Power supply apparatus having switchable switching regulator and linear regulator
US7812580B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 2006 |
| Grant date | Oct 12, 2010 |
| Priority date | — |
| Expiry date | Jul 13, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control circuit is provided in which two power sources can be efficiently switched, for a power supply apparatus provided with a step down switching regulator and a linear regulator. A PWM controller generates a pulse width modulation signal with which a duty ratio is controlled so that output voltage of the switching regulator approaches a predetermined reference voltage. A compulsory OFF circuit monitors a switching voltage, and when a first threshold voltage is exceeded, switches a synchronous rectifier transistor OFF. A minimum ON time setting circuit limits the duty ratio of the pulse width modulation signal, so that ON time of the switching transistor is longer than a predetermined minimum value. A selector circuit monitors an error voltage, and when a predetermined state continues for a predetermined first period, puts the linear regulator in an operating state, and the step down switching regulator in a halt state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.