Patent ID: 8797006

Claim:
A switching power supply, comprising: a) a driver circuit configured to receive a bias voltage, and to drive a gate of a power transistor in a power stage of said switching power supply; b) said driver circuit being enabled when said bias voltage is at least as high as an expected bias voltage, wherein a ratio of an output voltage of said switching power supply to said expected bias voltage of said driver circuit is configured as a proportionality coefficient; c) a bias voltage generating circuit configured to generate said bias voltage for said driver circuit based on a first voltage, wherein said bias voltage generating circuit comprises a first diode having an anode coupled to a first resistor, and a cathode coupled to said driver circuit and configured as said bias voltage; and d) an H-shaped inductor directly connected by a center tap thereof to an input of said bias voltage generating circuit at said first resistor, wherein a voltage at said center tap is configured as said first voltage, and wherein a location of said center tap is determined by a number of turns of said H-shaped inductor and said proportionality coefficient.