Boost power factor correction controller

摘要

The present invention relates to a power factor correction (PFC) controller. In one embodiment, a boost PFC controller configured in an AC/DC converter can include: (i) a conductive signal generator configured to receive a first sampling signal, and to generate a conductive signal according to the first sampling signal and a first control signal; (ii) a shutdown signal generator configured to compare a second control signal against a third control signal, and to generate a shutdown signal when the second control signal reaches a level of the third control signal; and (iii) a logic controller coupled to the conductive signal generator and the shutdown signal generator to control a switching state of a power switch in AC/DC converter.

主权项

1. A power factor correction (PFC) controller configured for an AC/DC converter, the PFC controller comprising:
a) a conductive signal generator configured to receive a first sampling signal that represents an inductor current, wherein said first sampling signal is configured to be compared against a first control signal, wherein said first control signal is in proportion to and rises during a shutdown time of a power switch of said AC/DC converter, wherein when said first control signal reaches a level of said first sampling signal, said conductive signal generator is configured to output a conductive signal; b) a shutdown signal generator configured to compare a second control signal against a third control signal, wherein said second control signal is in proportion to and rises during a conductive time of said power switch with a first proportionality coefficient, wherein said third control signal is in proportion to a duty cycle of said power switch with a second proportionality coefficient, wherein when said second control signal reaches a level of said third control signal, said shutdown signal generator is configured to output a shutdown signal; and c) a logic controller coupled to said conductive signal generator and said shutdown signal generator, wherein when said conductive signal is activated, said logic controller is configured to turn said power switch on, and wherein when said shutdown signal is activated, said logic controller is configured to turn said power switch off.