Low noise high PSRR band-gap with fast turn-on time
US6278320A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 1999 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | Dec 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/30
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A band-gap filter circuit is disclosed for use in a voltage regulator. A capacitor charger (or "cap charger") circuit quickly charges a filter capacitor when power is applied to the voltage regulator circuit. At start-up, the cap charger begins charging the filter capacitor. Once an output node equals or nearly equals the voltage at the input node, the cap charger shuts off. The circuit provides a very fast turn-on time, reaching 95% of its steady state value within 200 microseconds, thus overcoming the long turn-on times associated with other designs. The present invention may be utilized in power sensitive applications, such as cellular telephones, that wish to shut off the voltage regulator in order to conserve power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.