| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply that suppresses the occurrence of resonance between a parasitic capacitance of a switching element and a reactor during a discontinuous mode of operation.SOLUTION: A switching power supply 100 for transforming a voltage input from a DC power supply 1 to feed a load 7 includes: an input capacitor 2 connected in parallel with the DC power supply 1; an output capacitor 6 connected in parallel with the load 7; a chopper circuit connected in parallel between the input capacitor 2 and the output capacitor 6 and having a switching element 3, a freewheeling diode 4 and a reactor 5; and a backflow prevention diode 9 as a backflow prevention element disposed on a first current path directed from a negative terminal of the input capacitor 2 to a positive terminal of the input capacitor 2 via the reactor 5 and the switching element 3 to block a current flowing in the first current path in a direction from the negative terminal of the input capacitor 2 to the positive terminal of the input capacitor 2. |
