Switching power supply circuit using a silicon based LED for feedback
US6885016B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Sep 3, 2002 |
| Grant date | Apr 26, 2005 |
| Priority date | — |
| Expiry date | Sep 16, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/30107
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Flyback power supplies require three chip integrated circuits to control the switching cycles on the primary of a transformer including a chip that detects when a voltage threshold and optionally when a current threshold has been crossed on the secondary side of the transformer, an opto-coupler to isolate the secondary to primary feedback from the first chip, and a switch control circuit that receives the feedback information from the opto-coupler and uses the information to modulate the primary pulses in order to regulate the secondary voltage and to optionally set a current compliance limit on the secondary current. This invention shows how these three integrated circuits can be combined into one package using silicon based LEDs. Furthermore, circuit techniques are presented that allow the detection of low level light produced by silicon based LEDs. These techniques include disconnecting the power supply from sensing circuits and using a charge capacitor for power and performing the sensing operation during a period of time when clocked digital circuits are inactive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.