Power supply current detection circuit and battery management system

Abstract

The utility model provides a power supply current detection circuit, comprising a sampling and operational amplification module connected between a power supply output terminal and a grounding terminal; sampling points are arranged on an output line of the sampling and operational amplification module; the sampling and operation processing module is connected with a sampling point; the sampling and operation processing module is used for collecting sampling point voltage and calculating a current value output by the power supply output end according to the sampling point voltage; the operational amplifier voltage-stabilizing power supply module comprises a voltage-stabilizing unit, one end of which is connected with the power supply output end, and the other end of which is connected with one end of the voltage-dividing unit, and is used for providing stable working voltage for the sampling and operational amplifier module; the positive and negative power supply ends of the sampling and operational amplification module are connected to the two ends of the voltage stabilizing unit in parallel, the other end of the voltage dividing unit is grounded, and the enabling output end of the power supply current detection circuit is connected with the control end of the voltage dividing unit and used for dividing voltage with the voltage stabilizing unit. And the voltage of the negative power supply end of the sampling and operational amplification module is increased.

Description

Technical Field

[0001] This utility model relates to the field of power supply current detection, and in particular to a power supply current detection circuit and a battery management system. Background Technology

[0002] Currently, most current sensing solutions on the market use a small resistor and a differential operational amplifier (op-amp) to directly sample the op-amp's output voltage and calculate the current flowing through the small resistor. In this method, if the small resistor is placed at the power supply end, a rail-to-rail op-amp with a high common-mode voltage tolerance is required, and the op-amp's output voltage can only approach the power rail at most. Op-amps meeting these requirements are expensive. Because the current in a low-voltage battery management system is around 100 mA, and a large sampling resistor would result in a large voltage drop, only milliohm-level resistors can be used. This leads to a small range of op-amp output voltage variation, making it impossible for the subsequent ADC module to accurately measure the system current.

[0003] Therefore, providing a low-cost solution for increasing the negative power rail supply voltage of the operational amplifier and using a low common-mode voltage operational amplifier, thereby reducing costs without affecting sampling accuracy, has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] To overcome the aforementioned technical deficiencies, the purpose of this invention is to provide a power supply current detection circuit and a battery management system. This invention, by constructing a regulated power supply module as the positive and negative power supply circuits for the sampling and operational amplification modules, ensures that: as the power supply voltage increases, the negative power rail voltage also increases accordingly, while simultaneously providing a stable power supply voltage. This reduces the circuit's requirement for common-mode voltage tolerance at the power input terminal, allowing the use of integrated operational amplifiers with lower common-mode voltage, thereby reducing costs. The elimination of the need for a separate power supply further saves hardware costs.

[0005] This utility model discloses a power supply current detection circuit, including: a sampling and operational amplification module, and a sampling and operational processing module;

[0006] The sampling and operational amplification module is connected between the power output terminal and the ground terminal; sampling points are provided on the output line of the sampling and operational amplification module.

[0007] The sampling and processing module is connected to the sampling point; the sampling and processing module is used to collect the voltage of the sampling point and calculate the current value output by the power supply output terminal based on the voltage of the sampling point.

[0008] It also includes: operational amplifier voltage regulator power supply module;

[0009] The operational amplifier voltage regulator power supply module includes: a voltage regulator unit and a voltage divider unit;

[0010] One end of the voltage regulator unit is connected to the power output terminal, and the other end is connected to one end of the voltage divider unit;

[0011] The positive and negative power supply terminals of the sampling and operational amplification module are connected to the two ends of the voltage regulation unit; the voltage regulation unit is used to provide a stable operating voltage for the sampling and operational amplification module.

[0012] The other end of the voltage divider unit is grounded, and the enable output terminal of the power supply current detection circuit is connected to the control terminal of the voltage divider unit; the voltage divider unit is used to divide the voltage together with the voltage regulator unit after the enable output terminal outputs a current sampling enable signal; and

[0013] This is used to increase its own voltage division when the voltage at the power output terminal increases, thereby increasing the voltage at the negative power supply terminal of the sampling and operational amplifier module.

