空气式静电放电的实验分析

针对国际电工委员会标准IEC 61000-4-2静电放电抗扰度试验方法存在的问题,对空气式静电放电进行实验研究.利用新型静电放电(ESD)模拟测试系统,在较宽范围的电压电平下,用数字存储示波器对放电电流的上升时间、峰值、自制金属半圆环天线上的耦合电压峰一峰值进行测量.测量结果的分析表明:不同空气湿度下的ESD特性存在着...     

固定间隙的空气式静电放电

为更好地研究空气式静电放电,利用新型ESD模拟测试系统研究了固定间隙的空气式静电放电特性。在较宽范围的电压电平下,用数字存储示波器测量放电电流的上升时间、峰值、自制金属半圆环上的耦合电压峰-峰值,并记录了放电电流和耦合电压的波形。分析测量结果及其与放电电压和放电间隙之间的变化关系,可知在一定的间隙间距上,放电电流随着放电电压的增大而增大,高压放电也能产生上升沿比较陡的电流脉冲;在一定的放电电压下,存在着一个放电间隙间距使得放电电流峰值最大或耦合电压最大;不同电压下的频谱分布和能量分布不一样。     

空气静电放电若干特性分析

针对国际电工委员会标准IEC61000-4-2静电放电抗扰度试验方法存在的问题,对影响空气静电放电的一个重要因素-电弧结构进行了讨论。在此基础上,利用新研制的静电放电模拟测试系统,分析了接近速度和放电电压对放电电流峰值、上升时间、感应电压峰—峰值以及试验结果重复性的影响。试验结果表明:放电电压一定时,放电电流峰值、感应电压峰-峰值随接近速度的增大而增大;上升时间随接近速度的增大而减小;在一定的接近速度和放电电压下,空气静电放电也可以实现较好的重复性。这些规律性的试验结果,为建立静电放电抗扰度试验新方法提供了依据。     

空气式静电放电抗扰度试验方法

静电放电(electrostatic discharge,ESD)抗扰度试验作为电磁兼容(EMC)试验的一项重要内容,其执行标准IEC 61000-4-2还存在诸多问题,尤其是空气式ESD的重复性问题。为此,基于动能-势能转换原理,采用导轨带动电极运动结构和步进电机装置,用近似单摆结构的试验方法,设计和研制了2种新的ESD抗扰度试验平台,实现了空气式ESD抗扰度试验中对放电电极接近速度的准确控制。利用这2种ESD抗扰度试验平台对空气式ESD的重复性进行了研究。试验结果表明,ESD参数如放电电流峰值、接近速度和放电电压具有很好的规律性,并且在一定的放电电压和接近速度下,空气式ESD也可以具有较好的重复性。在相同放电电压和接近速度下,利用第2种ESD抗扰度试验平台得到的放电电流峰值和上升时间的变异系数均小于利用第1种ESD抗扰度试验平台得到的放电电流峰值和上升时间的变异系数,因此第2种单摆式ESD抗扰度试验平台的重复性要好于第1种ESD抗扰度试验平台的重复性。     

聚合物ESD抑制器抑制特性的测试方法

为了消除静电放电时产生的辐射场对静电放电抑制器测试结果的影响,基于法拉第笼的屏蔽效应、依据国际电工委员会IEC61000-4-2标准和国军标GJB911-1990,利用静电放电模拟器和静电放电电流波形测试装置等设备,测试了某型号聚合物静电放电抑制器的抑制特性。测试结果表明,采用IEC61000-4-2标准规定的电流靶结合法拉第笼的方法,测试静电放电时通过抑制器的电流,能够保证电流波形不失真;而加在抑制器两端的电压,须使用有效带宽足够宽的电压探头配合示波器来测量,同时应尽可能消除静电放电时产生的辐射场对电压探头的影响。     

影响空气式静电放电特性的相关因素分析

为了提高静电放电特别是空气式静电放电试验结果的重复性,从理论和试验两方面对影响空气式静电放电(ESD)特性的相关因素进行了研究,结果表明:电弧长度是影响空气式ESD特性的一个最直接因素,不同电弧长度会得到差别很大的空气式ESD事件,相同放电条件下,电弧长度越短,峰值电流越大,上升时间越小;其它条件一定的情况下,电极的接近速度会影响到电弧长度而引入时间相关效应,进而影响空气式ESD特性,比如当放电电压一定时,接近速度越快,峰值电流越大,上升时间越小;不同的放电电极极性将产生空间极性效应或空间电荷效应,从而影响空气式ESD特性;不同的环境条件尤其是空气成分与空气湿度对空气式ESD的影响很大。这些研究成果将为空气式ESD的试验规律研究提供理论依据。     

多针-平板电极介质阻挡放电特性研究

通过电压-电流波形和电压-电荷李萨育图的测量,研究了空气中多针-平板电极介质阻挡放电特性,比较了这种放电和平板-平板电极介质阻挡放电的区别,并通过接触角测量比较了这两种形式放电对聚四氟乙烯(PTFE)进行表面改性的效果。结果表明:在相同的条件下,与平板-平板电极介质阻挡放电相比,多针-平板电极介质阻挡放电空间能产生更多的活性粒子;用这种放电对PTFE进行表面改性,能在更短的时间内获得和平板-平板电极介质阻挡放电相同的效果。     

