Littelfuse Semiconductor Fuses

Littelfuse certified high-speed fuses are optimized for performance and efficiency to better protect your critical power semiconductors against short circuits.  Backed by over 40 years of experience, Littelfuse engineered the POWR-Speed® line to help protect critical power electronics from overcurrents that may cause damage to equipment.

Semiconductor high speed fuses protect devices from overcurrents that may cause damage to equipment. High speed fuses are reliable, quick reactors that can reduce the amount of short circuit current. Littelfuse offers a variety of semiconductor fuses. Let us help you find the fuse that meets your needs now.

PSR Series High-Speed Square Body Fuse

Littelfuse PSR Series High-Speed Square Body Fuses are specially designed for protection of power semiconductor devices such as diodes, triacs, IGBTs, SCRs, MOSFETs and other solid state devices that are typically designed into power conversion and power conditioning equipment. Variable frequency drives, inverters, UPS, rectifiers and soft-starters are examples of typical equipment designed with sensitive power semiconductor devices that cannot withstand any line surge or overcurrent conditions and require high-speed protection.

Littelfuse POWR-SPEED® PSR Series products offer optimized circuit protection at the extremely fast speed required to protect modern day power conversion devices. Such products are commonly found in numerous applications including pulp and paper industries, cranes and heavy-lifting equipment, processing industries, wastewater treatment plants and various large factories and MRO facilities.


  • Best in Class DC performance

  • Extremely current limiting

  • Superior cycling capability

  • Global certification cURus, CCC, IEC

  • Direct bus-bar mount design

  • Visual and optional microswitch fuse blown indication

  • Low watt-loss design

  • Compliance with US and Canadian requirements

  • Class aR performance according to IEC60269-4


  • Power Conversion Devices (UPS, Inverter, Rectifiers, Drives)

  • DC Systems (DC Common Bus, DC Injection Braking)

  • Battery Protection Application (Energy Storage Systems)

  • Electric Vehicle Charging Stations

  • Heaters and Power Supplies


Download the POWR-Speed Product Catalog