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Efficient Spread Spectrum for LCD Panel

IP.com Disclosure Number: IPCOM000013235D
Original Publication Date: 2001-May-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 1 page(s) / 66K

Publishing Venue

IBM

Abstract

Recently, EMI noise issue has been increased due to high frequency of CLKs such as CPU clock, Memory clock and PCI BUS clock. On the other hand, EMI noise from LCD panel is getting bigger, as a resolution of LCD is getting higher. Then, some Video chip suppliers started providing video chips that make these EMI noise reduced. However, these efficiency is not enough because the width of Spread Spectrum cannot be wider due to limitations of input signals for transmitters like LVDS transmitter and DVI transmitter. This invention solves these kind of issues, and provides high efficency for reducing EMI noises. The following drawing shows the diagram of this invention. This invention gives us the following advantages. 1. Able to reduce EMI noise even with Video Chip that doesn't have Spread Spectrum Function. 2. Adaptive for not only Notebook, but also External LCD Monitor of Desktop PC.

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Efficient Spread Spectrum for LCD Panel

    Recently, EMI noise issue has been increased due to high frequency of CLKs such as CPU clock, Memory clock and PCI BUS clock. On the other hand, EMI noise from LCD panel is getting bigger, as a resolution of LCD is getting higher. Then, some Video chip suppliers started providing video chips that make these EMI noise reduced. However, these efficiency is not enough because the width of Spread Spectrum cannot be wider due to limitations of input signals for transmitters like LVDS transmitter and DVI transmitter. This invention solves these kind of issues, and provides high efficency for reducing EMI noises. The following drawing shows the diagram of this invention.

This invention gives us the following advantages.

1. Able to reduce EMI noise even with Video Chip that doesn't have Spread Spectrum Function.
2. Adaptive for not only Notebook, but also External LCD Monitor of Desktop PC.
3. No incompatibility Issue between System and LCD Panel.
4. Better EMI performance.

A dd for EM I improvement

LC D P anel

LCD Drivers

M odulated clock

Modulated clock

Modulated data

M odulator

LC D I/F Rcv.

clock

data

Sync.

ASIC

System

clock

data

diff. clk

diff. data

I/FDLCVideo

Trs.

1

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