PSM　(Pulse　Step　Modulation)　technology　is　a　combination　of　SM　(Step　Modulation)　technology　and　PWM　(Pulse　Width　Modulation)　technology,　and　a　wide　range　of　output　voltage　modulation　can　be　realized　by　this　modulation.　SPS　(Switching　Power　Supply)　module　is　the　basic　component　of　PSM　high　voltage　power　supply.　It　has　a　short　response　time　while　the　voltage　and　power　of　this　power　system　is　very　high.　It　is　necessary　to　ensure　that　the　power　supply　releases　less　energy　when　the　power　supply　module　is　breaking　down.　In　order　to　achieve　a　small　amount　of　energy　stored　when　the　SPS　module　fails,　the　logic　circuit　is　designed.　The　alternating　current　contactor　is　separated　in　time　to　cut　off　the　input　energy　when　the　SPS　module　fails.　In　this　paper,　the　logic　circuit　of　SPS　power　module　has　been　designed,　which　has　the　characteristics　of　simple　structure,　low　cost,　good　reliability　and　strong　protection　ability.　The　simulations　and　experiments　show　that　the　alternating　current　contactor　can　be　separated　from　the　AC　input　power　supply　by　the　logic　circuit　in　a　short　time,　and　the　stored　energy　is　very　low.　©　Beijing　Paike　Culture　Commu.　Co.,　Ltd.　2024.