Mobile terminal and power supply circuit of standby battery thereof

Abstract

The utility model relates to a mobile terminal and a power supply circuit of a standby battery thereof. The power supply circuit comprises a first detection module which is connected with the standby battery and the second switch tube module and is used for detecting whether the voltage of the standby battery is higher than a first preset voltage value and outputting a first detection signal to the second switch tube module. And the second detection module is connected with the standby battery, the first switching tube module and the second switching tube module, and 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 first switching tube module and the second switching tube module respectively. The first switch tube module is connected between the power supply module and the standby battery and used for adjusting connection and disconnection between the power supply module and the standby battery according to the second detection signal. And the second switching tube module is connected between an external system real-time clock power supply and a standby battery, and is used for adjusting the on-off between the system real-time clock power supply and the standby battery according to the first detection signal and the second detection signal.

Description

Technical Field

[0001] The utility model relates to the field of power supply circuits, in particular to a mobile terminal and a power supply circuit of 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 time of the mobile terminal from being lost or some programs running continuously.

[0003] The current solutions on the market generally use supercapacitors and RTC batteries to power the system power supply and system RTC (real-time clock) respectively, but this will lead to disadvantages such as increased costs. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a mobile terminal and a power supply circuit of a backup battery thereof in view of the above-mentioned defects.

[0005] The technical solution adopted by the utility model to solve the technical problem is: a power supply circuit of a backup battery of a mobile terminal, including a power supply module connected to a system power supply and supplying power to it, and also including:

[0006] A first detection module connected to the backup battery and the second switch tube module, configured to detect whether the voltage of the backup battery is higher than a first preset voltage value and output a first detection signal to the second switch tube module;

[0007] A second detection module connected to the backup battery, the first switch tube module and the second switch tube module, and configured 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 first switch tube module and the second switch tube module respectively; the second preset voltage value is greater than the first preset voltage value;

[0008] The first switch tube module is connected between the power supply module and the backup battery, and is used to adjust the connection between the power supply module and the backup battery according to the second detection signal;

[0009] The second switch tube module is connected between the external system real-time clock power supply and the backup battery, and is used to adjust the on-off between the system real-time clock power supply and the backup battery according to the first detection signal and the second detection signal.

[0010] Furthermore, in the power supply circuit of the mobile terminal backup battery described in the utility model, the first switch tube module includes a PMOS tube Q9 and a transistor Q13, the source of the PMOS tube Q9 is connected to the backup battery, and is respectively connected to the gate of the PMOS tube Q9 and the collector of the transistor Q13 through a resistor R38, the drain of the PMOS tube Q9 is connected to the power supply module, the base of the transistor Q13 is connected to the second detection module through a resistor R46, is connected to the emitter of the transistor Q13 through a resistor R48, and is grounded.

[0011] Further, in the power supply circuit of the mobile terminal backup battery described in the utility model, the second switch tube module includes a MOS tube Q10, a transistor Q16, a MOS tube Q11 and a transistor Q15, the source of the MOS tube Q10 is connected to the backup battery, and is respectively connected to the gate of the MOS tube Q10 and the emitter of the transistor Q16 through a resistor R80, the base of the transistor Q16 is connected to the second detection module through a resistor R51, the collector of the transistor Q16 is grounded, the drain of the MOS tube Q10 is connected to the source of the MOS tube Q11, and is respectively connected to the gate of the MOS tube Q11 and the collector of the transistor Q15 through a resistor R40, the base of the transistor Q15 is connected to the first detection module through a resistor R50, connected to the emitter of the transistor Q15 through a resistor R77, and grounded, and the drain of the MOS tube Q11 is connected to the system real-time clock power supply.

