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Home > Components & Tools > Electronics & Smart Controls > Maxim's New Four-String HB LED Driver Features Adaptive Output-Voltage Optimization
Products, Materials + Tools | Sep 09, 2009

Maxim's New Four-String HB LED Driver Features Adaptive Output-Voltage Optimization

Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX16814, a highly integrated four-string HB (high-brightness) Mid-Power LED driver capable of delivering up to 150mA per string .

This device packs in all the features necessary to implement a high-performance backlight driver for LCD TVs, monitors, and automotive displays or architectural lighting. Through this integration, the MAX16814 gives designers a cost-effective solution that greatly simplifies their lighting designs while offering unmatched performance.

The MAX16814 integrates a switching DC-DC controller to generate the voltage required to drive multiple strings of LEDs. It also features four linear current sinks with internal power MOSFETs to provide programmable current up to 150mA per string. An adaptive output-voltage control scheme optimizes efficiency and minimizes power dissipation in the LED current-sink paths. This architecture eliminates the need for multiple external components, thus saving space and easing design in space-constrained applications.

Key Features:    
• 4-Channel Linear LED Current Sinks with Internal MOSFETs
• Full-Scale LED Current Adjustable from 20mA to 150mA
• Drives One to Four LED Strings
• Boost, SEPIC, or Coupled-Inductor Buck-Boost Current-Mode DC-DC Controller
• 200kHz to 2MHz Programmable Switching Frequency
• External Switching Frequency Synchronization
• Adaptive Output-Voltage Optimization to Minimize Power Dissipation
• 4.75V to 40V Operating Input Voltage Range
• Less than 40µA Shutdown Current
• 5000:1 PWM Dimming at 200Hz
• Open-Drain Fault Indicator Output
• Open-LED and LED Short Detection and Protection
• Overtemperature Protection
• Thermally Enhanced, 20-Pin TQFN and TSSOP Packages
• Architectural, Industrial, and Ambient Lighting
• Automotive Displays LED Backlights
• Automotive RCL, DRL, Front Position, and Fog Lights
• LCD TV and Desktop Display LED Backlights
The MAX16814 high-efficiency, high-brightness LED (HB LED) driver provides up to four integrated LED current-sink channels. An integrated current-mode switching DC-DC controller drives a DC-DC converter that provides the necessary voltage to multiple strings of HB LEDs. The MAX16814 accepts a wide 4.75V to 40V input voltage range and withstands direct automotive load-dump events. The wide input range allows powering HB LEDs for small to medium-sized LCD displays in automotive and general lighting applications.
An internal current-mode switching DC-DC controller supports the boost, coupled-inductor buck-boost, or SEPIC topologies and operates in an adjustable frequency range between 200kHz and 2MHz. It can also be used for single-inductor buck-boost topology in conjunction with the MAX15054 and an additional MOSFET. The current-mode control with programmable slope compensation provides fast response and simplifies loop compensation. The MAX16814 also features an adaptive output-voltage control scheme that minimizes the power dissipation in the LED current-sink paths.
The MAX16814 consists of four identical linear current source channels to drive four strings of HB LEDs. The channel current is adjustable from 20mA to 150mA with an accuracy of ±3% using an external resistor. The external resistor sets all 4-channel currents to the same value. The device allows connecting multiple channels in parallel to achieve higher current per LED string. The MAX16814 also features pulsed dimming control, with very short minimum pulse width as low as 1µs, on all four channels through a logic input (DIM).
The MAX16814 includes an output overvoltage, open-LED detection and protection, programmable shorted LED detection and protection, and overtemperature protection. The device operates over the -40°C to +125°C automotive temperature range. The MAX16814 is available in the 6.5mm x 4.4mm, 20-pin TSSOP and 4mm x 4mm, 20-pin TQFN packages.
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