the control input end of the backup battery (80) and the first switch tube module (50), used to detect whether the voltage of the backup battery (80) is lower than a first preset voltage value and input a corresponding on or off control signal to the first switch tube module (50), thereby preventing over-discharge when the backup battery (80) is discharged to the system power supply (90) by turning on or off the first switch tube module (50); a second switch tube module (60) connected between the output end of the boost module (20) and the first switch tube module (50), wherein one end of the second switch tube module (60) connected to the output end of the boost module (20) is also connected to the system power supply (90); a second detection module (40) connected to the backup battery (80) and the main control module (10), and used to detect whether the voltage of the backup battery (80) is higher than a second preset voltage value and output a second detection signal to the main control module (10), wherein the second preset voltage value is greater than the first preset voltage value; The control output end of the main control module (10) is also connected to the control input end of the second switch tube module (60), and a corresponding on or off control signal is input to the second switch tube module (60) according to the second detection signal, so that the on or off of the second switch tube module (60) can prevent overcharging when the boost module (20) charges the backup battery (80).

2. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 1, characterized in that: The charge and discharge protection circuit also includes: A third switch tube module (70) is connected between the input end of the boost module (20) and the system power supply (90); the control output end of the main control module (10) is also connected to the control input end of the third switch tube module (70), and a corresponding on or off control signal is input to the third switch tube module (70) according to the second detection signal.

3. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 2, characterized in that: The third switch tube module (70) comprises a MOS tube Q1 and a triode Q2, the base of the triode Q2 being connected to the control output end of the main control module (10) via a resistor R14 and being grounded via a resistor R17, the emitter of the triode Q2 being grounded, the collector of the triode Q2 being connected to the gate of the MOS tube Q1 and being connected to the source of the MOS tube Q1 via a resistor R11, the source of the MOS tube Q1 being also connected to the system power supply (90), and the drain of the MOS tube Q1 being connected to the input end of the boost module (20) and being grounded via a capacitor C14.

4. The charge and discharge protection circuit of the mobile terminal backup battery according to any one of claims 1 to 3, characterized in that: The first switch tube module (50) comprises a MOS tube Q3 and a triode Q5, the base of the triode Q5 being connected to the first detection module (30) via a resistor R29, and being connected to the emitter of the triode Q5 via a resistor R31 and being grounded, the collector of the triode Q5 being connected to the gate of the MOS tube Q3, and being connected to the source of the MOS tube Q3 via a resistor R23, the source of the MOS tube Q3 being also connected to the backup battery (80), and the drain of the MOS tube Q3 being connected to the second switch tube module (60).

5. The charge and discharge protection circuit of the mobile terminal backup battery according to any one of claims 1 to 3, characterized in that: The second switch tube module (60) comprises a MOS tube Q4 and a triode Q6, the base of the triode Q6 being connected to the control output end of the main control module (10) via a resistor R30, and being connected to the emitter of the triode Q6 via a resistor R32 and being grounded, the collector of the triode Q6 being connected to the gate of the MOS tube Q4, and being connected to the source of the MOS tube Q4 via a resistor R79, the source of the MOS tube Q4 being also connected to the output end of the boost module (20) and the system power supply (90), respectively, and the drain of the MOS tube Q4 being connected to the first switch tube module (50).

6. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 1, characterized in that: The first detection module (30) comprises a first detection chip U2, a first pin of the first detection chip U2 is connected to the first switch tube module (50), and is connected to a working power supply via a resistor R78, a third pin and a fourth pin of the first detection chip U2 are connected to the backup battery (80), and are grounded via a capacitor C4, and a fifth pin of the first detection chip U2 is grounded via a capacitor C12; and / or The second detection module (40) comprises a second detection chip U11, a first pin of the second detection chip U11 is connected to the main control module (10) and is connected to a working power supply via a resistor R28, a third pin and a fourth pin of the second detection chip U11 are connected to the backup battery (80) and are grounded via a capacitor C28, and a fifth pin of the second detection chip U11 is grounded via a capacitor C31.

7. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 1, characterized in that: The first detection module (30) is used to input a low-level signal to the first switch tube module (50) when detecting that the voltage of the backup battery (80) is lower than the first preset voltage value during the discharge process of the backup battery (80), so that the first switch tube module (50) is turned off and the backup battery (80) stops discharging; The second detection module (40) is used to input a high-level signal to the main control module (10) when detecting that the voltage of the backup battery (80) is higher than a second preset voltage value during the charging process of the backup battery (80), and the main control module (10) inputs a corresponding shutdown control signal to the second switch tube module (60), so that the second switch tube module (60) is turned off and the charging of the backup battery (80) is stopped.

8. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 1, characterized in that: The boost module (20) comprises a boost chip U15, wherein a first pin and an eleventh pin of the boost chip U15 are connected to each other, and are connected to the system power supply (90), and are grounded via capacitors C26 and C14 respectively; a seventh pin of the boost chip U15 is connected to the second switch tube module (60) via a resistor R22, and is grounded via capacitors C21 and C24 respectively; a sixth pin of the boost chip U15 is connected to the seventh pin of the boost chip U15 via a resistor R24, and is grounded via a resistor R27.

9. The charge and discharge protection circuit of the mobile terminal backup battery according to claim 1, characterized in that: The backup battery (80) is a lithium-ion supercapacitor; and / or The first preset voltage value is 2.5V, and the second preset voltage value is 3.8V.

10. A mobile terminal, comprising a main battery and a backup battery (80), characterized in that: The backup battery (80) is used to continue to supply power to the system power supply (90) when the main battery loses power. The mobile terminal also includes a charge and discharge protection circuit for the mobile terminal backup battery according to any one of claims 1 to 9.

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