Power factor control circuit

摘要

An integrated power factor control circuit (12) for keeping an average AC line current sinusoidal and in phase with the line voltage. The integrated power factor control circuit (12) provides a boosted DC voltage greater than the amplitude of the line voltage. A transconductance amplifier (16) provides a boosted source and sink current when an output voltage is significantly out of regulation. The boosted source and sink current of the transconductance amplifier (16) increases the speed in which the voltage control loop can react to an output voltage change and reduces the time needed to generate the regulated voltage under startup. A comparator (17) provides a boost current at start up and senses a no-load condition during normal operation. The comparator (17) senses the no-load condition and stops switching to eliminate further output charging before an out of range condition occurs. $$