Direct conduction control for power factor correction circuit
AssigneeTexas Instruments Incorporated
InventorWilliam James Long
Life of this patent
Estimating the term…
Abstract
A system includes a switching power supply that includes switch devices configured to provide a regulated output voltage based on an input voltage. A controller is configured to control the switch devices based on a power demand signal. A direct conduction avoidance circuit is configured to provide a direct conduction avoidance signal based on the regulated output voltage exceeding a direct conduction threshold voltage. The direct conduction avoidance signal is combined with a compensation signal to provide the power demand signal to the controller. An override circuit is configured to disable the direct conduction avoidance circuit based on the input voltage of the switching power supply being below an override threshold voltage.
Claims19
A system, comprising:
- a switching power supply that includes switch devices configured to provide a regulated output voltage based on an input voltage;
- a controller coupled to the switching power supply and configured to control the switch devices based on a power demand signal;
- an error amplifier configured to receive the regulated output voltage and a reference voltage and generate a compensation signal based on the regulated output voltage and the reference voltage;
- a direct conduction avoidance circuit configured to provide a direct conduction avoidance signal based on the regulated output voltage exceeding a direct conduction threshold voltage;
- a summing junction in which the direct conduction avoidance signal is combined with the compensation signal to generate the power demand signal;
- and
- an override circuit configured to disable the direct conduction avoidance circuit based on the input voltage of the switching power supply being below an override threshold voltage.
A circuit, comprising:
- a controller including outputs coupled to switching devices of a power supply including an input voltage input coupled to an input voltage, the controller including a power demand input;
- a direct conduction avoidance circuit including inputs coupled to the power supply and a direct conduction threshold voltage, the direct conduction avoidance circuit including a direct conduction output coupled to the power demand input;
- an override circuit including first and second inputs coupled to the input voltage of the power supply and an override threshold voltage respectively, the override circuit including an output coupled to the direct conduction avoidance circuit;
- and
- an error amplifier including first and second inputs coupled to an output voltage of the power supply and a reference voltage respectively, the error amplifier including an output coupled to the compensation input of the controller.
A device, comprising:
- a controller configured to control on and off timing of switch devices of a switching power supply to provide a regulated output voltage based on an input voltage to the switching power supply and a power demand signal;
- a direct conduction avoidance circuit configured to monitor the regulated output voltage of the switching power supply with respect to a direct conduction threshold voltage and to provide a direct conduction avoidance signal to adjust the power demand signal to the controller based on the regulated output voltage exceeding the direct conduction threshold voltage;
- an override circuit configured to disable the direct conduction avoidance circuit based on the input voltage of the switching power supply being below an override threshold voltage and to enable the direct conduction avoidance circuit based on the input voltage of the switching power supply being above the override threshold voltage;
- and
- an error amplifier configured to sense the regulated output voltage and a reference voltage, the error amplifier generating a compensation signal based on the regulated output voltage and the reference voltage, the compensation signal being combined with the direct conduction avoidance signal to create the power demand signal.
Dependencies are inferred from the claim text.