AN IDDQ SENSOR FOR CONCURRENT TIMING ERROR-DETECTION

Error control is a major concern in many computer systems, particularl y those deployed in critical applications. Experience shows that most malfunctions during system operation are caused by transient faults, w hich often manifest themselves as abnormal signal delays that may resu lt in violations of circuit element timing constraints. We present a n ovel complementary metal-oxide-semiconductor-based concurrent error-de tection circuit that allows a hip-hop (or other timing-sensitive circu it element) to sense and signal when its data has been potentially cor rupted by a setup or hold timing violation. Our circuit employs on-chi p quiescent supply current evaluation to determine when the input chan ges in relation to a clock edge. Current through the detection circuit should be negligible while the input is stable. If the input changes too close to the clock time, the resulting switching transient current in the detection circuit exceeds a reference threshold at the time of the clock transition, and an error is flagged. We have designed, fabr icated, and evaluated a test chip that shows that such an approach can be used to detect setup and hold time violations effectively in clock ed circuit elements.