[0012] Further, in the power supply circuit of the backup battery of the mobile terminal described in the utility model, when the second detection module detects that the voltage of the backup battery is higher than the second preset voltage value, the second detection signal input to the first switch tube module is a high level signal, at this time, the first switch tube module is turned on, and the second switch tube module is turned off, thereby making the power supply module and the backup battery conductive to form a power supply path for the system power supply;

[0013] When the second detection module detects that the voltage of the backup battery is lower than the second preset voltage value, and when the first detection module detects that the voltage of the backup battery is higher than the first preset voltage value, the second detection signal and the first detection signal input to the second switch tube module are respectively a low level signal and a high level signal. At this time, the second switch tube module is turned on and the first switch tube module is turned off, thereby making the system real-time clock power supply and the backup battery conductive to form a power supply path for the system real-time clock power supply.

[0014] Further, in the power supply circuit of the mobile terminal backup battery described in the utility model, the power supply circuit also includes a diode D3 for preventing backflow, the positive electrode of the diode D3 is connected to the power supply module, and the negative electrode of the diode D3 is connected to the system power supply; and / or

[0015] The power supply circuit further includes a diode D2 for preventing backflow, wherein the anode of the diode D2 is connected to the second switch tube module, and the cathode of the diode D2 is used to connect to the real-time clock power supply of the system.

[0016] Furthermore, in the power supply circuit of the mobile terminal backup battery described in the utility model, the power supply circuit also includes a third switch tube module connected in parallel with the diode D3, and the impedance generated by the third switch tube module when it is turned on is less than the impedance generated by the diode D3, and the control input end of the third switch tube module is used to input an on or off control signal corresponding to the main battery status.

[0017] Further, in the power supply circuit of the mobile terminal backup battery described in the utility model, the third switch tube module includes a PMOS tube Q12 and a transistor Q14, the drain of the PMOS tube Q12 is connected to the positive electrode of the diode D3, the source of the PMOS tube Q12 is connected to the negative electrode of the diode D3, and the gate of the PMOS tube Q12 and the collector of the transistor Q14 are respectively connected through a resistor R44, the base of the transistor Q14 is connected to one end of the resistor R31, and is connected to the emitter of the transistor Q14 through a resistor R32, and is grounded, and the other end of the resistor R31 is used to receive an on or off control signal.

[0018] Further, in the power supply circuit of the backup battery of the mobile terminal described in the utility model, the first detection module includes a first detection chip U2, a first pin of the first detection chip U2 is connected to the second switch tube module, and is connected to the working power supply via a resistor R78, a third pin of the first detection chip U2 is respectively connected to the fourth pin of the first detection chip U2 and the backup battery, and is grounded via a capacitor C4, a fifth pin of the first detection chip U2 is connected to the second pin of the first detection chip U2 via a capacitor C12, and is grounded; and / or

[0019] The second detection module includes a second detection chip U5, the first pin of the second detection chip U5 is respectively connected to the first switch tube module and the second switch tube module, and is connected to the working power supply through a resistor R12, the third pin of the second detection chip U5 is respectively connected to the fourth pin of the second detection chip U5 and the backup battery, and is grounded through a capacitor C15, and the fifth pin of the second detection chip U5 is connected to the second pin of the second detection chip U5 through a capacitor C18 and is grounded.

[0020] Further, in the power supply circuit of the mobile terminal backup battery described in the utility model, the power supply module includes a DCDC chip, the tenth pin of the DCDC chip is respectively connected to the first switch tube module and the first pin of the DCDC chip, and is connected to the fifth pin of the DCDC chip via a resistor R57, the sixth pin of the DCDC chip is connected to the system power supply, and is connected to the fourth pin of the DCDC chip via a resistor R69, and is connected to the third pin of the DCDC chip via the resistor R69 and the resistor R79 and is grounded, and the seventh pin of the DCDC chip is connected to the ninth pin of the DCDC chip via an inductor L5 and an inductor L9 connected in parallel; and / or

[0021] 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 2.7V.

[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 power the mobile terminal when the main battery loses power, and also includes a power supply circuit connected to the backup battery, such as the mobile terminal backup battery mentioned above.

