The UCC28070 has a feature called Quantized Voltage Feed-Forward. In general, feed-forward improves transient response from input line changes. A feed-forward filter is typically used to filter out spikes so that the controller can discriminate between spikes and actual line voltage changes. Having this feature internal to the UCC28060 eliminates the external filter and also incorporates a multiple gain step amplifier. This amplifier better optimizes the gain of the multiplier for various line input voltage ranges with no adverse contribution to Total Harmonic Distortion (THD). The term Quantized is used to describe this multiple step gain feature.