| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact and low cost switching power supply in which circuit components can be prevented from being destroyed due to heat.SOLUTION: A switching power supply includes a chopper circuit including a transistor 2, a reflux diode 3, a reactor 4, and a control IC 10 for turning the transistor 2 on/off, a start-up circuit 8 including a transistor 23 and generating a power supply voltage VCC1 for starting up the control IC 10 based on an input voltage Vi, a power supply circuit 9 generating a power supply voltage VCC2 for operating the control IC 10 steadily based on the voltage between terminals of a reactor 5 coupled electromagnetically with the reactor 4, and a heatsink 30 for heating the transistors 2, 23. |
