DC-DC controller drives over 250W of LED power

The LT3797 features a fixed frequency, current-mode architecture that delivers constant, accurately regulated LED current over a wide range of supply and output voltages. Each of the LT3797’s three channels can drive a wide range of LED power in either step-up, step-down or SEPIC topologies. Offering efficiencies as high as 93% 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. Offering the high safety and reliability designs required for automotive applications, each channel also offers both robust open-LED and short-circuit protection in boost mode.

Seperately operated by an independent True Color PWM signal, each of the three channels can be dimmed to ratios as high as 3000:1. Allowing the user to program the frequency between 100kHz and 1MHz, a frequency adjust pin optimises efficiency while minimising external component size. A highly compact solution footprint for 20W to 250W LED applications, the LT3797 is supplied in a thermally enhanced 7 mm x 8 mm QFN package.

Designed so that each channel can use the most suitable configuration to drive its LED string, the LT3797 uses step-up, step-down, SEPIC or a combination of these. Offering a wide range of design flexibility, rail-to-rail current sense enables outputs from 0V to 100V and high-side current sense enables each channel to be used in the same or different configurations. Other features include overvoltage and undervoltage lockout, 20:1 analog diming via the CTRL pin and external synchronization.

Available from stock in a thermally enhanced 52-lead 7 mm x 8 mm QFN package, the LT3797EUKG is priced from $4.95 (USD) each a in 1,000-piece quantities. Tested and guaranteed to operate from a -40°C to 125°C operating junction temperature, the LT3797IUKG is also available from stock with pricing starting at $5.54 (USD) each in 1,000-piece quantities.