Auto Electronics

Dual 1.3 A white LED step-up converters drive 16 100 mA LEDs with 1000:1 dimming ratio

Linear Technology Corporation has introduced the LT3486, a dual step-up dc/dc converter specifically designed to drive up to 16 white LEDs (eight LEDs in series per channel) with constant current and, as a result, constant color. Dimming is controlled with the duty cycle of the PWM driver, thus allowing for a 1000:1 dimming range. The LT3486's two independent converters are capable of driving asymmetric LED strings (up to eight in a series per converter) from an input voltage of 2.5 V to 24 V, delivering efficiencies up to 85%. Packaged in a 5 mm x 3 mm DFN package, the device offers a 2.5 V to 24 V input voltage range that enables it to support automotive backlighting applications, among others.

Linear Technology is also offering the LTC4414, an "ideal diode" PowerPath controller for driving large PFETs with substantial gate capacitance. Permitting low-loss OR-ing of multiple input dc power sources, the device offers a forward voltage (20 mV) significantly lower than that of a Schottky diode. As a result, the LTC4414 increases efficiency by an order of magnitude, due to lower power loss and less self-heating, in systems requiring automatic switching or load sharing between power sources. The LTC4414 is guaranteed to meet performance specifications over an ambient temperature range of -40 °C to 125 °C and an operating voltage range of 3 V to 36 V.

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