Current sampling circuit and device

Abstract

The utility model discloses a current sampling circuit and device, and relates to the field of control circuits. In the circuit, a first end of a first sampling resistor is connected with an inverted input end of a first operational amplifier, a second end of the first sampling resistor is connected with a normal input end of the first operational amplifier, and an output end of the first operational amplifier is connected with a second input end of a digital signal processor; the first end of the second sampling resistor is connected with the inverting input end of the second operational amplifier, the second end of the second sampling resistor is connected with the non-inverting input end of the second operational amplifier, and the output end of the second operational amplifier is connected with the first input end of the digital signal processor. At the moment, dual-channel operational amplifier sampling is realized through a first sampling resistor and a first operational amplifier which are connected with each other and a second sampling resistor and a second operational amplifier which are connected with each other, so that the precision of current sampling is improved. And the sampling channel is formed by the sampling resistor and the operational amplifier, so that the circuit cost is reduced.

Description

Technical Field

[0001] The utility model relates to the field of control circuits, in particular to a current sampling circuit and a device. Background Art

[0002] With the rapid development of automobile chargers, existing automobile chargers can have both charging and discharging functions, where the current corresponding to the charging function can be a forward current, and the current corresponding to the discharging function can be a reverse current. Existing automobile chargers sample forward and reverse currents through current transformers or analog sampling chips. At this time, the accuracy of the collected current is low, and the cost of the current transformers or analog sampling chips is high.

[0003] In view of the above-mentioned prior art, finding out how to collect current with higher accuracy while reducing the cost is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0004] The purpose of the utility model is to provide a current sampling circuit and device, which is used to solve the problem that the accuracy of the collected current is low and the cost of the current transformer or the analog sampling chip is high when sampling the forward current and the reverse current using a current transformer or an analog sampling chip.

[0005] In order to solve the above technical problems, the utility model provides a current sampling circuit, including: a first sampling resistor, a second sampling resistor, a first operational amplifier, a second operational amplifier, and a digital signal processor;

[0006] The first end of the first sampling resistor is connected to the inverting input end of the first operational amplifier, the second end of the first sampling resistor is connected to the non-inverting input end of the first operational amplifier, and the output end of the first operational amplifier is connected to the second input end of the digital signal processor;

[0007] The first end of the second sampling resistor is connected to the inverting input end of the second operational amplifier, the second end of the second sampling resistor is connected to the non-inverting input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first input end of the digital signal processor.

[0008] On the other hand, it also includes: a synchronous rectification circuit;

[0009] The synchronous rectification circuit includes: a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube; the gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube are used to receive control signals for controlling the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube;

[0010] The drain of the first switch tube is connected to the drain of the third switch tube, the source of the first switch tube is connected to the drain of the second switch tube, the source of the third switch tube is connected to the drain of the fourth switch tube, the source of the second switch tube is connected to the source of the fourth switch tube, and the common end formed by the source of the second switch tube and the source of the fourth switch tube is connected to the first end of the first sampling resistor.

[0011] On the other hand, it also includes: a resonant circuit;

[0012] The resonant circuit includes: an inductor and a capacitor; the first end of the inductor serves as the input end of the resonant circuit, the second end of the inductor is connected to the first end of the capacitor, and the second end of the capacitor serves as the output end of the resonant circuit and is connected to a common end formed by a source of a first switching tube and a drain of a second switching tube.

[0013] On the other hand, it also includes: a transformer; the primary side of the transformer is connected to the voltage conversion circuit, the first end of the secondary side of the transformer is connected to the input end of the resonant circuit, and the second end of the secondary side of the transformer is connected to the common end formed by the source of the third switching tube and the drain of the fourth switching tube.

[0014] On the other hand, it also includes: a filter; the input end of the filter is connected to the common end formed by the drain of the first switch tube and the drain of the third switch tube, and the output end of the filter is connected to the common end formed by the source of the second switch tube and the source of the fourth switch tube.

