Date: 17/02/2009

Reference design for a high voltage LCD integrated power supply for LCD TV

Microsemi and ON Semiconductor have developed GreenPoint open reference design for a high voltage LCD integrated power supply (HV-LIPS) for an LCD TV.

The GreenPoint reference design has all the functional blocks of the HV-LIPS LCD TV power supply, and includes Microsemi's latest high voltage backlight inverter and CCFL drive and JIN Current Balancer technology for CCFL. The design also utilizes new power management devices from ON Semiconductor.

"Microsemi and ON Semiconductor have collaborated to provide customers with an optimized, turnkey LCD TV backlight solution that brings outstanding performance and functionality to eco-friendly LCD TVs," said Tom Kapucija, director of marketing in the Analog Mixed Signal Group of Microsemi. "The LX6503 from Microsemi delivers synchronization and lamp current accuracy while supporting a broader range of signal frequencies and sources than alternative solutions for mainstream HV-LIPS applications. This gives HV-LIPS display users a superior visual experience whether they are watching TV broadcasts or playing DVD or Blu-Ray content. The integration of the LX6503 CCFL inverter controller into ON Semiconductor's GreenPoint 400V HV-LIPS reference design creates a complete solution for our customers."

The GreenPoint reference design supports the 180 Watt HV-LIPS architecture, which combines the main system power with the backlight inverter, enabling the inverter to be directly powered from the 400 volt (V) PFC rail. This eliminates a complete power conversion stage, improving overall system efficiency while simplifying the design and reducing bill of materials costs. The design supports the need for higher efficiency power supplies to meet the active and standby power requirement of the ENERGY STAR 3.0 TV standard that went into place in November 2008.

"Our customers have expressed interest in the design, as HV-LIPS power supplies are starting to enter the mainstream market for 32 inch and larger LCD TVs," said Bill Schromm, senior vice president and general manager of ON Semiconductor's Computing and Consumer Group. "The reference design merges the power supply with the inverter onto a single PCB with a maximum height of 25 mm, to meet the tight form factor constraints of LCD TVs."

The GreenPoint reference design for LCD TV power supplies meets IEC 61000-3-2 harmonic content requirements, and exceeds global standby requirements with typical standby power consumption of 400 milliwatts (mW) with a 50 mW load.

The LX6503 provides the key functions needed for LCD TV / Monitor displays in a simplified controller while providing reliable lamp striking, comprehensive brightness control modes and support for 24V inverter topologies in existing backlight applications. The SYNC capability 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. TheLX6503 controller also features tighter lamp current accuracy as compared to competitive solutions. A
wide range of supply operation from 6 V to 27 V is complemented with 600 mA source/sink drive and an on chip regulator with UVLO protection. Reliable operation is supported via programmable Strike Time, Strike Frequency, Burst Dimming Frequency, and Fault Time as well as multiple fault detection capabilities such as open lamp, over voltage, short circuit, and over current protection.

Microsemi's LX6503 CCFL Inverter Controller with SYNC can be used with Push-Pull, Half-Bridge, or Full-Bridge Inverter configurations for a competitive solution to off-PFC applications. A wide range of supply operation from 6 V to 27 V is complemented with 600 mA source/sink drive and an on chip regulator with UVLO protection. Reliable operation is supported via programmable Strike Time, Strike Frequency, Burst Dimming Frequency, and Fault Time as well as multiple fault detection capabilities such as
open lamp, over voltage, short circuit, and over current protection.