Design A High Reliable Medical Switching Power Supply Based On NCP1203

Medical switching power supply is the important component of medical equipment,it is different from general power supply,and its reliability and safety ensure the medical system work stably and reliably.Because medical switching power supply must comply with specific safety regulations,this results in smaller market proportion and production scale small.And since it needs lots of time and capital to meet the strict safety standard certification,it caused the development of medical switching power supply is behind the fast boom of whole medical industrial.In view of current medical switching power supply status,and according to development requirements,this paper is to design a high reliable medical switching power supply based on NCP1203.The content of the paper is following:Firstly the paper gives out the switching power supply design framework according with the parameters of required medical switching power supply,the designed input/out adopts the isolated anti-excitation transformer structure,calculates transformer working parameters;based on NCP1203 topological structure to design switching power supply circuit,analyzes circuits of input port,output port and PWM control etc.and designs protection circuit for turning off switching power supply while over-voltage,over-loading and shorting and so on.Meanwhile to conduct EMC and PCBA reliability design of switching power supply.Secondly performs the reliability test for designed medical switching power supply through analyzing the failure mode of electronic component.Under the condition of meeting switching power supply technical parameters,given the corresponding testing conditions,respectively tests thermal stress of components,verifies the working parameters of main components and tests switching power supply technical parameters.The test result shows that switching power supply meets the thermal stress requirements when heating the components of switching power supply and theirs surface temperature is less than 120? and the working parameters of switching power supply's MOS circuit,absorption circuit and output rectifier tube are all less than nominal specifications with margin and all electronic components work stably,this means the technical specifications of switching power supply meets the design requirements.Lastly verifies the safety regulations for the designed medical switching power supply according to IEC60950(Rev 3),the verified items are dielectric and leakage current test.And the testing result shows there is no breakdown,arcing and damage and switching power supply works normally.The testing result is passed,and the leakage current lowers than the limitations and meets the requirements of medical equipment safety regulations.The medical switching power supply basing on NCP1203 chipset designed in this paper has high reliability,works stably and safely,and uses less peripheral components,highly cost effective,and is capable for using on related medical equipment.