RGB LED Driver and Charge Pump

The LTC3212 is a low noise charge pump RGB LED driver capable of driving three LEDs up to 25mA each from a 2.7V to 5.5V input. Low external part count (one flying capacitor, two bypass capacitors and one to three programming resistors) makes the LTC3212 ideally suited for small, battery-powered applications.

Built-in soft-start circuitry prevents excessive inrush current during start-up and mode switching. High switching frequency enables the use of small external capacitors. The charge pump shuts down to a high impedance mode to prevent LED leakage while the LTC3212 is off.

Each LED may be individually turned on or off via a single pin interface. The current through the LEDs may be individually programmed with resistors or may share a single programming resistor. White mode adjusts the red, green and blue LED current ratios for a white light when all three LEDs are programmed to be on.

LED currents are regulated using internal low dropout current sources. Automatic mode switching optimizes effi ciency by monitoring the LED current drivers and switches mode only when dropout is detected. The part is available in a 3mm × 2mm 12-lead DFN package.

Applications

* Cellular Phones

* Media Players

* RGB Back Lights

* Power and Current Control for Driving RGB LEDs

* Individually Programmable Current Sources

* 1x or 2x Mode, Low Noise, Constant Frequency Charge Pump

* Single Wire Enable Control for All LEDs

* White Mode Adjusts R, G, B Currents for White Light

* 25mA Maximum LED Current

* VIN Range: 2.7V to 5.5V

* Automatic Soft-Start, Mode Switching and Output Disconnect in Shutdown Mode

* Available in 12-Lead (3mm × 2mm) DFN Package