White LED Driver with I2C Compatible Interface from the PowerWise® Family
National Semiconductor
Description
The LM27966 is a highly integrated charge-pump-based display LED driver. The device can drive up to 6 LEDs in parallel with a total output current of 180mA. Regulated internal current sources deliver excellent current and brightness matching in all LEDs. The LED driver current sources are split into two independently controlled groups. The primary group, which can be configured with 4 or 5 LEDs, can be used to backlight the main phone display. An additional, independently controlled led driver is provided for driving an indicator or other general purpose LED function. The LM27966 has an I2C compatible interface that allows the user to independently control the brightness on each bank of LEDs. The device provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in Pass-Mode. The proper gain for maintaining current regulation is chosen, based on LED forward voltage, so that efficiency is maximized over the input voltage range. The LM27966 is available in National's small 24-pin Leadless Leadframe Package (LLP-24).
Features
91% Peak LED Drive Efficiency
No Inductor Required
0.3% Current Matching
Drives 6 LEDs with up to 30mA per LED
180mA of total driver current
I2C Compatible Brightness Control Interface
Adaptive 1×- 3/2× Charge Pump
Resistor-Programmable Current Settings
External Chip RESET Pin (RESET#)
Extended Li-Ion Input: 2.7V to 5.5V
Small low profile industry standard leadless package, LLP 24 : (4mm x 4mm x 0.8mm)
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