| 摘要 |
<p>PURPOSE:To eliminate malfunction caused by the variations of a specific value in elements by constituting the protective circuit which detects a short-circuit of output voltage by the comparison between the voltage of a power supply output terminal and the reference voltage at a reference voltage source used for the main portion of a power supply stabilization circuit by means of a differential type voltage comparator. CONSTITUTION:In normal operation in stabilized power supply the output of a differential type voltage comparator 9 is in the stable state near the potential of a power supply input terminal 1, where a PMOSFET 8 is kept in OFF state and the protective circuit portion composed of the differential type voltage comparator 9 and the PMOSFET 8 is functionally in the separated state from the main portion of a power supply stabilization circuit. When the output voltage is in the short-circuit state, the output of the differential type voltage comparator 9 is reversed and becomes stable near ground level since the potential of a non-reversing input terminal of the differential type voltage comparator 9 becomes equal to the potential of a ground terminal 3. And the PMOSFET 8 turns ON, the gate voltage of a control MOSFET 4 is raised and the protective circuit will work so that no excessive current will flow to the control MOSFET 4.</p> |
