I wonder if there is some simple solution to drive LEDs powered from single rectified voltage.
Assume AC is 220 V, each LEDs is 3.0 - 3.2 V 150 mA. I reckon series connection made it simpler but not sure if the optocoupler is able to provide the current.
Adding a BJT/MOSFET at the opto output should be OK but I am not sure how to connect it. Protective part can be advised but I wish to have the basic ON/OFF function working first.
EDIT on 2019-01-28 12:34
Actually, my design consists of two 30xLEDs paths and wish to end them with an optocoupler to Neutral.
Thanks to JonRB and Transistor, they discovered several fatal issues, so i retry and hope this would make more sense.
Refer to this active current limiter, i wonder if the optocoupler can attach to it. Now, with 60 x LEDs (3.0 - 3.2 V 150 mA):
100k Resistor to turn IRF740 FET On. 8 Ohm Resistor with BC817 BJT to limit the current to ~150mA. Optocoupler PC817 would shutdown both transistors.
I think IRF740((400Vds) should be capable of AC peak voltage and current limiter can save the LEDs from destory as well.