[0015] On the other hand, it also includes: a battery; the input end of the battery is connected to the input end of the filter, the output end of the battery is connected to the output end of the filter, the maximum voltage value of the battery is 500V, and the minimum voltage value of the battery is 0V.

[0016] On the other hand, the filter includes: a common mode inductor, a first filter capacitor, and a second filter capacitor;

[0017] The first end of the first filter capacitor is connected to the common end formed by the drain of the first switching tube and the drain of the third switching tube, and the second end of the first filter capacitor is connected to the common end formed by the source of the second switching tube and the source of the fourth switching tube; the first end of the common-mode inductor is connected to the first end of the first filter capacitor, the second end of the common-mode inductor is connected to the second end of the first filter capacitor, the third end of the common-mode inductor is connected to the first end of the second filter capacitor, the fourth end of the common-mode inductor is connected to the second end of the second filter capacitor, the first end of the second filter capacitor is connected to the input end of the battery, and the second end of the second filter capacitor is connected to the output end of the battery.

[0018] On the other hand, it also includes: a prompt device; the prompt device is connected to the digital signal processor.

[0019] In order to solve the above technical problems, the utility model also provides a current sampling device including all the current sampling circuits mentioned above.

[0020] On the other hand, it also includes: a charger; the charger is connected to the current sampling circuit.

[0021] The current sampling circuit provided by the utility model, wherein the first end of the first sampling resistor is connected to the inverting input end of the first operational amplifier, the second end of the first sampling resistor is connected to the non-inverting input end of the first operational amplifier, and the output end of the first operational amplifier is connected to the second input end of the digital signal processor; the first end of the second sampling resistor is connected to the inverting input end of the second operational amplifier, the second end of the second sampling resistor is connected to the non-inverting input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first input end of the digital signal processor. At this time, dual-channel operational amplifier sampling is realized by interconnecting the first sampling resistor and the first operational amplifier and the second sampling resistor and the second operational amplifier, so as to improve the accuracy of current sampling. And only using sampling resistors and operational amplifiers to form sampling channels reduces circuit costs.

[0022] The utility model also provides a current sampling device, which has the same effect as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present utility model, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A circuit diagram of a current sampling circuit provided by the utility model;

[0025] Figure 2 The present invention is a schematic structural diagram of a current sampling device provided by the present invention.

[0026] Among them, 1 is a current sampling circuit, 2 is a digital signal processor, 3 is a synchronous rectification circuit, 4 is a resonant circuit, 5 is a filter, 6 is a battery, 7 is a voltage conversion circuit, and 8 is a charger. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the utility model.

[0028] The core of the utility model is to provide a current sampling circuit and device, which can improve the accuracy of the collected current and reduce the circuit cost.

[0029] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] Figure 1 A circuit diagram of a current sampling circuit provided by the utility model, such as Figure 1 As shown, the current sampling circuit 1 in this embodiment includes: a first sampling resistor Rt1, a second sampling resistor Rt2, a first operational amplifier U1, a second operational amplifier U2, and a digital signal processor 2;

[0031] The first end of the first sampling resistor is connected to the inverting input end of the first operational amplifier, the second end of the first sampling resistor is connected to the non-inverting input end of the first operational amplifier, and the output end of the first operational amplifier is connected to the second input end of the digital signal processor;

[0032] The first end of the second sampling resistor is connected to the inverting input end of the second operational amplifier, the second end of the second sampling resistor is connected to the non-inverting input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first input end of the digital signal processor.

[0033] At this time, dual-channel operational amplifier sampling is realized by interconnecting the first sampling resistor and the first operational amplifier and the second sampling resistor and the second operational amplifier, so as to improve the accuracy of current sampling. And only using sampling resistors and operational amplifiers to form the sampling channel reduces the circuit cost.

