I need to supply a uC from 42V power source (battery). The uC controlls a buck converter to 12V output which will drive some Leds (0.5A). If the whole device will not be used (no Led driving), a months maybe, the uC will be in sleep mode draining as little power as possible.
A uC will be supplyed from a buck, but i need to start it from 42V battery directly and then switch to supply from a buck. It is because supplying a zener diode from 42V is too lossy, so i will have to disconnect a 42V supply after buck powers on.
I designed two different legs for driving buck also , one "light" for sleep mode and another "heavy" for Led driving.
Does anyone see some possible improvement, simplifying? Or do you see some problems in design?