Patent ID: 8035311
Filing Date: 2011-10-11
Classification: H05B

Abstract:
1. An electronic device comprising circuitry for driving a light-emitting semiconductor device, the circuitry comprising: a first switch coupled with the light-emitting semiconductor device for switching a current through the light-emitting semiconductor device; a sensor for sensing a magnitude of the current and outputting a respective sensing signal; an error amplifier coupled to receive the sensing signal and to provide a first control voltage based on the deviation of the sensed current magnitude and a current target value; a lowpass filter coupled to the error amplifier for providing a filtered second control voltage based on the first control voltage; a voltage follower coupled to receive the filtered second control voltage from the lowpass filter and to provide a third control voltage for controlling the switching of the first switch; and a second switch for switching on and off a supply current to the voltage follower.