[0024] The implementation of the mobile terminal and the power supply circuit of the backup battery of the utility model has the following beneficial effects: the application realizes that the same backup battery can power both the system power supply and the RTC through the cooperation of two voltage detection modules and two switch tube modules, thus achieving the dual purpose of the backup battery, saving RTC battery materials and reducing production costs. 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 power supply circuit of a backup battery of a mobile terminal according to an embodiment of the present application;

[0027] Figure 2 is a schematic diagram of the structure of a power supply circuit of a backup battery of a mobile terminal in some embodiments of the present application;

[0028] Figure 3 is a schematic diagram of the structure of a power supply circuit of a backup battery of a mobile terminal in some embodiments of the present application;

[0029] Figure 4 is a circuit diagram of a power supply circuit of a backup battery of a mobile terminal in some embodiments of the present application;

[0030] Figure 5 yes Figure 4Circuit diagram of the first detection module and the second detection module.

[0031] Description of reference numerals:

[0032] 10. Power supply module; 20. First detection module; 30. Second detection module; 40. First switch tube module; 50. Second switch tube module; 60. System power supply; 70. Backup battery; 80. System real-time clock power supply; 90. Third switch tube module. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] It should be noted that the power supply circuit of the present application refers to a circuit in which a backup battery provides a power supply voltage for the system power supply or system RTC of a mobile terminal. The system real-time clock power supply of the present application refers to the power supply access port of the system real-time clock, and the system power supply refers to the power supply access port of the circuit system in the mobile terminal. In addition, when the backup battery supplies power to the system power supply of the mobile terminal, the entire system does not lose power and can continue to operate normally, that is, the system real-time clock can also obtain the power supply voltage from the system power supply to maintain normal operation.

[0039] refer to Figure 1 An embodiment of the present application discloses a power supply circuit of a backup battery of a mobile terminal, which is used to select a corresponding power supply path through the voltage of a backup battery 70 monitored in real time so that the backup battery 70 can supply power to a system power supply 60 or only supply power to a system RTC. The power supply circuit of the backup battery of the mobile terminal of this embodiment includes a power supply module 10 connected to the system power supply 60 and supplying power to it, and also includes:

[0040] The first detection module 20 is connected to the backup battery 70 and the second switch tube module 50 and is used to detect whether the voltage of the backup battery 70 is higher than a first preset voltage value and output a first detection signal to the second switch tube module 50 .

[0041] A second detection module 30 connected to the backup battery 70, the first switch tube module 40 and the second switch tube module 50, for detecting whether the voltage of the backup battery 70 is higher than the second preset voltage value and outputting a second detection signal to the first switch tube module 40 and the second switch tube module 50 respectively. The second preset voltage value is greater than the first preset voltage value. As an option, the second preset voltage value is 2.7V, and the first preset voltage value is 2.5V. Of course, the present application can also make different specific limitations on the preset voltage value according to different system voltage requirements of different mobile terminals, for example, the second preset voltage value can also be 2.9V, 3.8V, and the first preset voltage value can be 2.7V, 3.6V, etc.

[0042] The first switch tube module 40 is connected between the power supply module 10 and the backup battery 70, and is used to adjust the connection between the power supply module 10 and the backup battery 70 according to the second detection signal.

[0043] The second switch tube module 50 is connected between the external system real-time clock power supply 80 and the backup battery 70, and is used to adjust the connection between the system real-time clock power supply 80 and the backup battery 70 according to the first detection signal and the second detection signal.

[0044] The working principle of the utility model is as follows: when the main battery of the mobile terminal loses power, when the second detection module 30 detects that the voltage of the backup battery 70 is higher than the second preset voltage value, the second detection signal input to the first switch tube module 40 is a high-level signal. At this time, the first switch tube module 40 is turned on and the second switch tube module 50 is turned off, thereby making the power supply module 10 and the backup battery 70 conductive to form a power supply path for the system power supply 60.

[0045] When the second detection module 30 detects that the voltage of the backup battery 70 is lower than the second preset voltage value, and when the first detection module 20 detects that the voltage of the backup battery 70 is higher than the first preset voltage value, the second detection signal and the first detection signal input to the second switch tube module 50 are respectively a low level signal and a high level signal. At this time, the second switch tube module 50 is turned on and the first switch tube module 40 is turned off, thereby making the system real-time clock power supply 80 and the backup battery 70 conductive, so as to form a power supply path for the system real-time clock power supply 80.