[0014] Optionally, the voltage regulating unit includes: a first resistor and a Zener diode;

[0015] The first end of the first resistor is connected to the power output terminal, and the second end of the first resistor is connected to one end of the voltage divider circuit.

[0016] The negative and positive terminals of the Zener diode are respectively connected to the first terminal of the first resistor and the...

[0017] The second terminal; the Zener diode is used to stabilize the voltage across the first resistor;

[0018] The positive and negative power input terminals of the sampling and operational amplification module are respectively connected to the first...

[0019] The first and second terminals of a resistor.

[0020] Optionally, the voltage divider unit includes a first transistor and a second resistor;

[0021] The collector of the first transistor is connected to the second terminal of the first resistor, and the emitter is connected to the...

[0022] One end of the second resistor is connected to the enable output terminal via its base; the other end of the second resistor is grounded.

[0023] When the enable output terminal receives a current sampling enable signal, the first transistor is turned on, causing the first transistor, the second resistor, and the first resistor to divide the voltage output by the power supply output terminal.

[0024] Furthermore, when the voltage input to the power input terminal increases, the voltage division between the first transistor and the second resistor increases accordingly, thereby increasing the voltage at the negative power supply terminal of the sampling and operational amplifier module.

[0025] Optionally, the operational amplifier voltage regulator power supply module further includes a third resistor and a fourth resistor;

[0026] The third resistor is connected in series between the enable output terminal and the base of the first transistor;

[0027] One end of the fourth resistor is connected to the base of the first transistor, and the other end is connected to the other end of the second resistor and grounded.

[0028] Optionally, the sampling and operational amplification module includes: an operational amplifier and a sampling resistor;

[0029] One end of the sampling resistor is connected to the power supply output terminal;

[0030] The positive input terminal of the operational amplifier is coupled to the other end of the sampling resistor, and the negative input terminal is coupled to one end of the sampling resistor.

[0031] The positive and negative power supply terminals of the operational amplifier are respectively connected to the first and second terminals of the first resistor; a sampling point is provided on the output line of the operational amplifier.

[0032] The sampling and processing module is connected to the sampling point and is used to collect the voltage of the sampling point and calculate the current value of the current flowing through the sampling resistor based on the voltage of the sampling point.

[0033] Optionally, the power supply current detection circuit further includes a fifth resistor, a sixth resistor, and a seventh resistor;

[0034] The fifth resistor is connected between the other end of the sampling resistor and the positive input terminal of the operational amplifier;

[0035] One end of the sixth resistor is connected to one end of the sampling resistor, and the other end of the sixth resistor is connected to the negative input terminal of the operational amplifier.

[0036] One end of the seventh resistor is connected to the output of the operational amplifier, and the other end is coupled to the sampling point.

[0037] Optionally, the sampling and operational amplification module further includes: a second transistor and an eighth resistor;

[0038] The emitter of the second transistor is connected to the other end of the sixth resistor and the negative output terminal of the operational amplifier at the same node; the base of the second transistor is connected to the other end of the seventh resistor, and the collector is connected to one end of the eighth resistor;

[0039] The other end of the eighth resistor is connected to the ground terminal; the sampling point is provided between the eighth resistor and the collector of the second transistor.

[0040] Optionally, the sampling and processing module is used to acquire the voltage at the sampling point and use equation (1),

[0041] According to the sampling point voltage U o Calculate the current value Io flowing through the sampling resistor;

[0042] Io=(Uo*R6) / (R0*R8) Equation (1);

[0043] Among them, R6, R0 and R8 are the resistance values ​​of the sixth resistor, the sampling resistor and the eighth resistor, respectively.

[0044] This utility model also provides a battery management system, including a power current detection circuit as described in any of the preceding claims.

