Miniaturization Design And Realization Of Four Way Power Distribution Protection Switch

With the development of aerospace products,the size and amounts of each on-board unit are growing increasingly;however,its carrying capability is relatively lower for spacecraft payload platform currently,which results in a larger gap relative to the increasing payload employing needs,and this gap cannot be eliminated in a short period of time.Therefore,it is inevitable gradually that makes electronic unit integration and miniaturization for electronics system development in the future.This paper focuses on the development process of small four way power distribution protection switch for aerospace products.Firstly,it introduced domestic and foreign research current status of quad power distribution protection switch,for large volume,heavy weight,it's designed in the structure of "stacked between upper plate,conduction plate and the lower plate based on three-dimensional stack assembly methodology,which improves assembly density;adopts thick film hybrid circuit technology to realize miniaturization,which can meet the stringent requirements of the product size and weight for users.It designs parts layout and drawings for stacked structure.Completing the anti-mechanical simulation analysis and thermodynamic simulation analysis by MSC/PATRAN software,the results show that the three-dimensional stack structure design can meet the requirements of performance and reliability testing.According to three-dimensional stacked structure layout scheme,assembly process is in conformance with the principle of “high temperature,then low temperature,first lower plate,after upper",it discusses the content of each process steps and attentions.And,also introduces the process control items and main technology involved in the assembly process.For the techniques and technical difficulties during the assembly process,it carries out techniques research on special items one by one.In order to meet substrate tin-ball solder requirement,it provides special soldering ball assembly;optimizes the parameters of ball solder paste such as pressure,gap etc;realizing the required ball welding joints;makes multiple welding curve for adjustment and optimization,satisfying the requirements of mixed soldering lead and lead-free;adopts CCD image overlapping alignment,realizing the laminated substrate placement accurately.Finally,it performs electrical performance test for the assembled four distribution protection switch,the specifications can meet the requirements;in accordance with the related requirements of GJB548B”Microelectronics test methods and procedures,it performed screening and QML test,all items are passed,the specifications can meet the requirement.