Two-way high-precision small current acquisition circuit

By designing a dual-channel high-precision low-current acquisition circuit, utilizing a low-dropout linear regulator and integrated circuit chip, and combining sampling resistors with different amplification factors and resistance values, the problem of complex and costly current signal acquisition in power systems was solved, achieving high-precision and low-cost current acquisition.

CN224247797UActive Publication Date: 2026-05-15GUIZHOU ZHENHUA QUNYING ELECTRIC CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
GUIZHOU ZHENHUA QUNYING ELECTRIC CO LTD
Filing Date
2025-05-12
Publication Date
2026-05-15

AI Technical Summary

Technical Problem

The circuits for acquiring small current signals in existing power systems are complex and costly, especially when acquiring multiple signals, which requires multiple independent circuits, resulting in a large number of components that cannot be used in parallel.

Method used

A dual-channel high-precision low-current acquisition circuit is adopted, including a voltage conversion circuit, a processor circuit, an acquisition amplification circuit, and a power circuit. It uses a low-dropout linear regulator, a microcontroller, an integrated circuit chip, and a MOSFET. By selecting sampling resistors with different amplification factors and resistance values, dual-channel current acquisition is achieved.

Benefits of technology

It simplifies the circuit structure, reduces costs, and achieves high-precision dual-channel current acquisition. It also has a small footprint and is suitable for aviation power and conventional power systems.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model specifically relates to a double-path high-precision small current acquisition circuit, comprising a voltage conversion circuit, the voltage conversion circuit is connected with a processor circuit and an acquisition amplification circuit, the acquisition amplification circuit is connected with a power circuit through a sampling resistor, and the acquisition amplification circuit is also connected with the processor circuit; the voltage conversion circuit is also connected with the input end of a power supply Vin, the sampling resistor is also connected with a power supply, and the power circuit is also connected with a driving power supply and a load; according to the utility model, by selecting the acquisition amplification circuits with different amplification factors and the sampling resistors with different resistance values, the acquisition of two paths of milliampere-level or ampere-level current is realized; the problems that in the power utilization field of an existing power system, a signal amplification circuit built through multi-stage filtering and an operational amplifier is complex in circuit and high in cost when used for collecting small current signals are solved, and the effects of being small in occupied space and saving cost are achieved.
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Description

Technical Field

[0001] This utility model belongs to the field of current acquisition circuits, specifically relating to a dual-channel high-precision small current acquisition circuit. Background Technology

[0002] In the field of power consumption in aviation power systems and conventional power systems, it is often necessary to collect small currents in the milliampere or ampere range, and there is often a need for multiple data acquisition channels. In non-isolated low-power power systems, it is also often necessary to collect the current of power circuits and control circuits in real time and feed the information back to the processing circuits in real time.

[0003] Currently, in the field of power system electricity consumption, signal amplification circuits built with multi-stage filters and operational amplifiers are commonly used to collect small current signals. When multiple acquisitions are required in isolated or non-isolated circuits, multiple such multi-stage filtering and signal amplification circuits need to be equipped. This involves more components and cannot be used in parallel, which increases costs and makes the circuit more complex. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a dual-channel high-precision low-current acquisition circuit.

[0005] This utility model is achieved through the following technical solution.

[0006] A dual-channel high-precision low-current acquisition circuit includes a voltage conversion circuit, a processor circuit, an acquisition amplification circuit, a sampling resistor, and a power circuit. The voltage conversion circuit is connected to both the processor circuit and the acquisition amplification circuit. The acquisition amplification circuit is connected to the power circuit through the sampling resistor and is also connected to the processor circuit. The voltage conversion circuit is also connected to the power supply Vin input terminal. The sampling resistor is also connected to the power supply, and the power circuit is also connected to the drive power supply and the load.

[0007] The voltage conversion circuit includes a low dropout linear regulator (LDO) and capacitors C1 to C3. The LDO uses RUNIC's RS3215-3.3XF5-G. Pins 1 and 3 of the LDO are connected to the power input Vin and one end of capacitor C2. Pin 2 is connected to the other end of capacitor C2 and power ground. Pins 4 and 5 are connected to power ground through capacitors C3 and C1, respectively.

[0008] The processor circuit includes a microcontroller (MCU), resistor R7, and capacitors C4 to C6. The MCU is a CMSemicon BAT32A237KE24NA. Pin 1 of the MCU is connected to one end of resistor R7 and capacitor C4. Pin 5 is connected to one end of capacitor C5 and power ground. Pin 6 is connected to the other end of capacitor C5 and pin 5 of the low dropout linear regulator (LDO). Pin 14 is connected to pin 5 of the LDO. Pin 18 is connected to one end of capacitor C6 and pin 5 of the LDO. The other ends of capacitors C6 and C4 are connected to power ground. The other end of resistor R7 is connected to pin 5 of the LDO.