不同电极结构介质阻挡放电特性比较

采用电压-电流波形测量、发光图像拍摄、光谱分析等手段研究大气压空气中刃-板电极、针-板电极和柱-板电极结构介质阻挡放电(DBD)的放电特性,并研究电压幅值、电源频率及气隙距离对放电功率和分子振动温度等放电参量的影响,结合放电理论对不同电极结构DBD的特性进行分析。结果表明：3种电极结构DBD的电压电流波形、Lissajous图形以及光谱谱线体现出不同的特点,相同条件下柱-板电极结构DBD放电强烈,消耗放电功率多,粒子谱线强度高,放电电流可达200 mA。电极布置差异导致电场不均匀系数的不同是放电特性出现差异的主要原因。随着电压幅值、电源频率的增加和气隙距离的减小,3种电极结构放电增强,放电功率和分子振动温度增加。     

空气间隙固定和连续变化时的空气静电放电事件研究

为得到2种状态下空气静电放电（ESD）辐射电磁场与放电间隙间距、放电电压和电极接近速度之间的关系,在-30～30kV的宽电压范围和多种温湿度条件下,通过实验测量记录了两种状态的空气ESD事件;给出了空气ESD事件的解释;提出了空气ESD存在“增长间隙区”、“跌落间隙区”、“平坦间隙区”和“零放电间隙区”4个放电间隙区。...     

多针-平板电极介质阻挡放电的特性及影响因素研究

通过电压-电流波形图和电压-电荷李萨育图形的测量，研究了空气中多针-平板电极介质阻挡放电特性，比较了这种放电和平板-平板电极介质阻挡放电的区别。通过实验研究了放电间隙距离、多针电极针的密度、阻挡介质材料性质对多针-平板电极介质阻挡放电放电功率的影响。实验结果表明，在相同的条件下，与平板-平板电极介质阻挡放电相比，多针-平板电极介质阻挡放电消耗较大的放电功率；放电空间消耗的功率随外加电压和介电常数的增加而增加，随气隙距离的增加而减小。     

Effect of Moving Speed of Charged Metallic Spherical Electrode on Electrostatic Discharge

In this investigation, the nature of the electrostatic discharge (ESD) that occurs when a charged object moves toward a stationary grounded object is experimentally clarified. The spark lengths, discharge currents, and induced voltages in a magnetic probe were measured when a charged metallic spherical electrode connected to a 422 pF capacitor approached a stationary grounded object, which was the current target, for different moving speeds of the charged metallic spherical electrode in a range of 1 mm/s to 100 mm/s. The charge voltages of the capacitor were +6.5 kV and +10 kV. Based on the results, the average gap length shortened with the speed of the spherical electrode. The average peak values of the discharge current and the induced voltage were likely to increase with the speed of the spherical electrode. The average rise times of the discharge current and the induced voltage were likely to drop with the speed of the spherical electrode. The relation between the spark length and the discharge current due to the ESD can be explained qualitatively by using an equation derived from the spark resistance formula proposed by Rompe and Weizel.     

Variations in discharge current waveforms and their power spectra injected from contact discharges of ESD‐gun with different arrangements

The International Electrotechnical Commission (IEC) has prescribed an immunity test (IEC61000‐4‐2) of electronic equipment against electrostatic discharges (ESDs), in which a discharge current to be injected onto equipment under test is specified. As for the waveform, however, not the whole waveform but only the rise time, the first peak, and the current amplitudes at 30 and 60 ns are given in the time domain together with their uncertainties, which are required to check on the condition that an ESD generator (ESD‐gun) shall be arranged vertically to an IEC‐recommended calibration target and its earth return wire is kept away as far as possible from a vertical ground plane (IEC standard arrangement). In this study, to clarify how arrangements of an ESD‐gun and its earth return wire affect discharge currents, we measured discharge current waveforms for contact discharges of an ESD‐gun onto an IEC calibration target with respect to various inclinations of the ESD‐gun and arrangements of its earth return wire, and also calculated their current power spectra normalized to that of the discharge current for the IEC standard arrangement. As a result, we found that inclinations of the ESD gun affect the first peak current, which increases current power spectra by 14 dB at frequencies over 300 MHz, and that arrangements of the return wire influence the current waveforms between the first and second peaks, which provides variations in power spectra by ±12 dB in the frequency range from 10 MHz to 200 MHz. This finding suggests that arrangements of an ESD‐gun and its earth return wire are likely to cause different immunity test results. It was also found that in comparison with measured discharge currents for the standard arrangement, the calculated waveform of a discharge current from a formula, which has been included in the recent standard, has a more gentle falling waveform, and produces power spectra of +15 dB in the frequency range from 10 MHz to 200 MHz and –12 dB at frequencies over 300 MHz. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(1): 9–14, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21270     

