一种基于霍尔传感器的交直流通用检测电路
By designing a universal AC/DC detection circuit for Hall sensors, the problem that existing Hall sensors cannot simultaneously sample AC and DC currents is solved, achieving high accuracy and wide range current measurement, reducing cost and complexity, and making it suitable for smart grids and industrial automation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGYIN SPARK ELECTRONICS TECH
- Filing Date
- 2025-06-06
- Publication Date
- 2026-07-17
AI Technical Summary
Existing Hall sensors cannot simultaneously sample AC and DC currents and output them via serial port on the same product, resulting in high cost, increased complexity, and space occupation. Furthermore, traditional MCU sampling modes have bottlenecks in measurement accuracy and range, making it difficult to meet the high accuracy and wide range requirements of smart grids and industrial automation.
A general-purpose AC/DC detection circuit based on a Hall sensor was designed, including a power management circuit, a constant current circuit, an operational amplifier circuit, a switching circuit, a single-phase SOC metering chip, and an RS485 isolation circuit. The output voltage is calibrated by an adjustable resistor, and the single-phase SOC metering chip performs signal processing and calibration to achieve accurate measurement of AC/DC current and stable serial port output.
It enables precise measurement of AC and DC current on the same product, improves measurement accuracy and range, reduces equipment cost and space occupation, meets the requirements of high accuracy and wide measurement range, and enhances anti-interference capability and data transmission stability.
Smart Images
Figure CN224518826U_ABST
Abstract
Claims
1. A Hall sensor-based AC / DC universal detection circuit, characterized by, It includes a power management circuit, a constant current circuit, an operational amplifier circuit, a switching circuit, a single-phase SOC metering chip, and an RS485 isolation circuit, as well as a Hall sensor circuit with two interconnected output terminals. The power management circuit is connected to the constant current circuit, operational amplifier circuit, SOC single-phase metering chip and RS485 isolation circuit respectively for power supply. The constant current circuit includes a voltage regulator module and a current amplification module. The voltage regulator module includes interconnected voltage regulators and adjustable resistors, and its output is connected to both the current amplification module and the control input terminals of two amplifying transistors. The emitters of the two amplifying transistors are connected to the power supply through series resistors, and their collectors are connected to the input terminals of two Hall sensors. The Hall sensor circuit consists of a Hall sensor and a capacitor connected to the output terminal of the Hall sensor, and the output terminal of the Hall sensor is connected to the input terminal of the operational amplifier circuit. The detection circuit also includes a comparison circuit, which uses a comparator as its core component. Its non-inverting input is connected to the sampling input (V1P) of the SOC single-phase metering chip, and its inverting input is grounded through the 21st resistor (R21). The positive power supply pin V+ is connected to the output (out1) of the comparator through the 34th resistor (R34). The output of the comparison circuit is connected to the SOC single-phase metering chip. The operational amplifier circuit mainly consists of an operational amplifier and peripheral circuits. Its output terminal (ADC1) is connected to the positive input terminal of the comparator circuit and the sampling input terminal (V1P) of the SOC single-phase metering chip, respectively. The switching circuit includes a DIP switch SW1, one end of which is connected to an I / O port of the SOC single-phase metering chip and connected to the power supply via the second isolation resistor (R2), and grounded via another isolation resistor (R14). The other end of the DIP switch is grounded. The serial port of the SOC single-phase metering chip is connected to the serial port of the RS485 isolation circuit. The RS485 isolation circuit also includes a protection module for the output signal. The protection module includes a bidirectional transient suppression diode and a load resistor connected in parallel, and a fuse is connected between the two parallel terminals of the bidirectional Zener diode and the load resistor.
2. The AC / DC universal detection circuit based on Hall sensor according to claim 1, characterized in that, In the constant current circuit, the power supply of the voltage regulator module is connected to the first port of the first adjustable resistor (RV1), and the second port of the first adjustable resistor (RV1) is connected to the first port by the fifth resistor (R5); the third port of the first adjustable resistor (RV1) is connected in series with the third voltage divider resistor (R3), the reference terminal of the first voltage regulator (U1) is connected between the third resistor (R3) and the fourth resistor (R4), and the anode of the first voltage regulator (U1) is grounded through the first resistor (R1), forming a voltage regulation loop, and its cathode is connected to the power supply; in the current amplification module, the bases of its two transistors are connected to the fourth resistor (R4) in the voltage regulator module, the emitters are connected to the power supply through the seventh resistor (R7) and the ninth resistor (R9) respectively, and the collectors are connected to the input terminals of the two Hall sensor circuits respectively.
