Battery fuel gauge, electronic device, and method for determining state of charge of battery

Abstract

A battery fuel gauge (100), an electronic device, and a method for determining the state of charge of a battery. The battery fuel gauge (100) is used for detecting the state of charge of a target battery (201) in a battery circuit (200), and comprises: a power supply unit (110) used for outputting power supply voltage; a bias voltage unit (120) connected to the power supply unit (110) and used for converting the power supply voltage into bias voltage; a differential sampling unit (130) connected to the bias voltage unit (120) and connected to a unit under test (202) in the battery circuit (200), wherein the differential sampling unit (130) is used for outputting voltage difference data on the basis of the voltage of the unit under test (202) and the bias voltage; and a control unit (140) connected to the differential sampling unit (130) and the bias voltage unit (120) and used for sampling the bias voltage outputted by the bias voltage unit (120) and the voltage difference data outputted by the differential sampling unit (130), and obtaining the state of charge of the target battery (201) on the basis of the difference between the voltage difference data and the bias voltage. The accuracy of the acquired state of charge of the target battery (201) can be improved.

Description

Battery fuel gauges, electronic devices and methods for determining battery capacity

[0001] This application claims priority to Chinese Patent Application No. 202510054334.5, filed on January 13, 2025, entitled "Battery Fume Meter, Electronic Device and Method for Determining Battery Power", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery testing technology, specifically to a battery fuel gauge, electronic device, and method for determining battery capacity. Background Technology

[0003] Currently, in various electronic devices equipped with batteries, the control unit typically calculates the battery's charge level by reading the battery voltage provided by the battery management unit. However, directly obtaining the battery voltage from the battery management unit has the problem of significant measurement errors, resulting in low accuracy of the battery charge level obtained from the battery voltage. Consequently, it fails to provide users with accurate battery charge information, thus degrading the user experience. Summary of the Invention

[0004] In view of this, this application provides a battery fuel gauge, an electronic device, and a method for determining battery capacity, to improve the accuracy of obtaining the capacity of a target battery. The technical solution of this application is as follows:

[0005] A battery fuel gauge is disclosed for detecting the charge level of a target battery in a battery circuit. The battery fuel gauge includes: a power supply unit for outputting a power supply voltage; a bias voltage unit connected to the power supply unit for converting the power supply voltage into a bias voltage; a differential sampling unit connected to the bias voltage unit and connected to a device under test in the battery circuit, the differential sampling unit outputting differential voltage data based on the voltage of the device under test and the bias voltage; and a control unit connected to the differential sampling unit and the bias voltage unit for sampling the bias voltage output by the bias voltage unit and the differential voltage data output by the differential sampling unit, and obtaining the charge level of the target battery based on the difference between the differential voltage data and the bias voltage.

[0006] In one embodiment of this application, the unit under test is connected to the positive and negative terminals of the target battery. The positive terminal of the target battery includes the ground terminal of the power circuit of the target battery, and the negative terminal of the target battery includes the battery ground terminal.

[0007] In one embodiment of this application, the differential sampling unit includes a differential amplifier circuit connected to the unit under test and the bias voltage unit, for receiving the voltage of the unit under test and the bias voltage, and outputting the differential voltage data based on the voltage of the unit under test and the bias voltage.

[0008] In one embodiment of this application, the differential sampling unit further includes a filtering circuit connected to the differential amplifier circuit and the control unit, used to filter the differential pressure data and then transmit it to the control unit.

[0009] In one embodiment of this application, the differential amplifier circuit includes a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor; the first input terminal of the first amplifier is connected to the positive terminal of the target battery and the first terminal of the unit under test through the first resistor, and the second input terminal of the first amplifier is connected to the negative terminal of the target battery and the second terminal of the unit under test through the second resistor; the first input terminal of the first amplifier is also connected to the output terminal of the first amplifier through the third resistor, and the second input terminal of the first amplifier receives the bias voltage through the fourth resistor; the first capacitor is connected in parallel with the unit under test.

