High-efficiency bias voltage generating circuit

摘要

Disclosed are bias voltage generating circuits and methods for a switching power supply. In one embodiment, a switching power supply can include: (i) a driver circuit configured to receive a bias voltage, and to drive a switch in a power stage of the switching power supply; (ii) where a ratio of an output voltage of the switching power supply to an expected bias voltage of the driver circuit is configured as a proportionality coefficient; (iii) a bias voltage generating circuit configured to generate the bias voltage for the driver circuit based on a first voltage; and (iv) an H-shaped inductor coupled to an input of the bias voltage generating circuit, where the first voltage is configured to be generated based on a number of turns of the H-shaped inductor and the proportionality coefficient.

主权项

1. 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.