Patent ID: 7046532

Claim:
A switching power supply comprising: (a) a plurality of capacitors for dividing the voltage of a DC power supply; (b) a plurality of DC-DC converters, the input sides of which respectively receive the voltages divided by said plurality of capacitors and the output sides of which are connected in parallel; (c) output voltage error detecting means for detecting the output voltage of said DC-DC converters and for generating an error signal between the output voltage and a reference voltage; (d) input voltage deviation detecting means for detecting voltages corresponding to the input voltages of said DC-DC converters and for generating the deviation signal of the input voltages of said DC-DC converters; and (e) control means, receiving the error signal from said output voltage error detecting means and the deviation signal from said input voltage deviation detecting means, for drive-controlling said DC-DC converters, wherein said input voltage deviation detecting means detects voltages induced in auxiliary windings added to a transformer at the time when switching mean are in the ON state.