L6462ATR

The L6462A is a control IC for Transition Mode (TM) Boost PFC converters, suitable for building cost-sensitive, energy-efficient solutions.

It embeds a special implementation of current-mode control that enables wide-range mains operation with low THD over a broad load range with no need for input voltage sensing and without a classical analog multiplier.

A pair of special circuits (Current Reference Generator, RCG, and Current Reference Shaper, CRS) shape the reference for the peak current of the inductor to maintain a sinusoidal input current regardless of the converter’s operation, whether TM or DCM. This way, it is possible to improve efficiency at intermediate and light loads with minimum impact on input current distortion.

At full load and low AC line, the device synchronizes the turn-on of the power switch to the valley of the ringing following demagnetization of the boost inductor (valley switching – quasi-resonant operation). At high AC line, and as the load is reduced, the IC skips ringing valleys to reduce the operating frequency progressively, so that the converter operates in Discontinuous Conduction Mode (DCM) to optimize efficiency, while maintaining valley switching.

Boost inductor demagnetization sensing is done via the gate driver output. No auxiliary winding or other interface components are needed.

The output voltage is controlled by means of a transconductance type error amplifier and an accurate (2% overall) internal voltage reference. The dynamic response to large-load transients is improved by an enhanced error amplifier that prevents excessive overshoots or undershoots in the output.

The device features low consumption (<60 µA before start-up and 2.3 mA while driving a 1nF capacitive load at 70 kHz) and includes a disable function suitable as a protection or for IC remote ON/OFF from a cascaded conversion stage.

The device offers protection functions against overcurrent, output overvoltage, feedback failure and inductor saturation/shorts in the by-pass diode.

The totem pole output stage, capable of at least 300 mA source and 600 mA sink current, is suitable for MOSFET driving. All these features make the device an excellent low-cost solution for EN 61000-3-2 compliant SMPS.

L6462A is optimized to address 90 VAC - 264 VAC / 400 VOUT applications.