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_IN Range 2.5V to 6V, V_OUT Range 3V to 6V
• TFT Supply Efficiency Up to 90%
• LED Supply Efficiency Up to 78%
• Two independently Enabled LED Strings
• 200 to 1 True Color PWM Dimming
• Tiny External Solution
• 24-Lead QFN Package (4mm x 4mm x 0.75mm)

Typical Application

Description

The LTC3524 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 25mA TFT supply of up to 6.0V. Regulated, low ripple charge pumps are used to generate up to +20V and -20V at 2mA. 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 25mA.

The LTC3524 is offered in the 4mm x 4mm 24-pin QFN package, minimizing the total solution footprint.