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Backlight controller improves LCD TV contrast

Posted: 09 Dec 2009 ?? ?Print Version ?Bookmark and Share

Keywords:backlight controller? inverter? LCD? CCFL?

LX6503A backlight controller

From Microsemi Corp. comes a CCFL backlight inverter controller that improves black-level quality and dynamic contrast performance in 40-inch-and-larger LCD TVs.

The new backlight controllers feature Microsemi's patented PureBLACK technology while setting new standards for image uniformity, reliability and protection, and lowering overall bill of material costs.

PureBLACK technology was developed by Dr. Xiaoping Jin, inventor of Microsemi's Jin Balancer concepts for economical lamp-voltage control and current balancing. PureBLACK technology achieves its superior black levels and dynamic contrast performance by building upon the Jin Balancer's unique ability to ensure lamp striking with very small duty cycles.

Designated the LX6503A, Microsemi's latest addition to its CCFL inverter controller family brings advanced mega-contrast dimming to large-screen displays, including those that use the energy-saving high voltage LCD integrated power supply (HV-LIPS) topology.

Like Microsemi's recently introduced LX6523A solution for 37-inch-and-smaller displays, the LX6503A features soft-start capability, fault indication and flexible configuration support for push-pull, full-bridge or half-bridge drive topologies for ultra-low-cost large-screen displays. It includes synchronization (SYNC) functionality which significantly improves display quality by synchronizing both the frequency and phase of the lamp current between inverters or to external signals from a wide variety of sources including DVD and Blu-ray devices.

The LX6503A controller integrates all necessary functionality for LCD TV/monitor displays in a single controller that also provides reliable lamp striking, comprehensive brightness control modes and support for 24V inverter topologies in existing backlight applications. The LX6503A controller features tighter lamp current accuracy as compared to competitive solutions.

The LX6503A features black level and dynamic contrast performance with built-in support for over-voltage and open-lamp protection. Flexible and easy to use, the controller includes support for push-pull, half-bridge or full-bridge inverter configurations. It also packs inverter SYNC functionality; PWM- or analog-based burst dimming; wide range of supply operation from 6V to 27V and 600mA source/sink drive and on-chip regulator with under-voltage lockout protection.

The backlight controller also boasts reliable operation supported via programmable strike time and strike frequency; user-settable burst dimming frequency and fault time. The LX6503A also features multiple fault detection capabilities including open-lamp, over-voltage, short-circuit and over-current protection. The device operates at -40C to +85C range.

"Microsemi has been a pioneer in CCFL backlighting technology for many years," said Tom Kapucija, director of marketing with Microsemi's analog mixed signal group. "With CCFL backlit TVs projected to remain the dominant display technology for the next four or five years, it is important for Microsemi customers to offer the same dynamic contrast and performance possible with our industry's emerging technologies. PureBLACK technology fulfills that need while improving the energy efficiency of the display."

The LX6503A is production-released and is priced at less than $0.60 in OEM quantities. It is housed in a 16-lead, narrow-body small outline plastic package.

For application notes on backlight controllers click here.

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