[0009] The acquisition and amplification circuit includes an integrated circuit chip U1; the integrated circuit chip U1 is a CSA2302 series chip from Analog Semiconductor. Pins 7 and 6 of the integrated circuit chip U1 are connected to pins 20 and 22 of the microcontroller MCU, respectively, pin 8 is connected to pin 5 of the low dropout linear regulator LDO, and pin 5 is connected to the power supply ground.

[0010] The sampling resistors include resistor R1 and resistor R2; one end of resistor R1 is connected to pin 2 of integrated circuit chip U1, and the other end is connected to pin 1 of integrated circuit chip U1 and the input terminal of power supply V1; one end of resistor R2 is connected to pin 4 of integrated circuit chip U1, and the other end is connected to pin 3 of integrated circuit chip U1 and the input terminal of power supply V2.

[0011] The power circuit includes N-channel MOSFETs Q1 and Q2, and resistors R3 to R6. The drain of N-channel MOSFET Q1 is connected to the other end of resistor R1, the source is connected to one end of resistor R3 and the load terminal, the gate is connected to the other end of resistor R3 and one end of resistor R4, and the other end of resistor R4 is connected to the input terminal of the drive power supply V3. The drain of N-channel MOSFET Q2 is connected to one end of resistor R2, the source is connected to one end of resistor R5 and the load terminal, the gate is connected to the other end of resistor R5 and one end of resistor R6, and the other end of resistor R6 is connected to the input terminal of the drive power supply V4.

[0012] The beneficial effects of this utility model are as follows:

[0013] This invention achieves the acquisition of dual-channel milliampere or ampere-level currents by selecting acquisition amplification circuits with different amplification factors and sampling resistors with different resistance values. It solves the problems of circuit complexity and high cost in the current power system field where signal amplification circuits built with multi-stage filtering and operational amplifiers are used to acquire small current signals, and achieves the effect of small space occupation and cost saving. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a dual-channel high-precision low-current acquisition circuit according to the present invention.

[0015] Figure 2 This is a schematic diagram of the voltage conversion circuit of this utility model;

[0016] Figure 3 This is the schematic diagram of the processor circuit of this utility model;

[0017] Figure 4 This is a schematic diagram of the acquisition amplification circuit, sampling resistor, and power circuit of this utility model. Detailed Implementation

[0018] The technical solution of this utility model is further described below, but the scope of protection is not limited to what is described.

[0019] like Figure 1 The diagram shows a schematic of a dual-channel high-precision low-current acquisition circuit according to this invention. The dual-channel high-precision low-current acquisition circuit includes a voltage conversion circuit, which is connected to both a processor circuit and an acquisition amplification circuit. The acquisition amplification circuit is connected to a power circuit via a sampling resistor and is also connected to the processor circuit. The voltage conversion circuit is also connected to the power supply Vin input terminal, the sampling resistor is also connected to the power supply, and the power circuit is also connected to the drive power supply and the load.

[0020] like Figure 2 This is a schematic diagram of the voltage conversion circuit of this utility model; the voltage conversion circuit includes a low dropout linear regulator (LDO), the LDO uses RUNIC's RS3215-3.3XF5-G, pins 1 and 3 of the LDO are connected to the power supply Vin input terminal and one end of capacitor C2, pin 2 is connected to the other end of capacitor C2 and power supply ground, and pins 4 and 5 are connected to power supply ground through capacitors C3 and C1 respectively;

[0021] Specifically, a low-dropout linear regulator (LDO) is used to convert the externally input power supply Vin into the power supply voltage Vcc required by the processor circuit and the acquisition amplifier circuit. This power supply voltage Vcc is output through pin 5 of the LDO. Using a low-dropout linear regulator (LDO) can achieve the effects of low cost, low noise and low quiescent current.

[0022] like Figure 3The diagram shows the schematic of the processor circuit of this utility model. The processor circuit includes a microcontroller (MCU). The microcontroller (MCU) uses a BAT32A237KE24NA from CMSemicon. Pin 1 of the microcontroller (MCU) is connected to one end of resistor R7 and capacitor C4. Pin 5 is connected to one end of capacitor C5 and power ground. Pin 6 is connected to the other end of capacitor C5 and pin 5 of low dropout linear regulator (LDO). Pin 14 is connected to pin 5 of LDO. Pin 18 is connected to one end of capacitor C6 and pin 5 of LDO. The other ends of capacitors C6 and C4 are connected to power ground. The other end of resistor R7 is connected to pin 5 of LDO.