[0034] On the basis of the above embodiment, a synchronous rectification circuit 3 is further provided; the synchronous rectification circuit includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, and a fourth switch tube Q4;

[0035] The gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube are used to receive control signals for controlling the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube;

[0036] It should be noted that the control signal received by the gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube can be a pulse signal or a square wave signal, as long as it can be used to control the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube to be in a working state. In addition, the first end of the sampling resistor is arranged on the synchronous rectification side of the synchronous rectification circuit;

[0037] The drain of the first switch tube is connected to the drain of the third switch tube, the source of the first switch tube is connected to the drain of the second switch tube, the source of the third switch tube is connected to the drain of the fourth switch tube, the source of the second switch tube is connected to the source of the fourth switch tube, and the common end formed by the source of the second switch tube and the source of the fourth switch tube is connected to the first end of the first sampling resistor.

[0038] It should be noted that synchronous rectification refers to the process of achieving rectification by completely synchronizing the voltage and frequency on the transmission side with the power supply side through the charging system. Synchronous rectification can be divided into two types: direct synchronous rectification and indirect synchronous rectification. Direct synchronous rectification means that the power supply side and the transmission side are directly connected, and the electric energy on the power supply side is transferred to the transmission side through equipment such as transformers. Indirect synchronous rectification ensures that the voltage and frequency on the transmission side are synchronized with the power supply side through the operating status of the power grid.

[0039] Synchronous rectification has the following advantages:

[0040] First, high stability: Synchronous rectification can ensure that the voltage and frequency on the transmission side are completely synchronized with the power supply side through the charging system to achieve higher stability;

[0041] Second, high efficiency: Synchronous rectification has high efficiency and low transmission loss of electric energy;

[0042] Third, strong controllability: synchronous rectification can accurately control the voltage, frequency and other parameters at the transmission end through the charging system.

[0043] On the basis of the above embodiment, this embodiment is further provided with a resonant circuit 4; the resonant circuit includes: an inductor L and a capacitor Cl; the first end of the inductor serves as the input end of the resonant circuit, the second end of the inductor is connected to the first end of the capacitor, and the second end of the capacitor serves as the output end of the resonant circuit and is connected to the common end formed by the source of the first switching tube and the drain of the second switching tube.

[0044] At this time, the inductor and the capacitor are connected in series, so it can be seen that the resonant circuit in this embodiment is a series resonance mode. At this time, the resonant frequency of the circuit can be calculated according to the formula of the series resonance mode; in addition, it should be noted that the resonant circuit of this embodiment can also be set as an inductor and a capacitor connected in parallel. At this time, the inductor and the capacitor are connected in parallel. It can be seen that the resonant circuit in this embodiment is a parallel resonance mode. At this time, the resonant frequency of the circuit can be calculated according to the formula of the parallel resonance mode.

[0045] In addition, based on the above embodiment, a transformer T is further provided; the primary side of the transformer is connected to the voltage conversion circuit 7, the first end of the secondary side of the transformer is connected to the input end of the resonant circuit, and the second end of the secondary side of the transformer is connected to the common end formed by the source of the third switch tube and the drain of the fourth switch tube.

[0046] It should be noted that the first end of the primary side of the transformer is connected to the first end of the voltage conversion circuit, and the second end of the primary side of the transformer is connected to the second end of the voltage conversion circuit. The voltage conversion circuit is used to convert a high-voltage DC voltage into a low-voltage DC voltage. It should also be noted that the front stage of the voltage conversion circuit is also provided with other circuits, and such circuits can be collectively referred to as the front stage circuit of the charger.

[0047] In some embodiments, a filter 5 and a battery 6 are also provided; the input end of the filter is connected to the common end formed by the drain of the first switch tube and the drain of the third switch tube, and the output end of the filter is connected to the common end formed by the source of the second switch tube and the source of the fourth switch tube; the input end of the battery is connected to the input end of the filter, and the output end of the battery is connected to the output end of the filter. The maximum voltage value of the battery is 500V, and the minimum voltage value of the battery is 0V.

