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
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
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
Up to 150 mA per channel
±2 % absolute LED current accuracy Peak LED current programmable with
and channel-to-channel matching
External power supply voltage from 10 V Three boost converters from VIN up to
to 42 V and 5 V for low voltage circuitry 75 V output voltage
Constant 500 kHz frequency peak
High efficiency up to 90 %
current mode control
Low value output capacitor (2 μF)
14-bit PWM dimming (either defined by
system-generated PWMs, or internally
generated) from 2.0 kHz to 24 kHz (duty
cycle from 0.1 % to 100 %)
Accurate internal oscillator
All power FETs integrated