DESCRIPTION

· The UCC38050 and UCC38051 are PFC controllers designed for low-to-medium power applications requiring compliance with IEC 1000-3-2 harmonic reduction standard.

· They operate in transition mode (boundary-conduction mode or critical conduction-mode) and feature a transconductance voltage amplifier, a multiplier, a current-sense comparator, PWM logic, and a totem-pole driver.

· The PWM circuit is self-oscillating, with turn-on governed by an inductor zero-current detector and turn-off by the current-sense comparator.

· Additional features include peak current limit, default timer, overvoltage protection (OVP), and enable.

FEATURES

· Transition Mode PFC Controller for low implementation cost.

· Industry pin compatibility with improved feature set.

· Improved transient response with slew-rate comparator.

· Zero power detect to prevent overvoltage protection (OVP) during light load conditions.

· Accurate internal VREF for tight output regulation.

· Two UVLO options.

· OVP, open-feedback protection, and enable circuits.

· ±750-mA peak gate drive current.

· Low start-up and operating currents.

· Lead (Pb)-free packages.

APPLICATIONS

· Single-stage PFC flyback converters for lighting and motor drives.

· Switch-mode power supplies for desktops, monitors, TVs, and set-top boxes (STBs).

· AC adapter front-end power supplies.

· Electronic ballasts.