| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply which can reduce a loss and a beat tone of a transformer.SOLUTION: A switching power supply 10 includes: a transformer Tr which includes a primary winding N1 and a secondary winding N2; an N-channel field effect transistor Q4 which switches on and off the application of an input voltage to the primary winding N1; a feedback part which generates a feedback signal according to the secondary-side output voltage of the transformer Tr; and a power control IC 12 which controls the field effect transistor Q4 on the basis of the feedback signal. The feedback part includes a shunt regulator S1 and a variable current part 11, disposed at the secondary side of the transformer Tr, for making a variable current which flows into the shunt regulator S1. |
