LED drive circuit
US8203506B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 2005 |
| Grant date | Jun 19, 2012 |
| Priority date | — |
| Expiry date | Sep 19, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0626
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An LED array includes a plurality of LED segments connected in a common cathode configuration at a common cathode node. A high side driver is operable responsive to segment control signals to selectively supply current to certain LED segments. A low side driver is provided to sink current from the common cathode node. A plurality of selectively actuated current sink paths are provided in each low side driver. A control logic circuit actuates a current sink path within the low side driver for each LED segment that is selectively supplied current by the high side driver. A substantially constant low side voltage drop through these sink paths is provided regardless of the number of LED segments that are supplied current by the high side driver so as to achieve a substantially constant LED segment brightness. A common anode configuration operating in an analogous way is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.