[0046] It should be noted that the mobile terminal supplies power to the system through the main battery and the backup battery 70 in parallel. Since the main battery voltage is relatively high, 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, the backup battery 70 will continue to support the system directly. In the case of power failure of the main battery of the mobile terminal, and the voltage of the backup battery 70 is greater than the second preset voltage value, the power supply path of the system power supply 60 is turned on and the power supply path of the RTC is disconnected; when the first preset voltage value is less than the voltage of the backup battery 70 and less than the second preset voltage value, the power supply path of the RTC is turned on and the power supply path of the system power supply 60 is disconnected; when the voltage of the backup battery 70 is less than the first preset voltage value, both the power supply path of the system power supply 60 and the power supply path of the RTC are disconnected.

[0047] The present application realizes that the same backup battery 70 can power both the system power supply 60 and the RTC through the cooperation of two voltage detection modules and two switch tube modules, thereby achieving dual-purpose of the backup battery 70, saving RTC battery materials and reducing production costs.

[0048] In some embodiments, Figure 4 As shown, the first switch tube module 40 includes a PMOS tube Q9 and a transistor Q13, the source of the PMOS tube Q9 is connected to the backup battery 70, and is respectively connected to the gate of the PMOS tube Q9 and the collector of the transistor Q13 via a resistor R38, the drain of the PMOS tube Q9 is connected to the power supply module 10, the base of the transistor Q13 is connected to the second detection module 30 via a resistor R46, is connected to the emitter of the transistor Q13 via a resistor R48, and is grounded.

[0049] In some embodiments, Figure 4As shown, the second switch tube module 50 includes a MOS tube Q10, a transistor Q16, a MOS tube Q11 and a transistor Q15. The source of the MOS tube Q10 is connected to the backup battery 70, and is respectively connected to the gate of the MOS tube Q10 and the emitter of the transistor Q16 via a resistor R80. The base of the transistor Q16 is connected to the second detection module 30 via a resistor R51, and the collector of the transistor Q16 is grounded. The drain of the MOS tube Q10 is connected to the source of the MOS tube Q11, and is respectively connected to the gate of the MOS tube Q11 and the collector of the transistor Q15 via a resistor R40. The base of the transistor Q15 is connected to the first detection module 20 via a resistor R50, connected to the emitter of the transistor Q15 via a resistor R77, and is grounded. The drain of the MOS tube Q11 is connected to the system real-time clock power supply 80, and is grounded via capacitors C32 and C33 connected in parallel.

[0050] In some embodiments, Figure 2 As shown, the power supply circuit further includes a diode D3 for preventing backflow, the positive electrode of the diode D3 is connected to the power supply module 10 , and the negative electrode of the diode D3 is connected to the system power supply 60 .

[0051] The power supply circuit also includes a diode D2 for preventing backflow, the anode of the diode D2 is connected to the second switch tube module 50 , and the cathode of the diode D2 is used to connect to the system real-time clock power supply 80 .

[0052] In some embodiments, Figure 3 As shown, the power supply circuit also includes a third switch tube module 90 connected in parallel with the diode D3. When the third switch tube module 90 is turned on, the impedance generated is less than the impedance generated by the diode D3. The control input end of the third switch tube module 90 is used to input a turn-on or turn-off control signal corresponding to the main battery state. Specifically, when the main battery is in a power-off state, a turn-on control signal is input to the control input end of the third switch tube module 90, and then the third switch tube module 90 realizes the conduction of the power supply path between the power supply module 10 and the system power supply 60.

[0053] It is understandable that since the process of the third switch tube module 90 changing from the off state to the on state takes time, the third switch tube module 90 will not be turned on immediately when receiving the on control signal, that is, there is a turn-on delay time. Therefore, during the period from the third switch tube module 90 being off to being turned on, the power supply module 10 supplies power to the system power supply 60 through the diode D3. According to the current characteristic that the current will flow from a place with smaller impedance, when the third switch tube module 90 is turned on, the power supply module 10 supplies power to the system power supply 60 through the third switch tube module 90 with smaller impedance, and at this time, the diode D3 is equivalent to being disconnected (the diode has a larger voltage drop).

