Light emitting diode driver circuit with shunt switch
US7622871B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 1, 2007 |
| Grant date | Nov 24, 2009 |
| Priority date | — |
| Expiry date | Aug 8, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/38
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A LED driver circuit avoids undesirable light generated by a LED due to leakage current by shunting the output terminal to the feedback terminal during periods when it is desired that the LED remain turned off. The shunting operation is achieved by providing a switch (e.g., a FET) that is connected between the output and feedback terminals of the LED, and is controlled by the user supplied reference signal. During active operation (i.e., when the user supplied reference signal is “enabled” and the LED is lit), the switch remains open, allowing the driver circuit to generate the desired driving voltage across the LED. During inactive periods (i.e., when the user supplied reference signal is “disabled” and the LED is intended to be off), the switch is closed, which couples the output and feedback terminals to generate an essentially zero voltage drop across the LED.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.