TI开发出液晶显示屏内部高速总线技术

ＴＩ最近开发出了连结液晶控制器ＬＳＩ和液晶驱动器ＩＣ的接口技术“ｍｉ－ｎｉ－ＬＶＤＳ”,该技术适用于像素数明显增加的笔记本电脑的液晶显示屏。随着笔记本电脑像素的增加,满足电磁干扰（ｅｌｅｃ－ｔｒｏｍａｇｎｅｔｉｃ ｉｎｔｅｒｆｅｒｅｎｃｅ,ＥＭＩ）标准的难度也越来越大。而且,安装有液晶控制器 ＬＳＩ和液晶驱动器 ＩＣ的印刷电路板的大小和厚度,也影响着液晶显示屏的薄型化。 １２２ ＮＨｚ／５信道传输的“ｍｉｎｉ－ＬＶＤＳ”技术,便是为了彻底地解决上述问题而开发的。具体来说是首先降低了信号的振幅,以前是…     

液晶显示模块电磁干扰的防护

液晶显示模块是由ITO玻璃、液晶驱动芯片、背光模块与软性印刷电路板所组成,基于这种设计架构,当处理器通过输入/输出传输接口传送大量显示数据至液晶驱动芯片的过程中,会产生相当程度的电磁波,并通过模块上的软性印刷电路板（FPC）发散出来,进而影响电子产品内部的组件效能,因此文中将针对电磁干扰的问题说明一些防护的方法。     

用于液晶显示屏的经济可靠技术

COG(Chip On Glass)的价值定位如今,很多液晶显示器都通过连接一个带封装的液晶驱动器IC实现显示功能,其通过印刷电路板(PCB)进行物理显示(见图1a)。这个概念(后文称为"表面贴装器件"或SMD概念)提供了一个坚固的机械解决方案,但要求更复杂及区域聚集的PCB设计。COG(Chip On Glass)技术是另一种设计方法,其液晶驱动器直接安装于显示屏上(见图1b)。这个概念(后文称为COG概念)减少了PCB上的走线和层数,削减了电     

TFT液晶显示屏驱动器技术发展趋势

对于液晶驱动器的要求，除功能之外，还有低成本等；最近，液晶不仅用于笔记本计算机，也用于照相机、便携式信息终端；对于液晶的要求，也随之变得多种多样。液晶驱动器现现迄今，面向液晶显示屏的驱动器大规模集成电路（在下文中，简称为驱动器）市场，在很大程度上，为面向个人机的液晶显示屏市场所左右。驱动器厂家主要关心的是，面向个人机的液晶显示屏市场的需求变化、价格升降、画面尺寸、以及高精细化的趋势，因为这些因素不仅关系到驱动器的规格，也直接关系到玻璃的使用数量，对于驱动器的需求量有很大的影响。不过，任何一项因素…     

液晶驱动器技术发展趋势

液晶显示屏随着信息化社会的进展，在经历了二十余年的技术革新之后，应用领域日益广阔。液晶驱动器作为左右液晶显示屏性能与显示质量的器件，重要性日益增加，而随着液晶显示屏面的增大和清晰度的提高，ＳＴＮ液晶驱动器和ＴＦＴ液晶驱动器的技术也都大有发展。液晶驱动...     

计算机的电磁辐射分析与防护

针对计算机电磁信息泄漏对信息安全的影响,结合屏幕分辨率为1 280×1 024的液晶显示屏的信号辐射情况,利用计算机进行了仿真,分析了辐射信号的时频特性,并对计算机进行了屏蔽设计与实测。测试结果表明,所设计电子屏蔽箱的辐射发射总体<35 dBμV/m,适当增加防护半径,其辐射发射量可降到20 dBμV/ m以下,低于20 dBμV/m的环境噪声,达到防电磁泄漏的要求。     