[0054] Specifically, Figure 4As shown, the third switch tube module 90 includes a PMOS tube Q12 and a transistor Q14, the drain of the PMOS tube Q12 is connected to the anode of the diode D3, the source of the PMOS tube Q12 is connected to the cathode of the diode D3, and is respectively connected to the gate of the PMOS tube Q12 and the collector of the transistor Q14 via a resistor R44, the base of the transistor Q14 is connected to one end of the resistor R31, and is connected to the emitter of the transistor Q14 via a resistor R32, and is grounded, and the other end of the resistor R31 is used to receive an on or off control signal.

[0055] Combination Figure 4 , the working principle of the utility model is further explained. When 2.7V < the voltage of the backup battery 70, the first detection module 20 outputs a high-level signal through the INT1_2.5V interface, and the second detection module 30 outputs a high-level signal through the INT2_2.7V interface. At the moment when the main battery is unplugged (the BAT_DET_INT interface outputs a high-level signal to the third switch tube module 90 to turn it on), Q13 is turned on, Q9 is turned on, and the backup battery 70 is boosted through the power supply module 10, and first supplies power to the system power supply 60 (VPH_PWR) through the diode D3; after a period of time, Q14 is turned on, and Q12 is also turned on, and the power supply module 10 will output voltage to VPH_PWR through Q12. At the same time, Q16 is turned off, and the power supply path of the backup battery 70 to the RTC is disconnected.

[0056] When 2.5V<backup battery 70 voltage<2.7V, INT1_2.5V outputs a high level signal, INT2_2.7V outputs a low level signal, and when the main battery is unplugged (BAT_DET_INT outputs a high level signal), Q13 is turned off, and the backup battery 70 disconnects the power supply path for the system power supply 60. At the same time, Q16 is turned on, Q10 is turned on, Q15 is turned on, Q11 is turned on, and the backup battery 70 turns on the power supply path for the RTC.

[0057] When the voltage of the backup battery 70 is lower than 2.5V, INT1_2.5V outputs a low-level signal, and INT2_2.7V outputs a low-level signal. When the main battery is unplugged (BAT_DET_INT outputs a high level), Q13 is turned off, so the power supply path from the backup battery 70 to the system power supply 60 is disconnected. At the same time, Q16 is turned on, Q10 is turned on, but since Q15 is turned off, Q11 is also turned off, so the power supply path from the backup battery 70 to the RTC is disconnected.

[0058] In some embodiments, Figure 5As shown, the first detection module 20 includes a first detection chip U2, a first pin of the first detection chip U2 is connected to the second switch tube module 50, and is connected to the working power supply through a resistor R78, a third pin of the first detection chip U2 is respectively connected to the fourth pin of the first detection chip U2 and the backup battery 70, and is grounded through a capacitor C4, and a fifth pin of the first detection chip U2 is connected to the second pin of the first detection chip U2 through a capacitor C12, and is grounded; and / or

[0059] The second detection module 30 includes a second detection chip U5, the first pin of the second detection chip U5 is respectively connected to the first switch tube module 40 and the second switch tube module 50, and is connected to the working power supply through the resistor R12, the third pin of the second detection chip U5 is respectively connected to the fourth pin of the second detection chip U5 and the backup battery 70, and is grounded through the capacitor C15, and the fifth pin of the second detection chip U5 is connected to the second pin of the second detection chip U5 through the capacitor C18 and is grounded.

[0060] The voltage detection chip of this embodiment may be a detection chip of model SGM803-SXN3L-TR.

[0061] For example, Figure 4 As shown, the power supply module 10 includes a DCDC chip, the tenth pin of the DCDC chip is respectively connected to the first switch tube module 40 and the first pin of the DCDC chip, and is connected to the fifth pin of the DCDC chip via a resistor R57, the sixth pin of the DCDC chip is connected to the system power supply 60, and is connected to the fourth pin of the DCDC chip via a resistor R69, and is connected to the third pin of the DCDC chip via resistors R69 and R79 and is grounded, and the seventh pin of the DCDC chip is connected to the ninth pin of the DCDC chip via inductors L5 and L9 connected in parallel.