[0045] Compared with existing technologies, the above technical solution has the following advantages:

[0046] 1. By using simple discrete components such as transistors, Zener diodes, and resistors, a positive and negative power supply circuit for the operational amplifier is built, providing a stable power supply voltage for the operational amplifier. This eliminates the need for a power supply chip, simplifies the circuit, and saves costs.

[0047] 2. As the voltage of T30 increases, the voltage of the negative power supply rail of the op-amp also increases, thereby reducing the circuit's requirements for the common-mode voltage tolerance of the op-amp input terminal. In applications, integrated op-amps with lower common-mode voltages can be selected, thereby reducing costs.

[0048] 3. The operation amplifier's amplification region is equipped with transistors that further amplify the output voltage, improving the acquisition accuracy of the ADC module. Attached Figure Description

[0049] Figure 1 A schematic diagram of a power supply current detection circuit;

[0050] Figure 2 A schematic diagram of a source current detection circuit according to an embodiment of this utility model;

[0051] Figure label:

[0052] 1-Operational amplifier voltage regulator power supply module;

[0053] 11-Voltage Regulator Unit;

[0054] 12-Voltage divider unit;

[0055] 2-Sampling and operational amplification module;

[0056] 3-Sampling and processing module;

[0057] OP1 - Operational amplifier;

[0058] R0 - Sampling resistor;

[0059] R1~R8 - the first resistor to the eighth resistor;

[0060] Q1 - First transistor;

[0061] Q2 - Second transistor;

[0062] D1 - Zener diode. Detailed Implementation

[0063] The advantages of this utility model are further illustrated below with reference to the accompanying drawings and specific embodiments.

[0064] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0065] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0066] In the description of this utility model, it should be understood that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0067] In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0068] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrating this invention and has no specific meaning in itself. Therefore, "module" and "part" can be used interchangeably.

[0069] Figure 1 A power supply current detection circuit is shown. Its specific detection scheme is as follows: Figure 1 As shown, the sampling resistor R0 is connected in series to the output terminal of power supply T30. The positive and negative input terminals of operational amplifier OP1 are connected to both ends of resistor R0 through resistors R2 and R1, respectively. The positive power supply terminal VCC of operational amplifier OP1 is connected to a fixed power supply, such as a 5V power supply, and the negative power supply terminal GND is directly connected to T31 (the 0 level of the entire vehicle). The output terminal of operational amplifier OP1 is connected to an ADC module to collect its output voltage U0, and the output current of power supply T30 is calculated based on U0 to realize power supply current detection. Since the normal voltage range of T30 is 6-18V (the voltage here refers to the voltage relative to T31), and the transient voltage may reach 34V, the input terminal of operational amplifier OP1 must be able to withstand at least 18V steady-state and 34V transient common-mode voltage, and a certain safety margin should be reserved when selecting it. Operational amplifiers that meet this requirement are relatively expensive.

[0070] Therefore, in order to reduce the requirements for the common-mode voltage at the input terminal of the operational amplifier and reduce costs, this utility model provides a power supply current detection circuit, which cleverly achieves the effect of raising the voltage at the negative power supply terminal of the operational amplifier, thus solving the above-mentioned technical problems.

[0071] Figure 2 A circuit for power supply current detection according to an embodiment of the present invention is shown. (See also...) Figure 2 The power supply current detection circuit is connected to the power supply output terminal. The detection circuit includes: a sampling and operational amplification module 2 and a sampling and operational processing module 3.

[0072] The sampling and operational amplification module 2 is connected between the power output terminal and the ground terminal; sampling points are provided on the output line of the sampling and operational amplification module 2.

[0073] The sampling and processing module 3 is connected to the sampling point; the sampling and processing module 3 is used to collect the voltage of the sampling point and calculate the current value output by the power supply output terminal based on the voltage of the sampling point.

[0074] The power supply current detection circuit provided by this utility model further includes: an operational amplifier voltage regulator module 1; the operational amplifier voltage regulator module 1 includes: a voltage regulator unit 11 and a voltage divider unit 12.

