High-current LED driver controller handles 250W of LED power
Its 2.5V to 40V input voltage range with transient tolerance up to 60V makes it suitable for automotive applications as well as a wide range of industrial applications. Each of the LT3797’s channels can drive a wide range of LED power in either step-up, step-down or SEPIC topologies. In a boost configuration, it powers three channels of up to 90V of LEDs with LED currents in excess of 1A, delivering over 250W of power from a nominal 12V input with efficiencies as high as 93%. Each of the three channels is operated by an independent “True Color” PWM signal, enabling each channel to be dimmed to ratios as high as 3000:1.
Each channel also offers both robust open-LED and short-circuit protection in boost mode, providing high safety and reliability designs required in automotive applications. A frequency-adjust pin enables the user to program the frequency between 100 kHz and 1 MHz to optimise efficiency while minimising external component size. Its thermally-enhanced 7 x 8 mm QFN package provides a compact solution footprint for 20W to 250W LED applications.
The LT3797 is designed so that each channel can use the most suitable configuration to drive its LED string, whether step-up, step-down, or SEPIC, or a combination of these. Its high-side current sense enables each channel to be used in the same or different configurations while rail-to-rail current sense enables outputs from 0V to 100V, offering a wide range of design flexibility. Other features include overvoltage and undervoltage lockout, 20:1 analogue dimming via the CTRL pin and external synchronisation.
It comes in a thermally enhanced 52-lead 7 x 8 mm QFN package for $4.95. (1,000). For extended temperature ranges, LT3797IUKG operates over -40°C to 125°C operating junction temperature, for $5.54 (1,000).
Linear Technology; www.linear.com/product/LT3797
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