[0062] Alternatively, the backup battery 70 of this embodiment may be a lithium-ion supercapacitor.

[0063] In another preferred embodiment, the mobile terminal of this embodiment includes a main battery and a backup battery 70, wherein the backup battery 70 is used to continue to power the mobile terminal when the main battery loses power, and also includes a power supply circuit connected to the backup battery 70, such as the mobile terminal backup battery of the above embodiment.

[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 present application realizes that the same backup battery can power both the system and the RTC through the cooperation of two voltage detection modules and two switch tube modules, thus achieving dual-purpose of the backup battery, saving RTC battery materials and reducing production costs.

[0066] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present utility model.

[0067] 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 power supply circuit for a backup battery of a mobile terminal, comprising a power supply module (10) connected to a system power supply (60) and supplying power thereto, characterized in that: Also includes: A first detection module (20) connected to the backup battery (70) and the second switch tube module (50), used to detect whether the voltage of the backup battery (70) is higher than a first preset voltage value and output a first detection signal to the second switch tube module (50); A second detection module (30) connected to the backup battery (70), the first switch tube module (40) and the second switch tube module (50), and used to detect whether the voltage of the backup battery (70) is higher than a second preset voltage value and output a second detection signal to the first switch tube module (40) and the second switch tube module (50), respectively; the second preset voltage value is greater than the first preset voltage value; The first switch tube module (40) is connected between the power supply module (10) and the backup battery (70), and is used to adjust the on-off between the power supply module (10) and the backup battery (70) according to the second detection signal; The second switch tube module (50) is connected between an external system real-time clock power supply (80) and the backup battery (70), and is used to adjust the on / off between the system real-time clock power supply (80) and the backup battery (70) according to the first detection signal and the second detection signal.

2. The power supply circuit of the mobile terminal backup battery according to claim 1, characterized in that: The first switch tube module (40) comprises a PMOS tube Q9 and a transistor Q13, the source of the PMOS tube Q9 is connected to the backup battery (70), and is respectively connected to the gate of the PMOS tube Q9 and the collector of the transistor Q13 via a resistor R38, the drain of the PMOS tube Q9 is connected to the power supply module (10), the base of the transistor Q13 is connected to the second detection module (30) via a resistor R46, is connected to the emitter of the transistor Q13 via a resistor R48, and is grounded.

3. The power supply circuit of the mobile terminal backup battery according to claim 1, characterized in that: The second switch tube module (50) comprises a MOS tube Q10, a transistor Q16, a MOS tube Q11 and a transistor Q15; the source of the MOS tube Q10 is connected to the backup battery (70), and is respectively connected to the gate of the MOS tube Q10 and the emitter of the transistor Q16 via a resistor R80; the base of the transistor Q16 is connected to the second detection module (30) via a resistor R51; the collector of the transistor Q16 is grounded; the drain of the MOS tube Q10 is connected to the source of the MOS tube Q11, and is respectively connected to the gate of the MOS tube Q11 and the collector of the transistor Q15 via a resistor R40; the base of the transistor Q15 is connected to the first detection module (20) via a resistor R50, and is connected to the emitter of the transistor Q15 via a resistor R77 and is grounded; the drain of the MOS tube Q11 is connected to the system real-time clock power supply (80).

4. The power supply circuit of the mobile terminal backup battery according to claim 1, characterized in that: When the second detection module (30) detects that the voltage of the backup battery (70) is higher than a second preset voltage value, the second detection signal input to the first switch tube module (40) is a high-level signal, and at this time, the first switch tube module (40) is turned on and the second switch tube module (50) is turned off, thereby making the power supply module (10) and the backup battery (70) conductive, so as to form a power supply path for the system power supply (60); When the second detection module (30) detects that the voltage of the backup battery (70) is lower than the second preset voltage value, and when the first detection module (20) detects that the voltage of the backup battery (70) is higher than the first preset voltage value, the second detection signal and the first detection signal input to the second switch tube module (50) are respectively a low level signal and a high level signal. At this time, the second switch tube module (50) is turned on and the first switch tube module (40) is turned off, thereby making the system real-time clock power supply (80) and the backup battery (70) conductive, so as to form a power supply path for the system real-time clock power supply (80).

