摘要： A high voltage multiplexer which is used to transmit and transform high common-mode voltage in battery management system (BMS) is proposed. The high voltage multiplexer consists of some high voltage switches and a level shift circuit. In the level shift circuit, two kinds of schemes implemented with resistance-voltage-divider and metal-layer finger capacitor are used to break through the barrier that normal capacitor cannot withstand high voltage. A calibration scheme used to calibrate the mismatch of capacitors and resistors and reference voltage deviation is proposed. A battery monitor IC with the proposed high voltage multiplexer is designed with a 0.25 μm 1-poly 4-metal 80 V BCD process. The post-layout-extracted simulation results of high voltage multiplexer indicate that the maximum error decreases to 1.9% from 11.2% with resistance-voltage-divider scheme and the maximum error reduces to 2.7% from 8.7% with metal-finger-capacitor scheme. The high voltage multiplexer can transmit and transform 0-70 V common voltage.