Multi-display LED Driver provides 95% efficiency.
August 18, 2005 -
Suited for cell phone LED displays, 850 kHz Model LTC3208 features input voltage of 2.9-4.5 V and 1 A total output current. It can drive up to 17 LED current sources including 1-4 main, 1-2 sub, 1-3 RGB, 1-4 camera, and 1-4 auxiliary displays. Each display has digital control with independent dimming and programming via 2-wire I2C(TM) serial interface. Housed in 5 x 5 mm QFN-32 package, Model LT3208 utilizes 1x/1.5x/2x charge pump for optimal efficiency.
(Archive News Story - Products mentioned in this Archive News Story may or may not be available from the manufacturer.)
Original Press release
Linear Technology Corp.
1630 McCarthy Blvd.
Milpitas, CA, 95035
USA
Five-Display Cell Phone LED Driver Features 1A Total Output Current & 95% Efficiency
MILPITAS, CA - August 10, 2005 - Linear Technology Corporation announces the LTC3208, a fully integrated, 850kHz, low noise, high efficiency 1x/1.5x/2x charge pump multi-display LED driver. It can drive up to 17 LED current sources: a 1-4 LED Main display, 1-2 LED Sub display, a 1-3 LED RGB display, a 1-4 Camera LED display, and a 1-4 LED Auxiliary display, all from a compact 5mm x 5mm QFN package. Each display has digital control with independent dimming and programming via a two-wire I2C(TM) serial interface. The LTC3208's input voltage range of 2.9V to 4.5V is optimized for single cell Li-Ion cellular applications. Efficiencies when driven from a Li-Ion battery (3.6V nominal) reach 95% with quiescent current of only 250uA, maximizing battery run-time. The LTC3208 requires only four small capacitors and one resistor to create a tiny, low profile (<34mm2, 0.75mm high) solution footprint capable of powering all LEDs used in five separate displays.
The LTC3208 charge pump automatically optimizes efficiency based on VIN and LED forward voltage conditions. The device powers up in 1x mode and automatically switches to boost mode (1.5x) when any enabled LED current source approaches dropout. A subsequent dropout switches the part into 2x mode. Maximum currents for the Main/Sub/RGB/CAM/Aux displays are set with a single resistor. LED currents are controlled with precision internal current sources while dimming and ON/OFF control for all displays are achieved via a 2-wire I2C serial interface. 256 brightness levels are available for the Main and Sub displays, and 4096 color combinations are available for the RGB display. Internal circuitry prevents inrush current and excessive input noise during start-up and mode switching.
The LTC3208EUH is available from stock in a 32-lead QFN (5mm x 5mm) package. Pricing starts at $2.55 each for 1,000-piece quantities.
Summary of Features: LTC3208
o Up to 95% Efficiency without Inductors
o Multi-Mode, Automatic Mode Switching 1x/1.5x/2x Charge Pump for Optimal Efficiency
o Up to 1A Total Output Current
o 17 Current Sources Available as Main, Sub, RGB, CAM and Aux LED Drivers
o LED ON/OFF, Brightness Level and Display Configuration Programmable Using 2-Wire I2C Interface
o 0.5% (TYP) LED Current Matching
o Low Noise, Constant Frequency Operation
o 2.9V to 4.5V Input Voltage Range
o Tiny Solution Footprint <34mm2, <0.75mm Profile
o 5mm x 5mm QFN-32 Package
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
LT and LTC are registered trademarks of Linear Technology Corp. All other trademarks are the property of their respective owners.
North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
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