[0010] In one embodiment of this application, the filter circuit includes a fifth resistor and a second capacitor; the first end of the fifth resistor is connected to the output terminal of the differential amplifier circuit, and the second end of the fifth resistor is connected to the control unit; the first end of the second capacitor is connected to the second end of the fifth resistor, and the second end of the second capacitor is grounded.

[0011] In one embodiment of this application, the bias voltage unit includes: a voltage divider circuit connected to the power supply unit, used to divide the power supply voltage and output a divided voltage; and a voltage follower circuit connected to the voltage divider circuit, used to convert the divided voltage into the bias voltage and output it to the differential sampling unit and the control unit.

[0012] In one embodiment of this application, the voltage divider circuit includes a sixth resistor and a seventh resistor, and the voltage follower circuit includes a second amplifier, a third capacitor, and a fourth capacitor; the first input terminal of the second amplifier is connected to the output terminal, the second input terminal of the second amplifier is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor is used to receive the supply voltage, and the second input terminal of the second amplifier is also grounded through the seventh resistor and the third capacitor respectively; the output terminal of the second amplifier is grounded through the fourth capacitor and connected to the differential sampling unit and the control unit.

[0013] In one embodiment of this application, the power supply unit includes a power chip, a fifth capacitor, and a sixth capacitor; the input terminal of the power chip is used to receive the power supply voltage and is grounded through the fifth capacitor; the ground terminal of the power chip is used to ground; the output terminal of the power chip is used to output the power supply voltage and is grounded through the sixth capacitor.

[0014] In one embodiment of this application, the output terminal of the power chip is also connected to the control unit to provide a reference voltage to the control unit.

[0015] In one embodiment of this application, the difference between the differential pressure data and the bias voltage is equal to n times the voltage of the unit under test, where n is the amplification factor of the differential amplifier circuit.

[0016] In one embodiment of this application, the current value flowing through the unit under test is the same as the current value flowing through the target battery, and the unit under test is a sampling resistor.

[0017] A second aspect of this application provides an electronic device, including a battery circuit and the aforementioned battery fuel gauge.

[0018] A third aspect of this application provides a method for determining battery charge, applied to a battery fuel gauge. The battery fuel gauge is used to detect the charge of a target battery in a battery circuit. The battery fuel gauge includes: a power supply unit, a bias voltage unit, and a differential sampling unit; the power supply unit is used to output a power supply voltage; the bias voltage unit is connected to the power supply unit and is used to convert the power supply voltage into a bias voltage; the differential sampling unit is connected to the bias voltage unit and to a device under test in the battery circuit, and the differential sampling unit is used to output differential voltage data based on the voltage of the device under test and the bias voltage; the method includes: sampling the bias voltage output by the bias voltage unit and the differential voltage data output by the differential sampling unit; and obtaining the charge of the target battery based on the difference between the differential voltage data and the bias voltage.

[0019] It is understood that this application outputs a power supply voltage through a power supply unit, which is then converted into a bias voltage by a bias voltage unit and transmitted to a differential sampling unit and a control unit. The differential sampling unit is connected to the target battery through the unit under test in the battery circuit to obtain the voltage difference data between the voltage of the unit under test and the bias voltage. The obtained voltage difference data is transmitted to the control unit. Since the control unit also receives the bias voltage, it can sample the bias voltage and voltage difference data through the same analog-to-digital conversion module. When calculating, the bias voltage and voltage difference data are subtracted to eliminate the error caused by the sampling of the analog-to-digital conversion module, thereby improving the accuracy of obtaining the power of the target battery. Attached Figure Description

[0020] Figure 1 is a schematic block diagram of a battery power meter provided in an embodiment of this application.

[0021] Figure 2 is a schematic block diagram of a differential sampling unit provided in an embodiment of this application.

[0022] Figure 3 is a circuit diagram of a differential sampling unit provided in an embodiment of this application.

[0023] Figure 4 is a schematic block diagram of a bias voltage unit provided in an embodiment of this application.

[0024] Figure 5 is a circuit diagram of a bias voltage unit provided in an embodiment of this application.