5. The power supply circuit of the mobile terminal backup battery according to claim 1, characterized in that: The power supply circuit further comprises a diode D3 for preventing backflow, wherein the positive electrode of the diode D3 is connected to the power supply module (10), and the negative electrode of the diode D3 is connected to the system power supply (60); and / or The power supply circuit also includes a diode D2 for preventing backflow, wherein the anode of the diode D2 is connected to the second switch tube module (50), and the cathode of the diode D2 is used to connect to the system real-time clock power supply (80).

6. The power supply circuit of the mobile terminal backup battery according to claim 5, characterized in that: The power supply circuit further comprises a third switch tube module (90) connected in parallel with the diode D3, the impedance generated by the third switch tube module (90) when turned on is smaller than the impedance generated by the diode D3, and the control input end of the third switch tube module (90) is used to input an on or off control signal corresponding to the state of the main battery.

7. The power supply circuit of the mobile terminal backup battery according to claim 6, characterized in that: The third switch tube module (90) comprises a PMOS tube Q12 and a transistor Q14, the drain of the PMOS tube Q12 is connected to the anode of the diode D3, the source of the PMOS tube Q12 is connected to the cathode of the diode D3, and is respectively connected to the gate of the PMOS tube Q12 and the collector of the transistor Q14 via a resistor R44, the base of the transistor Q14 is connected to one end of a resistor R31, and is connected to the emitter of the transistor Q14 via a resistor R32, and is grounded, and the other end of the resistor R31 is used to receive an on or off control signal.

8. The power supply circuit of the mobile terminal backup battery according to claim 1, characterized in that: The first detection module (20) comprises a first detection chip U2, a first pin of the first detection chip U2 is connected to the second switch tube module (50), and is connected to a working power supply via a resistor R78, a third pin of the first detection chip U2 is respectively connected to a fourth pin of the first detection chip U2 and the backup battery (70), and is grounded via a capacitor C4, and a fifth pin of the first detection chip U2 is connected to a second pin of the first detection chip U2 via a capacitor C12, and is grounded; and / or The second detection module (30) comprises a second detection chip U5, wherein a first pin of the second detection chip U5 is respectively connected to the first switch tube module (40) and the second switch tube module (50), and is connected to a working power supply via a resistor R12, a third pin of the second detection chip U5 is respectively connected to a fourth pin of the second detection chip U5 and the backup battery (70), and is grounded via a capacitor C15, and a fifth pin of the second detection chip U5 is connected to a second pin of the second detection chip U5 via a capacitor C18, and is grounded.

9. The power supply circuit of the mobile terminal backup battery according to any one of claims 1 to 8, characterized in that: The power supply module (10) comprises a DCDC chip, the tenth pin of the DCDC chip is respectively connected to the first switch tube module (40) and the first pin of the DCDC chip, and is connected to the fifth pin of the DCDC chip via a resistor R57, the sixth pin of the DCDC chip is connected to the system power supply (60), and is connected to the fourth pin of the DCDC chip via a resistor R69, and is connected to the third pin of the DCDC chip via the resistors R69 and R79 and is grounded, and the seventh pin of the DCDC chip is connected to the ninth pin of the DCDC chip via an inductor L5 and an inductor L9 connected in parallel; and / or The backup battery (70) is a lithium-ion supercapacitor; and / or The first preset voltage value is 2.5V, and the second preset voltage value is 2.7V.

10. A mobile terminal, comprising a main battery and a backup battery (70), wherein the backup battery (70) is used to continue to supply power to the mobile terminal when the main battery loses power, characterized in that: It also includes a power supply circuit of the mobile terminal backup battery according to any one of claims 1 to 9, which is connected to the backup battery (70).

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