| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device and an image forming apparatus that implement improved efficiency in an energy saving standby mode.SOLUTION: The power supply device for producing a DC voltage from an AC power supply comprises: rectifying/smoothing means connected to the AC power supply to rectify and smooth an AC voltage; a first DC-DC converter A for converting a DC voltage from the rectifying/smoothing means to output a first DC voltage; a second DC-DC converter B for outputting a second DC voltage lower than the first DC voltage through a switching action of switching means on receipt of the first DC voltage from the first DC-DC converter; and state transition means 746 for making a transition to a state in which the output voltage of the first DC-DC converter is reduced from the first DC voltage to a third DC voltage lower than the second DC voltage and the switching means of the second DC-DC converter is driven in a continuously conductive state. |
