Digital Power Factor Correction
A typical power factor correction circuit has two feedback loops: a high frequency one for maintaining near-sinusoidal input current and a low frequency one for keeping the output DC voltage at the desired level. This method splits the job of the regulation into two paths. One is based on a dedicated logic for fast regulation of the input current and the second one is executed in the main routine of a standard microcontroller at a much lower rate. In this way the main algorithm routine becomes greatly simplified while the current loop may be executed at a very high rate with a relatively simple hardware.