LED driver circuit having efficiency-improving function
US9480110B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 19, 2013 |
| Grant date | Oct 25, 2016 |
| Priority date | — |
| Expiry date | Apr 14, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An LED driving circuit having an efficiency improvement function and connected to an alternating current (AC) power supply, includes: a rectifier circuit that rectifies the AC power supply; a control circuit connected to an output of the rectifier circuit; an LED load and a constant-current circuit that are connected to an output of the control circuit in series; a capacitor that is connected in parallel to the LED load and the constant-current circuit that are connected in series to each other, the capacitor smoothing the output of the rectifier circuit; and a detection circuit that detects whether the rectified voltage exceeds a predetermined particular voltage value that is equal to or greater than the sum of a voltage applied to the LED load when the LED load is turned on and a voltage applied to the constant-current circuit at a time when the LED load starts being turned on.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.