Circuits and systems for extending the detection range of coulomb counters

Abstract

The present invention provides a circuit and system for expanding the detection range of a coulomb meter, comprising: a chip including a coulomb meter, a memory, and an internal processing module; the coulomb meter including an internal voltage divider circuit and an internal analog-to-digital converter; the input end of the internal voltage divider circuit is connected to the voltage input end of the chip, and the output end is connected to the input end of the internal analog-to-digital converter; the output end of the internal analog-to-digital converter is connected to the input end of the internal processing module, and the internal processing module is connected to the memory; an external voltage divider circuit is arranged outside the chip, the input end is connected to the battery voltage end, and the output end is connected to the voltage input end; a calibration circuit is arranged outside the chip, the first input end is connected to the battery voltage end, the second input end is connected to the output end of the external voltage divider circuit, and the output end is connected to the communication end of the internal processing module. Compared with the prior art, the present invention can use a coulomb meter in an application processor AP or a microcontroller unit MCU to measure the voltage of multiple series-connected batteries.

Description

Technical field

[0001] The present invention belongs to the technical field of circuit design, and in particular relates to a circuit and system for expanding the detection range of a coulomb counter. [Background Technology]

[0002] Please refer to Figure 1 Figure 1 shows a circuit diagram of a coulomb counter in the prior art, which can be used to detect battery charge. The principle is to indirectly obtain remaining battery charge information by detecting the battery voltage. The battery voltage is connected to VIN, divided by resistors R2 and R1, and then input into the analog-to-digital converter (ADC). The ADC converts the analog signal into a digital signal, outputting DATA as a digital signal. DATA can be a single-bit serial digital signal or a multi-bit parallel digital signal. These coulomb counters are often integrated into microcontrollers (MCUs) or application processors. These chips typically use low-voltage processes and generally only support a maximum voltage of 5V. Therefore, they can only detect the voltage of a single lithium-ion battery and cannot be used to detect the voltage of multiple lithium-ion batteries connected in series. In some system applications, multiple lithium-ion batteries can be connected in series to provide power, such as in Bluetooth speakers. (High-power speakers can achieve higher output power by connecting lithium-ion batteries in series, for example, resulting in louder volume or longer operating time.) However, in such applications, the application processor's coulomb counter cannot be used for direct measurement.

[0003] Therefore, it is necessary to provide a circuit and system for extending the detection range of the coulomb meter. [Summary of the invention]

[0004] The object of the present invention is to provide a circuit and system for expanding the detection range of a coulomb counter, which can measure the voltage of multiple series-connected batteries using a coulomb counter in an application processor AP or a microcontroller unit MCU.

[0005] According to one aspect of the present invention, the present invention provides a circuit for expanding the detection range of a coulomb counter, comprising: an integrated chip, comprising a coulomb counter, a memory, and an internal processing module, the coulomb counter comprising an internal voltage divider circuit and an internal analog-to-digital converter, the input end of the internal voltage divider circuit being connected to the voltage input end VIN of the integrated chip, and the output end thereof being connected to the input end of the internal analog-to-digital converter; the output end of the internal analog-to-digital converter being connected to the input end of the internal processing module, and the internal processing module being connected to the memory; an external voltage divider circuit being arranged outside the integrated chip, the input end of the external voltage divider circuit being connected to the battery voltage end VBAT, and the output end thereof being connected to the voltage input end VIN; a calibration circuit being arranged outside the integrated chip, the first input end of the calibration circuit being connected to the battery voltage end VBAT, the second input end thereof being connected to the output end of the external voltage divider circuit, and the output end thereof being connected to the communication port IO of the internal processing module.

