TECH NOTE: Adding Protection when Switching Inductive Loads

This technical paper will explain the importance of adding protection to the load terminals in all inductive load switching applications by reviewing important inductor behaviors.


Topics Discussed:

  • Inductor Behavior Using Simplified Low-Side Switched Inductor or Relay Coil (Sinking) Examples
    • RL Charging (Storage) Cycle
    • RL Steady State (Fully Charged)
    • Traditional RL Discharge Cycle without Protection but with a Constrained Voltage Spike
    • Common RL Discharge Cycle without Protection Where the Reverse VL Spike is not Constrained to Vs
    • Common RL Discharge Cycle with Added Protection
  • AC Inductive Load Switching