Date: 19/12/2008

Current-mode HB LED driver for solid state lighting applications

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.

Some of the other features include:

1. The MAX16834 implements boost or buck-boost DC-DC converters with minimal external components.
2. 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.
3. The device also offers analog dimming that allows the LED current to be controlled by an external DC voltage.
4. 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.
5. 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.
6. It includes a fault-output flag for overvoltage, overcurrent, and thermal warning faults.
7. Provides > 92% of input power factor correction without the need for an additional PFC controller.
8. Specified over the -40°C to +125°C automotive temperature range

Package: 20-pin TQFN package with exposed paddle
Size: 4mm x 4mm
Prices: start at $1.24 (1000-up, FOB USA).

For more information, go to: www.maxim-ic.com