An electronic circuit for a high-precision closed-loop Hall current sensor

Abstract

A high-precision closed-loop electronic circuit for a Hall current sensor acquires a current signal from a power supply end of an operational amplifier and performs static bias on an output triode; the operational amplifier and the output triode form a voltage-controlled current supply and have a variable current amplification multiple; an output end of the operational amplifier directly drives a voltage-controlled load resistor or drives a voltage-controlled load resistor with electrical level shift; and Hall elements are operated in a constant voltage manner, and the arithmetic mean value of the output voltages of a plurality of Hall elements is calculated. The present invention belongs to the field of electronic circuitry for a Hall current sensor.

Description

technical field [0001] The invention relates to the field of electronic circuits for Hall current sensors, in particular to an electronic circuit for high-precision closed-loop Hall current sensors. Background technique [0002] Current sensor is a widely used electronic component, which is widely used in various current conversion technologies, AC numerical control devices and other automatic control fields where current is the control object. [0003] There are many non-contact measurement and monitoring methods for current. Hall current sensors are widely used and industrialized because of their excellent cost performance. Hall current sensors usually have two working modes: open loop and closed loop. Closed loop Hall current sensors are composed of It is made of soft magnetic material with an air-gapped annular magnetic core, a Hall element, a secondary coil and an appropriate power amplifier circuit. The high-sensitivity Hall element made of InSb material is selected, ...

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Problems solved by technology

while in Figure three , Figure four Among them, when the power supply voltage of the sensor is constant, the Hall elements in the two electronic circuits work under constant current conditions. When the working temperature is lower than 0°C, the zero temperature drift of the sensor will be very large, which seriously affects the current measurement of the sensor. accuracy, which limits the operating temperature range of the sensor

[0005] 2. The output of the operational amplifier in the two electronic circuits drives an unbiased emitter follower, so when the current sensor using this electronic circuit measures alternating current, there is a very serious crossover distortion in the output waveform! exist Figure three Among them, the unbiased emitter follower output structure makes the output voltage of the current sensor unable to reach rail to rail, which affects the linear measurement range of the current sensor and the anti-saturation ability of the current sensor.

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