An DC Overvoltage Surge Suppression Circuit for Airborne High-Current Avionics Equipment

The avionics equipment used in harsh environment needs to meet the requirements of corresponding overvoltage surge test. The traditional avionics equipment uses two kinds of overvoltage surge suppression circuit, electromagnetic compatibility suppression and linear power limiting, which can meet the requirements of the product, but cannot solve the application problem of high-current avionics equipment. In this paper, two kinds of traditional circuits are explained and compared, the limitations and shortcomings of their application are pointed out, and an improved type of overvoltage surge suppression circuit is proposed and verified by experiment. The circuit passed the 50 V/12.5 ms overvoltage surge test in accordance with the overvoltage surge requirements of GJB181A-2003 and worked normally. In addition, the experimental test results show that the maximum impedance is only 0.98 W in the input voltage range of 18 V–32 V under 400 W load condition. The hybrid improved circuit can solve various problems of traditional overvoltage surge suppression circuit in high current applications, and the performance index and reliability of avionics equipment can be significantly improved by using this circuit.