[0025] Figure 6 is a circuit diagram of a power supply unit provided in an embodiment of this application.

[0026] Figure 7 is a flowchart illustrating a method for determining battery power according to an embodiment of this application. Detailed Implementation

[0027] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0028] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0029] Currently, in various electronic devices equipped with batteries, the control unit typically calculates the battery's charge level by reading the battery voltage provided by the battery management unit. However, directly obtaining the battery voltage from the battery management unit has the problem of significant measurement errors, resulting in low accuracy of the battery charge level obtained from the battery voltage. Consequently, it fails to provide users with accurate battery charge information, thus degrading the user experience.

[0030] This application provides a battery fuel gauge, an electronic device, and a method for determining battery power, which improves the accuracy of obtaining the power of a target battery.

[0031] Please refer to Figure 1, which is a schematic block diagram of a battery fuel gauge provided in an embodiment of this application. The battery fuel gauge 100 is used to detect the charge of the target battery 201 in the battery circuit 200. The battery fuel gauge 100 includes a power supply unit 110, a bias voltage unit 120, a differential sampling unit 130, and a control unit 140.

[0032] In this embodiment, the power supply unit 110 is used to output a power supply voltage. The bias voltage unit 120 is connected to the power supply unit 110 and is used to convert the power supply voltage into a bias voltage. The differential sampling unit 130 is connected to the unit under test 202 in the battery circuit 200. The unit under test 202 is connected to the target battery 201, and the differential sampling unit 130 is also connected to the bias voltage unit 120. The differential sampling unit 130 is used to output differential voltage data based on the voltage of the unit under test 202 and the bias voltage. In some embodiments, the unit under test 202 can be the target battery 201, that is, the differential sampling unit 130 is directly connected to the target battery 201 in the battery circuit 200.

[0033] The control unit 140 is connected to the differential sampling unit 130 and the bias voltage unit 120. The control unit 140 is used to sample the bias voltage output by the bias voltage unit 120 and the differential voltage data output by the differential sampling unit 130, and obtain the charge of the target battery 201 based on the difference between the differential voltage data and the bias voltage.

[0034] In some embodiments, in an electronic device equipped with the battery power meter 100 described above, the control unit 140 may be the main controller of the electronic device.

[0035] The power supply voltage output by the power supply unit 110 can also be transmitted to the control unit 140. That is, the control unit 140 receives the power supply voltage from the power supply unit 110 as a voltage reference source, thereby improving the accuracy of the control unit 140 when digitally sampling the differential pressure data.

[0036] It is understood that this application outputs a power supply voltage through the power supply unit 110, and the bias voltage unit 120 converts the power supply voltage into a bias voltage and transmits it to the differential sampling unit 130 and the control unit 140. The differential sampling unit 130 is connected to the target battery 201 through the test unit 202 in the battery circuit 200 to obtain the voltage difference data between the voltage of the test unit 202 and the bias voltage. The obtained voltage difference data is transmitted to the control unit 140. Since the control unit 140 receives the bias voltage at the same time, the control unit 140 can sample the bias voltage and voltage difference data through the same analog-to-digital conversion module. When calculating, the bias voltage and voltage difference data are subtracted to eliminate the error caused by the sampling of the analog-to-digital conversion module, thereby improving the accuracy of obtaining the power of the target battery.

[0037] In some embodiments, the unit under test 202 is connected to the positive and negative terminals of the target battery 201. The positive terminal of the target battery 201 includes the ground terminal of the power circuit of the target battery 201, and the negative terminal of the target battery 201 includes the battery ground terminal, so as to avoid signal crosstalk between the power circuit of the target battery 201 and the differential sampling unit 130, thereby further improving the calculation accuracy of the battery power.

[0038] The current flowing through the test unit 202 is the same as the current flowing through the target battery 201. The current of the test unit 202 can be obtained by calculating the voltage of the test unit 202, and then the charge of the target battery 202 can be calculated based on the current of the target battery 202.

[0039] Please refer to Figure 2, which is a schematic block diagram of a differential sampling unit 130 provided in an embodiment of this application. The differential sampling unit 130 includes a differential amplifier circuit 131 and a filter circuit 132.

