Current measurement circuit based on Hall chip and shunting resistor

Abstract

The invention discloses a current measurement circuit based on a Hall chip and a shunting resistor. The current measurement circuit comprises a Hall chip and a shunting resistor in parallel arrangement; the Hall chip and the shunting resistor perform shunting on loop current, and the loop current is measured through an internal resistance value of the Hall chip, the resistance value of the shunting resistor and an output voltage of the Hall chip. Through the scheme of combining the Hall chip and the shunting resistor, the shunting can be performed by using the small resistance and the internalresistance of the Hall chip, thereby realizing the measurement of the large current loop; the loss of the shunting resistor can be reduced, the temperature rise of the shunting resistor is reduced, thereby reducing the current error and improving the current measurement precision; the whole current measurement circuit is isolated from the loop, and the circuit has high security.

Description

technical field [0001] The invention relates to the technical field of circuit measurement, in particular to a current measurement circuit based on a Hall chip and a shunt resistor. Background technique [0002] The Hall chip can be used to measure small currents. The Hall chip is designed based on the principle of Hall induction. It consists of a precise low-offset linear Hall sensor circuit and a copper foil located close to the surface of the IC. The current flows through the copper foil. When a magnetic field is generated, the Hall element induces a linear voltage signal according to the magnetic field. After internal amplification, filtering, chopping and correction circuits, a voltage signal is output. The signal is output from the seventh pin of the chip, which directly reflects the The magnitude of the current flowing through the copper foil. For example, the Hall chip ACS712 is divided into three specifications according to the suffixes: ±5A, ±20A, ±30A. [0003] ...

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Problems solved by technology

[0003] However, the measurement method for large currents cannot be measured by Hall chips. Generally, the current flows through the shunt resistance to form a certain voltage, and then the current is calculated according to the voltage.

This method of measurement shunt resistance consumes too much power and generates serious heat; at the same time, as the temperature rises, the measurement error becomes larger; in addition, it is directly connected to the current loop, which is less safe.

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