The Effect of Electrolytic Capacitors on SMPS’s Failure Rate

Abstract

Abstract-Recently, reliability is one of the serious requirements of electronic systems. The numbers of system failures, repair cost, guarantee and etc are estimated by reliability prediction. In this paper, the reliability of a switching power supply, which is used for personal computers, evaluates. It will show that electrolytic capacitors, used in input and output filters, play a significant role on the computer's power supply's life time. Ambient temperature, derating, and capacitance effect on the failure rate will discuss. The remedies are recommended for more life time.Index Terms-Electrolytic capacitor, reliability, SMPS, PC. I. INTRODUCTIONSwitch Mode Power Supplies (SMPSs) are used in Personal Computers (PCs), because of their high efficiency and low volume and weight. SMPSs are used in all PCs for convert the voltage to different levels and establish it against input voltage and load variations [1].The efficiency of joinery SMPSs, are used in PCs, is about 70% and all the power consumption of PC produced by subsystem. So they are the most critical point of PCs from reliability lookout and almost 90% of PC failures belong to their SMPSs.Lifetime and failure rate of a system can be predicted by reliability calculations. Recently, reliability became to a prevalent issue in power electronic systems. The effect of transformer leakage inductance on SMPSs reliability is discussed in [2]. The effect of equivalent series resistance of capacitors on the reliability of SMPSs is presented in [3]. Reliability modification of power electronic converter for full cell and photovoltaic application are discussed [4]- [6]. Dissertation of operating mode (continuous and discontinuous modes) with aim of reliability, for SMPSs, presented in [7] and using a single integrated power module (IPM) instead of paralleling power electronic devices are given in [8].The method of reliability calculation, for a PC's SMPS, is presented, and the most critical points are introduced in previous work [9]. It is shown that electrolytic capacitors have a major role in the SMPS's reliability.AC voltage is converted to DC via a rectifier and a bulk capacitor in the input stage of a SMPS. At the output stage of SMPSs, usually, an LC filter, which is composed of an inductor and a capacitor, is placed to filter out the ripple voltage and noises caused by the switching devices. So, it has Manuscript received January 5, 2013; revised May 18, 2013. This work was supported in part by Damavand Branch, Islamic Azad University.The Authors are with Damavand Branch, Islamic Azad University, Damavand, Tehran, Iran (e-mail: babakabdi@ieee.org).to be used some high capacitive capacitors in the input and output stages of SMPSs. Due to its large capacity and low cost, electrolytic capacitors with the abilities of energy storage and voltage regulation are used for filters of SMPSs. In order to reduce the size and cost, as well as to improve the performance of the SMPSs, different ratings of electrolytic capacitors are used in the design and construction proces...

Summary of the economic impacts of power quality on consumers

“…These power supplies are directly exposed to the incoming supply voltage. The electrolytic DC filter capacitor in the SMPS is often cited as the weakest link and the one of the most likely component to fail in electronic equipment [12]. These capacitors are generally very sensitive to the input voltage level.…”