[0006] Furthermore, the internal voltage-dividing circuit includes a second voltage-dividing resistor R2 and a first voltage-dividing resistor R1 connected in series to the voltage input terminal VIN and the ground terminal, and a connection node A between the second voltage-dividing resistor R2 and the first voltage-dividing resistor R1 serves as the output terminal of the internal voltage-dividing circuit; the external voltage-dividing circuit includes a fourth voltage-dividing resistor R4 and a third voltage-dividing resistor R3 connected in series to the battery voltage terminal VBAT and the ground terminal, and a connection node B between the fourth voltage-dividing resistor R4 and the third voltage-dividing resistor R3 serves as the output terminal of the external voltage-dividing circuit.

[0007] Furthermore, when the circuit for extending the coulomb counter detection range is in calibration mode, the voltage of the battery voltage terminal VBAT is a set voltage, and the set voltage is within the operating voltage range of the battery; the external voltage divider circuit is used to divide the set voltage, and the voltage of the connection node B is the output voltage of the external voltage divider circuit; the calibration circuit is used to measure the voltage of the battery voltage terminal VBAT and the voltage of the output end of the external voltage divider circuit, and transmit the measured voltage of the battery voltage terminal VBAT and the voltage of the output end of the external voltage divider circuit to the internal processing module; the internal processing module calculates a calibration value K2 based on the measured voltage of the battery voltage terminal VBAT and the voltage of the output end of the external voltage divider circuit, and stores the calibration value K2 in the memory, the calibration value K2 = VB / VBAT, wherein VBAT is the voltage of the battery voltage terminal VBAT measured by the calibration circuit, and VB is the voltage of the output end of the external voltage divider circuit measured by the calibration circuit.

[0008] Furthermore, when the circuit for extending the coulomb counter detection range is in normal use mode, the battery voltage terminal VBAT is connected to the battery. At this time, the voltage of the battery voltage terminal VBAT is equal to the voltage of the battery; the external voltage divider circuit is used to divide the voltage of the battery, and the voltage of the connection node B is the output voltage of the external voltage divider circuit; the internal voltage divider circuit is used to divide the voltage of the voltage input terminal VIN, and the voltage of the connection node A is the output voltage VA of the internal voltage divider circuit; the internal analog-to-digital converter is used to convert the output voltage VA of the internal voltage divider circuit into a corresponding digital signal DAT A, and outputs the digital signal DATA through its output end; the memory stores the calibration value K2 and the voltage divider ratio K1 of the internal voltage divider circuit, the voltage divider ratio K1=R2 / R1, wherein R2 is the resistance value of the second voltage divider resistor R2, and R1 is the resistance value of the first voltage divider resistor R1; the internal processing module reads the digital signal DATA output by the internal analog-to-digital converter, reads the calibration value K2 and the voltage divider ratio K1 from the memory, and substitutes them into formula 1 for calculation, VBAT=DATA*(1+K1) / K2 formula 1, wherein the calculated VBAT represents the voltage value of the battery.

[0009] Furthermore, the internal processing module obtains the remaining battery power of the battery corresponding to the calculated VBAT by looking up a table; and / or the internal processing module is an application processor or a micro control unit.

[0010] Furthermore, the calibration circuit includes a voltage source V1, a first external analog-to-digital converter, a second external analog-to-digital converter, and an external processing module, wherein the positive electrode of the voltage source V1 is connected to the battery voltage terminal VBAT, and the negative electrode thereof is grounded; the input end of the first external analog-to-digital converter is connected to the battery voltage terminal VBAT, and the output end thereof is connected to the first input end of the external processing module; the input end of the second external analog-to-digital converter is connected to the output end of the external voltage divider circuit, and the output end thereof is connected to the second input end of the external processing module; and the output end of the external processing module is connected to the communication port IO of the internal processing module.

