In the vehicle electric power steering(EPS)system,most of the motor bus power supply uses relay technology solutions,and a small part uses the metal-oxide-semiconductor field effect transistor(MOSFET)technology solutions,and basically the drive circuit is a non-isolated control signal.DC-DC boost circuit or integrated booster chip is needed to be used as the MOSFET driving voltage source in the MOSFET technology solutions.However,these two technology solutions will not be able to cut off the control circuit of motor bus power supply under certain circumstances such as collapse of the EPS system.In response to this issue,a solution is proposed that uses capacitor to isolate and transmit the control signal,and bootstrap boost to drive the MOSFET to be realized at the same time,which improves the safety performance of the EPS system.
EPSbus power supplyisolation controlbootstrap boostingpre-charging