Zero current and valley detection for power factor correction
AssigneeTexas Instruments Incorporated
InventorsAnanthakrishnan VISWANATHAN, Salvatore GIOMBANCO, Joseph Michael LEISTEN, Philomena Cleopha BRADY
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Abstract
A power factor correction circuit includes a power transistor, an inductor, and detection circuitry. The inductor is coupled to a drain terminal of the power transistor. The detection circuitry is coupled to the drain terminal of the power transistor. The detection circuitry is configured to determine an input voltage applied to the inductor based on resonant ringing of voltage at the drain terminal, and to detect a valley in the voltage at the drain terminal based on the input voltage applied to the inductor.
Claims20
A power factor correction circuit, comprising:
- a power transistor;
- an inductor coupled to a drain terminal of the power transistor;
- and
- detection circuitry coupled to the drain terminal of the power transistor, the detection circuitry configured to:
- determine a value of input voltage applied to the inductor based on a resonant ringing of a voltage at the drain terminal;
- and
- detect a valley in the resonant ringing of the voltage at the drain terminal based on the value of the input voltage applied to the inductor.
A method for controlling power factor correction, comprising:
- driving an inductor coupled to a drain terminal of a power transistor;
- determining, by detection circuitry coupled to the drain terminal, an input voltage applied to the inductor based on a resonant ringing of a voltage at the drain terminal;
- detecting an edge in the resonant ringing of the voltage at the drain terminal based on the input voltage applied to the inductor;
- identifying a valley in the resonant ringing of the voltage at the drain terminal based on the detected edge;
- and
- providing a signal indicative of the valley to circuitry controlling activation of the power transistor.
A power factor correction controller, comprising:
- a transistor driver configured to drive a power transistor;
- and
- detection circuitry configured for connection to a drain terminal of the power transistor, the detection circuitry configured to:
- determine, based on a resonant ringing of a voltage at the drain terminal of the power transistor, an input voltage applied to an inductor coupled to the drain terminal of the power transistor;
- detect an edge in the resonant ringing of the voltage at the drain terminal based on the input voltage applied to the inductor;
- and
- identify a valley in the resonant ringing of the voltage at the drain terminal based on the edge;
- wherein the power factor correction controller is configured to drive a control terminal of the power transistor based on the valley.
Dependencies are inferred from the claim text.