[0011] Furthermore, when the circuit for extending the coulomb counter detection range is in calibration mode, the voltage source V1 provides the set voltage for the battery voltage terminal VBAT; the first external analog-to-digital converter measures the voltage of the battery voltage terminal VBAT and converts it into a corresponding digital signal D1, and outputs the digital signal D1 to the external processing module through its output terminal; the second external analog-to-digital converter measures the voltage at the output terminal of the external voltage divider circuit and converts it into a corresponding digital signal D2, and outputs the digital signal D2 to the external processing module through its output terminal; the external processing module transmits the received digital signal D1 and digital signal D2 to the internal processing module; the internal processing module calculates a calibration value K2 based on the received digital signal D1 and digital signal D2, and stores the calibration value K2 in the memory, wherein the calibration value K2 = D2 / D1, wherein D1 is the digital signal D1 output by the first external analog-to-digital converter, and V2 is the digital signal D2 output by the second external analog-to-digital converter.

[0012] Furthermore, the external processing module is an application processor or a micro control unit; and / or the external processing module is connected to the communication port 10 of the internal processing module through wired communication or wireless communication.

[0013] Furthermore, the battery includes a plurality of battery cells connected in series.

[0014] According to another aspect of the present invention, the present invention provides a system for extending the detection range of a coulomb counter, comprising: a battery; and a circuit for extending the detection range of a coulomb counter as described above.

[0015] Compared with the prior art, the present invention sets a corresponding circuit outside the application processor AP or the microcontroller unit MCU so that the coulomb meter in the application processor AP or the microcontroller unit MCU can measure the voltage of multiple batteries connected in series, thereby expanding the detection range of the coulomb meter.

Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0017] Figure 1 1 is a circuit diagram of a coulomb meter in the prior art;

[0018] Figure 2FIG1 is a schematic diagram of a circuit for extending the detection range of a coulomb counter in a calibration mode according to an embodiment of the present invention;

[0019] Figure 3 FIG. 1 is a circuit diagram of a circuit for extending the detection range of a coulomb counter in a normal use mode according to an embodiment of the present invention. [Specific implementation method]

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to separate or selective embodiments that are mutually exclusive of other embodiments. Unless otherwise specified, the terms "connected," "connected," and "connected" herein, indicating electrical connection, refer to direct or indirect electrical connection.

[0022] Please refer to Figure 2 As shown, it is a circuit diagram of a circuit for extending the detection range of a coulomb counter in a calibration mode in one embodiment of the present invention. Figure 3 As shown in FIG, it is a circuit diagram of a circuit for extending the detection range of a coulomb counter in a normal use mode in one embodiment of the present invention. Figure 2 and Figure 3 The circuit for extending the detection range of the coulomb counter shown indirectly obtains the remaining power information of the battery BATTERY by detecting the voltage of the battery BATTERY.

[0023] Depend on Figure 2 and Figure 3 It can be seen that the circuit for extending the detection range of the coulomb counter shown in the present invention includes an integrated chip 210 , an external voltage divider circuit 220 and a calibration circuit 230 .

[0024] Integrated chip 210 includes a coulomb counter 212, an internal processing module AP214, and a memory MEM216. Coulomb counter 212 includes an internal voltage divider circuit 2122 and an internal analog-to-digital converter ADC2124. The input of internal voltage divider circuit 2122 is connected to voltage input VIN of integrated chip 210, and its output is connected to the input of internal analog-to-digital converter ADC2124. The output of internal analog-to-digital converter ADC2124 is connected to the input of internal processing module AP214, which is connected to memory MEM216. External voltage divider circuit 220 is disposed outside integrated chip 210. The input of external voltage divider circuit 220 is connected to battery voltage VBAT, and the output of external voltage divider circuit 220 is connected to the output of external voltage divider circuit 220. The calibration circuit 230 is disposed outside the integrated chip 210 . A first input terminal of the calibration circuit 230 is connected to the battery voltage terminal VBAT, a second input terminal thereof is connected to the voltage input terminal VIN, and an output terminal thereof is connected to the communication port IO of the internal processing module AP214 .

