Solid State Relay (SSR) and Contactor

While circuit breakers typically respond to overloads or short circuits in the load path to protect wires and keep hazards and damage away from people and equipment, relays and connectors are remotely controlled on/off switches. Infineon's solid state relay  (SSR) approaches are switches with complete galvanic isolation from input to output. Using an SSR allows for low-power control (e.g., from a microprocessor) over a high-power signal (e.g., switching of AC and DC loads) while isolating the logic part of a circuitry and high-power signals.  The combination of galvanic isolator plus power MOSFETs or IGBTs avoids damaging, e.g., microprocessor by high-voltage spikes while getting the flexibility to create SSRs for different kinds and magnitudes of load currents.

No supply power is needed at the secondary side of the galvanic isolator. Options for overcurrent, MOSFET Temperature, and Miller Clamp protection are given by the Infineon "iSSI" family of products. Along with CoolMOS™ S7 600 V MOSFETs, which have a built-in temperature sensor,  Infineon's SSR approach is superior to classic Electromagnetic Relays (EMRs) and TRIACs.