| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply capable of detecting an over current more reliably.SOLUTION: A comparator 15 compares the terminal voltage of a resistive element 2 arranged in an electrification path, through which a current flows when a P channel MOSFET3 connected in series with a coil 4 is turned on, with a reference voltage VREF2 for overcurrent detection. A flip-flop 16 latches the output signal from the comparator 15 during a period when a P channel MOSFET2 transits from on to off, by using a signal in the signal path from the output terminal of a comparator 11 to the gate of the P channel MOSFET3. More specifically, the output signal PWMOUT from a waveform shaping circuit 12, for outputting the PWM signal from the comparator 11 while shaping the waveform, is given to the clock terminal CLK of the flip-flop 16, as a latch signal. |
