Research On On-line Measurement Method Of Bipolar Transistor Junction Temperature And Its Application

Bipolar Transistors(BJTs)are widely used in amplifying circuits and switch control modules for aerospace engineering and medical devices because of their good gain amplification,power control,and high-speed switching characteristics.Generally speaking,for every 10? increase in temperature,the life of the bipolar transistor is reduced by half.The junction temperature is a key factor that restricts the reliability of the device.Therefore,junction temperature measurement is an important issue in engineering applications.Since the on-line test junction temperature can better reflect the state of the bipolar transistor during normal operation and monitor its characteristic data during normal operation,it is helpful to analyze whether the device is faulty and analyze the lifetime of the device.Therefore,on-line measurement of junction temperature has become a research hotspot.In order to realize the measurement and monitoring of the transistor junction temperature,the electrical temperature measurement method is used as the basis,and the electrical parameters in the actual work of the device are selected as the temperature sensitive parameters.The correlation software is used to fit the optimization algorithm to build the temperature curve library,and the relevant temperature is collected.The sensitivity parameter gives the device junction temperature online.Because the working current and voltage of the transistor are relatively large,the pulse test must be used to avoid self-heating when measuring the temperature curve.Different types of devices have different requirements for the pulse test conditions.There is no automatic pulse test and construction that can be engineered in the current market.Temperature measuring equipment.In order to solve this problem,this article studies the implementation and application of online temperature measurement equipment.Based on this,it proposes an efficient and rapid method for measuring junction temperature.The specific content is as follows:1.Pulse device design and construction.Pulsed hardware circuit is designed to generate pulsed analog signal;FPGA-based pulsed duty cycle and pulsed period variable pulsed digital signals;FPGA-based chip driver converts the collected analog signals into digital signals.2.Control interface design.Based on the MFC design software user interface,the pulse measurement settings can be controlled and the temperature profile library can be established.According to the online measurement time-emission junction voltagecollector current,the corresponding junction temperature at each time can be calculated in the calibration temperature curve library.Also shows the trend of measuring junction temperature online.3.Temperature measurement equipment implementation and application.It can be used independently to realize the automatic real-time on-line monitoring of transistor junction temperature;it can be integrated in various types of equipment to realize the integrated flow of program-controlled temperature curve acquisition and automatic temperature measurement.4.An efficient junction temperature measurement method based on transistor temperature-electrical model is proposed.Based on the mathematical function relationship between the emission junction voltage Vbe and the temperature T,combined with the theoretical model operation,the purpose of efficiently monitoring the junction temperature of the transistor is achieved.