| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to obtain a high power factor and a high VA efficiency regardless of a small load or a large load. SOLUTION: By a control signal from an external control circuit 12, an SW switching circuit 11 selects either choke input rectifying circuit or active filter circuit as an operation circuit. In a state of applying a power supply circuit 1 having this configuration to a image forming equipment, a choke input, rectifying circuit is selected by a control circuit 12 when the picture forming equipment, is in waiting state. When the choke input rectifying circuit is selected, a charging current is smoothened by the choke coil L1, the peak value of current is lowered, and components of higher harmonics are reduced. Also in this state of selection, noise can be reduced and power supply efficiency can be improved compared to the power supply efficiency. |
