FAULT TOLERANT FAIL-SAFE LINK COMPRISING PARALLEL BRANCHES

The present disclosure is directed to a fail-safe link with a branch comprising a plurality of solid state switches of varying periphery sizes connected in series between a power source and a load. A built-in test circuit senses an overvoltage condition across one or more of the switches of varying periphery sizes and opens or closes the one or more of the switches of varying periphery sizes in accordance with a measured voltage across at least one solid state switch of the plurality of solid state switches. In an arrangement comprising a plurality of branches, the test circuit is connected with the supply side switches and the load switches of the plurality of branches and provides an indication whether a failure has occurred in the supply side switches or the load side switches.