Design of High Voltage Multiplexer for Battery Monitoring Chip

A design of high voltage(HV)analog multiplexer(MUX)circuit has been presented.MUX circuit has voltage inputs of eight series connected battery cells, which is suitable for battery monitoring chip voltage detecting front-end.The main part of HV MUX is several parallel connected HV switches.A HV switch is composed of complementary DMOS devices and gate drive circuit, and has eliminated the error in the signal path caused by quiescent current.The MUX circuit drives a wide common mode range differential voltage detecting circuit.Elimination of level shifter circuit causes reduction in power consumption, and greatly improves the detecting accuracy.HV MUX has been designed under 0.5μm 60 V BCD process.The simulation results show that the operating current of MUX circuit is 30μA, and the error introduced by the HV MUX circuit without calibration is less than 0.2mV.