[0023] Specifically, the microcontroller (MCU) receives the voltage signals of the first and second analog signals from the acquisition and amplification circuit, and then calculates the current of the two loops.

[0024] like Figure 4 The diagram shows the schematic of the acquisition amplification circuit, sampling resistor, and power circuit of this utility model.

[0025] The acquisition and amplification circuit is an integrated circuit chip U1; the integrated circuit chip U1 uses the CSA2302 series chip from Analog Semiconductor. Pins 7 and 6 of the integrated circuit chip U1 are connected to pins 20 and 22 of the microcontroller MCU, respectively. Pin 8 is connected to pin 5 of the low dropout linear regulator LDO, and pin 5 is connected to the power supply ground.

[0026] Specifically, the integrated circuit chip U1 is packaged in MSOP-8, has a small size, and has four signal amplification factors of 10x, 20x, 50x, and 100x.

[0027] The sampling resistors include resistor R1 and resistor R2; one end of resistor R1 is connected to pin 2 of integrated circuit chip U1, and the other end is connected to pin 1 of integrated circuit chip U1 and the input terminal of power supply V1; one end of resistor R2 is connected to pin 4 of integrated circuit chip U1, and the other end is connected to pin 3 of integrated circuit chip U1 and the input terminal of power supply V2.

[0028] The power circuit includes N-channel MOSFETs Q1 and Q2. The drain of N-channel MOSFET Q1 is connected to the other end of resistor R1, the source is connected to one end of resistor R3 and the load, the gate is connected to the other end of resistor R3 and one end of resistor R4, and the other end of resistor R4 is connected to the input terminal of the drive power supply V3. The drain of N-channel MOSFET Q2 is connected to one end of resistor R2, the source is connected to one end of resistor R5 and the load, the gate is connected to the other end of resistor R5 and one end of resistor R6, and the other end of resistor R6 is connected to the input terminal of the drive power supply V4.

[0029] Specifically, the sampling resistor converts the current signal in the power circuit into a voltage signal. Voltage acquisition points are led out on the pads at both ends of the sampling resistor, and the signal is led to the acquisition point of the acquisition amplifier circuit using a Kelvin layout connection method to form a differential voltage signal, thereby reducing interference on the line.

[0030] Specifically, the acquisition amplifier circuit acquires the voltage across the sampling resistor, amplifies it, and transmits it to the microcontroller MCU for real-time acquisition. The single-ended voltage of the sampling terminal of the acquisition amplifier circuit of this invention can withstand up to 76V. The acquisition circuit in this paper does not require an external operational amplifier feedback circuit and a multi-stage filtering circuit. It can directly acquire the voltage across the sampling resistor in each channel and output it to the microcontroller MCU.

[0031] Specifically, the acquisition amplifier circuit does not require an external operational amplifier feedback circuit or multi-stage filtering circuit. It can directly sample the voltage across the sampling resistors in each channel and output it to the microcontroller (MCU). Users can input appropriate sampling resistors into the high or low side of the circuit to be sampled, while ensuring acquisition accuracy, and select an acquisition amplifier circuit with an appropriate gain. When acquiring dual channels, connect both channels of the acquisition amplifier circuit; if four channels need to be acquired, only two channels of the acquisition amplifier circuit are needed. The principle is simple, saves design space, and reduces operating costs.

[0032] Specifically, by selecting acquisition amplifier circuits with different amplification factors and sampling resistors with different resistance values, it is possible to acquire milliampere or ampere-level currents.

[0033] Example:

[0034] In this embodiment of the invention, the voltage of the externally input power supply Vin is 5V. Through the low dropout linear regulator LDO, the voltage obtained by the microcontroller MCU and the integrated circuit chip U1 is 3.3V, that is, the analog signal output by the integrated circuit chip U1 can reach 3.3V.

