| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply apparatus controlling a resonant converter to always work at a constant oscillatory frequency and preventing abnormal oscillation or intermittent oscillation from being generated. <P>SOLUTION: A switching power supply apparatus comprises: a rectification circuit rectifying AC power and outputting DC voltage; a switching element and a control circuit performing on-off control on the switching element; and with use of an active filter stepping up/down and smoothing DC voltage of the rectification circuit, a resonant converter converting an input DC voltage stepped up/down by the active filter to AC voltage of high frequency, and a frequency/voltage converter converting oscillatory frequency of the resonant converter to output voltage, a frequency control circuit controlling the oscillatory frequency of the resonant converter according to the input DC voltage of the resonant converter which is stepped up/down by controlling the controlling circuit of the active filter by use of the output voltage of the frequency/voltage converter. <P>COPYRIGHT: (C)2012,JPO&INPIT |
