LT3932 36 V, 2 A Synchronous Step-Down LED Driver

By Analog Devices Inc 48

LT3932 36 V, 2 A Synchronous Step-Down LED Driver

Power by Linear™ / Analog Devices' introduces the LT3932, a monolithic, synchronous, step-down DC/DC converter with internal 36 V, 2 A power switches and an internal PWM generator. Its fixed frequency, peak current mode control accurately regulates current within ±1.5% for strings of up to 2 A LEDs. Its integrated PWM generator offers a 128:1 dimming ratio. If dimming ratios of up to 5000:1 are required, the LT3932 and an external PWM generator can accommodate these applications.

The LT3932's 3.6 V to 36 V input voltage range is ideal for a wide variety of applications, including automotive, industrial, and architectural lighting. The combination of its Silent Switcher topology and spread spectrum frequency modulation minimizes EMI concerns and can drive up to eight 2 A white LEDs from a nominal 32 V input, delivering in excess of 50 watts.

This device delivers efficiencies of 93% while switching at 2 MHz, eliminating the need for external heat sinking and offering a tiny, compact solution footprint. Internal open/short LED protection and fault indication offers added reliability. The switching frequency is programmable from 200 kHz to 2 MHz or it can be synchronized to an external clock signal. Combined with a thermally enhanced 4 mm x 5 mm QFN package, the LT3932 offers a very compact high power LED driver solution. Other features include accurate LED current sense with a monitor output, 99.9% duty cycle operation and programmable UVLO.

Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown.

Typical Applications

Features
  • ±1.5% LED current regulation
  • ±1.2% output voltage regulation
  • 5000:1 PWM dimming at 100 Hz
  • 128:1 internal PWM dimming
  • Spread spectrum frequency modulation
  • Silent Switcher architecture for low EMI
  • 3.6 V to 36 V input voltage range
  • 0 V to 36 V LED string voltage
  • 2 A, 36 V internal switches
  • 200 kHz to 2 MHz with SYNC function
  • 99.9% maximum duty cycle
  • Analog or duty cycle LED current control
  • Open/short LED protection and fault indication
  • Accurate LED current sense with monitor output
  • Programmable UVLO
  • Thermally enhanced 28-lead (4 mm x 5 mm) QFN
Applications
  • Automotive lighting
  • Industrial and general purpose lighting

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