[0075] One end of the voltage regulator unit 11 is connected in series to the power output terminal, and the other end is connected to one end of the voltage divider unit 12; the positive and negative power supply terminals of the sampling and operational amplifier module 2 are connected in parallel to the two ends of the voltage regulator unit 11; the voltage regulator unit 11 is used to provide a stable operating voltage for the sampling and operational amplifier module 2.

[0076] The other end of the voltage divider unit 12 is grounded, and the enable output terminal of the power supply current detection circuit is connected to the control terminal of the voltage divider unit 12. The voltage divider unit 12 is used to divide the voltage together with the voltage regulator unit 11 when the enable output terminal outputs a current sampling enable signal; and it is used to increase its own voltage division when the voltage of the power supply output terminal increases, so that the voltage of the negative power supply terminal of the sampling and operational amplifier module 2 increases, that is, the voltage of the negative power supply terminal of the sampling and operational amplifier module 2 rises, which can reduce the requirements for the common-mode voltage range of the operational amplifier module, saving costs. At the same time, the voltage across the voltage regulator unit 11 can remain unchanged, so that it can provide a stable voltage for the operational amplifier module. In addition, there is no need to set up a separate 5V power supply, further saving expenses.

[0077] In a further optional embodiment, the voltage regulator unit 11 includes: a first resistor R1 and a Zener diode D1; a first end of the first resistor R1 is connected to the power output terminal, and a second end of the first resistor R1 is connected to one end of the voltage divider unit 12; the negative and positive terminals of the Zener diode D1 are respectively connected to the first and second ends of the first resistor R1; the Zener diode D1 is used to stabilize the voltage across the first resistor R1. The positive and negative power input terminals of the sampling and operational amplifier module 2 are respectively connected to the first and second ends of the first resistor R1.

[0078] In this scheme, the voltage across the first resistor R1, which is connected in parallel to the positive and negative power supply terminals of the sampling and operational amplifier module 2, determines the power supply voltage of the sampling and operational amplifier module 2. The Zener diode D1 is connected in parallel across the first resistor R1 for voltage regulation. Because of the presence of the Zener diode D1, the voltage across the first resistor R1 will not increase with the increase of T30, thus achieving the effect of using T30 to provide a stable working power supply for the sampling and operational amplifier module 2, while simplifying a 5V power supply and saving costs.

[0079] Based on this, in order to raise the negative power supply voltage and reduce the requirement for the common-mode voltage at the operational amplifier input, in a further preferred embodiment, the voltage divider unit 12 includes a first transistor Q1 and a second resistor R2. The collector of the first transistor Q1 is connected to the second terminal of the first resistor R1, the emitter is connected to one end of the second resistor R2, and the base is connected to the enable output terminal; the other end of the second resistor R2 is grounded. When the enable output terminal receives a current sampling enable signal, the first transistor Q1 is turned on, causing the first transistor Q1, the second resistor R2, and the first resistor R1 to divide the voltage input to the power supply output terminal. Furthermore, when the voltage input to the power supply terminal increases, the voltage division by the first transistor Q1 and the second resistor R2 increases accordingly, causing the voltage at the negative power supply output terminal of the sampling and operational amplifier module 2 to increase, i.e., the negative power supply voltage U5 increases.

[0080] In this scheme, the first transistor Q1, the second resistor R2, and the first resistor R1 work together to divide the voltage. When the microcontroller's enable output terminal outputs a current sampling enable signal T30_CURRENT_EN, and this signal is high, the first transistor Q1 is turned on and operates in amplification mode. Current flows through the first resistor R1, the second resistor R2, and the first transistor Q1, dividing the voltage of T30. At this time, the power supply voltage of OP1 is equal to the voltage across R1, supplying power to OP1. As the voltage of T30 increases, the voltage across the first transistor Q1 and the second resistor R2 also increases, and the negative power rail voltage U5 increases accordingly, while the voltage division of the first resistor R1 remains unchanged. This achieves the technical effect of increasing the common-mode voltage range of the input of the sampling and operational amplifier module 2, while ensuring that fluctuations in the power supply voltage T30 do not affect the normal operation of the sampling and operational amplifier module 2, ensuring the stability of the power supply voltage at the positive and negative power supply terminals. It also avoids the impact of voltage fluctuations on the current sampling accuracy.

