基于人体起电实验外推超低电压研究

Extrapolated voltage based on ultra-low human body electrification experiment

随着电子工业技术的飞速发展,电子产品静电放电(electrostatic discharge, ESD)敏感度电压已经低于人体模型(human body model,HBM)电压50 V,然而现有防静电工作区(electrostatic discharge protected area, EPA)配置要求标准只是针对于ESD敏感电压不低于HBM 100 V的电子产品.为了研究人体起电超低电压EPA配置,文中依据ANSI/ESD S20.20标准进行人体行走实验,在较高湿度条件下,选择对地电阻值远低于标准规定109Ω的防静电地板与防静电鞋,测试人体起电的系统电阻及其行走起电电压.基于短时间的实验数据利用切比雪夫不等式外推特定概率下最大可能电压,使短时间实验数据具有实践意义.实验研究发现:虽然人体行走电压与其系统电阻之间呈正相关关系,但是离散性较大,仅通过系统电阻控制人体起电电压,无法得到良好的结果.最后,依据外推电压对EPA的防护可靠性进行风险评估,提出了降低失效风险的建议和措施.

With the rapid development of electronic industry technology, the electrostatic discharge(ESD)sensitivity voltage of electronic products has been lowered than the 50 V human body model(HBM) voltage. However,the existing ESD protected area(EPA) configuration standard works only for the electronic products whose ESD sensitive voltage is not less than 100 V. In order to study the configuration of EPA to achieve ultra-low human charge voltage, this paper investigates on the human walk experiment according to the ANSI/ESD S20.20 standard. Under high humidity conditions, the ESD mitigation floor and shoes with resistance widely below the 109 Ω standard are selected in the experiment for testing the system resistance of the human body and the walk charge voltage. Based on the shortterm experimental data, the Chebyshev inequality is used to extrapolate the possible maximum voltage in a certain probability level which approves practical significance. The performed empirical research highlights innovatively that although the HB walk voltage is positively correlated with its system resistance, the discreteness is relatively large. If the system resistance is the only parameter used to control the HB charge voltage, we can not achieve good enough results. A risk assessment related to EPA protection reliability is determined based on the extrapolated voltage with suggestions to reduce EPA failures.