LED Backlighting Drivers
AnalogicTech Launches Family of Direct and Edge LED Backlighting Drivers; Unveils Strategic Roadmap for LED Backlit LCD Televisions
News Release from:
Advanced Analogic Technologies Inc., Europe
19 November 2009
As part of its market expansion and diversification strategy, Advanced Analogic Technologies, Inc. today made its official move into the LED backlit LCD television market with the first chip set families in a series of innovative power management semiconductor systems designed to significantly enhance energy efficiency and user-experience for LED backlit LCD televisions.
“The launch of these new products for the LED backlit television market represents our continued drive to offer innovative solutions that conserve power and deliver a better end-user experience,” stated Richard Williams, CEO of AnalogicTech. “We have a wealth of experience seamlessly integrating our ModularBCD™-based LED drivers into tier one handset manufacturers’ high-end handset designs. This technology allows us to deliver the same high-performance and energy efficiency to innovative solutions in the LED backlit LCD television space.”
The intelligent control of LED current sinks in direct/matrix backlight applications can provide precise brightness of individual segments based on image content and can give the consumer truer blacks and improved contrast for a significantly better, more natural viewing experience. Dynamic LED backlighting also makes it possible to meet the increasingly stringent energy consumption specifications for large panel TVs such as the state of California is considering.
“The unique design and process advantages of our proprietary ModularBCD™ process allow the effective integration of low voltage digital circuitry with high-voltage analog circuitry. This combination enables the dynamic management of high current, high voltage LED current sinks and results in significant power savings,” added Williams.
As its initial entry point into the LED television market, AnalogicTech announced 7 new products:
• LED Driver Chipset with Integrated Boost converter for Direct/Matrix Backlighting
• AAT2400 (8ch Master) & AAT2401 Unlatched (8ch Slave) Chipset
• AAT2402M (8ch Master) & AAT2402S Latched (8ch Slave) Chipset
• Dedicated LED Driver for Direct/Matrix Backlighting
• AAT2403 (16ch) Latched LED Driver
• Dedicated LED Driver for Edge Backlighting
• AAT2405 PWM with phase shift (6ch) LED Driver
• AHK2417E Latched (8ch) LED Driver
• AHK2418E Latched (16ch) LED Driver
• DC/DC Boost Controller
• AAT2404 High Voltage Boost Controller
These devices utilize AnalogicTech’s patent pending Multiple Chip Voltage Feedback technique that ensures the proper LED supply voltage is simultaneously regulated across up to 16 chipsets (or 256 channels) allowing precise control of up to 2560 LEDs for direct or dynamic backlighting solutions or up to 16 channels for Edge.
AnalogicTech’s Direct/Matrix Backlighting Solutions
The AAT2400/01 and AAT2402M/S chipsets produce a 16-channel high current LED driver capable of driving up to 10 LEDs in a single string. Each master and slave contains 8 high-voltage current sinks capable of sinking up to 100mA/channel. Using a SPI interface, up to 16 chipsets (or 256 channels) can be sequentially addressed and controlled. Each channel features 8-bit DOT correction, 12-bit grayscale, 12-bit delay time and on/off control. Protection against over-voltage, short or open circuit LEDs, over-temperature and over-current is included, with the information reported via the SPI bus and a fault flag. To provide the power for the LED strings, the AAT2400 and AAT2402M includes a boost converter with an integrated lateral TrenchDMOS output device, which uses the current sink information from each channel to ensure that the output voltage can correctly bias all LED strings regardless of LED forward voltage.
The AAT2403 is a dedicated 16-channel high current LED driver capable of driving LEDs in a single string powered from an external Step-up or Step-down converter. Each current sink is capable of sinking up to 100mA/channel. Utilizing a SPI bus interface, up to 16 chipsets (or 256 channels) can be sequentially addressed and controlled. Each channel features 8-bit DOT correction, 12-bit grayscale control, 12-bit delay time and on/off control. As with the AAT2402 Master and Slave, protection against over-voltage, short or open circuit LEDs, over-temperature and over-current is included, with the information reported via the SPI bus and a fault flag.
AnalogicTech’s Edge Backlighting Solutions
The AAT2405 (6-channel), edge lighting driver can be paired with the AAT2404 high voltage boost controller to deliver a configurable solution for Edge LCD Backlighting. With simple adjustable phase delay, the AAT2405 can be configured as a 2- ch, 3- ch, 4-ch or 6-ch driver, dependant on the number of LED strings per light bar. Utilizing internal current sensing, the AAT2405 eliminates high tolerance, high cost external sensing resistors. Each output can regulate up to 150mA/channels with +/-2.5% accuracy and matching. These devices can be cascaded for multiple LED strings, with communication between the ICs maintaining the correct PWM and Phase information.
Also released for edge applications are the AHK2417E (8-channnel) and AHK2418E (16-channel).This solution is for systems with up to 100mA/channel LED output current with ±2.5% accuracy and matching. The chipset features integrated fault protection for shorted & open circuit LEDs, over-current, over-voltage and over-temperature protection with fault reporting via the SPI bus.
DC-DC Boost Controllers
The AAT2404 is a DC-DC boost controller IC which can operate from a 12V or 24V input supply and boosts the voltage dependent upon the number of LEDs in the string. Integrating a high speed, low impedance gate driver IC, the AAT2404 uses externally connected MOSFETs to provide up to 3.2A of output current. The AAT2404 directly connects to the current sink feedback pin of the LED backlight drivers to provide the correct string voltage.
Powering Innovative Solutions in the TV Market
In addition to a family of new LED backlight driver products, AnalogicTech outlined plans to deliver a total power management solution for TVs including, for example, enhancements to AnalogicTech’s existing Class D Audio power amplifier products. Product development is underway and products will be rolled out over the next several months.
”Adoption of these new technologies will be driven by three key factors: Environmental mandates to eliminate the mercury CCFLs used in today’s backlighting, the continued price reduction of white LEDs bringing the cost of LED backlighting to parity with CCFLs, and the consumers’ desire for a better viewing experience,” stated Phil Dewsbury, Product Line Director, Display and Lighting Products. “With the products announced today and the pipeline of enhancements, we have the best system solution for the TV market to deliver on the promise of power conservation and enhanced user-experience.”
The AAT2400/01 and AAT2402M/S direct/matrix driver chipsets, the AAT2403 dedicated direct/matrix driver and AAT2405 and AHK2417/18 edge drivers as well as the AAT2404 DC/DC boost controller are all available for design-in.