News and New Products

LCD driver challenges TFT devices in mobile-phone applications

by NS Manjunath, EDN Asia -- EDN, 8/4/2005

Targeting mobile phones that rely on color displays, Hong Kong-based Solomon Systech Ltd has launched the first device in a series of innovative CSTN (color supertwist-nematic) LCD drivers. The SSD1784 display controller can support 132×60-pixel-resolution CSTN LCDs. Using the SSD1784, you can achieve 65,000 color combinations in a simple application circuit.

The SSD1784 features a dual OTP (one-time-programmable) ROM, an eight-color power-saving mode, and divider-level accuracy-improvement circuitry. The SSD1784 has more features and uses smaller die than its SSD1783 predecessor and is software-compatible with previous devices from Solomon Systech, which means that designers can reduce development time using the controller.

"CSTN LCDs are catching up with TFT [thin-film-transistor] LCDs in all aspects of display quality, including color depth, contrast, and viewing angle," says Eddy Luk, Solomon Systech's technical marketing engineer. According to Luk, CSTN LCDs also perform better than TFT LCDs in cost and cycle time in mass-production, and, for applications that require no ability to play video, CSTN is a good choice for cost, flexibility, and power consumption.

The SSD1784 offers partial-, sleep-, and eight-color standby modes. When you invoke the eight-color mode, the display controller's frame-rate control and PWM circuitry partially turn off. These circuit blocks generate gray-scale levels for RGB signals. Circuitry on the controller allows you to display red, green, blue, cyan, yellow, magenta, black, and white colors.

Solomon Systech Ltd, www.solomon-systech.com.