Circuit for improving small current acquisition precision of solid-state power controller

Abstract

The invention relates to a circuit for improving the low-current acquisition precision of a solid-state power controller. The circuit comprises a low-current acquisition circuit and a reference source circuit, the small current acquisition circuit comprises an operational amplifier M5B, resistors R64, R65, R67, R69, R11, R72 and R88 and filter capacitors C44 and C45, and the reference source circuit comprises a reference source chip U5; capacitors C106-C110, and a resistor R95. By arranging the lifting level circuit, acquisition errors caused by an operational amplifier dead zone are avoided, and the accuracy of output signals is ensured; and a reference source circuit is adopted, so that the level lifting precision is improved, and the overall acquisition precision of the low-current signal is ensured. The small current signal of 20 mA to 200 mA can be accurately collected, and the high-precision amplification of the weak signal of 0.1 mV to 1 mV is realized.

Description

technical field [0001] The invention relates to a circuit for improving the small current collection accuracy of a solid-state power controller, which belongs to the technical field of power electronics. Background technique [0002] The use of solid-state power controllers comes from the requirements of the development of aircraft from mechanization to electrification. It is an important part of the aircraft power supply system and undertakes the power supply and management functions of the electrical load of the entire aircraft. At present, there are a large number of 20mA-200mA small current collection requirements in aircraft electrical equipment, and the required collection accuracy range is ±5mA. [0003] When the traditional small current acquisition circuit collects a small current of 20mA to 200mA, it outputs a weak signal of 0.1mV to 1mV after being collected by a 5m ohm sampling resistor. The traditional small current acquisition circuit is directly amplified by ...

AI Technical Summary

Problems solved by technology

The traditional small current acquisition circuit is directly amplified by the operational amplifier. Since the signal collected by the small current is extremely small, the input voltage is small, and the output of the op amp is distorted. It is greatly affected by the resistance value and the ambient temperature, resulting in the final small current output deviation. Larger, the acquisition accuracy cannot meet the requirement of ±5mA

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