LCD segment drivers address automotive VA displays

July 09, 2013 // By Christoph Hammerschmidt
NXP Semiconductors has introduced two new chip-on-glass (COG) LCD segment drivers – the PCF8538 and PCA8538 – specifically designed for driving vertical alignment (VA) displays. Designed to drive VA displays in harsh environments, the PCA8538 variant is also AEC-Q100-compliant for automotive applications such as climate control units, instrument clusters and car infotainment systems.

Providing high contrast, true black background, a wide viewing angle, and excellent image quality even at extreme temperatures, VA displays offer many advantages, but typically require a higher LCD supply voltage and higher frame frequency compared to conventional twisted nematic (TN) displays.

The PCF8538 and PCA8538 allow an LCD voltage up to 12V with accurate, software-programmable temperature compensation for high and stable contrast over an extended temperature range of −40°C to +105°C. The new COG segment drivers also offer an on-chip oscillator with programmable, calibrated frame frequency in the range of 45 Hz to 300 Hz. The drivers can also be used to drive conventional TN displays with any backlight color.

Both the PCF8538 and PCA8538 are single-chip LCD drivers that generate drive signals for any static or multiplexed LCD with up to 9 backplanes, 102 segments, and graphics of up to 918 display elements.

According to NXP, vertical alignment displays are now growing in popularity not only in automotive LCD applications, but also in home appliances, medical devices and other consumer and industrial applications where reliable, high-contrast passive LCD displays are required. By designing chip-on-glass LCD segment drivers specifically with VA displays in mind, NXP has been able to address the requirements of display module manufacturers and automotive Tier 1 suppliers, while also making it easier for non-automotive OEMs to incorporate VA displays into their designs.

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