Measurement Methodologies for Acoustic Noise Induced by Multilayer Ceramic Capacitors of Power Distribution Network in Mobile Systems
Measurement Methodologies for Acoustic Noise Induced by Multilayer Ceramic Capacitors of Power Distribution Network in Mobile Systems
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DOI：
10.1109/temc.2020.2993850
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发表时间：
2020-08-01
影响因子：
2.1
通讯作者：
Yang, Zhiping
中科院分区：
文献类型：
--
作者：
Sun, Yin;Wu, Songping;Yang, Zhiping
本文研究了多层陶瓷电容器（mlcc）在配电网（PDN）上引入的印刷电路板（PCB）噪声。通过电学、振动和声学测量，在实际移动产品上展示了PDN电源轨噪声、mlcc和PCB动态特性以及PCB声学噪声的相关性。提出了两种测量方法来识别电源导轨上有问题的mlcc。一种方法是在产品板的电源导轨上施加外部电信号，分析电路板和mlcc的振动特性。另一种测量方法是根据产品运行过程中电源轨信号与MLCC振动特性之间的相干值来检测有问题的MLCC。通过将原有的mlcc替换为低噪声的mlcc， PCB的振动明显减少。在研究mlcc对PCB振动影响的基础上，提出了一种分析PCB固有振动特性的测量方法。应用PCB的固有模态响应预测mlcc引起的PCB振动。得到的模态响应也可以为MLCC的布置提供设计指导，以降低PCB的振动水平。
In this article, acoustic noise of printed circuit board (PCB) introduced by multilayer ceramic capacitors (MLCCs) on power distribution network (PDN) is studied. The correlation of PDN power rail noise, MLCCs and PCB dynamic characteristics, and PCB acoustic noise is demonstrated on a real mobile product through electrical, vibrational, and acoustic measurements. Two measurement methodologies are proposed to identify the problematic MLCCs on the power rail. One method analyzes the board and MLCCs vibration properties with the external electrical signal applied on the power rail on a product board. Other measurement detects the problematic MLCCs based on the coherence value between the power rail signal during product operation and MLCC vibration characteristics. By replacing the identified original MLCCs with low acoustic noise ones, the PCB vibration is clearly reduced. With the MLCCs' influence on PCB vibration studied, a measurement methodology is also proposed to analyze the PCB intrinsic vibration properties. The intrinsic modal response of PCB is applied to predict the MLCC-induced PCB vibration. The obtained modal response can also provide design guidelines for MLCC placement to reduce the level of PCB vibration.