Research On The Performance Of SCB Pyrotechnics With Combined Electromagnetic Protection Devices

The Semiconductor Bridge(SCB)is a new type of electrical explosive devices(EEDs).It has a certain ability to not fire in the electromagnetic environment,but due to the increasingly stringent electromagnetic environment and safety standards,the safety of SCB pyrotechnics to the electromagnetic environment still needs to be further improved.Therefore,in this dissertation,based on the analysis of the advantages and disadvantages of different electrostatic/RF protection devices,the combination of TVS diode and NTC thermistor is used to comprehensively protect the SCB pyrotechnics from static electricity and radio frequency.The original pyrotechnic structure was redesigned to integrate TVS diodes and NTC thermistors while maintaining the same volume.Finally,through experiments,the fire performance and electromagnetic compatibility of the pyrotechnics were studied and the following conclusions were obtained:(1)When the breakdown voltage is less than 12 V,the influence of the TVS diode on the ignition performance of the SCB pyrotechnic capacitor is gradually reduced with the gradual increase of the breakdown voltage;when the breakdown voltage of the TVS diode is 12 V,the ignition time is 6.5 μs and the ignition energy is 0.54 mJ.The NTC thermistors selected in this paper have no effect on the capacitor discharge and ignition performance of SCB pyrotechnics.The integration of the protective device causes the constant current ignition performance of the SCB pyrotechnics to change mainly due to the shunt of the NTC thermistor.(2)Integrated combination protection device allows SCB to no-ignite under 25 kV,500Ω,500 pF electrostatic test conditions.The lower the breakdown voltage of TVS diodes,the smaller the performance change of SCB pyrotechnics after electrostatic action.(3)The no-fire constant current of SCB pyrotechnics with integrated combination protection device can be increased to 1.5A.The high temperature generated by the SCB pyrotechnics during constant current does not change the performance of the integrated TVS diode,and the SCB pyrotechnics can still maintain the original antistatic performance.(4)In the structural design of the SCB pyrotechnics,in order to improve the reliability and safety margin against the constant current capability,measures such as limiting the resistance value of the SCB chip to a narrow range and using a blunt ignition powder can be employed.