| 摘要 |
PROBLEM TO BE SOLVED: To prevent the destruction of a set by an overcurrent, by interrupting an overcurrent output at an arbitrary time during overcurrent operation in a switching power supply and by interrupting the operation of the switching power supply. SOLUTION: This protective circuit, which is the circuit for preventing an overcurrent which flows in an output terminal of the power supply, comprises a control signal generation circuit, which generates a first control signal according to an overcurrent of an output, a signal detection circuit that detects the level of the first control signal and outputs a second control signal if the detected signal becomes a predetermined level or higher, a timer circuit 220, which is driven by the second control signal outputted from the signal detection circuit, to which the first control signal is transferred during its operation and in which the first control signal is charged by a prescribed time constant, and a latch operation portion 230, which generates a third control signal for preventing an overcurrent if the first control signal becomes a predetermined value or larger after charged by the timer circuit. The latch operation is performed in an arbitrary period of time after the intermittent operation is started. COPYRIGHT: (C)2008,JPO&INPIT
|