基于PLC的静电放电试验系统的设计

设计了基于可编程控制器(PLC)的静电放电实验系统,对静电保护器件压敏电阻进行静电放电自动测试。首先根据IEC61000-4-2标准,设计静电放电发生源回路,选择可控放电频率的转盘式放电开关和具有纳秒级响应时间和集肤效应小的鼠笼式分流器。其次设计由工控机、示波器、PLC、触摸屏等组成的控制系统,开发相应的控制软件及数据处理系统,实现静电放电自动测试。最后选用不同等级的压敏电阻作为测试对象,对测试装置进行实验验证,结果表明,研究开发的静电放电自动测试装置可以满足压敏电阻静电放电测试的要求,对压敏电阻静电防护的研究具有重要意义。     

Calculation of magnetic near field generated by the contact discharge of an ESD gun

An ESD (electrostatic discharge) testing is specified in the IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected by an ESD gun is prescribed. However, due to lack of understanding of the discharge process, it is difficult to confirm whether or not the IEC current waveform can be injected onto actual equipment. We thus previously proposed an equivalent circuit model for the ESD gun based on its geometrical structure, and showed decisive factors for the discharge current. In this study, in order to confirm the feasibility of the above equivalent circuit model, we measured with a 6‐GHz wide‐band digital oscilloscope the discharge current through an SMA connector and the resultant magnetic near field for the contact discharge of an ESD gun. As a result, we found that both measured waveforms approximately agree with those calculated from our equivalent circuit model. We then measured with respect to charge voltages the magnetic near fields for the contact discharge of the ESD gun to the ground, which revealed that the measured waveform around the first peak is in fair agreement with the calculated one. Furthermore, we found that the magnetic field peak increases with increasing charge voltage, whose dependence can be predicted from our equivalent model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(1): 17–24, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20194     

A Case Study of Problems in JEDEC HBM ESD Test Standard

There is a current need for modification of EIA/JEDEC Human-Body model (HBM) electrostatic discharge (ESD) test standard, which does not define start and step test voltages. In the current standard, some measurements start at several kilovolts, which ignore the fact that ESD protection devices may fail under low voltage stresses. In this paper, a grounded-gate structure with an n-well ballast resistor connecting its drain and PAD is investigated for HBM ESD sustaining levels. When tested with a Zapmaster starting from 1 kV, the withstand voltage exceeds 8 kV, whereas the structure failed at 350 V when the test starts from 50 V. The test results from a transmission-line-pulsing system validate the phenomenon. The reason for the failure is also studied and confirmed with optical-beam-induced resistor change system failure analysis results. To address this general issue, a suggestion for improving the present HBM ESD testing standards for industry applications is made.      

Characteristic measurement of discharge current injected by the air discharge of an ESD gun onto a ground

An immunity testing method for electrostatic discharge (ESD) is being specified in IEC 61000‐4‐2, in which the contact discharge of an ESD gun is being normally specified. Air discharge testing is known to be a severe immunity test compared to contact discharge testing, while the discharge current injected is not well reproduced. Grasping the behavior of the current injected by the air discharge would be helpful in establishing the worst‐case ESD immunity testing. We previously measured the discharge currents for air discharge testing onto the IEC‐recommended current transducer with a commercially available ESD gun, and showed that there exists a specific relationship of Ip·tr^ξ/V_c=constant (ξ=0.75), between rise time tr and current peak Ip. The current transducer, however, has a frequency‐dependent transfer impedance which should affect the measured current waveform. In this study, we investigated whether the above‐mentioned specific relationship can be obtained for air discharge of an ESD gun onto a ground that assumes a metal enclosure of electronic equipment under test. A method was presented for estimating the discharge current from simultaneously measured magnetic fields with two magnetic field probes regardless of the distance between the gun discharge‐point and the probe position. This method was validated for contact discharge of an ESD gun to an SMA connector. With this method, we estimated the discharge currents injected onto a ground for air discharge testing of an ESD gun with intentionally fast and slow approaches. As a result, we could confirm a specific relationship between rise time tr and current peak Ip of Ip·tr^ξ/V_c=constant with ξ=0.57 independent of charge voltages and gun approaches. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 51– 59, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20454     

Equivalent circuit modeling of discharge current injected in contact with an ESD‐gun

The transient electromagnetic (EM) fields caused by an electrostatic discharge (ESD) have broadband frequency spectra, which cause serious failure to high‐tech information equipment. From this perspective, ESD testing for the EM immunity of the equipment is specified by IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected onto the IEC recommended Pellegrini target in contact with an ESD‐gun is prescribed for calibration. However, the factors for determining the current waveform remain unclear, and thus the IEC prescribed current waveform is unlikely to be injected into actual equipment. In this study, based on the structure of an ESD‐gun, an equivalent circuit modeling is proposed for analyzing the discharge current injected onto a 50‐Ω SMA connector instead of the IEC target that has frequency‐dependent transmission characteristics. Its validity is confirmed by comparing the calculated current waveform with the measured result. The proposed circuit modeling is also validated from measurement of the discharge current injected onto a transmission line by the ESD‐gun. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 8–14, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10367