[0048] Among them, the filter 5 includes: a common-mode inductor Lg, a first filter capacitor C1, and a second filter capacitor C2; the first end of the first filter capacitor is connected to the common end formed by the drain of the first switching tube and the drain of the third switching tube, and the second end of the first filter capacitor is connected to the common end formed by the source of the second switching tube and the source of the fourth switching tube; the first end of the common-mode inductor is connected to the first end of the first filter capacitor, the second end of the common-mode inductor is connected to the second end of the first filter capacitor, the third end of the common-mode inductor is connected to the first end of the second filter capacitor, the fourth end of the common-mode inductor is connected to the second end of the second filter capacitor, the first end of the second filter capacitor is connected to the input end of the battery, and the second end of the second filter capacitor is connected to the output end of the battery.

[0049] In addition, it should be noted that, in the present embodiment, it can be known that the additionally arranged battery can determine that the battery can also perform reverse power supply. At this time, the current flowing through the sampling resistor can be divided into a forward current and a reverse current. Correspondingly, the forward current is transmitted from the first end of the first sampling resistor and the second sampling resistor to the second end of the first sampling resistor and the second sampling resistor, and the reverse current is transmitted from the second end of the first sampling resistor and the second sampling resistor to the first end of the first sampling resistor and the second sampling resistor. The reverse current is the current generated on the first sampling resistor and the second sampling resistor by the reverse power supply of the power supply.

[0050] Finally, the circuit also includes a prompt device connected to the digital signal processor. The prompt device in this embodiment can output prompt information when the circuit fails to sample or succeeds in sampling, so as to prompt the staff to perform further operations. In some embodiments, the prompt device can be set as a buzzer, a prompt light, etc. In this embodiment, the implementation method of the prompt device is not limited, and can be set accordingly according to the specific implementation scenario.

[0051] like Figure 1 As shown, the specific structure of the current sampling circuit is:

[0052] The first end of the voltage conversion circuit is connected to the first end of the primary side of the transformer, the second end of the voltage conversion circuit is connected to the second end of the primary side of the transformer, the first end of the secondary side of the transformer is connected to the first end of the inductor in the resonant circuit, the second end of the inductor is connected to the first end of the capacitor, the second end of the capacitor is connected to the common end formed by the source of the first switch tube and the drain of the second switch tube of the synchronous rectification circuit, the second end of the secondary side of the transformer is connected to the common end formed by the source of the third switch tube and the drain of the fourth switch tube of the synchronous rectification circuit, the common end formed by the source of the second switch tube and the source of the fourth switch tube is connected to the first end of the first sampling resistor, the common end formed by the drain of the first switch tube and the drain of the third switch tube is connected to the first end of the first filter capacitor in the filter, the second end of the first filter capacitor is connected to the second end of the first sampling resistor, and the first end of the common mode inductor in the filter is connected to the first filter capacitor. The first end of the common-mode inductor is connected to the first end of the second filter capacitor, the second end of the common-mode inductor is connected to the second end of the first sampling resistor, the third end of the common-mode inductor is connected to the first end of the second filter capacitor, the fourth end of the common-mode inductor is connected to the second end of the second filter capacitor, the second end of the second filter capacitor is connected to the first end of the second sampling resistor, the first end of the second filter capacitor is connected to the first end of the battery, the second end of the second sampling resistor is connected to the second end of the battery, the first end of the first sampling resistor is also connected to the inverting input terminal of the first operational amplifier, the second end of the first sampling resistor is connected to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected to the second input terminal of the digital signal processor; the first end of the second sampling resistor is connected to the inverting input terminal of the second operational amplifier, the second end of the second sampling resistor is connected to the non-inverting input terminal of the second operational amplifier, and the output terminal of the second operational amplifier is connected to the first input terminal of the digital signal processor.

[0053] The above describes in detail the current sampling circuit embodiment. The present invention also provides a corresponding embodiment of a current sampling device.

[0054] The current sampling device provided in this embodiment includes all the above-mentioned current sampling circuits. Figure 2 A schematic diagram of the structure of a current sampling device provided by the utility model is shown in FIG. Figure 2 As shown, a charger 8 connected to the current sampling circuit is also provided in the current sampling device.

