含X電容放電控制之IC（ICX）用於交換式電源供應器之安規驗證

IC including X Capacitor Discharge Control used for Safety Certification of Switching Power Supplies

徐勝豐(Sheng-Feng Hsu)

X電容 ； 交換式電源供應器 ； ICX ； IEC 62368-1 ； 安規驗證 ； X Capacitor ； SMPS ； ICX ； IEC 62368-1 ； Safety Certification

聯大學報

21卷1期（2024 / 08 / 01）

45 - 68

繁體中文;英文

交換式電源供應器（SMPS），通常在供應器前端加入抑制電磁干擾（EMI）的跨線電容器（X CAP），以通過如美國聯邦通訊委員會（FCC）的測試和認證，如此也增加產品安全上電源斷電時電容放電觸及人體的危險性。含電容放電功能的IC稱ICX，ICX已被廣泛應用在資通訊影音科技設備（ITAV）的SMPS之中。本文以文獻回顧確定IEC62368-1為標準，透過型式試驗探討ICX用於SMPS之安規驗證。分析ICX用於SMPS樣品所做的2項檢查1項試驗顯示IEC 62368-1防止電氣導致傷害之組件安全防護為：（1）SMPS之X電容器做為電氣安全防護應先符合絕緣耐壓要求，（2）ICX及任何與X電容器對可觸及部件放電功能關鍵之相關組件應進行故障試驗，（3）SMPS電源斷開後X電容器放電可觸及電壓應進行量測。研究發現ICX用於SMPS電容放電中，安規驗證準則為:（1）X電容器用作電氣安全防護應符合IEC60384-14絕緣耐壓標準，（2）ICX型號TEA19162T已單獨試驗符合IEC 62368-1附錄G.16.2要求，並且使用於SMPS中之放電組件都在試驗範圍內，依G.16.1規定SMPS可免進行故障試驗，（3）SMPS電源斷開後X電容放電應依IEC62368-1條文5.5.2.2在斷電2秒後量測電壓，電壓應符合IEC62368-1條文5.2.2.3之ES1限制值。為防止ITAV和SMPS電擊傷害，若電氣能量源分級會因ICX失效而改變，則ICX應被視作安全防護，設計者應透過安全標準對組件安全防護進行檢查和試驗以確保產品安全和合規。

Switching power supplies (SMPS) usually add electromagnetic interference (EMI) suppression cross-line capacitors (X CAP) at the front end of the power supply to pass testing and certification by the U.S. Federal Communications Commission (FCC), which also increases the risk of product safety when capacitor discharge touches the human body upon disconnection of power. ICs with capacitor discharge functions are called ICX. ICX has been widely used in SMPS of information communication audio and video technology equipment (ITAV). This article determines IEC 62368-1 as the standard based on literature review, and discusses the safety certification of ICX for SMPS through type testing. Analysis of 2 inspections and 1 test conducted by ICX on SMPS samples shows that IEC 62368-1 component as safeguard to prevent electrical injury is: (1) SMPS X capacitors as electrical safeguard should first meet the insulation withstand voltage requirements, (2) ICX and any related components that are critical to the discharge function of the X capacitor on accessible parts should be subjected to fault tests. (3) The accessible voltage of X capacitor discharge should be measured after the SMPS power disconnected. Research has found that ICX used in SMPS capacitor discharge, and the safety certification criteria are: (1) X capacitors used for electrical safeguard should comply with IEC 60384-14 insulation withstand voltage standards, (2) ICX model TEA19162T has been tested separately complies with IEC 62368- 1Appendix G.16.2 requirements, and the discharge components used in SMPS within the range tested, so the fault testing can be exempted per G.16.1. (3) After SMPS power disconnected, the X capacitor discharge should be measured according to IEC 62368-1 clause 5.5.2.2 and the voltage should be measured 2 seconds after power disconnected, the accessible voltage should comply with the ES1 limit value of IEC 62368-1 clause 5.2.2.3. To prevent ITAV and SMPS electric shock injuries, if the electrical energy source classification will change due to ICX failure, the ICX should be regarded as a safeguard. The designer should inspect and test the component as safeguard through safety standards to ensure product safety and compliance.