Datasheet Summary
Low-Voltage, Secondary-Side Shunt Regulator
General Description
The MIC4043 is a shunt regulator optimized for secondaryside regulation in low-voltage power supplies. Featuring an output stage guaranteed to swing within 400mV of ground, the MIC4043 can be used in power supplies operating down to 1.8V, even with opto-isolators requiring greater than 1.2V of headroom.
In power supply applications, the MIC4043 normally drives the LED of an optically isolated feedback circuit. The MIC4043 monitors a resistively-divided output voltage and sinks error current through the opto-isolator’s LED (secondary side); the opto-isolator’s transistor (primary side) provides this signal to the...