[0040] The differential amplifier circuit 131 is connected to the unit under test 202 and the bias voltage unit 120, and is used to receive the voltage and bias voltage of the unit under test 202, and output differential voltage data according to the voltage and bias voltage of the unit under test 202.

[0041] The filter circuit 132 is connected to the differential amplifier circuit 131 and the control unit 140, and is used to filter the differential pressure data before transmitting it to the control unit 140.

[0042] Please refer to Figure 3, which is a circuit diagram of a differential sampling unit 130 provided in an embodiment of this application. The differential sampling unit 130 includes a differential amplifier circuit 131 and a filter circuit 132.

[0043] In this embodiment of the application, the unit under test 202 in the battery circuit 200 is a sampling resistor R0. The first end of the sampling resistor R0 is connected to the positive terminal of the target battery 201 and the first input terminal of the differential amplifier circuit 131, and the second end of the sampling resistor R0 is connected to the negative terminal of the target battery 201 and the second input terminal of the differential amplifier circuit 131.

[0044] The positive terminal of the target battery 201 includes the ground terminal PGND of the power circuit of the target battery 201, and the negative terminal of the target battery 201 includes the battery ground terminal GND_BAT.

[0045] The differential amplifier circuit 131 includes a first amplifier A1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1. The first input terminal -IN1 of the first amplifier A1 is connected via the first resistor R1 to the positive terminal of the target battery 201 (the power circuit ground terminal PGND) and the first terminal of the unit under test 202 (sampling resistor R0). The second input terminal +IN1 of the first amplifier A1 is connected via the second resistor R2 to the negative terminal of the target battery 201 (the battery ground terminal GND_BAT) and the second terminal of the unit under test 202 (sampling resistor R0). The first input terminal -IN1 of the first amplifier A1 is also connected to the output terminal OUT1 via the third resistor R3, and the second input terminal +IN1 of the first amplifier A1 receives the bias voltage Vref via the fourth resistor R4. The first capacitor C1 is connected in parallel with the unit under test 202 (sampling resistor R0).

[0046] It is understood that in this embodiment, the first operational amplifier A1 amplifies the voltage difference across the sampling resistor R0 by a preset factor and then performs differential processing with the bias voltage Vref to output voltage difference data. Therefore, the difference between the voltage difference data and the bias voltage is equal to n times the voltage of the unit under test 202, where n is the amplification factor of the differential amplifier circuit. For example, when the amplification factor of the first operational amplifier A1 is 10 times, then V... sum =Vref-(V 差 ×10), where V sum For differential pressure data, V 差 This represents the voltage difference across the sampling resistor R0.

[0047] The filter circuit 132 includes a fifth resistor R5 and a second capacitor C2. The first end of the fifth resistor R5 is connected to the output terminal OUT1 of the differential amplifier circuit 131, and the second end of the fifth resistor R5 is connected to the control unit 140. The first end of the second capacitor C2 is connected to the second end of the fifth resistor R5, and the second end of the second capacitor C2 is grounded.

[0048] Please refer to Figure 4, which is a schematic block diagram of a bias voltage unit 120 provided in an embodiment of this application. The bias voltage unit 120 includes a voltage divider circuit 121 and a voltage follower circuit 122.

[0049] Voltage divider circuit 121 is connected to power supply unit 110 and is used to receive the power supply voltage output by power supply unit 110, divide the power supply voltage and output the divided voltage. Voltage follower circuit 122 is connected to voltage divider circuit 121 and is used to convert the divided voltage into a bias voltage and output it to differential sampling unit 130 and control unit 140.

[0050] Please refer to Figure 5, which is a circuit diagram of a bias voltage unit 120 provided in an embodiment of this application. The bias voltage unit 120 includes a voltage divider circuit 121 and a voltage follower circuit 122. The voltage divider circuit 121 includes a sixth resistor R6 and a seventh resistor R7. The voltage follower circuit 122 includes a second amplifier A2, a third capacitor C3, and a fourth capacitor C4.

