TRANSITION MODE PFC POWER CONVERTER ADAPTED TO SWITCH FROM DCM TO CCM UNDER HIGH LOAD AND CONTROL METHOD

摘要

A transition mode power factor correction converter comprising a boost inductor, a switch, a diode, and output tank capacitor, has circuit means of limitation of the off-time interval of the switch to a fraction of the off-time interval, “complementary” to the on-time interval that is normally controlled for regulating the output voltage, during part of a cycle of a rectified sinusoidal voltage waveform input to the converter, when the current flowing in the inductor reaches a maximum threshold, causing the mode of operation of the device to switch from transition mode to continuous current mode for a middle phase angle region of a rectified sinusoidal input voltage waveform, under high load conditions, defined by said maximum current threshold. Current peaks amplitude and ripple are effectively reduced for same output power.