| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an insulated switching power supply that can set an appropriate restart time. <P>SOLUTION: A control circuit 2 includes an overcurrent detection section 24, a control winding voltage detection section 22, an overcurrent mode determination section 21, a restart section 23, and a flip-flop FF2. The overcurrent detection section 24 determines whether or not a current flowing through a switch element Q1 is overcurrent. The control winding voltage detection section 22 determines whether or not a voltage at an end of a control winding T2 of a transformer T is below a threshold voltage. The overcurrent mode determination section 21 sets a first time as a restart time when there is no overcurrent, and sets a second time longer than the first time as the restart time if there is overcurrent. The restart section 23 and the flip-flop FF2 turn on the switch element when the switch element is off and the voltage at the end of the control winding T2 of the transformer T is below the threshold voltage for the restart time. <P>COPYRIGHT: (C)2012,JPO&INPIT |
