LTC3524 Datasheet | Linear Technology

Features Generates Three Adjustable, Low Noise Rails for Small/Medium TFT Displays - Drives Up to Ten White LEDs - LED Dimming and Open-Circuit Protection - Controlled Power-Up/Power-Down Sequencing - 1.5MHz Fixed Frequency, Low Noise Operation .. - V Range 2.5V to 6V, V IN OUT Range 3V to 6V - TFT Supply Efficiency Up to 90% - LED Supply Efficiency Up to 78% - Two Independantly Enabled LED Strings - 200 to 1 True Color PWMTM Dimming - Tiny External Solution - 24-Lead QFN Package (4mm × 4mm × 0.75mm) - LTC3524 Adjustable TFT Bias Supply with WLED Driver DESCRIPTION The LTC®3524 is an integrated BIAS and white LED power converter solution for small/medium-sized polysilicon thin film transistor (TFT) liquid crystal (LCD) display panels. The device operates from a single Lithium-Ion/polymer battery or any voltage source between 2.5V and 6V. A 1.5MHz synchronous boost converter generates a programmable low noise, high efficiency 25m A TFT supply of up to 6.0V. Regulated, low ripple charge pumps are used to generate up to +20V and - 20V at 2m A. Output sequencing is internally controlled to insure proper initialization and rapid discharge of the LCD panel in shutdown. A second 1.5MHz boost converter powers one or two LED strings with up to five series elements each. LED current and display brightness can be controlled over a wide range using analog or digital means up to 25m A. The LTC3524 is offered in the 4mm × 4mm 24-pin QFN package, minimizing the total solution footprint. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. True Color PWM is a registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. APPLICATIONS - - - - - PDAs, Palmtop puters Digital Still and Video Cameras Handheld GPS Portable Instrument Displays Portable Media Players TYPICAL APPLICATION +5V, - 7.5V, +12.5V, 8 LED Power Supply + - +5V 25m A 2.2μF SW1 10μH VIN 3.3μH SW2 VLED LED2 LED1 LTC3524...