LED lighting is becoming more and more common. The major advantages over other types of lighting are that LEDs are very efficient and use less energy. These also have very long lifetimes, which reduce the need to replace the lighting source. Transistor output optocouplers can be used in the lighting control circuitry in the feedback loop from the output current detector circuit and the control IC to the switching circuit. Transistor output optocouplers can also be used to isolate the control circuit from the LED driver or to isolate an RS232 communication link with other functions.