[0051] In this embodiment, the first input terminal -IN2 of the second amplifier A2 is connected to the output terminal OUT2. The second input terminal +IN2 of the second amplifier A2 is connected to the first terminal of the sixth resistor R6, and the second terminal of the sixth resistor R6 is used to receive the supply voltage V. The second input terminal +IN2 of the second amplifier A2 is also grounded through the seventh resistor R7 and the third capacitor C3. The output terminal OUT2 of the second amplifier A2 is grounded through the fourth capacitor C4 and connected to the differential sampling unit 130 and the control unit 140.

[0052] It can be understood that in the circuit of the bias voltage unit 120, the supply voltage V is input to the second amplifier A2 after passing through the sixth resistor R6 and the seventh resistor R7, forming a voltage follower circuit. This circuit can convert the supply voltage V into a bias voltage Vref after passing through the second amplifier A2, while improving the anti-interference capability of the bias voltage Vref and making the bias voltage Vref more stable, thereby improving the sampling accuracy of the differential sampling unit 130.

[0053] Please refer to Figure 6, which is a circuit diagram of a power supply unit 110 provided in an embodiment of this application. The power supply unit 110 includes a power chip U1, a fifth capacitor C5, and a sixth capacitor C6.

[0054] In this embodiment, the input terminal IN of the power chip U1 is used to receive the power supply voltage VCC and is grounded through the fifth capacitor C5. The ground terminal GND of the power chip U1 is used for grounding. The output terminal OUT of the power chip U1 is used to output the power supply voltage V and is grounded through the sixth capacitor C6.

[0055] In this embodiment, the control unit 140 is further configured to, based on the sampling resistance, amplification factor, bias voltage Vref, and differential voltage data V of the differential sampling unit 130... sum The high-precision battery current of the target battery 201 is obtained, and the charge of the target battery 201 is obtained based on the battery current and the real-time voltage of the target battery 201.

[0056] For example, the sampling resistance of the differential sampling unit 130 is the same as the sampling resistor R0 in the above embodiment, and the amplification factor of the differential sampling unit 130 is the same as the amplification factor of the first amplifier A1 (10 in the example). Then, according to the formula: V sum =Vref-(V 差×10), V 差 =I×R0, and the high-precision battery current I can be obtained.

[0057] In some embodiments, the output terminal OUT of the power chip U1 is also connected to the control unit 140 to provide a reference voltage for the control unit 140. Since the reference voltage output by the power chip U1 is stable and accurate, the accuracy of the analog-to-digital conversion module of the control unit 140 during sampling can be improved.

[0058] In this embodiment, after obtaining the battery current and real-time voltage, the control unit 140 can obtain the real-time power of the target battery 201 based on the battery current and real-time voltage. By integrating the real-time power and dividing it by the rated capacity of the target battery 201, the current charging or discharging percentage of the target battery 201 can be obtained. During discharging, the control unit 140 subtracts the aforementioned percentage from the remaining percentage of the target battery 201 to obtain the current capacity of the target battery 201. During charging, the control unit 140 adds the aforementioned percentage to the remaining percentage of the target battery 201 to obtain the current capacity of the target battery 201.

[0059] In some embodiments, the control unit 140 can be connected to the battery management unit of the target battery 201 to obtain the real-time voltage of the target battery 201, or the battery fuel gauge 100 can also be provided with a voltage sampling unit, which is connected to the positive terminal and the negative terminal of the target battery 201 respectively, for collecting the real-time voltage of the target battery 201 and transmitting it to the control unit 140.

[0060] Among them, the control unit 140 can also adjust the differential pressure data V sum The relationship between the magnitude of the bias voltage Vref and the current bias voltage Vref determines whether the target battery 201 is currently in a discharging or charging state.

[0061] This application also provides an electronic device, including a target battery 201 and a battery fuel gauge from any of the above embodiments. It is understood that the beneficial effects of the electronic device can be referenced from the beneficial effects of the battery fuel gauge in the foregoing embodiments, and will not be repeated here. The electronic device can be an intelligent robot such as a lawnmower, and the control unit 140 can be the main controller of the lawnmower.

