Control circuit for LED and corresponding operating method
US6515434B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 2001 |
| Grant date | Feb 4, 2003 |
| Priority date | — |
| Expiry date | Jun 6, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S362/80
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A drive circuit for an LED array, comprising at least two clusters of LEDs, in which one cluster comprises a number of LEDs arranged in series which are connected to a supply voltage (UBatt), with a semiconductor switch (T) being arranged in series between each LED cluster and the associated supply voltage, which semiconductor switch (T) allows the LED current to be supplied in a pulsed manner, with a measurement resistor (RShunt) being arranged in series with the LEDs in the path for the forward current IF between the LEDs and ground. A control loop controls the semiconductor switch (T1) in a first LED cluster, referred to as the master cluster in the following text, such that a constant mean value of the LED current is achieved, wherein the master cluster has a predetermined number X of LEDs in its cluster, and with this control loop also driving at least the semiconductor switch (T2) in a further, LED cluster, referred to in the following text as the slave cluster.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.