[0035] In this embodiment, the load current is sampled as 50mA-2.75A. The resistance values ​​of sampling resistors R1 and R2 can be selected as 12mΩ. An integrated circuit chip U1 with a magnification factor of 100 is chosen. If the loop current is 50mA, the voltage across the sampling circuit is 0.05*0.012 = 0.0006V. After amplification by 100 times, the analog voltage signal transmitted to the microcontroller (MCU) is 0.0006*100 = 0.06V = 60mV. If the loop current is 2.75A, the voltage across the sampling circuit is 2.75*0.012 = 0.033V. After amplification by 100 times, the analog voltage signal transmitted to the MCU is 0.033*100 = 3.3V. If the MCU uses a 12-bit ADC with a reference of 3.3V, the sampling accuracy of the MCU can reach 3.3 / 2. 12 =0.8mV, the accuracy fully meets the acquisition requirements; for other acquisition requirements with a wider range, users can adjust according to the ADC accuracy of the microcontroller MCU, the sampling resistor, and the acquisition amplification circuit factor.

[0036] This utility model discloses a dual-channel high-precision small current acquisition circuit. By selecting acquisition amplifier circuits with different amplification factors and sampling resistors with different resistance values, it can acquire milliampere-level or ampere-level currents. It solves the problems of circuit complexity and high cost in the existing power system field, which uses signal amplification circuits built with multi-stage filtering and operational amplifiers to acquire small current signals. It achieves the effect of small space occupation and cost saving.

Claims

1. A dual-channel high-precision low-current acquisition circuit, characterized in that: It includes a voltage conversion circuit, a processor circuit, a data acquisition and amplification circuit, a sampling resistor, and a power circuit. The voltage conversion circuit is connected to both the processor circuit and the data acquisition and amplification circuit. The data acquisition and amplification circuit is connected to the power circuit through the sampling resistor and is also connected to the processor circuit. The voltage conversion circuit is also connected to the power supply Vin input terminal. The sampling resistor is also connected to the power supply. The power circuit is also connected to the drive power supply and the load.

2. The dual-channel high-precision low-current acquisition circuit as described in claim 1, characterized in that: The voltage conversion circuit includes a low dropout linear regulator (LDO) and capacitors C1 to C3. The LDO uses RUNIC's RS3215-3.3XF5-G. Pins 1 and 3 of the LDO are connected to the power input Vin and one end of capacitor C2. Pin 2 is connected to the other end of capacitor C2 and power ground. Pins 4 and 5 are connected to power ground through capacitors C3 and C1, respectively.

3. The dual-channel high-precision low-current acquisition circuit as described in claim 1, characterized in that: The processor circuit includes a microcontroller (MCU), resistor R7, and capacitors C4 to C6. The MCU is a CMSemicon BAT32A237KE24NA. Pin 1 of the MCU is connected to one end of resistor R7 and capacitor C4. Pin 5 is connected to one end of capacitor C5 and power ground. Pin 6 is connected to the other end of capacitor C5 and pin 5 of the low dropout linear regulator (LDO). Pin 14 is connected to pin 5 of the LDO. Pin 18 is connected to one end of capacitor C6 and pin 5 of the LDO. The other ends of capacitors C6 and C4 are connected to power ground. The other end of resistor R7 is connected to pin 5 of the LDO.

4. The dual-channel high-precision low-current acquisition circuit as described in claim 3, characterized in that: The acquisition and amplification circuit includes an integrated circuit chip U1; the integrated circuit chip U1 is a CSA2302 series chip from Analog Semiconductor. Pins 7 and 6 of the integrated circuit chip U1 are connected to pins 20 and 22 of the microcontroller MCU, respectively, pin 8 is connected to pin 5 of the low dropout linear regulator LDO, and pin 5 is connected to the power supply ground.

5. The dual-channel high-precision low-current acquisition circuit as described in claim 4, characterized in that: The sampling resistors include resistor R1 and resistor R2; one end of resistor R1 is connected to pin 2 of integrated circuit chip U1, and the other end is connected to pin 1 of integrated circuit chip U1 and the input terminal of power supply V1; one end of resistor R2 is connected to pin 4 of integrated circuit chip U1, and the other end is connected to pin 3 of integrated circuit chip U1 and the input terminal of power supply V2.

6. The dual-channel high-precision low-current acquisition circuit as described in claim 5, characterized in that: The power circuit includes N-channel MOSFETs Q1 and Q2, and resistors R3 to R6. The drain of N-channel MOSFET Q1 is connected to the other end of resistor R1, the source is connected to one end of resistor R3 and the load terminal, the gate is connected to the other end of resistor R3 and one end of resistor R4, and the other end of resistor R4 is connected to the input terminal of the drive power supply V3. The drain of N-channel MOSFET Q2 is connected to one end of resistor R2, the source is connected to one end of resistor R5 and the load terminal, the gate is connected to the other end of resistor R5 and one end of resistor R6, and the other end of resistor R6 is connected to the input terminal of the drive power supply V4.