Power factor control circuit and power factor control method
AssigneeAcbel Polytech Inc.
InventorsChia-An YEH, Hsiang-Yi CHEN
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Abstract
A power factor control circuit has a power factor controller that determines if the power factor control circuit is operated at a continuous current mode (CCM) or a discrete current mode (DCM), and outputs PWM signals corresponding to the present current mode. A duty cycle of the PWM signals is equal to a sum of a feed-forward control parameter and a current compensation parameter. The current compensation parameter contains a difference value between a reference current and an inductor current in the power factor control circuit. Accordingly, a switching power supply circuit can acquire the PWM signals corresponding to the present current mode to effectively resolve the issue of harmonic distortion.
Claims17
A power factor control circuit comprising:
- an input terminal, an output terminal, an inductor, an output capacitor, a diode, an active switch, and a power factor controller connected to the input terminal and the output terminal of the power factor control circuit, having an output control terminal connected to the active switch, determining that the power factor control circuit is operated at one of a continuous current mode (CCM) and a discrete current mode (DCM), and outputting pulse width modulation (PWM) signals corresponding to different current modes operated by the power factor control circuit, wherein
- the PWM signals corresponding to the CCM have a first duty cycle being equal to a sum of a CCM feed-forward control parameter and a CCM current compensation parameter;
- the PWM signals corresponding to the DCM have a second duty cycle being equal to a sum of a DCM feed-forward control parameter and a DCM current compensation parameter, and
- the current compensation parameter has a difference value between a reference current and an inductor current.
A power factor control method executed in a power factor control circuit having an inductor, the power factor control method comprising steps of:
- determining if a present current mode operated by the power factor control circuit is a CCM or a DCM;
- if the present current mode is the CCM, outputting a PWM signal, wherein a duty cycle of the PWM signal is equal to a sum of a feed-forward control parameter and a current compensation parameter, and the current compensation parameter has a difference value of a reference current and an inductor current;
- and
- if the present current mode is the DCM, outputting a PWM signal, wherein a duty cycle of the PWM signal is equal to a sum of a feed-forward control parameter and a current compensation parameter, and the current compensation parameter has a difference value of a reference current and an inductor current.
Dependencies are inferred from the claim text.