The L6563H is a current-mode PFC controller operating in transition mode (TM) which
embeds the same features existing in the L6563S with the addition of a high voltage start-up
source. These functions make the IC especially suitable for applications that have to be
compliant with energy saving regulations and where the PFC pre-regulator works as the
master stage.
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% at 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 too.
In addition to an over voltage 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 preregulator 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 handle the PFC stage in case of light load for the DC-DC converter,
to make it easier to comply with energy saving regulations (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.