3. The AC / DC universal detection circuit based on Hall sensor according to claim 1, characterized in that, The Hall sensor circuit includes a Hall sensor (H1). The two output pins of the Hall sensor (H1) are grounded through the fourth capacitor (C4) and the fifth capacitor (C5), respectively, and are also connected to the input terminal of the operational amplifier circuit.
4. The AC / DC universal detection circuit based on Hall sensor according to claim 1, characterized in that, The operational amplifier circuit comprises two stages. The first stage includes a first operational amplifier (U3A), whose non-inverting input is grounded via resistor R19, and whose inverting input is connected to its output via feedback resistor R20. The output of the first stage is connected to the second stage operational amplifier via resistor R22, which is centered around a second operational amplifier (U3B). Its input signal is connected to the non-inverting input of the second operational amplifier (U3B), and its inverting input is connected to its output through the parallel 24th resistor (R24) and 36th capacitor (C36) to form a feedback circuit. At the same time, the output of the second operational amplifier (U3B) is connected in series with a 25th resistor (R25), and the 25th resistor (R25) is grounded through the 17th capacitor (C17). The output of the operational amplifier circuit (ADC1) is connected to the non-inverting input of the comparator circuit and the sampling input (V1P) of the SOC single-phase metering chip.
5. The AC / DC universal detection circuit based on Hall sensor according to claim 1, characterized in that, The power management circuit consists of a voltage regulator conversion circuit, a voltage regulation and protection circuit, and a level conversion circuit. The voltage regulator conversion circuit includes a voltage regulator chip (U6) and its peripheral filter capacitors. The power input pin (VI) of the voltage regulator chip (U6) is grounded through the 19th capacitor (C19), and its output pin (VO) is connected to the RS485 isolation circuit and the SOC single-phase metering chip through the 24th capacitor (C24) and the 26th capacitor (C26) connected in parallel. The power input terminal VCC of the voltage regulation and protection circuit is connected to the input pin (VI) of the linear regulator chip (U8) through the fourth diode (D4). Simultaneously, the power input terminal VCC is connected in parallel with ground by the 20th capacitor (C20), the 25th capacitor (C25), and the 3rd transient suppression transistor (D3). The adjustment pin ADJ of the linear regulator chip (U8) is grounded through the 32nd resistor (R32), and its adjustment pin ADJ is connected to the output pin (VO) through the 33rd resistor (R33). The output pin (VO) is also grounded through the 29th capacitor (C29). The output terminal of the voltage regulation and protection circuit is connected to the level conversion circuit. The level conversion circuit is based on a level converter chip (U7). A 27th capacitor (C27) is connected between the positive terminal C+ and the negative terminal C- of the external capacitor of the level converter chip. The level conversion circuit also includes a 21st capacitor (C21) and a 22nd capacitor (C22) connected in parallel between the output pin Vout of the level converter chip (U7) and ground. The filtered output signal is further transmitted to the constant current circuit and the operational amplifier circuit.
6. The AC / DC universal detection circuit based on Hall sensor according to claim 1, characterized in that, The RS485 isolation circuit includes an isolation chip (U4) and its peripheral circuits. The power input pin VCC of the isolation chip (U4) is grounded through the parallel connection of capacitors 13 (C13) and 14 (C14). The isolated power output pin Viso is connected in parallel with ground through capacitors 15 (C15) and 16 (C16). The RS485 isolation circuit also includes an output signal protection module, which is connected to pins 12 and 13 of the isolation chip. The signal protection module includes a second bidirectional transient suppression diode (D2) and a load resistor (R31) connected in parallel. A fuse is connected in series between the two parallel terminals of the bidirectional Zener diode and the load resistor.