The ADM8845ACPZ-REEL uses charge pump technology to provide thepower required to drive up to six LEDs. The LEDs are used forbacklighting a color LCD display, having regulated constant current for uniform brightness intensity. The main display canhave up to four LEDs, and the sub display can have one or two LEDs. The digital CTRL1 and CTRL2 input control pins controlthe shutdown operation and the brightness of the main and subdisplays.
To maximize power efficiency, the charge pump can operate ina 1×, 1.5×, or 2× mode. The charge pump automaticallyswitches between 1×/1.5×/2× modes, based on the input voltage,to maintain sufficient drive for the LED anodes at the highestpower efficiency.
Improved brightness matching of the LEDs is achieved by afeedback pin to sense individual LED current with a maximum matching accuracy of 1%.
Feature
- Drives 6 LEDs from 2.6 V to 5.5 V (Li-Ion) input supply
- 1×/1.5×/2× fractional charge pump to maximize power efficiency
- 1% max LED current matching
- Up to 88% power efficiency over Li-Ion range
- Powers main and sub display LEDs with individual shutdown
- Package footprint only 9 mm2 (3 mm × 3 mm)
- Package height only 0.75 mm
- Low power shutdown mode
- Shutdown function
- Soft-start limiting in-rush current
Applications
- Cellular phones with main and sub displays
- White LED backlighting
- Camera flash/strobes and movie lights
- Micro TFT color displays
- DSC
- PDAs
(Picture: Pinout)
