| 摘要 |
PURPOSE:To eliminate a need of a driving transformer and to stabilize a circuit by alternately driving a P-channel FET(field effect transistor) and an N-channel FET by the operation of a photocoupler to turn on and off a switching element. CONSTITUTION:A photocoupler 6 is turned on/off by a control IC isolated from a driving circuit. A P-channel FET 3 and an N-channel FET 2 are alternately driven by this turning-on/off, and the voltage of a voltage source 7 is controlled to turn on/off a switching FET 1. Thus, a switching power supply circuit is obtained which does not require a driving transformer and secures a film insulated from the control IC to stabilize the operation. |
