L6563S

The L6563S is a current-mode PFC controller operating in transition mode (TM). Coming with the same pin-out as its predecessor L6563, it offers improved performance and additional functions.

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. Loop’s stability is optimized by the voltage feedforward function (1/V2 correction), which in this IC uses a proprietary technique that considerably improves line transient response as well in case of mains both drops and surges (“bidirectional”).

Additionally, the IC provides the option for tracking boost operation, i.e. the output voltage is changed tracking the mains voltage.

The device includes disable functions suitable for remote ON/OFF control both in systems where the PFC pre-regulator works as a master and in those where it works as a slave. In addition to an overvoltage protection able to keep the output voltage under control during transient conditions, the IC is provided also with a protection against feedback loop failures or erroneous settings. Other on-board protection functions allow that brownout conditions and boost inductor saturation can be safely handled.

An interface with the PWM controller of the DC-DC converter supplied by the PFC pre-regulator is provided: the purpose is to stop the operation of the converter in case of anomalous conditions for the PFC stage (feedback loop failure, boost inductor’s core saturation, etc.) and to disable the PFC stage in case of light load for the DC-DC converter, so as to make it easier to comply with energy saving norms (Blue Angel, EnergyStar, Energy2000, etc.).

The totem-pole output stage, capable of 600 mA source and 800 mA sink current, is suitable for big 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 need to be compliant with EN61000-3-2 and JEITA-MITI standards.