Products, Materials + Tools | Jul 22, 2010

Highly Efficient, Flexible HB LED Driver Supports Green Lighting Designs

Maxim Integrated Products (NASDAQ: MXIM) introduces 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.
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.
Main Features:
• Wide Input Operating Voltage Range (4.75V to 28V)
• 3000:1 PWM Dimming
• Analog Dimming
• Integrated PWM Dimming MOSFET Driver
• Integrated High-Side Current-Sense Amplifier for LED Current Sense in Buck-Boost Converter
• 100kHz to 1MHz Programmable High-Frequency Operation
• External Clock Synchronization Input
• Programmable UVLO
• Internal 7V Low-Dropout Regulator
• Fault Output (FLT) for Overvoltage, Overcurrent, and Thermal Warning Faults
• Programmable True Differential Overvoltage Protection
• 20-Pin TQFN-EP Package
This LED driver is fully specified over the -40 degrees Celsius to +125 degrees Celsius automotive temperature range and is available in a thermally enhanced, 4mm x 4mm, 20-pin TQFN package with exposed paddle. Prices start at $1.24 (1000-up, FOB USA).
DATA SHEET: MAX16834 on the web.   
About Maxim Integrated Products:
Maxim Integrated Products is a publicly traded company that designs, manufactures, and sells high-performance semiconductor products. The Company reported revenue in excess of $2 billion for fiscal 2008. Maxim was founded over 25 years ago with the mission to deliver innovative analog and mixed-signal engineering solutions that add value to its customers' products. To date, it has developed over 5900 products serving the industrial, communications, consumer, and computing markets. For more information, go to