高速印刷电路板设计技术研究

为了解决高速印刷电路板设计中因高频辐射和边缘极值速度所产生的干扰、振铃、反射以及串扰等噪声对系统性能的损害问题,从电源分配系统及其影响、传输线及其相关的设计准则、串扰及其消除、电磁干扰等四个方面详细讨论了高速印刷电路板(PCB)的设计技术。结合实际应用给出了这些技术的实现方法和有关参数计算公式。实践表明:这些技术在高速印刷电路板的实际设计中是可行的。     

液晶显示屏组件装配设备概述

设备的主要作用液晶显示屏制造工艺中的组件装配工序，是决定产品最终成品率的重要工序，其中包括：在显示屏上装接驱动器集成电路的ＯＬＢ（或ＣＯＧ）工序，连接向驱动器集成电路输入信号的印制电路板的工序。而驱动器集成电路的装接工序，又可以分为两种：装接ＴＹＣＰ（带载封装器件）的ＯＬＢ工序，将对集成电路直接面朝下地装接于显示屏上的ＣＯＧ工序。印制电路板（用于输入信号的）连接工序也有两种：焊接，ＡＣＦ连接。设备种类驱动器集成电路的装接工序（ＯＬＢ工序或者ＣＯＧ工序），主要采用三种装连设备，即：ＡＣＦ贴装设备，…     

高速PCB近区场电磁骚扰研究

分析了高速电子电路产生的电磁干扰(EMI)及相关印刷电路板(PCB)上电磁骚扰源的模型特征。利用电偶极子与磁偶极子模型分别对PCB上的共模辐射源和差模辐射源建模,着重探讨近区场辐射特征。以一种500MHz的高速电路为例,在MATLAB平台上分别对其电场与磁场进行仿真。结果表明,其近区场电场与磁场强度最高分别可达5×1011μV/m和9×1011μA/m。依据所使用模型及其仿真结果,有针对性地提出几种降低高速PCB电磁骚扰的方案,并比较了这几种方案的优劣。     

印刷电路板供电系磁性材料涂层的应用

印刷电路板（PCB）的电磁兼容问题,随着数字电路的工作频率越来越高而变得尤为重要。本文以印刷电路板中的电源接地层供电系构造为切入点,讨论与其相关的电磁兼容问题。在高频段,印刷电路板的电源和接地层构造相当于一个平行平板谐振器,对周围的电路产生电磁干扰（EMI）。基于全腔模模型,已经发展了用于高效准确计算供电系阻抗的快速算法。利用此算法,通过计算机仿真,结果表明PCB电源接地层导体内侧增加磁性材料涂层能够提高表面阻抗,进而减小端口输入阻抗的谐振峰并改善信号完整性。     

Electromagnetic Design Techniques for Liquid Crystal Display Driver ICs

A simple method of verifying electromagnetic interference (EMI) reduction effects for liquid crystal display (LCD) driver integrated circuits (ICs) is proposed. In this paper, we discuss correlations between radiated emissions and high-frequency currents of power system at three different levels: print circuit board (PCB) level, chip level, and functional circuit level. The EMI design points for LCD driver ICs are presented too. Simulated and measured results prove that our EMI design effectively reduces LCD EMI noise.     

不符合20H规则的阻抗线参考层设计对阻抗测量的影响

20 H规则作为PCB典型布线规则,随着传输信号工作频率逐步提高,其越来越被PCB设计人员采用以用来减少EMI问题。当然,PCB制造人员无法模拟20 H规则的EMI但须控制特性阻抗,故本文试图首次阐述20 H规则对特性阻抗控制的影响,并通过相关试验与量产过程进行证明。     

An EMI Resisting LIN Driver in 0.35-micron High-Voltage CMOS

This paper describes the design of a local interconnect network (LIN) integrated output driver circuit exhibiting a high degree of immunity against conducted electromagnetic interference (EMI). The transmitted signal of this driver is shaped with a predefined slope so as to reduce electromagnetic emission at higher frequencies. The effect of EMI coupling from the data bus into the driver circuit is countered using a new feedback scheme which shields the slope shaping function from the output stage. Although the output signal may be heavily corrupted by EMI, the LIN driver continues to deliver an unaltered duty cycle, which is mandatory to obtain an error-free data transmission. Measurements show that this driver circuit manages to withstand the highest levels of the direct power injection (DPI) measurements independently of the injected EMI level.     

