60V driver delivers more than 100W of led power

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Linear Technology has unveiled a synchronous buck boost dc/dc led driver and voltage controller that can deliver more than 100W of led power.

According to the analogue ic specialist, the LT3791 has a 4.7 to 60V input voltage range, making it suitable for automotive, industrial and architectural lighting applications. The device's output can be set from 0 to 60V, enabling it to drive a range of leds in a single string. Its internal four switch buck boost controller operates from input voltages above, below or equal to the output voltage. Linear describes transitions between buck, pass through and boost operating modes as 'seamless' and are said to offer a well regulated output even with wide variations of supply voltage. According to Linear, the LT3791's unique design - utilising three control loops to monitor input current, led current and output voltage – deliver optimal performance. The device uses four external switching mosfets and delivers from 5 to more than 100W of continuous led power, with efficiencies up to 98.5%. LED current accuracy of 6% is designed to ensure constant lighting, while 2% output voltage accuracy enables the converter to operate as a constant voltage source. It utilises either analogue or PWM dimming as required by the application, while its switching frequency can be programmed between 200 and 700KHz or synchronised to an external clock. Additional features include output disconnect, input and output current monitors, open and shorted led detection and integrated fault protection. The LT3791EFE is available in 38 lead thermally enhanced TSSOP package and an extended temperature version, or I grade, the LT3791IFE, is also available. A high temperature version, or H grade, the LT3791HFE, is also available, along with a high reliability MP grade version, the LT3791MPFE.