| 摘要 |
PURPOSE:To miniaturize the title device by ORing the inverse output of a flip flop, which is set by the output pulse of the clock generator being externally triggered by the voltage detection output of the tertiary coil of an insulating transformer with the output pulses of the clock generator, and driving a switching element by the output. CONSTITUTION:In the unstable operation period when the voltage of a terminal VCC transits, by a comparator 22 for comparison and a three-input OR gate 24, a transistor Q1 is turned off, and a transistor Q2 is turned on, and the output OUT of a control circuit 20 is kept at low level. Accordingly, with this timing, the switching element SW is off. Next, when the a flip flop 28 is set by the pulse of certain cycle and the output pulse of a clock generator 26 goes to a low level, the three-input OR gate 24 outputs low level as noninverse output and high level as inverse output. And the OUT of the control circuit 20 goes to a high level, and the switching element SW is turned on. |