液晶显示器电磁泄漏信息侦收难度分析

根据各类液晶显示器的特性以及适用场合,确定透射型TFT液晶显示器为研究对象。按照电磁泄漏的来源,分别介绍了液晶显示面板、驱动电路、VGA接口＼DVI接口及视频预处理电路的工作原理,以及各部分中传输信号的特性。通过研究显示器各部分电磁泄漏信号的特点,分析了泄露信息的截获复现难度,认定视频预处理电路存在泄密隐患,且液晶显示器有可能通过Soft Tempest方式泄露信息。     

Field-Line-Circuit Coupling Based Method for Predicting Radiated Electromagnetic Emission of IGBT-PMSM Drive System

Electric drive system with Insulated gate bipolar transistor (IGBT) power device is widely used in Electric vehicle (EV), which consists of inverter, cables and Permanent magnet synchronous motor (PMSM). Due to the fast switching in di/dt and dv/dt of IGBT device, the system produces serious radiated Electromagnetic interference (EMI) through the interconnection cables. Thus, modeling of EMI source, propagation path and load PMSM is the key to accurately evaluate the system's radiation level. In addition, the system's radiated EMI involves the integrated calculation of circuit, cable and electromagnetic field, which cannot be solved by using a single circuit or electromagnetic calculation method. Therefore, this paper develops an effective field-linecircuit coupling based method to investigate the radiated EMI problems for IGBT-PMSM drive system, which is validated by experimental measurement. Besides, the impact of power cable parameters on radiated EMI is discussed. The proposed approach has guiding significance for electromagnetic compatibility design of EV.     

射频电子设备的辐射电磁干扰诊断与抑制技术研究

射频电子设备产生的电磁干扰(EMI)噪声包括传导干扰噪声和辐射干扰噪声。其中,辐射EMI噪声是以空间电磁场形式影响其它电子设备的。针对射频电子设备产生的辐射EMI噪声,该文分别建立因传输线缆与芯片时钟信号引起的辐射EMI噪声理论模型与等效电路。同时,还针对上述辐射EMI噪声理论模型提出了相应的噪声抑制方法。实验结果表明,采用该文中方法,某型家用液晶显示器的EMI噪声得到了很好的抑制,从而验证了方法的有效性。     

开关电源差模电流辐射干扰的模拟与分析

本文采用电磁场数值模拟的方法对开关电源差模电流的辐射干扰进行了模拟,并对模拟的结果进行分析,得出了差模电流辐射的基本特性和闭合印制线回路的变化对它的影响.     

Cavity Model for the Slot Radiation of an Enclosure Excited by Printed Circuit Board Traces With Different Loads

Traces on a printed circuit board (PCB) couple to the cavity consisting of the PCB ground plane and a metallic enclosure cover. We introduce this common-mode coupling of a PCB trace to the cavity field by an analytical model that is verified with 3-D simulations using HFSS. The cavity field causes radiated emission from the slots of the cavity. For an accurate calculation of the cavity field inside the enclosure and the radiated emission, we consider the radiation loss by a multiport approach. Comparisons of the analytical results for the radiated field to measurements show good agreement. Radiated emission can be calculated for arbitrary geometric enclosure shapes as a function of frequency, position of the trace on the PCB, and trace load/driver impedances.      

Modelling finite-size PCBs for radiated EMI analysis

Typical printed circuit boards (PCBs) in the EMI regulated frequency range 30-1000 MHz are electrically finite-sized. The conventional full-wave method is not suitable for modelling finite-sized PCBs because of the assumption of infinite ground and substrate. The authors present a full-wave moment method approach for computing radiated electromagnetic interference produced by realistic finite-size PCBs. Numerical agreement with another approach is demonstrated