Switching power supply having alternate function signal
AssigneeChampion Microelectronic Corp.
InventorJeffrey Hwang
Life of this patent
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Abstract
A switching power supply with a signal having a shared or alternate function. In one aspect, a bleed resistor supplies power to a switch controller. Then, when an output of the power supply is able to provide power for the switch controller, current through the bleed resistor is inhibited from supplying power to the switch controller. The bleed resistor may then optionally provide a different function. For example, the different function may be to provide a power factor correction (PFC) signal to the switch controller. The PFC signal allows the switch controller to modulate current from the power source to be substantially in phase with the voltage of the AC power source.
Claims20
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- control circuitry coupled to the switch for controlling operation of the switch wherein operation of the switch provides power to the control circuitry;
- a bleed resistor for supplying current from the source to the control circuitry when the switch is inactive;
- and
- means for inhibiting the current supplied to the control circuitry via the bleed resistor when the switch is active.
A switching power supply for drawing power from a source and for forming a regulated output voltage, the switching power supply comprising:
- a switch for modulating current from the source for forming the regulated output voltage by alternately charging and discharging a reactive element;
- control circuitry coupled to the switch for controlling operation of the switch wherein operation of the switch provides power to the control circuitry;
- means for supplying a power factor correction signal to the control circuitry when the switch is active, the power factor correction signal for sensing an AC voltage signal of the source;
- and
- means for inhibiting the power factor correction signal when the switch is inactive.
Dependencies are inferred from the claim text.