Controller for power factor corrector and method of operation thereof
First Claim
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1. For use with a power factor corrector (PFC) operable in a discontinuous conduction mode (DCM) and having a controllable switch, a controller, comprising:
- a current mode control circuit adapted to sense a current of said PFC and develop a current control signal based thereon; and
a drive circuit adapted to drive said controllable switch, including;
a voltage compensation circuit adapted to receive a signal representing an output voltage of said PFC and develop an intermediate signal therefrom, and a modulator, coupled to said voltage compensation circuit, adapted to develop a drive signal for said controllable switch based on said intermediate signal and a sum of said current control signal and a ramp signal, said drive circuit thereby capable of reducing a duty cycle of said controllable switch based thereon to reduce input current distortion in said PFC.
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Abstract
A controller for a power factor corrector (PFC), having a controllable switch and operable in a discontinuous conduction mode (DCM), and a method of controlling the controllable switch. In one embodiment, the controller includes: (1) a drive circuit adapted to drive the controllable switch and (2) a current mode control circuit adapted to sense a current of the PFC and develop a current control signal based thereon. The drive circuit reduces a duty cycle of the controllable switch based on the current control signal to reduce input current distortion in the PFC.
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Citations
25 Claims
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1. For use with a power factor corrector (PFC) operable in a discontinuous conduction mode (DCM) and having a controllable switch, a controller, comprising:
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a current mode control circuit adapted to sense a current of said PFC and develop a current control signal based thereon; and
a drive circuit adapted to drive said controllable switch, including;
a voltage compensation circuit adapted to receive a signal representing an output voltage of said PFC and develop an intermediate signal therefrom, and a modulator, coupled to said voltage compensation circuit, adapted to develop a drive signal for said controllable switch based on said intermediate signal and a sum of said current control signal and a ramp signal, said drive circuit thereby capable of reducing a duty cycle of said controllable switch based thereon to reduce input current distortion in said PFC. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
a boost converter;
a buck converter;
a forward converter;
a flyback converter; and
a SEPIC converter.
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8. The controller as recited in claim 1 wherein said PFC is further operable in a continuous conduction mode (CCM).
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9. The controller as recited in claim 1 wherein said PFC comprises an input filter.
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10. A method of controlling a controllable switch of a power factor corrector (PFC) operable in a discontinuous conduction mode (DCM), comprising:
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sensing a current of said PFC and developing a current control signal based thereon;
developing an intermediate signal from a signal representing an output voltage of said PFC;
developing a signal representing a sum of said current control signal and a ramp signal; and
developing a drive signal for said controllable switch based on said intermediate signal and said signal representing said sum of said current control signal and said ramp signal, said drive signal reducing a duty cycle of said controllable switch based thereon to reduce input current distortion in said PFC. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
sensing a rectified voltage of said PFC;
developing a voltage control signal based thereon; and
modifying a switching frequency of said controllable switch based on said voltage control signal.
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12. The method as recited in claim 11 wherein said sensing said rectified voltage is performed by a voltage divider.
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13. The method as recited in claim 10 wherein said sensing a current of said PFC is performed by a current mode control circuit including a current sensor to sense said current and a filter to develop said current control signal based thereon.
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14. The method as recited in claim 10 wherein said developing said intermediate signal further comprises comparing said signal representing said output voltage to a reference signal.
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15. The method as recited in claim 10 wherein said developing said drive signal is performed by a duty cycle comparator that receives said intermediate signal and said signal representing said sum of said current control signal and said ramp signal to develop said drive signal.
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16. The method as recited in claim 10 wherein said PFC employs a topology selected from the group consisting of:
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a boost converter;
a buck converter;
a forward converter;
a flyback converter; and
a SEPIC converter.
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17. The method as recited in claim 10 wherein said PFC is further operable in a continuous conduction mode (CCM).
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18. The method as recited in claim 10 wherein said PFC comprises an input filter.
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19. A power factor corrector (PFC) operable in a discontinuous conduction mode (DCM), comprising:
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an electromagnetic interference (EMI) filter;
a rectifier coupled to said EMI filter;
a converter coupled to said rectifier and having a controllable switch; and
a controller, including;
a current mode control circuit that senses a current of said PFC and develops a current control signal based thereon, and a drive circuit that drives said controllable switch, including;
a voltage compensation circuit that receives a signal representing an output voltage of said PFC and develops an intermediate signal therefrom, and a modulator, coupled to said voltage compensation circuit, that develops a drive signal for said controllable switch based on said intermediate signal and a sum of said current control signal and a ramp signal, said drive circuit thereby capable of reducing a duty cycle of said controllable switch based thereon to reduce input current distortion in said PFC. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification