| 摘要 |
PROBLEM TO BE SOLVED: To prevent the circuit configuration of a switching power supply from becoming complicated and reduced in efficiency while restraining the timing to start intermittent oscillation control from changing.SOLUTION: A switching power supply 1 having an LLC resonance circuit and switch elements Q1, Q2 detects an error between the voltage value of an output voltage and the target value of the output voltage determined by the power supply voltage of a reference voltage source Vref, and changes the voltage of a terminal P1 according to the detection result. Also, the switching power supply 1 controls, by using a control circuit 10, the on/off frequency of the switch elements Q1, Q2 on the basis of the voltage of the terminal P1, and temporarily stops the oscillation of the switch elements Q1, Q2 when the voltage of the terminal P1 becomes equal to or greater than a first threshold voltage. Also, the switching power supply 1 detects, by using an input voltage detection unit 20, an input voltage or a voltage corresponding to the input voltage, and sets, by using the control circuit 10, the first threshold voltage according to a voltage detected by the input voltage detection unit 20. |
