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Column driver chips for large-format LCD screens

Edited by the Electronicstalk editorial team Mar 16, 2007

Column-driver ICs will help drive acceptance of LCDs in large-format high-definition TVs .

STMicroelectronics has started sampling its first column-driver ICs for the large-size LCD TV market to key customers, including Chunghwa Picture Tubes (CPT), a leading display company based in Taiwan.

Developed in the company's Asia-Pacific Design Centre (APDC) in Singapore, the STD8420C and STD8420A are the first chips in ST's new LCD driver family.

Widely used in computer monitors, LCDs (Liquid Crystal Displays) are increasingly being used for flat-screen TVs as large LCD-panel prices continue to fall.

Demand for large-size LCD TVs is growing rapidly, especially in countries such as Korea, China, Taiwan and Japan, with the establishment of HDTV (high-definition TV) services.

Many consumers are upgrading from CRT (Cathode Ray Tube) television sets.

Analyst iSuppli predicts that sales of large-size LCD panels will continue to rise in the first half of 2007, compared with the end of 2006, in contrast to normal seasonal patterns.

The device uses PPDS (point-to-point differential signaling) display technology licensed from National Semiconductor to dramatically simplify the LCD intra-panel interconnect and to reduce the total number of column-driver signals required, aiding manufacturers by enabling a physically smaller bezel around the TV screen while providing cinema-quality display performance.

The use of this technology in the new LCD driver complements ST's long experience and expertise in display systems and technologies, including computer monitors, TV applications, mobile displays, plasma screens, small-size LCD and OLED (Organic LED) displays.

"We have been working very closely with ST's Asia-Pacific Design Centre in the design-in of this innovative new LCD-driver IC", says Wei Chun An, R and D Director for TV at CPT.

"ST is already an important player in the display market and we believe this new family of LCD drivers will make a significant contribution to our mission to deliver world-class displays and further accelerate the use of large-size LCDs in consumer products".

The STD8420x is being produced in a leading-edge process technology, developed by ST specifically for this application.

Other products in the new family will also be designed in ST's APDC in Singapore.

Key features of the STD8420C include: 414/420 outputs, PPDS interface compatible, support for independent digital gamma control of each RGB colour, support for Dot and N- line inversion drive schemes, operation over a wide output voltage range, and 1024 gray levels per output built from internal 12bit linear digital-to- analogue convertors.

The STD8420A incorporates all the features of the STD8420C with the exception of output gray levels, which are limited to 256 steps.

ST is setting up a complete business unit in Singapore for LCD drivers to establish a fully integrated presence at the centre of major LCD-panel production.

This unit provides a total value chain including design, product engineering, field application support and marketing services, assisting manufacturers in meeting their customers' expectations for performance, TV set appearance and economy.

Additionally, the chip design resources of the Asia- Pacific Design Centre in Singapore have increased four-fold in the last five years, enabling the design of this innovative and cost-effective LCD column driver close to major flat-panel TV manufacturers to minimise time to market.

"These first large-size LCD source-driver ICs are clearly an important milestone in the company's strategy to become a major player in the mainstream high-end LCD TV market", says Philippe Berger, General Manager of ST's Display Division.

"The company plans to offer extremely competitive driver products based around the PPDS display architecture and implemented in our leading-edge process technology developed specially for the application, together with dedicated design and display driver support resources located close to the key fast-growing markets in Asia".

Pricing for the new ICs is in the range of US $3 to $4.