DUALOUTPUT-ISOFLYBACK-REF, Dual Output Isolated Flyback Design of 5V @ 0.2A, 12V @ 2.1A w/2 addl out 3.3V @ 0.5A, 5V @ 0.5A

DUALOUTPUT-ISOFLYBACK-REF, Dual Output Isolated Flyback Design of 5V @ 0.2A, 12V @ 2.1A w/2 addl out 3.3V @ 0.5A, 5V @ 0.5A. Dual Output Isolated Flyback Design of 5V @ 0.2A, 12V @ 2.1A w/2 addl out 3.3V @ 0.5A, 5V @ 0.5A. This design utilizes the LM5020 Current Mode PWM Controller configured in a dual output Flyback converter. This isolated design operates at 300 kHz and uses a custom transformer to convert the input voltage, via flyback action, to an output voltage level of 12V at 2.1A, as well as produce an isolated 5V@0.2A rail. The LM5020 has a minimum input voltage of 13V so a start-up bias circuit was added to apply an external voltage to Vcc until the input voltage reached the proper threshold level