[0062] Please refer to Figure 7, which is a flowchart illustrating a method for determining battery power according to an embodiment of this application. The method for determining battery power is applied to a battery fuel gauge, which detects the power of a target battery in the battery circuit. The battery fuel gauge includes a power supply unit, a bias voltage unit, and a differential sampling unit as described in any of the above embodiments.

[0063] The power supply unit outputs the supply voltage. The bias voltage unit is connected to the power supply unit and converts the supply voltage into a bias voltage. The differential sampling unit is connected to the bias voltage unit and also to the unit under test in the battery circuit. The differential sampling unit outputs differential voltage data based on the voltage of the unit under test and the bias voltage.

[0064] The method for determining battery power includes the following steps:

[0065] Step S71: Sample the bias voltage output by the bias voltage unit and the differential voltage data output by the differential sampling unit.

[0066] Step S72: Obtain the target battery's charge based on the difference between the differential pressure data and the bias voltage.

[0067] In the embodiments of this application, the beneficial effects of the method for determining battery power can be referred to the beneficial effects of the battery power meter in any of the foregoing embodiments, and will not be repeated here.

[0068] This application also provides a computer storage medium storing a computer program that, when executed by a processor, causes the processor to perform the aforementioned method for determining battery power.

[0069] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital versatile discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0070] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.

[0071] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A battery fuel gauge, characterized in that, The battery fuel gauge is used to detect the charge level of a target battery in a battery circuit, and the battery fuel gauge includes: The power supply unit is used to output the power supply voltage; A bias voltage unit, connected to the power supply unit, is used to convert the power supply voltage into a bias voltage; A differential sampling unit is connected to the bias voltage unit and to the unit under test in the battery circuit. The differential sampling unit is used to output differential voltage data based on the voltage of the unit under test and the bias voltage. The control unit is connected to the differential sampling unit and the bias voltage unit, and is used to sample the bias voltage output by the bias voltage unit and the differential voltage data output by the differential sampling unit, and obtain the charge of the target battery based on the difference between the differential voltage data and the bias voltage.

2. The battery fuel gauge as described in claim 1, characterized in that, The unit under test is connected to the positive and negative terminals of the target battery. The positive terminal of the target battery includes the grounding terminal of the power circuit of the target battery, and the negative terminal of the target battery includes the battery grounding terminal.

3. The battery fuel gauge as described in claim 1, characterized in that, The differential sampling unit includes: A differential amplifier circuit, connected to the unit under test and the bias voltage unit, is used to receive the voltage of the unit under test and the bias voltage, and output the differential voltage data based on the voltage of the unit under test and the bias voltage.

4. The battery fuel gauge as described in claim 3, characterized in that, The differential sampling unit further includes: A filtering circuit, connected to the differential amplifier circuit and the control unit, is used to filter the differential pressure data before transmitting it to the control unit.

5. The battery fuel gauge as described in claim 3, characterized in that, The differential amplifier circuit includes a first amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor; The first input terminal of the first amplifier is connected to the positive terminal of the target battery and the first terminal of the unit under test through the first resistor, and the second input terminal of the first amplifier is connected to the negative terminal of the target battery and the second terminal of the unit under test through the second resistor. The first input terminal of the first amplifier is also connected to the output terminal of the first amplifier through a third resistor, and the second input terminal of the first amplifier receives the bias voltage through a fourth resistor; the first capacitor is connected in parallel with the unit under test.

6. The battery fuel gauge as described in claim 4, characterized in that, The filter circuit includes a fifth resistor and a second capacitor; The first end of the fifth resistor is connected to the output terminal of the differential amplifier circuit, and the second end of the fifth resistor is connected to the control unit; the first end of the second capacitor is connected to the second end of the fifth resistor, and the second end of the second capacitor is grounded.

