Maxim Integrated Products introduced the MAX16834, a current-mode, high-brightness LED (HB LED) driver for boost, buck-boost, SEPIC, and high-side buck topologies. This device is designed to reduce the size, complexity, and cost of solid-state lighting (SSL) designs such as MR16 spotlights, thus simplifying the implementation of green lighting technology. Towards this end, it integrates a high-side, current-sense amplifier; a PWM-dimming MOSFET driver; and robust protection circuitry. Providing the efficiency and thermal-management capabilities critical to LED system designs, the MAX16834 is ideal for applications such as LED automotive exterior lighting, LCD backlighting, and architectural lighting.
The MAX16834’s comprehensive feature set enables the implementation of boost or buck-boost dc-dc converters with minimal external components. In addition to driving an n-channel power MOSFET by the switching controller, the MAX16834 drives an n-channel PWM-dimming switch to achieve a wide, 3000:1 PWM-dimming range. To further enhance design flexibility, the device offers analog dimming that allows the LED current to be controlled by an external dc voltage. The built-in, high-voltage current-sense amplifier and up to 1MHz switching frequency allow designs to be optimized in terms of efficiency and size.
The MAX16834 integrates protection circuitry to ensure reliable operation in rugged environments. The driver provides analog thermal-foldback protection to allow the use of an external thermistor (NTC) to reduce the LED current when the temperature of the LED string exceeds a specified temperature point. Additionally, it includes a fault-output flag for overvoltage, overcurrent, and thermal warning faults, while its programmable, true-differential overvoltage protection meets stringent automotive requirements for LED lighting and display backlighting.
The MAX16834 features a proprietary (patent pending) solution that provides excellent (> 92%) input power factor correction without the need for an additional PFC controller. This feature, together with thermal-foldback protection and low cost, makes this HB LED driver ideal for MR16 spotlights and similar applications powered from AC voltage sources.
This LED driver is fully specified over the -40 to +125°C automotive temperature range and is available in a thermally enhanced, 4 x 4mm, 20-pin TQFN package with exposed paddle. Prices start at $1.24 (1000-up, FOB USA).