ADM8845 Charge Pump Driver for 6 White LED LCD Backlights

The ADM8845 uses charge pump technology to provide the power required to drive up to six LEDs. The LEDs are used for backlighting a color LCD display, having regulated constant current for uniform brightness intensity. The main display can have up to four LEDs, and the sub display can have one or two LEDs. The digital CTRL1 and CTRL2 input control pins control the shutdown operation and the brightness of the main and sub displays.

To maximize power efficiency, the charge pump can operate in a 1×, 1.5×, or 2× mode. The charge pump automatically switches between 1×/1.5×/2× modes, based on the input voltage, to maintain sufficient drive for the LED anodes at the highest power efficiency

Improved brightness matching of the LEDs is achieved by a feedback pin to sense individual LED current with a maximum matching accuracy of 1%.

Applications

Cellular phones with main and sub displays
White LED backlighting
Camera flash/strobes and movie lights
Micro TFT color displays
DSC
PDAs

Features and Benefits

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 0.9 mm
Low power shutdown mode
Shutdown function
Soft-start limiting in-rush current

Power Management

Data Sheets

Document	note
ADM8845: Charge Pump Driver for LCD White LED Backlights Data Sheet (Rev. C)	PDF 392 kB

Order Information

Part Number	Package	Packing Qty	Temp Range	Price 1000+	RoHS
ADM8845ACP-REEL Obsolete	16 ld LFCSP (3x3mm, 1.50mm exposed pad)	REEL 5000		0	N
ADM8845ACP-REEL7 Obsolete	16 ld LFCSP (3x3mm, 1.50mm exposed pad)	REEL 1500		0	N
ADM8845ACPZ-REEL Obsolete	16 ld LFCSP (3x3mm, 1.50mm exposed pad)	REEL 5000	-40 to 85C	0	Y
ADM8845ACPZ-REEL7 Production	16 ld LFCSP (3x3mm, 1.50mm exposed pad)	REEL 1500	-40 to 85C	0.71	Y

Evaluation Boards

Part Number	Description	Price	RoHS
ADM8845EB-EVALZ	Evaluation Board	156.35	Y

Reference Materials

Solutions Bulletins & Brochures：Charge Pumps Products (March 2003)

ADM8845: Charge Pump Driver for LCD White LED Backlights Data Sheet (Rev. C) adm8845

Charge Pumps Products (March 2003) adm660