[0025] exist Figure 2 and Figure 3 In the illustrated embodiment, the internal voltage-dividing circuit 2122 includes a second voltage-dividing resistor R2 and a first voltage-dividing resistor R1 connected in series with the voltage input terminal VIN and the ground terminal, respectively, and a connection node A between the second voltage-dividing resistor R2 and the first voltage-dividing resistor R1 serves as the output terminal of the internal voltage-dividing circuit 2122.

[0026] exist Figure 2 and Figure 3 In the illustrated embodiment, the external voltage-dividing circuit 220 includes a fourth voltage-dividing resistor R4 and a third voltage-dividing resistor R3 connected in series to the battery voltage terminal VBAT and the ground terminal, respectively. A connection node B between the fourth voltage-dividing resistor R4 and the third voltage-dividing resistor R3 serves as an output terminal of the external voltage-dividing circuit 220.

[0027] When the circuit for extending the detection range of the coulomb counter of the present invention is in calibration mode (see Figure 2), the voltage at the battery voltage terminal VBAT is a set voltage, the external voltage divider circuit 220 is used to divide the set voltage, and the voltage at the connection node B is the output voltage VB of the external voltage divider circuit 220; the calibration circuit 230 is used to measure the voltage at the battery voltage terminal VBAT and the voltage VB at the output terminal of the external voltage divider circuit 220 (i.e., the output voltage VB of the external voltage divider circuit 220), and transmit the measured voltages at the battery voltage terminal VBAT and the output voltage VB of the external voltage divider circuit 220 to the internal processing module AP214; the internal processing module AP214 calculates a calibration value K2 based on the measured voltage at the battery voltage terminal VBAT and the output voltage VB of the external voltage divider circuit 220, and stores the calibration value K2 in the memory MEM216. Calibration value K2 = VB / VBAT, where VBAT is the voltage at the battery voltage terminal VBAT measured by the calibration circuit 230, and VB is the voltage VB at the output terminal of the external voltage divider circuit 220 measured by the calibration circuit 230.

[0028] When the circuit for extending the detection range of the coulomb counter of the present invention is in normal use mode (see Figure 3 ), the battery voltage terminal VBAT is connected to the battery BATTERY. At this time, the voltage of the battery voltage terminal VBAT is equal to the voltage of the battery BATTERY; the external voltage divider circuit 220 is used to divide the voltage of the battery BATTERY, and the voltage connected to the node B is the output voltage VB of the external voltage divider circuit 220; the internal voltage divider circuit 2122 is used to divide the voltage of the voltage input terminal VIN, and the voltage connected to the node A is the output voltage VA of the internal voltage divider circuit 2122; the internal analog-to-digital converter ADC2124 is used to convert the output voltage VA of the internal voltage divider circuit 2122 into a corresponding digital signal DATA, and output it through The digital signal DATA is outputted from the terminal; the memory MEM216 stores the calibration value K2 and the voltage divider ratio K1 of the internal voltage divider circuit 2122, where the voltage divider ratio K1 = R2 / R1, where R2 is the resistance value of the second voltage divider resistor R2, and R1 is the resistance value of the first voltage divider resistor R1. The internal processing module AP214 reads the digital signal DATA outputted by the internal analog-to-digital converter ADC2124, reads the calibration value K2 and the voltage divider ratio K1 from the memory MEM216, and substitutes them into Formula 1 for calculation: VBAT = DATA*(1+K1) / K2. Formula 1, where the calculated VBAT represents the voltage value of the battery BATTERY. In one embodiment, the internal processing module AP214 obtains the remaining battery charge of the battery BATTERY corresponding to the calculated VBAT by looking up the table.

[0029] It should be noted that the voltage divider ratio K1 of the internal voltage divider circuit 2122 is fixed, and it is easy to achieve a high-precision resistance value ratio in the integrated chip 210. For example, the voltage divider ratio K1 is designed to be R2 / R1. A high-precision voltage divider ratio K1 can be achieved by matching the design in the layout, and the value of the voltage divider ratio K1 can also be stored in the memory MEM216.

