Hey @analogoutput , would you mind explaining how you came up with this circuit? 
I read a bit on northcoast synthesis and found that your circuit is similar to (D), but I don’t understand the two diodes D1 and D2 (I assume it’s some kind of reverse voltage protection, but couldn’t that be done with a anti-parallel diode to the LED?)
Why the additional 1k resistor? And tC1 is for some kind of stabilization/filtering?