[0055] Among them, the charger is an on-board charger suitable for electric vehicles. At this time, the on-board charger can realize the electric vehicle access function (Vehicle to Grid, V2G), vehicle-to-vehicle charging function (Vehicle to Vehicle, V2V), and vehicle external discharge function (Vehicle to Load, V2L).

[0056] An on-board charger refers to a charger that is fixedly installed on an electric vehicle. It has the ability to safely and automatically charge the electric vehicle's power battery. The charger can dynamically adjust the charging current or voltage parameters based on the data provided by the battery management system, perform corresponding actions, and complete the charging process.

[0057] The on-board charger can be charged in the following ways:

[0058] Different charging methods for the battery of the on-board charger will have different degrees of impact on the battery life. Using an appropriate charging method can extend the battery life.

[0059] Common charging methods for on-board chargers include constant voltage charging, DC charging, staged charging, pulse charging, etc.

[0060] First, constant voltage charging: the charging voltage remains unchanged during the entire charging process, and the charging current gradually decreases as the charging time increases. Charging stops when the charging current is less than a certain value. The energy consumption during the entire charging process is low, which can effectively prevent battery overcharging. The control is simple and easy to operate. However, the initial voltage value of the battery to be charged is often small, resulting in a large charging current at the beginning of charging. On the one hand, excessive current will cause battery polarization and affect the charging speed; on the other hand, it will cause the battery temperature to rise rapidly, which can easily burn the battery and cause an accident in severe cases. Therefore, at the beginning of charging, the charging current value needs to be limited to keep the battery charged within an acceptable current range.

[0061] Second, DC charging: At the beginning, the power battery is charged with a constant current. When it is about to be fully charged, a constant small current is used for floating charge to replenish the remaining power and compensate for the battery self-discharge. When the charging voltage reaches the rated voltage, the charging is stopped. Constant current charging avoids the problem of excessive constant voltage charging current, and the current is always limited to the acceptable range of the battery pack.

[0062] Third, staged charging: It can be divided into two-stage charging or three-stage charging according to the actual application. The first stage is constant current charging, which uses a large current to quickly charge the battery so that the battery voltage reaches a certain voltage value (set according to the voltage of the power battery pack); the second stage is constant voltage charging, which continues to charge the battery with a current smaller than the constant current; the third stage is floating charging, which charges the battery with a trickle current to ensure that the battery can be fully charged. When the charging system detects that the charging current is less than a certain set value, the charging is terminated. Staged charging combines the advantages of constant voltage and constant current charging methods, which is beneficial to reduce battery polarization and avoid overcharging and high current charging shock.

[0063] The charging voltage and current of constant voltage charging, constant current charging and staged charging are continuous, and the battery is not given enough rest time to eliminate polarization. Polarization can cause battery overheating, gassing and other phenomena, limit the charging speed, and seriously affect the battery life. Pulse charging and positive and negative pulse charging use discontinuous charging current, which can effectively reduce or eliminate the occurrence of polarization, speed up the charging speed and prolong the battery life.

[0064] Fourth, pulse charging: Pulse charging is used to provide the battery with sufficient rest time, which is conducive to the full reaction of the active substances inside the battery, effectively reducing and eliminating the occurrence of polarization, and can use a larger current for charging without worrying about battery overheating. It can effectively improve charging efficiency, shorten charging time, and prolong battery life.

[0065] The positive and negative pulse charging method is an improvement on the pulse charging method. The entire charging process includes positive pulse charging, intermittent rest and negative pulse discharge. First, positive pulse charging is performed, and after a period of rest, a short negative pulse discharge is performed. The short negative pulse discharge of the battery can effectively remove the occurrence of polarization, accelerate the electrochemical reaction inside the battery, and reduce the battery temperature. Although some electrical energy is lost, it can enable the battery to be charged at a higher charging current, which can effectively speed up the charging speed and improve the charging efficiency, and prolong the battery life.

