HIGH SPEED LED DRIVER

摘要

An electronic device includes circuitry for driving a light emitting semiconductor device (LED). The circuitry includes a first switch (NM5) coupled with the light emitting semiconductor device (LED) for switching a current (ID) through the light emitting semiconductor device (LED), a sensing means (RS) for sensing a magnitude of the current (ID) and outputting a respective sensing signal (SEN); an error amplifier (AMP2) for receiving the sensing signal (SEN) and a preset target value (ISET) for the current (ID) for providing a first control voltage (VG1) based on the deviation of the current s actually sensed magnitude and the preset target value (ISET); a lowpass filter coupled to the error amplifier (AMP2) for filtering the first control voltage (VG1) and providing thereby a second control voltage (VG2), a voltage follower (NM3) coupled to the lowpass filter and the first switch for receiving the second control voltage (VG2) and providing a third control voltage (VG3) for controlling the first switch's (NM5) switching activity and a second switch (PM1, NM4) for switching a supply current (IDS3) of the voltage follower (NM3) for switching the voltage follower (NM3) on and off.