The highly linear multiplier, along with a special correction circuit that reduces crossover distortion of the mains current, allows wide-range-mains operation with an extremely low THD even over a large load range.
The output voltage is controlled by means of a voltage-mode error amplifier and an accurate (1% @TJ = 25 °C) internal voltage reference. The loop stability is optimized by the voltage feedforward function (1/V2 correction), which in this IC uses a proprietary technique that also considerably improves line transient response in case of both mains drops and surges (“bidirectional”).
In addition to overvoltage protection able to control the output voltage during transient conditions, the IC also provides protection against feedback loop failures or erroneous settings. Other on-board protection functions allow brownout conditions and boost inductor saturation to be safely handled.
The totem-pole output stage, capable of a 600 mA source and 800 mA sink current, is suitable for a high power MOSFET or IGBT drive. This, combined with the other features and the possibility to operate with ST's proprietary fixed-off-time control, makes the device an excellent solution for SMPS up to 400 W that requires compliance with EN61000-3-2 and JEITA-MITI standards.