Analysis of the Degradation of MOSFETs in Switching Mode Power Supply by Characterizing Source Oscillator Signals

Xueyan Zheng,Xiaojuan Li,Lifeng Wu,Yong Guan

doi:10.1155/2013/302563

Abstract

Switching Mode Power Supply (SMPS) has been widely applied in aeronautics, nuclear power, high-speed railways, and other areas related to national strategy and security. The degradation of MOSFET occupies a dominant position in the key factors affecting the reliability of SMPS. MOSFETs are used as low-voltage switches to regulate the DC voltage in SMPS. The studies have shown that die-attach degradation leads to an increase in on-state resistance due to its dependence on junction temperature. On-state resistance is the key indicator of the health of MOSFETs. In this paper, an online real-time method is presented for predicting the degradation of MOSFETs. First, the relationship between an oscillator signal of source and on-state resistance is introduced. Because oscillator signals change when they age, a feature is proposed to capture these changes and use them as indicators of the state of health of MOSFETs. A platform for testing characterizations is then established to monitor oscillator signals of source. Changes in oscillator signal measurement were observed with aged on-state resistance as a result of die-attach degradation. The experimental results demonstrate that the method is efficient. This study will enable a method to predict the failure of MOSFETs to be developed.

Highlights

With the rapid development of power electronic technology, Switching Mode Power Supply (SMPS) has come to play an important role in electronic equipment
According to statistics on the failure of devices relating to two topological structures of DC/DC power supply, the component most prone to failure in switch-mode drives is the controllable power semiconductor (i.e., IGBT and MOSFETs) [2]
A nonidealized model and the degradation mechanism of MOSFETs were described in this paper

Summary

Introduction

With the rapid development of power electronic technology, SMPS has come to play an important role in electronic equipment. The second is on predicting the remaining useful life of MOSFETs using off-line accelerated aging tests [4]. Degradation models are set up according to the function of the usage time based on accelerated life tests [9]. The primary goal is to realize on-line fault prediction and evaluate the remaining useful life of MOSFETs. The approach that is followed is to use the pulsewidth modulation (PWM) signals. By analyzing the source signal, the paper establishes key parameters of failure related to the natural characteristic response. Judgments and predictions can be made about the state of MOSFETs. the method is an integration of signal processing with an analytical model. As far as the degradation of MOSFETs is concerned, this is a new perspective

The Failure Mechanism and a Nonidealized Model of MOSFETs

Analysis of the Characterization of the Source Oscillator Signal

Physics Experiments and the Results of the Data Analysis

Findings

Conclusions