Quantized voltage feed-forward a power factor correction controller

A quantized voltage feed-forward (QVFF) circuit and integrated circuits using this technique. The QVFF circuit includes a plurality of comparators in combination with a logic control circuit. The comparators are structured and arranged to establish various voltage threshold levels, each providing a digital state signal representative of the sensed input voltage level. The logic control circuit is structured and arranged to use the digital input signals from the comparators to output a voltage feed-forward factor (KVFF) signal that is representative of the V2rms voltage. Output from the logic control circuit is provided to an analog signal multiplier and used to shape an input current reference (IMO) waveform. This allows detection of changes in the rms level of the input voltage on the half-cycle of the AC line voltage, resulting in a rapid response to line voltage changes. Because the KVFF factor signal contains no AC ripple component, it does not contribute to THD of the input current reference, IMO.