| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly efficient and compact switching power supply by an insulated converter of single-stage configuration combining a power factor correction (PFC) function, an output stabilization function and an instantaneous power failure compensation function.SOLUTION: A capacitor 4 for instantaneous power failure compensation is provided on the DC side of a diode bridge 2 rectifying an AC input power, and subjected to step-up charging with power from the tertiary winding N3 of an insulated transformer 9 when correcting the power factor by controlling a switching element 5a during non-power failure. The drive frequency of the switching element 5a when delivering energy stored in the capacitor 4, by detecting power failure, to the insulated secondary via the insulated transformer 9 is set larger than the drive frequency during non-power failure depending on the step-up rate of the capacitor 4. |
