Linear charge pump delivers 1A with over 90% efficiency

Dec 2nd, 2004
Content Dam Leds En Ugc 2004 12 Linear Charge Pump Delivers 1a With Over 90 Efficiency Leftcolumn Article Thumbnailimage File
Date Announced: 02 Dec 2004

Linear Technology Corporation has announced the LTC3216, a fractional charge pump, high current white LED driver that delivers up to 1A of LED current.

Its high efficiency multi-mode architecture automatically switches between 1X, 1.5X or 2X boost modes by monitoring the voltage across the LED current source and switching modes only when ILED dropout is detected. This enables the LTC3216 to maximize efficiency (up to 92%) throughout the entire Li-Ion operating range.

A 900kHz switching frequency and a low external parts count (two flying capacitors, two programming resistors and two bypass capacitors at VIN and CPO) provide a tiny footprint ideally suited for video and flash applications in camera phone and other portable lighting applications.

The LTC3216 employs built-in soft-start circuitry which prevents excessive inrush current during start-up. Independent high and low current settings for flash and torch/video modes respectively are programmed by two external resistors. Shutdown mode and current output levels are selected via two logic inputs.

An ultralow dropout current source maintains accurate LED current as the input voltage approaches the LED forward voltage. The LTC3216 is available in a low profile (0.75mm), 3mm x 4mm 12-lead DFN package.

The LTC3216EDE is available from stock in a DFN-12 package. Pricing starts at $2.00 each for 1,000-piece quantities.

Summary of Features: LTC3216

* High Efficiency Operation: 1X, 1.5X or 2X Boost Modes with Automatic Mode Switching
* Ultralow Dropout ILED Current Control
* Output Current up to 1A
* Low Noise Constant Frequency Operation
* Independent Low Current/High Current
* Programming and Enable Pins
* Tiny Application Circuit (All Components <1mm profile)
* 3mm x 4mm 12-Lead DFN Package

Contact
Tel. +1-800-4-LINEAR (for literature only) John Hamburger, Director of Marketing Communications Tel: 408-432-1900 ext. 2419

E-mail:jhamburger@linear.com

Web Site:http://www.linear.com

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