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(11) | EP 2 611 263 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Circuits and methods for driving LED light sources |
| (57) A driving circuit for controlling power of a light-emitting diode (LED) light source
includes a transformer, a switch controller, and a dimming controller. The transformer
has a primary winding operable for receiving input power from an AC/DC converter and
a secondary winding operable for providing output power to the LED light source. The
switch controller coupled between an optical coupler and the primary winding is operable
for receiving a feedback signal indicative of a target level of a current flowing
through the LED light source from the optical coupler, and for controlling input power
to the primary winding according to the feedback signal. The dimming controller coupled
to the secondary winding is operable for receiving a switch monitoring signal indicative
of an operation of a power switch coupled between an AC power source and the AC/DC
converter, and for regulating the output power of the transformer by adjusting the
feedback signal according to the switch monitoring signal.
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