[0066] The current sampling circuit in this embodiment realizes dual-channel operational amplifier sampling by interconnecting the first sampling resistor and the first operational amplifier and the second sampling resistor and the second operational amplifier, so as to improve the accuracy of current sampling. And only using sampling resistors and operational amplifiers to form the sampling channel reduces the circuit cost.

[0067] The above is a detailed introduction to a current sampling circuit and device provided by the utility model. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referenced to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the utility model.

[0068] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A current sampling circuit, characterized in that: include: A first sampling resistor, a second sampling resistor, a first operational amplifier, a second operational amplifier, and a digital signal processor; The first end of the first sampling resistor is connected to the inverting input end of the first operational amplifier, the second end of the first sampling resistor is connected to the non-inverting input end of the first operational amplifier, and the output end of the first operational amplifier is connected to the second input end of the digital signal processor; The first end of the second sampling resistor is connected to the inverting input end of the second operational amplifier, the second end of the second sampling resistor is connected to the non-inverting input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first input end of the digital signal processor.

2. The current sampling circuit according to claim 1, characterized in that: Also includes: Synchronous rectification circuit; The synchronous rectification circuit comprises: a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube; The gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube are used to receive a control signal for controlling the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube; The drain of the first switch tube is connected to the drain of the third switch tube, the source of the first switch tube is connected to the drain of the second switch tube, the source of the third switch tube is connected to the drain of the fourth switch tube, the source of the second switch tube is connected to the source of the fourth switch tube, and the common end formed by the source of the second switch tube and the source of the fourth switch tube is connected to the first end of the first sampling resistor.

3. The current sampling circuit according to claim 2, characterized in that: Also includes: Resonant circuit; The resonant circuit comprises: an inductor and a capacitor; The first end of the inductor serves as the input end of the resonant circuit, the second end of the inductor is connected to the first end of the capacitor, and the second end of the capacitor serves as the output end of the resonant circuit and is connected to a common end formed by the source of the first switching tube and the drain of the second switching tube.

4. The current sampling circuit according to claim 3, characterized in that: Also includes: transformer; The primary side of the transformer is connected to the voltage conversion circuit, the first end of the secondary side of the transformer is connected to the input end of the resonant circuit, and the second end of the secondary side of the transformer is connected to the common end formed by the source of the third switching tube and the drain of the fourth switching tube.

5. The current sampling circuit according to claim 2, characterized in that: Also includes: filter; The input end of the filter is connected to a common end formed by the drain of the first switch tube and the drain of the third switch tube, and the output end of the filter is connected to a common end formed by the source of the second switch tube and the source of the fourth switch tube.

6. The current sampling circuit according to claim 5, characterized in that: Also includes: Battery; The input end of the battery is connected to the input end of the filter, the output end of the battery is connected to the output end of the filter, the maximum voltage value of the battery is 500V, and the minimum voltage value of the battery is 0V.

7. The current sampling circuit according to claim 6, characterized in that: The filter comprises: a common mode inductor, a first filter capacitor, and a second filter capacitor; The first end of the first filter capacitor is connected to the common end formed by the drain of the first switch tube and the drain of the third switch tube, and the second end of the first filter capacitor is connected to the common end formed by the source of the second switch tube and the source of the fourth switch tube; the first end of the common-mode inductor is connected to the first end of the first filter capacitor, the second end of the common-mode inductor is connected to the second end of the first filter capacitor, the third end of the common-mode inductor is connected to the first end of the second filter capacitor, the fourth end of the common-mode inductor is connected to the second end of the second filter capacitor, the first end of the second filter capacitor is connected to the input end of the battery, and the second end of the second filter capacitor is connected to the output end of the battery.

8. The current sampling circuit according to any one of claims 1 to 7, characterized in that: Also includes: Prompt device; The prompting device is connected to the digital signal processor.

9. A current sampling device, characterized in that: include: The current sampling circuit of any one of claims 1 to 8.

10. The current sampling device according to claim 9, characterized in that: Also includes: Battery charger; The charger is connected to the current sampling circuit.

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