[0081] The positive and negative power supply terminals of the sampling and operational amplification module 2 are respectively Figure 2 The VCC and GND terminals of OP1.

[0082] In a specific example, this invention selects a 5V regulated Zener diode D1 connected in parallel to the operational amplifier's power supply terminal, ensuring that both the positive and negative power supplies are also 5V. When T30 is 18V, the positive power supply VCC of OP1 is 18V. Due to the presence of Zener diode D1, the positive power supply VCC is 5V relative to the negative power supply GND, resulting in a negative power supply GND voltage U5 of 13V. Since the negative power supply voltage is boosted to 13V, when the input signal is 18V, the positive power supply voltage only needs to withstand a 5V common-mode voltage, significantly reducing the requirement for the common-mode voltage at the power input terminal.

[0083] In a further specific optional scheme, the operational amplifier voltage regulator power supply module 1 also includes a third resistor R3 and a fourth resistor R4. The third resistor R3 is connected in series between the enable output terminal and the base of the first transistor Q1; the fourth resistor R4 serves as a pull-down resistor, with one end connected to the base of the first transistor Q1 and the other end connected to the other end of the second resistor R2 and grounded.

[0084] In a further embodiment of this utility model, the sampling and operational amplification module 2 includes: operational amplifier OP1 and sampling resistor R0.

[0085] The sampling resistor R0 is connected in series to the output line of the power output terminal; one end of the sampling resistor R0 is connected to the power output terminal; and the other end is connected to the T30-PROT terminal.

[0086] The positive input terminal of the operational amplifier OP1 is coupled to the other end of the sampling resistor R0, and the negative input terminal is coupled to one end of the sampling resistor R0. The positive power supply terminal and the negative power supply input terminal VCC and GND of the operational amplifier OP1 are respectively connected to the first end and the second end of the first resistor R1. A sampling point is provided on the output line of the operational amplifier OP1, and its output terminal is connected to the ground terminal T31. The coupling can be a direct connection or an indirect connection.

[0087] The sampling and processing module 3 is connected to the sampling point and is used to acquire the voltage U0 at the sampling point, and calculate the current value I0 of the current flowing through the sampling resistor R0 based on the voltage U0. In a specific example, the sampling and processing module 3 is an ADC module.

[0088] Optionally, the power supply current detection circuit further includes a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The fifth resistor R5 is connected between the other end of the sampling resistor R0 and the positive input terminal of the operational amplifier OP1. One end of the sixth resistor R6 is connected to one end of the sampling resistor R0, and the other end is connected to the negative input terminal of the operational amplifier OP1. One end of the seventh resistor R7 is connected to the output terminal of the operational amplifier OP1, and the other end is coupled to the sampling point.

[0089] To further amplify the output voltage of operational amplifier OP1, in a preferred embodiment, the sampling and operational amplification module further includes: a second transistor Q2 and an eighth resistor R8; the emitter of the second transistor Q2 is connected to the other end of the sixth resistor and the negative output terminal of the operational amplifier at the same node; the base of the second transistor Q2 is connected to the other end of the seventh resistor, and the collector is connected to one end of the eighth resistor R8; the other end of the eighth resistor R8 is connected to the ground terminal; a sampling point is provided between the eighth resistor R8 and the collector of the second transistor Q2. The ADC module acquires the further amplified voltage at the sampling point, which can improve the acquisition accuracy of the ADC module. Here, the eighth resistor R8 serves as the sampling resistor for current I8, and the sampling point is provided between the eighth resistor R8 and the collector of the second transistor Q2.

