LM2759

LM2759 PRODUCT BRIEF: 1A Switched Capacitor Flash LED Driver with I2C Compatible Interface November 20, 2008 LM2759 PRODUCT BRIEF 1A Switched Capacitor Flash LED Driver with I2C Compatible Interface General Description LM2759 is an integrated low-noise, high-current switched capacitor DC/DC converter with a regulated current source. The device requires only four small ceramic capacitors making the total solution area less than 22 mm2 and the height less than 1 mm. The LM2759 is capable of driving loads up to 1A from a single-cell Li-Ion battery. Maximum efficiency is achieved over the input voltage range by actively selecting the proper gain based on the LED forward voltage and current requirements. The LED current can be programmed up to 1A via an I2Ccompatible interface, along with eight selectable Flash TimeOut durations. One high-current Flash LED can be driven either in a high-power Flash mode or a low-power Torch mode. The Strobe pin allows the flash to be toggled via a Flash enable signal from a camera module. The TX input pin limits the Flash LED current to the Torch current level during a RF PA pulse, to reduce high loads on the battery. Internal soft-start circuitry limits the amount of inrush current during start-up. LM2759 is offered in a small 12-pin thermally enhanced LLP package. Notice: This document is not a full datasheet. For more information regarding this product or to order samples, please contact your National Semiconductor sales office or visit http://www.national.com/support/dir.html. Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Up to 1A Output Current Solution Area < 22 mm2 No Inductor Required 90% Peak Efficiency Adaptive 1x, 1.5x and 2x Gains for Maximum Efficiency Load Disconnect in Shutdown Accurate Input Current Control During Gain Transitions Flash Time-Out TX Input Pin Ensures Synchronization with RF Power Amplifier Pulse Torch, Flash, and Indicator Modes External Flash Enable via Strobe Input Pin Strobe Input Disable via I2C Programmable Flash Pulse Duration, and Torch and Flash Currents via I2C-Compatible Interface 1MHz Constant Frequency Operation Low Profile 12–Pin LLP (3mm x 3mm x 0.8mm) Applications ■ Camera Flash in Cellular Phones Typical Application Circuit 30069301 © 2008 National Semiconductor Corporation 300693 www.national.com LM2759 PRODUCT BRIEF: 1A Switched Capacitor Flash LED Driver with I2C Compatible Interface Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock and Timing Data Converters Interface LVDS Power Management Switching Regulators LDOs LED Lighting Voltage Reference PowerWise® Solutions Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/vref www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH® Tools App Notes Reference Designs Samples Eval Boards Packaging Green Compliance Distributors Design Support www.national.com/webench www.national.com/appnotes www.national.com/refdesigns www.national.com/samples www.national.com/evalboards www.national.com/packaging www.national.com/quality/green www.national.com/contacts www.national.com/quality www.national.com/feedback www.national.com/easy www.national.com/solutions www.national.com/milaero www.national.com/solarmagic www.national.com/AU Quality and Reliability Feedback/Support Design Made Easy Solutions Mil/Aero Solar Magic® Analog University® THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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