New Drivers For 3G Displays

16th March , 2004

ASIA : NEC Electronics Corporation announced that the company started sampling the two liquid crystal display (LCD) driver products, named uPD161833M and uPD161605M, that dramatically facilitate the design of a mobile device such as 3G cellular phone featuring rotating high-quality thin film transistor (TFT) displays.

The two products are the first in the industry as LCD driver ICs to have a high-speed serial interface. The uPD161833M, for low temperature poly-silicon (LTPS) LCD panels with 240 x 320 resolution (QVGA), and the uPD161605M, for amorphous TFT-LCD panels with 176 x 240 resolution (QCIF+), both have Mobile CMADSTM (Current Mode Advanced Differential Signaling) as the interface with the baseband or application chip and enable mobile device makers to design simpler and flexible printed circuit boards with a reduced number of lines for data transfer.

Mobile CMADS is an interface technology for mobile devices developed by NEC Electronics, adopting high-speed serial interface instead of commonly-used parallel interface. It applies a method to transfer data using current instead of voltage swing, to achieve low power consumption and low electromagnetic interference (EMI) noise.

Use of these new products adopting Mobile CMADS will facilitate wiring design of the narrow rotating part of rotating or sliding displays, such as those used in cellular phone, by reducing the number of data lines required for the transfer of image data from 18 to just 4 lines. EMI noise will also be reduced by approximately 90 percent. Even at high data transfer speeds, power consumption will be equivalent to or lower than that of parallel interfaces. Furthermore, this new interface can easily be incorporated in application chips, etc., because the signal output circuit on the data transmitting side consists of simple N-channel open-drain transistors that do not require an analog circuit. An additional advantage is that it easily supports low voltage power supply (as low as 1.5 V) on the data transmitting side.

“For some time, NEC Electronics has worked on developing serial data transfer technology that minimizes power consumption and does not increase EMI noise, and last year the company successfully developed this Mobile CMADS,” said Kazumichi Aoki, general manager of 5th System LSI Division, NEC Electronics Corporation. “We will share the specifications of Mobile CMADS with LCD module manufacturers and cellular phone manufacturers, and will further strengthen our product lineup. Our aim is to promote it to make it an industry standard.”

Recently in the field of cellular phones, the 2.5 generation allowing the transmission of still pictures in addition to text data has been giving way to the 3rd generation supporting video transmission, and 3G cellular phones are expected to achieve explosive growth. At the same time, with the start of terrestrial digital television broadcasting, cellular phones are beginning to provide a variety of advanced services, resulting in the rapid increase in amounts of data to be transferred. Moreover, to cater to diverse user tastes, manufacturers are increasing the number of designs, and calls are rapidly rising for models featuring revolving or sliding displays. Under these circumstances, it is required to add more performance to the display and transfer data from the main body to the display part at a transfer rate in excess of 45 Mbps. In seeking to send such large amounts of data through narrow hinged parts, engineers naturally look in the direction of reducing the number of data transfer lines and switching from parallel wiring to serial wiring, but such a switch presents various challenges, including larger consumption power and higher EMI noise. It is to answer this pressing need for LCD driver LSIs enabling simpler circuit boards, lower EMI noise, and lower power consumption that NEC Electronics has introduced the new products, uPD161833M and uPD161605M.

The Mobile CMADS technology has been receiving support from other semiconductor manufacturers. The graphics controller LSIs for mobile handsets introduced from NVIDIA Corporation named GoForceTM Series, such as GoForceTM 2150 and GoForceTM3000, support Mobile CMADS. The combination of NEC Electronics' new driver ICs with these products will allow mobile device makers to easily design devices that meet user demands.

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