| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device which can get a more certain start-up property, and also which enables the user to select output power and start-up property independently, and is capable of design compatible with a wider range of load fluctuations. SOLUTION: This switching power supply device is provided with a transformer which has primary winding, auxiliary winding, and secondary winding, a switching element which performs the switching, being connected between the primary winding of the transformer and a DC power source generated by a commercial power supply, and a rectifying and smoothing part which rectifies and smoothes the AC voltage generated in the secondary winding of the transformer, and, between the switching element and the auxiliary winding, a control part which controls the above switching element, according to the DC output outputted from the rectifying and smoothing part. This switching power unit charges or discharges a time constant circuit which constitutes the control part, by a feedback signal from the DC output, with the auxiliary winding, and controls the switching element by the state of the time constant circuit. The time constant circuit has a plurality of time constants. COPYRIGHT: (C)2005,JPO&NCIPI
|
