Self-oscillating high frequency converter with power factor correction
AssigneeNexgen Power Systems, Inc.
InventorCharles Coles
Life of this patent
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Abstract
A self-oscillating converter includes a power transistor coupled to a primary winding for controlling current flow in the primary winding, and a turn-on circuit configured to turn on the power transistor for maintaining oscillation in the self-oscillating converter. The self-oscillating converter also includes a turn-off circuit configured to turn off the power transistor to maintain an on-time of the power transistor at a pre-set value for power factor correction, and modulate the on-time of the power transistor to regulate the output current in the load device.
Claims20
A self-oscillating converter with power factor correction and output current regulation, the self-oscillating converter comprising:
- a primary winding for coupling to an input voltage and providing a regulated output voltage to a load device;
- a power transistor coupled to the primary winding for controlling current flow in the primary winding;
- a first auxiliary winding coupled to the primary winding for providing a turn-on signal to the power transistor for maintaining oscillation in the self-oscillating converter;
- a second auxiliary winding coupled to the primary winding for providing a turn-off signal to the power transistor to maintain an on-time of the power transistor at a pre-set value for power factor correction;
- and
- a sensing circuit for sensing an output current in the load device and providing a modulating signal to modulate the on-time of the power transistor to regulate the output current in the load device.
A method for driving a load device with a self-oscillating converter, comprising:
- coupling a primary winding of the self-oscillating converter to receive an AC input voltage and providing an output voltage to the load device;
- controlling current flow in the primary winding using a power transistor coupled to the primary winding;
- providing a turn-on signal to the power transistor for maintaining oscillation in the self-oscillating converter, using a first auxiliary winding coupled to the primary winding;
- providing a turn-off signal to the power transistor to maintain an on-time of the power transistor at a pre-set value for power factor correction, using a second auxiliary winding coupled to the primary winding;
- and
- sensing a current in the load device and providing a modulating signal to modulate the on-time of the power transistor to regulate an output current in the load device, using a sensing circuit.
Dependencies are inferred from the claim text.