A high side current sensing circuit with high PSRR based on BCD process

Abstract

This paper describes an instrumentation amplifier for bidirectional high-side current sensing applications. It uses an advanced high-voltage process to design. To achieve high power supply voltage, the circuit adds a current source under the amplifier. So the circuit has a wide power supply voltage range from 4V–40V, and the input common-mode voltage of the amplifier also can go beyond its supply rail. The bipolar transistors as the input stages devices reduce the offset voltage. The amplifier uses the folded-casecode structure to increase the slew rate. Finally, the design has passed by the high-voltage BCD simulation library.