Features

• Multimode Charge Pump Provides Up to 94% Efficiency (1x, 1.5x, 2x)
• Up to 600mA Total Output Current
• LTC3209-1: 8 Current Sources Available as 6 × 25mA MAIN, 1 × 400mA CAM and 1 × 15mA AUX
• LTC3209-2: 8 Current Sources Available as 5 × 25mA MAIN, 2 × 200mA CAM and 1 × 15mA AUX
• LED On/Off and Brightness Level Programmable Using 2-Wire I²C^TM Interface
• Automatic Charge Pump Mode Switching or Fixed Mode for Power Supply Generation
• Low Noise Constant Frequency Operation*
• Internal Soft-Start Limits Inrush Current During Start-up and Mode Switching
• Short Circuit/Thermal/Open-Shorted LED Protection
• 256 Brightness States for MAIN Display
• 16 Brightness States for CAM Display
• 4 Brightness States for AUX Display
• 20-Lead (4mm × 4mm) QFN Package

Typical Application

Description

The LTC3209-1/LTC3209-2 are highly integrated multidisplay LED controllers. These parts contain a high efficiency, low noise charge pump to provide power to MAIN, CAM and AUX LED displays. The LTC3209-1/ LTC3209-2 require only four small ceramic capacitors and one current set resistor to form a complete LED power supply and current controller.

The maximum display currents are set by a single external resistor. Current for each LED is controlled by a precision internal current source. Dimming and On/Off for all displays is achieved via the I2C serial interface. 256 states are available for the MAIN display. Sixteen states are available for the CAM display and four states are available for the AUX display.

The charge pump optimizes efficiency based on the voltage across the LED current sources. The part powers up in 1x mode and will automatically switch to boost mode whenever any enabled MAIN or CAM LED current source begins to enter dropout. The first dropout switches the part into 1.5x mode and a subsequent dropout switches the part into 2x mode. The part resets to 1x mode whenever a data bit is updated via the I2C port. The parts are available in a 4mm × 4mm 20-lead QFN package.