[0030] exist Figure 2 In the illustrated embodiment, the calibration circuit 230 includes a voltage source V1, a first external analog-to-digital converter ADC_EX1 232, a second external analog-to-digital converter ADC_EX2 234, and an external processing module AP_EX 236. The positive electrode of the voltage source V1 is connected to the battery voltage terminal VBAT, and the negative electrode thereof is grounded. The input of the first external analog-to-digital converter ADC_EX1 232 is connected to the battery voltage terminal VBAT, and the output of the first external analog-to-digital converter ADC_EX1 232 is connected to the first input of the external processing module AP_EX 236. The input of the second external analog-to-digital converter ADC_EX2 234 is connected to the output of the external voltage divider circuit 220, and the output of the second external analog-to-digital converter ADC_EX2 234 is connected to the second input of the external processing module AP_EX 236. The output of the external processing module AP_EX 236 is connected to the communication port 10 of the internal processing module AP214.

[0031] exist Figure 2 In the specific embodiment shown, when the circuit for extending the detection range of the coulomb counter of the present invention is in calibration mode, the voltage source V1 provides a set voltage for the battery voltage terminal VBAT; the first external analog-to-digital converter ADC_EX1 232 measures the voltage of the battery voltage terminal VBAT and converts it into a corresponding digital signal D1, and outputs the digital signal D1 to the external processing module AP_EX 236 through its output terminal; the second external analog-to-digital converter ADC_EX2 234 measures the voltage VB at the output terminal of the external voltage divider circuit 220 and converts it into a corresponding digital signal D2, and outputs the digital signal D2 to the external processing module AP_EX 236 through its output terminal; the external processing module AP_EX 236 transmits the received digital signals D1 and D2 to the internal processing module AP214. The internal processing module AP214 calculates a calibration value K2 based on the received digital signal D1 (which is a digital signal corresponding to the measured voltage at the battery voltage terminal VBAT) and the digital signal D2 (which is a digital signal corresponding to the measured voltage VB at the output terminal of the external voltage divider circuit 220), and stores the calibration value K2 in the memory MEM216. The calibration value K2 = D2 / D1, where D1 is the digital signal D1 output by the first external analog-to-digital converter ADC_EX1 232, and D2 is the digital signal D2 output by the second external analog-to-digital converter ADC_EX2 234.

[0032] In one embodiment, the voltage source V1 provides a set voltage to the battery voltage terminal VBAT within the operating voltage range of the battery BATTERY. In one embodiment, the battery BATTERY includes multiple battery cells connected in series; the set voltage (or voltage source V1) is within the operating voltage range of the battery BATTERY (or the multiple battery cells connected in series). For example, for a battery cell connected in series, the typical operating voltage range is 5V to 9V, and one of these voltage values can be selected, for example, the set voltage (or voltage source V1) is 8V.

[0033] exist Figure 2 and Figure 3 In the illustrated embodiment, the internal processing module AP214 is an application processor AP (Application Processor). In another embodiment, the internal processing module AP214 may be a microcontroller unit MCU (Microcontroller Unit).

[0034] exist Figure 2 In the illustrated embodiment, the external processing module AP_EX 236 is an application processor AP. In another embodiment, the external processing module AP_EX 236 may be a microcontroller unit MCU.

[0035] In one embodiment, the external processing module AP_EX 236 is communicatively connected to the communication port 10 of the internal processing module AP 214 via wired or wireless communication. For example, the external processing module AP_EX 236 transmits the measured digital signals D1 and D2 to the internal processing module AP 214 in the integrated chip 210 via wired communication (e.g., via a wired communication interface such as GPIO, I2C, or I2S) or wireless communication (e.g., Bluetooth, Zigbee, Wi-Fi, etc.).

