LED DRIVER CONTROLLER

DESCRIPTION

Featured Device, UTC UL22, is a PWM controller with

innovative Free-DimmingTM technology. The controller drives one

of the two strings of LEDs by an ON/OFF AC wall switch and

provides a cost effective solution for light control. It supports

power-factor-correction function in applications.

UTC UL22 provides several protection features. It includes a

cycle-by-cycle current limit to the power switch; over-current

protection at the LED load; bias voltage VDD over-voltage

protection. In addition, the driver output (DRV) voltage is clamped

for driving the external power MOSFET effectively and safely. The

controller also features an internal over-temperature protection.

FEATURES

* Free-DimmingTM technology

* Proprietary technology using ON/OFF wall switch to select one of the two LED channels

* Supports high-side Buck, Buck-Boost and Flyback topologies

* High power factor with Discontinue-Current-Mode (DCM) control

* Low start-up current and operating current to maximize conversion efficiency

* Under-voltage lockout (UVLO) with hysteresis

* Provides complete protection functions

-Maximum gate driver output clamp

　-VDD pin Over-Voltage Protection

　-Cycle-by-cycle current limit

　-LEDs Over-Current Protection

　-LEDs Open-Loop Protection

　-LEDs Short-Circuit Protection

　-Internal Over-Temperature Protection