High-Power LED Controller Suits Projection, Lighting Apps

The MAX16818 pulse-width-modulation (PWM) controller provides high-output-current capability in a compact, lead-free package with a minimum number of external components. Average current-mode control, synchronous gate-drive circuitry, and a wide switching-frequency range make the device well-suited for the energy-efficient driving of high-power LEDs in light sources for business, portable, and pocket projectors; home theater systems; rear-projection TVs, and automotive and industrial lighting fixtures. The device can be used in synchronous and nonsynchronous step-down (buck) topologies, as well as in boost, buck-boost, SEPIC, and Cuk LED drivers. The average-current-mode control optimizes the charge and on-resistance characteristics of MOSFETs, minimizing the need for external heatsinking, even when delivering LED current up to 30A. Efficiencies to 94% are possible in 5W to 200W drivers. True differential sensing enables accurate control of the LED current. A wide dimming range is easily implemented to accommodate an external PWM signal. An internal regulator enables operation over a wide input-voltage range of 4.75V to 5.5V, 7V to 28V, or higher with a simple external biasing device. The wide switching-frequency range (up to 1.5 MHz) allows for the use of small inductors and capacitors. The MAX16818ETE+ is rated for the extended temperature range (-40°C to 85°) and the MAX16818ATE+ is rated for the automotive temperature range (-40°C to 125°C). Both come in a lead-free, 5 mm x 5 mm x 0.8 mm, 28-pin TQFN package with exposed pad. Prices start at $1.82 for the MAX16818ETE+ and $1.59 for the MAX16818ATE+ each/1,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.