LED driver integrates 36V, 2A synchronous step-up silent switcher

September 19, 2016 // By Julien Happich
The LT3922 is a monolithic, synchronous, step-up DC/DC converter with internal 40V, 2A power switches and an internal PWM generator.

Its fixed frequency peak current mode control accurately regulates current within ±2% for a string of LEDs up to 34V. Its integrated PWM generator offers up to 128:1 dimming ratio. If dimming ratios of up to 5,000:1 are required, the LT3922 and an external PWM generator can accommodate these applications. The LT3922’s 2.8V to 36V input voltage range is ideal for a wide range of applications, including automotive, industrial and architectural lighting. The LT3922 can drive up to 34V of 350mA white LEDs from an automotive input, delivering in excess of 10 watts.

The LT3922 can deliver efficiencies of 93% in the boost topology while switching at 2MHz, offering a tiny and compact solution footprint. Internal LED short-circuit protection enables added reliability. A frequency adjust pin permits the user to program the frequency between 200kHz and 2MHz. The chip comes in a thermally enhanced 4x5mm QFN package.

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