Hi Mike,
C1 is a supercap, 5 Farad or 10 Farad depending how much energy i require to power the load. D1 and D2 are sschottky steering diodes to prevent the capacitor discharging into the PSU and to bypass R6 in order to get maximum current flow out of the capacitor. R6 is used in the charging phase to adjust charging rate.
Ive made this circuit up on breadboard and its driving me crazy. It works fine with a resistive load but when i attach the small board computer (SBC) the mosfet never turns off fully and i get very strange oscillation close to the cutt off point. This shouldnt happen because my hysterisis is around 1V. Ive tried this with only the mosfet and TL431 without the front end capacitors etc and used a variable power supply. i still get the same symptoms.
Can you help any
thanks