Switching power supply device
US7787269B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 2008 |
| Grant date | Aug 31, 2010 |
| Priority date | — |
| Expiry date | Mar 3, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/33523
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a switching power supply device including a switching element, a control circuit controlling the switching element, a transformer having an auxiliary winding, a potential clamp circuit connected to one of outputs of the transformer, a delay capacitor connected to an output of the potential clamp circuit, a potential detection circuit detecting a potential at the delay capacitor, and an overload protection actuation circuit realizing overload protection. During an overload, the delay capacitor is charged only by ringing of the auxiliary winding, generated immediately after the switching element is turned off, through the potential clamp circuit. Then, the potential detection circuit supplies an actuation signal to a latch stop circuit by detecting that the potential at the delay capacitor rises. The latch stop circuit latches and stops the switching operation of the switching element to realize the overload protection when the actuation signal is fed into the latch stop circuit. Thus, the overload protection can be realized with a sufficient delay time by the relatively small delay capacitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.