Triple Output LED Driver

The LT3496 is a triple output DC/DC converter designed to operate as a constant-current source and is ideal for driving LEDs. The LT3496 works in buck, boost or buck-boost mode. The LT3496 uses a fixed frequency, current mode architecture resulting in stable operation over a wide range of supply and output voltages. A frequency adjust pin allows the user to program switching frequency between 330kHz and 2.1MHz to optimize efficiency and external component size.

The LT3496 supports 3000:1 dimming control on each channel. Each of the three regulators is independently operated by that channel’s PWM signal. The PWM feature allows precise adjustment of the color mixing or dimming ratio of the LED source. Each of the three channels has a built-in gate driver to drive an external LED-disconnect P-channel MOSFET, allowing high dimming range. The output current range of each channel of the LT3496 is programmed with an external sense resistor.

The CTRL pins are used to adjust the LED currents either for analog dimming or overtemperature protection.

Applications

* RGB Lighting

* Billboards and Large Displays

* Automotive and Avionic Lighting

* Constant-Current Sources

* True Color PWM™ Dimming Delivers Up to 3000:1 Dimming Ratio

* Built-In Gate Driver for PMOS LED Disconnect

* Three Independent Driver Channels with 750mA, 45V Internal Switches

* Operates in Buck, Boost, Buck-Boost Modes

* CTRL Pin Accurately Sets LED Current Sense Threshold Over a Range of 10mV to 100mV

* Adjustable Frequency: 330kHz to 2.1MHz

* Open LED Protection

* Wide VIN Supply Range:

* Operation from 3V to 30V

* Transient Protection to 40V

* Surface Mount Components

* 28-Lead (4mm × 5mm) QFN and TSSOP Packages