7. The battery fuel gauge as described in claim 1, characterized in that, The bias voltage unit includes: A voltage divider circuit, connected to the power supply unit, is used to divide the power supply voltage and output a divided voltage. A voltage follower circuit, connected to the voltage divider circuit, is used to convert the divided voltage into the bias voltage and output it to the differential sampling unit and the control unit.

8. The battery fuel gauge as described in claim 7, characterized in that, The voltage divider circuit includes a sixth resistor and a seventh resistor, and the voltage follower circuit includes a second amplifier, a third capacitor, and a fourth capacitor. The first input terminal of the second amplifier is connected to the output terminal, the second input terminal of the second amplifier is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor is used to receive the power supply voltage, the second input terminal of the second amplifier is also grounded through the seventh resistor and the third capacitor respectively; the output terminal of the second amplifier is grounded through the fourth capacitor and connected to the differential sampling unit and the control unit.

9. The battery fuel gauge as described in claim 1, characterized in that, The power supply unit includes a power chip, a fifth capacitor, and a sixth capacitor. The input terminal of the power chip is used to receive the power supply voltage and is grounded through the fifth capacitor; the ground terminal of the power chip is used to ground; the output terminal of the power chip is used to output the power supply voltage and is grounded through the sixth capacitor.

10. The battery fuel gauge as described in claim 9, characterized in that, The output terminal of the power chip is also connected to the control unit to provide a reference voltage to the control unit.

11. The battery fuel gauge as described in claim 3, characterized in that, The difference between the differential pressure data and the bias voltage is equal to n times the voltage of the unit under test, where n is the amplification factor of the differential amplifier circuit.

12. The battery fuel gauge as described in claim 1, characterized in that, The current value flowing through the unit under test is the same as the current value flowing through the target battery, and the unit under test is a sampling resistor.

13. An electronic device, characterized in that, Includes a battery circuit and a battery power meter as described in any one of claims 1 to 12.

14. A method for determining battery charge, characterized in that, An application is made to a battery fuel gauge, which is used to detect the charge of a target battery in a battery circuit. The battery fuel gauge includes: a power supply unit, a bias voltage unit, and a differential sampling unit. The power supply unit is used to output the power supply voltage; the bias voltage unit is connected to the power supply unit and is used to convert the power supply voltage into a bias voltage; the differential sampling unit is connected to the bias voltage unit and to the unit under test in the battery circuit, and the differential sampling unit is used to output differential voltage data based on the voltage of the unit under test and the bias voltage. The method includes: The bias voltage output by the bias voltage unit and the differential voltage data output by the differential sampling unit are sampled. The charge of the target battery is obtained based on the difference between the differential pressure data and the bias voltage.

15. The method for determining battery charge as described in claim 14, characterized in that, The unit under test is connected to the positive and negative terminals of the target battery. The positive terminal of the target battery includes the grounding terminal of the power circuit of the target battery, and the negative terminal of the target battery includes the battery grounding terminal.

16. The method for determining battery charge as described in claim 14, characterized in that, The differential sampling unit includes: A differential amplifier circuit, connected to the unit under test and the bias voltage unit, is used to receive the voltage of the unit under test and the bias voltage, and output the differential voltage data based on the voltage of the unit under test and the bias voltage.

17. The method for determining battery charge as described in claim 16, characterized in that, The difference between the differential pressure data and the bias voltage is equal to n times the voltage of the unit under test, where n is the amplification factor of the differential amplifier circuit.

18. The method for determining battery charge as described in claim 16, characterized in that, The differential sampling unit further includes: A filtering circuit, connected to the differential amplifier circuit and the control unit, is used to filter the differential pressure data before transmitting it to the control unit.

19. The method for determining battery charge as described in claim 14, characterized in that, The bias voltage unit includes: A voltage divider circuit, connected to the power supply unit, is used to divide the power supply voltage and output a divided voltage. A voltage follower circuit, connected to the voltage divider circuit, is used to convert the divided voltage into the bias voltage and output it to the differential sampling unit and the control unit.

20. The method for determining battery charge as described in claim 14, characterized in that, The current value flowing through the unit under test is the same as the current value flowing through the target battery, and the unit under test is a sampling resistor.

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