Fail safe logic design

Ideally, a circuit is said to be fail safe, if for every possible failure configuration, the circuit results in a safe side output. In order to guarantee safe side failures, it is imperative that the circuit detects any faults within it. A suitable procedure for doing this can be based on an error detecting code, such as the K out of N code. A number of circuit types are considered, taking into account a fault tolerant circuit, a fault secure circuit, a self testing circuit, a self checking circuit, a self checking checker, and a fail safe circuit. Attention is given to the realization of combinational circuits, aspects of safety and reliability, sequential circuits, the realization of sequential circuits, the occurrence of clock failure, and the design procedure.