LM2755 Datasheet | Texas Instruments

.ti. SNVS433D - OCTOBER 2007 - REVISED APRIL 2013 LM2755 Charge Pump LED Controller with I2C-patible Interface in DSBGA Package Check for Samples: LM2755 Features - 2 90% Peak Efficiency - Total solution size < 13mm2 - No Inductor Required: Only 4 Inexpensive Ceramic Caps - 3 Independently Controlled Constant Current Outputs - Programmable Trapezoidal Dimming Waveform on Each Output - Programmable Timing Control Via Internal Registers and External Clock Synchronization Input - 32 Exponential Dimming Steps with 800:1 Dimming Ratio - Programmable Brightness Control via I2Cpatible Interface - Hardware Enable Pin - Wide Input Voltage Range: 2.7V to 5.5V - Tiny 18-bump Thin DSBGA : 1.8mm x 1.6mm x 0.6mm APPLICATIONS - Indicator LEDs - Keypad LED Backlight - Display LED Backlight - Fun-light LEDs DESCRIPTION The LM2755 is a charge-pump-based, constant current LED driver capable of driving 3 LEDs with a total output current up to 90m A. The diode current waveforms of each LED can be trapezoidal with timing and level parameters (rise time, fall time, high level, low level, delay, high time, low time) programmed via an I2C-patible interface. The 32 brightness levels found on the LM2755 are exponentially spaced (as opposed to linearly spaced) to better match the response of the human eye to changing brightness levels. The device requires only four small and low-cost ceramic capacitors. The LM2755 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2 or in a gain of 1. Maximum efficiency is achieved over the input voltage range by actively selecting the proper gain based on the LED forward voltage...