[0036] According to another aspect of the present invention, the present invention provides a system for extending the detection range of a coulomb meter, which includes a battery BATTERY, and Figure 2 and Figure 3 The circuit shown here extends the detection range of the coulomb counter.

[0037] In summary, the present invention provides an external voltage divider circuit 220 and a calibration circuit 230 outside the application processor AP or the microcontroller unit MCU, so that the coulomb counter 212 in the application processor AP or the microcontroller unit MCU can measure the voltage of multiple batteries connected in series, thereby expanding the detection range of the coulomb counter 212.

[0038] In the present invention, words such as "connect," "connected," "connect," and "connected" that indicate electrical connection, unless otherwise specified, represent direct or indirect electrical connection. A direct electrical connection refers to a direct connection between two or more objects without any intervening objects, while an indirect electrical connection refers to a connection between two or more objects with one or more intervening objects (e.g., electrical components or electrical units such as resistors, capacitors, inductors, switches, and filters).

[0039] It should be noted that any changes made by those skilled in the art to the specific embodiments of the present invention do not depart from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited to the aforementioned specific embodiments.

Claims

1. A circuit for extending the detection range of a coulomb counter, which is used to detect the voltage of a battery, characterized in that: It includes: An integrated chip comprising a coulomb counter, a memory, and an internal processing module, wherein the coulomb counter comprises an internal voltage divider circuit and an internal analog-to-digital converter, wherein the input of the internal voltage divider circuit is connected to a voltage input terminal VIN of the integrated chip, and the output of the internal voltage divider circuit is connected to the input terminal of the internal analog-to-digital converter; the output terminal of the internal analog-to-digital converter is connected to the input terminal of the internal processing module, and the internal processing module is connected to the memory; An external voltage divider circuit is provided outside the integrated chip, wherein the input end of the external voltage divider circuit is connected to the battery voltage terminal VBAT, and the output end thereof is connected to the voltage input terminal VIN; A calibration circuit is provided outside the integrated chip, wherein a first input terminal of the calibration circuit is connected to the battery voltage terminal VBAT, a second input terminal of the calibration circuit is connected to the output terminal of the external voltage divider circuit, and an output terminal of the calibration circuit is connected to the communication port IO of the internal processing module. The calibration circuit includes a voltage source V1, a first external analog-to-digital converter, a second external analog-to-digital converter and an external processing module. The positive electrode of the voltage source V1 is connected to the battery voltage terminal VBAT, and the negative electrode thereof is grounded; The input terminal of the first external analog-to-digital converter is connected to the battery voltage terminal VBAT, and the output terminal thereof is connected to the first input terminal of the external processing module; The input end of the second external analog-to-digital converter is connected to the output end of the external voltage divider circuit, and the output end thereof is connected to the second input end of the external processing module; The output end of the external processing module is connected to the communication port 10 of the internal processing module.

2. The circuit for extending the detection range of the coulomb counter according to claim 1, characterized in that: The internal voltage-dividing circuit includes a second voltage-dividing resistor R2 and a first voltage-dividing resistor R1 connected in series to the voltage input terminal VIN and the ground terminal, and a connection node A between the second voltage-dividing resistor R2 and the first voltage-dividing resistor R1 serves as an output terminal of the internal voltage-dividing circuit; The external voltage-dividing circuit includes a fourth voltage-dividing resistor R4 and a third voltage-dividing resistor R3 connected in series to the battery voltage terminal VBAT and the ground terminal, respectively. A connection node B between the fourth voltage-dividing resistor R4 and the third voltage-dividing resistor R3 serves as an output terminal of the external voltage-dividing circuit.

