Analysis of the causes of high temperature failure of DCDC power modules

fish001

Analysis of the causes of high temperature failure of DCDC power modules [Copy link]

1. The dcdc power module is a switching power supply that uses power semiconductor switching devices to achieve dcdc power conversion. It is widely used in remote and data communications, computers, office automation equipment, industrial instruments, military, aerospace and other fields, involving all walks of life in the national economy, and has broad application prospects in the field of remote and digital communications. With the rapid development of electronic technology and the increasing application of switching power supplies, the working environment is becoming more and more severe. Statistics show that for every 2°C increase in temperature of electronic components, the reliability decreases by 10%, and the lifespan when the temperature rises to 50°C is only 1/6 of that when the temperature rises to 25°C.

　　2. The dcdc power module studied in this paper is a high-performance dcdc power module. It has the advantages of high output efficiency, low heat generation, and high surge resistance. The main components in the power structure of the dcdc power module are: pulse width modulator (control conversion efficiency), optocoupler (input and output isolation to avoid interference between the front and rear stages, and transmit sampling information to PWM to maintain the stability of the output voltage), VDMOS (power conversion component, using its good switching characteristics to improve conversion efficiency) and Schottky diode (rectification and filtering, is the main component of power output).

　　3. Relationship between the output voltage and operating temperature of the DC power module In order to understand the change of the electrical parameters of the DC power module with temperature, the DC power module is first heated as a whole to test its input current, output current, and output voltage (Vout) electrical parameters. The test conditions are: keep the input voltage at 28V, the output load at 15Ω, and the output current at 1A; test the change of input current and output voltage with temperature. It is found that the output voltage of the horizontal block has a significant decrease, and the change trend of the input current and output current is not very obvious. The change trend is that with the increase of temperature, the voltage of the DC power module gradually decreases, and the trend is very obvious, because the efficiency of the module is an important indicator of its performance. When the efficiency drops to a certain value, the module will also fail due to excessive heat generation. In the test, it was found that when the temperature rises to 150°C, the output voltage of the module is zero.