Motor drive circuit, and a drive circuit built-in motor and drive circuit built-in pump motor with a built-in it, and they equipped with air conditioner, ventilation fans, heat pump water heater, as well as built-in cold and hot water circulation air conditioning system

摘要

Regardless of the state of the load during operation, conducts the motor drive circuit capable of reducing the loss, and the drive circuit-integrated motor and drive circuit internal pump motor which was built, and an air conditioner equipped with them, ventilators heat pump water heater, as well as to obtain a built-cold water circulating air conditioner. An inverter circuit 18 for the upper stage switching elements 12 to 14 and the lower stage switching elements 15 to 17 are bridge-connected, when generating a gate signal of the inverter circuit 18, the OFF period of the upper stage switching elements 12 to 14, the lower the return current flowing to the side switching elements 15 to 17 I, when the forward voltage of the parasitic diode was Ron Vf, the on-resistance of the MOSFET, and is the same as the conditions that satisfy the relationship of I Vf / Ron, the timing at which the return current flows and a gate signal generating unit 6 for synchronous rectification that turns on control lower stage switching elements 15 to 17 in synchronism with the.