Switching regulator power supply main switching transistor turn off speed up circuit

In a switching regulator power supply, a main switching transistor turnoff speedup circuit comprising:

• a transformer having a primary and a secondary winding, said primary winding connected in series between the output electrode of the main switching transistor and the output terminal of the power supply, the first end of said secondary winding connected to said output electrode, said secondary winding being wound to produce signals at its second end that are oppositely phased from corresponding signals at said output terminal of said power supply;
• signal feedback circuitry including a capacitor coupled in series between said second end of said secondary winding and the base of said switching transistor for applying said oppositely phased signals to said base;
• and
• signal bypass means coupled across said secondary winding for suppressing forward bias enabling signals from the base of said transistor and for applying negative biased regenerative turnoff signals to said base.