Driver circuit for power supply, integrated driver circuit for power supply, and power supply

摘要

In the disclosed power supply, during startup, the input voltage of a switching power source is used as the drive power supply of the drive circuit which drives a high-side switching element, and loss generated by the startup circuit is reduced. Further, the startup circuit and drive circuit parts required in a high breakdown voltage process are configured in the control circuit as a single driver (IC). A control IC (30) generates a switching control signal for controlling a first switching element (Q1) and a second switching element (Q2). A drive circuit (22) in a high breakdown voltage driver IC (20) generates a gate drive voltage signal for the first switching element (Q1) and the second switching element (Q2) on the basis of the switching control signal inputted from the control IC (30). A startup circuit (21) supplies a partial voltage of the voltage inputted to a startup power source terminal (Vs) to the drive circuit (22) in the high breakdown voltage driver IC (20) and to the external control IC (30), and shuts off a switching element (Q3) after startup.