[0090] Optionally, the sampling and processing module 3 is used to acquire the voltage at the sampling point and calculate the current value Io flowing through the sampling resistor R0 based on the voltage Uo at the sampling point using equation (1); Io = (Uo*R6) / (R0*R8) equation (1); where R6, R0, and R8 are the resistance values ​​of the sixth resistor R6, the sampling resistor R0, and the eighth resistor R8, respectively. The sampling and processing module 2 and the sampling and processing module 3 describe the process of acquiring, amplifying, and calculating the power supply current as follows:

[0091] When the current sampling enable signal T30_CURRENT_EN is input to the enable output terminal, and when T30 is powered normally, the current Io flows through the sampling resistor R0 simultaneously, generating a voltage difference U1-U2 across it. This voltage difference U1-U2 is proportional to Io, such as: Io=(U1-U2) / R0 (Equation 2).

[0092] Meanwhile, the operational amplifier voltage regulator module 1 provides a stable power supply voltage for the operational amplifier OP1. The operational amplifier OP1 operates in linear amplification mode. Based on its virtual short and virtual open characteristics, the voltages at the positive input terminal U3 and the negative input terminal U4 are almost equal, i.e., U4 = U3 (Equation 3). U2 and U3 are also approximately equal, i.e., U3 = U2 (Equation 4). The output voltage of the operational amplifier OP1 is amplified based on the voltage difference at the input terminals and output to the second transistor Q2. The second transistor Q2 operates in the amplification region. In this state, the collector current Ic and emitter current Ie of Q1 are almost equal. Therefore, the current I8 flowing through resistor R8 is approximately equal to the current I6 flowing through resistor R6, i.e., I8 = I6. Thus, the eighth resistor R8 serves as the sampling resistor for the current I8, I8 = I6 = (U1 - U4) / R6 (Equation 5). Due to the amplification effect of the second transistor Q2, the signal is further amplified and output as Uo. The microcontroller collects the voltage of Uo through the ADC module, and according to the simultaneous equations (2)-(5), obtains equation (1): Io=(Uo*R6) / (R0*R8). Based on the resistance values ​​of R0\R8\R6, I0 can be calculated. Thus, the current value Io is accurately measured and used to calculate the SOC (State of Charge) of the battery.

[0093] In summary, this invention constructs a positive and negative power supply circuit for the operational amplifier using simple discrete components such as transistors, Zener diodes, and resistors, providing a stable power supply voltage for the operational amplifier. It also eliminates the need for a power supply chip, simplifying the circuit and saving costs. Furthermore, as the T30 voltage increases, the voltage of the operational amplifier's negative power rail also increases, thereby reducing the circuit's requirements for the common-mode voltage tolerance of the operational amplifier's input. In applications, integrated operational amplifiers with lower common-mode voltages can be selected, further reducing costs.

[0094] This utility model also provides a battery management system, including a power current detection circuit as described in any of the preceding claims.

[0095] It should be noted that the embodiments of this utility model have better implementability and are not intended to limit this utility model in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of this utility model without departing from the content of the technical solution of this utility model shall still fall within the scope of the technical solution of this utility model.

Claims

1. A power supply current detection circuit, characterized in that, include: Sampling and amplification module, and sampling and processing module; The sampling and operational amplification module is connected between the power output terminal and the ground terminal; sampling points are provided on the output line of the sampling and operational amplification module. The sampling and processing module is connected to the sampling point; the sampling and processing module is used to collect the voltage of the sampling point and calculate the current value output by the power supply output terminal based on the voltage of the sampling point. Its characteristic is that it further includes: an operational amplifier voltage regulator power supply module; The operational amplifier voltage regulator power supply module includes: a voltage regulator unit and a voltage divider unit; One end of the voltage regulator unit is connected to the power output terminal, and the other end is connected to one end of the voltage divider unit; the positive and negative power supply terminals of the sampling and operational amplification module are connected to the two ends of the voltage regulator unit; the voltage regulator unit is used to provide a stable operating voltage for the sampling and operational amplification module. The other end of the voltage divider unit is grounded, and the enable output terminal of the power supply current detection circuit is connected to the control terminal of the voltage divider unit; the voltage divider unit is used to divide the voltage together with the voltage regulator unit after the enable output terminal outputs a current sampling enable signal; and This is used to increase its own voltage division when the voltage at the power output terminal increases, thereby increasing the voltage at the negative power supply terminal of the sampling and operational amplifier module.

