FSL306LR HV buck supply

This is a buck converter for 35-400 V DC input to 12 V (9-24 V) output. It uses the excellent FSL306 buck converter IC. It has a fairly low output current of 450 mA max (1.8 A if using the alternative FSL336 IC but you'd need a bigger inductor). It's tested and has worked flawlessly. A B1212 provides isolation to one set out outputs for when this is needed - you don't have to populate it if you don't need this. Mounting holes are 4 mm with spacing of 40 mm and 90 mm. Obviously a fatal shock risk exists from this board due to the high voltage DC input and because its output is not isolated. The circuit has a low quiescent current and was designed in order to supply 12 v to microcontrollers etc. which control HV solar equipment. 

The input capacitor can be aluminium electrolytic but film is better for long life; the board has space for either. Solid capacitors are recommended at the output. It may be a good idea to put a variable resistor in the voltage feedback circuit if you need adjustable output voltage.