UBA3077HN

UBA3077HN Three-channel switched-mode LED driver Rev. 1 — 8 February 2011 Objective data sheet 1. General description The UBA3077HN is a high efficiency LED driver in an HVQFN40 package for general LED lighting or backlighting LCD displays. Operating from a supply of 10 V to 42 V, it can drive up to 3 strings of 20 LEDs each. The low voltage circuitry is powered by an external 5 V voltage supply. The chip can operate autonomously or be controlled via a 400 kHz I2C-bus. The peak current in each string is fixed by an external resistor. Three independent Pulse-Width Modulated (PWM) signals are available for dimming purposes. These PWM signals are delivered either directly by the graphic processor (direct control mode) to the pins PWM1, PWM2 and PWM3, or generated on-board based on data sent via the I2C-bus interface. Each LED string is supplied by its own boost converter delivering an output voltage from VIN up to 75 V. The switching frequency is 500 kHz. A power saving mode is entered when all PWM signals stay LOW for a period longer than 1 s. Several protection mechanisms are available: overvoltage, short-circuit and open LED, overcurrent, UnderVoltage LockOut (UVLO) and overtemperature with an advanced adaptive protection. An error self-recovery (hiccup) mechanism is available with programmable delay time via an external capacitor. 2. Features and benefits „ Three-channel LED backlight driver „ ±2 % absolute LED current accuracy and channel-to-channel matching „ External po...