2. The power supply current detection circuit as described in claim 1, characterized in that, The voltage regulator unit includes: a first resistor and a Zener diode; The first end of the first resistor is connected to the power output terminal, and the second end of the first resistor is connected to one end of the voltage divider unit. The negative and positive terminals of the Zener diode are respectively connected to the first and second terminals of the first resistor; the Zener diode is used to stabilize the voltage across the first resistor. The positive power input terminal and negative power input terminal of the sampling and operational amplification module are respectively connected to the first terminal and the second terminal of the first resistor.

3. The power supply current detection circuit as described in claim 2, characterized in that, The voltage divider unit includes a first transistor and a second resistor; The collector of the first transistor is connected to the second terminal of the first resistor, the emitter is connected to one terminal of the second resistor, and the base is connected to the enable output terminal; the other terminal of the second resistor is grounded. When the enable output terminal receives a current sampling enable signal, the first transistor is turned on, so that the first transistor, the second resistor, and the first resistor divide the voltage output by the power supply output terminal. Furthermore, when the voltage input to the power input terminal increases, the voltage division between the first transistor and the second resistor increases accordingly, thereby increasing the voltage at the negative power supply terminal of the sampling and operational amplifier module.

4. The power supply current detection circuit as described in claim 3, characterized in that, The operational amplifier voltage regulator power supply module also includes a third resistor and a fourth resistor; The third resistor is connected in series between the enable output terminal and the base of the first transistor; One end of the fourth resistor is connected to the base of the first transistor, and the other end is connected to the other end of the second resistor and grounded.

5. The power supply current detection circuit as described in claim 4, characterized in that, The sampling and operational amplification module includes: an operational amplifier and a sampling resistor; One end of the sampling resistor is connected to the power supply output terminal; The positive input terminal of the operational amplifier is coupled to the other end of the sampling resistor, and the negative input terminal is coupled to one end of the sampling resistor. The positive and negative power supply terminals of the operational amplifier are respectively connected to the first and second terminals of the first resistor; a sampling point is provided on the output line of the operational amplifier. The sampling and processing module is connected to the sampling point and is used to collect the voltage of the sampling point and calculate the current value of the current flowing through the sampling resistor based on the voltage of the sampling point.

6. The power supply current detection circuit as described in claim 5, characterized in that, The power supply current detection circuit also includes a fifth resistor, a sixth resistor, and a seventh resistor; The fifth resistor is connected between the other end of the sampling resistor and the positive input terminal of the operational amplifier; One end of the sixth resistor is connected to one end of the sampling resistor, and the other end of the sixth resistor is connected to the negative input terminal of the operational amplifier. One end of the seventh resistor is connected to the output of the operational amplifier, and the other end is coupled to the sampling point.

7. The power supply current detection circuit as described in claim 6, characterized in that, The sampling and operational amplification module further includes: a second transistor and an eighth resistor; The emitter of the second transistor is connected to the other end of the sixth resistor and the negative output terminal of the operational amplifier at the same node; the base of the second transistor is connected to the other end of the seventh resistor, and the collector is connected to one end of the eighth resistor; The other end of the eighth resistor is connected to the ground terminal; the sampling point is provided between the eighth resistor and the collector of the second transistor.

8. The power supply current detection circuit as described in claim 7, characterized in that, The sampling and processing module is used to collect the voltage at the sampling point and, using equation (1), calculate the voltage U at the sampling point. o Calculate the current value Io flowing through the sampling resistor; Io=(Uo*R6) / (R0*R8) Equation (1); Among them, R6, R0 and R8 are the resistance values ​​of the sixth resistor, the sampling resistor and the eighth resistor, respectively.

9. A battery management system, characterized in that, Includes the power supply current detection circuit as described in any one of claims 1-8.

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