3. The circuit for extending the detection range of the coulomb counter according to claim 2, characterized in that: When the circuit for extending the detection range of the coulomb counter is in calibration mode, The voltage of the battery voltage terminal VBAT is a set voltage, and the set voltage is within the operating voltage range of the battery; The external voltage divider circuit is used to divide the set voltage, and the voltage of the connection node B is the output voltage of the external voltage divider circuit; The calibration circuit is used to measure the voltage of the battery voltage terminal VBAT and the voltage of the output terminal of the external voltage divider circuit, and transmit the measured voltage of the battery voltage terminal VBAT and the voltage of the output terminal of the external voltage divider circuit to the internal processing module; The internal processing module calculates a calibration value K2 based on the measured voltage of the battery voltage terminal VBAT and the voltage of the output terminal of the external voltage divider circuit, and stores the calibration value K2 in the memory. The calibration value K2 = VB / VBAT, wherein VBAT is the voltage of the battery voltage terminal VBAT measured by the calibration circuit, and VB is the voltage of the output terminal of the external voltage divider circuit measured by the calibration circuit.

4. The circuit for extending the detection range of the coulomb counter according to claim 3, characterized in that: When the circuit for extending the detection range of the coulomb counter is in normal use mode, The battery voltage terminal VBAT is connected to a battery. At this time, the voltage of the battery voltage terminal VBAT is equal to the voltage of the battery; The external voltage-dividing circuit is used to divide the voltage of the battery, and the voltage of the connection node B is the output voltage of the external voltage-dividing circuit; The internal voltage divider circuit is used to divide the voltage of the voltage input terminal VIN, and the voltage of the connection node A is the output voltage VA of the internal voltage divider circuit; The internal analog-to-digital converter is used to convert the output voltage VA of the internal voltage divider circuit into a corresponding digital signal DATA, and output the digital signal DATA through its output terminal; The memory stores the calibration value K2 and the voltage dividing ratio K1 of the internal voltage dividing circuit, wherein the voltage dividing ratio K1=R2 / R1, wherein R2 is the resistance value of the second voltage dividing resistor R2, and R1 is the resistance value of the first voltage dividing resistor R1; The internal processing module reads the digital signal DATA output by the internal analog-to-digital converter, reads the calibration value K2 and the voltage divider ratio K1 from the memory, and brings them into formula 1 for calculation. VBAT=DATA*(1+K1) / K2 Formula 1, The calculated VBAT represents the voltage value of the battery.

5. The circuit for extending the detection range of the coulomb counter according to claim 4, characterized in that: The internal processing module obtains the remaining battery power of the battery corresponding to the calculated VBAT according to a table lookup; and / or The internal processing module is an application processor or a micro control unit.

6. The circuit for extending the detection range of the coulomb counter according to claim 1, characterized in that: When the circuit for extending the detection range of the coulomb counter is in calibration mode, The voltage source V1 provides a set voltage for the battery voltage terminal VBAT; The first external analog-to-digital converter measures the voltage of the battery voltage terminal VBAT, converts the voltage into a corresponding digital signal D1, and outputs the digital signal D1 to the external processing module through its output terminal; The second external analog-to-digital converter measures the voltage at the output end of the external voltage divider circuit, converts the voltage into a corresponding digital signal D2, and outputs the digital signal D2 to the external processing module through its output end; The external processing module transmits the received digital signal D1 and digital signal D2 to the internal processing module; The internal processing module calculates a calibration value K2 based on the received digital signal D1 and the digital signal D2, and stores the calibration value K2 in the memory. The calibration value K2 = D2 / D1, wherein D1 is the digital signal output by the first external analog-to-digital converter, and D2 is the digital signal output by the second external analog-to-digital converter.

7. The circuit for extending the detection range of the coulomb counter according to claim 6, characterized in that: The external processing module is an application processor or a micro control unit; and / or The external processing module is connected to the communication port 10 of the internal processing module through wired communication or wireless communication.

8. The circuit for extending the detection range of a coulomb counter according to claim 1, wherein: The battery includes a plurality of battery cells connected in series.

9. A system for extending the detection range of a coulomb counter, characterized in that: It includes: Battery; A circuit for extending the detection range of a coulomb counter as claimed in any one of claims 1 to 8.

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