Isolated Flyback Converter with 18V-28V Input and 12V Output

The project presented here is a micropower no-opto isolated flyback converter featuring the  LT8304  chip from Analog Devices. This circuit outputs  12V  and maintains tight regulation with a load current from  10mA up to 1A  and over an input voltage from  18V to 28V. The project needs less than 0.5% of its full output power as a minimum load to maintain good output voltage regulation. The transformer leakage inductance causes a voltage spike on the primary side after the power switch turns off. To limit this leakage inductance spike within the MOSFET voltage rating of  150V, an RC snubber, and a TVS clamp are installed to dampen the ringing and clamp the MOSFET drain voltage to a safe level.