Free running flyback DC power supply with current limit circuit

Claim 1

A DC power supply comprising: a power transformer having a primary winding and a secondary winding, with said primary winding being coupled to an unregulated DC source and the secondary winding being coupled to a load; electrical switching means, operatively coupled in series with said primary winding, which controls the flow of current to said primary winding; electrical control means for controlling switching action said switching means, according to the current flowing through the switching means; means for sensing said DC source, said sensing means providing a signal proportional to the voltage of said DC source, the sensing means being operatively coupled to the control means to vary the maximum peak current through the switching means, at switching means turnoff, as a function of the voltage of the DC source; slew rate limit circuit which limits rise of voltage across said switching means; and clamp circuit which prevents the voltage across said switching means from reaching an excessive level.