| 摘要 |
PROBLEM TO BE SOLVED: To suppress the power consumption of a switching power supply.SOLUTION: A power-supply system S includes a switching power supply 20 voltage-converting an input voltage applied from a main power-supply side 150 and outputting the converted voltage, and a control device 80 receiving power from the switching power supply 20. The switching power supply 20 includes a transformer 23, an FET 25 connected to a primary coil of the transformer 23, a control IC 50, and a rectifier smoothing circuit 27. The control IC 50 is started by power supply from the main power-supply side 150, and oscillates a primary side of the transformer 23 by starting switching control of the FET 25 to induce a voltage at a secondary side of the transformer 23. The control device 80 changes the switching power supply 20 to an output stop mode by stopping the oscillation of the transformer 23 by outputting a control pulse signal Sr to a switch control section 50 during an output mode. |
