the simple design of a passive PFC.

Active PFC is more complex and can achieve higher PF, up to 0.99 or higher. The first active PFC circuits just delayed the inrush. Newer ones work as an input and output condition-controlled step-up converter, supplying a single 400 V filter capacitor from a wide-range input source, usually between 80 and 240 V. Newer PFC circuits also replace the NTC-based inrush current limiter, which is an expensive part previously located next to the fuse.