Semiconductor device

摘要

If an exclusive OR circuit itself, a component of a signal delay detecting circuit, has failed to operate properly, a signal delay cannot be detected accurately. A malfunction pre-detecting circuit 12 includes a delay circuit DL to delay input data that is input in parallel to a data input terminal of a flip-flop FF1 provided in a subsequent stage of a flip-flop FF0, a flip-flop FFT that receives output of the delay circuit DL, and a comparator CMP that compares output of the flip-flop FF1 and output of the flip-flop FFT. Test data tv1 and test data tv2 are input to the malfunction pre-detecting circuit 12 in an operation test mode for testing operation of the malfunction pre-detecting circuit 12. The test data tv2 is input to the delay circuit DL. The comparator CMP compares the test data tv1 and output of the flip-flop FFT in the operation test mode.

主权项

1. A semiconductor device comprising:
a first central processing unit (CPU); a first circuit that includes a first logic circuit and a first malfunction pre-detecting circuit; a power supply circuit; and a first switch that is disposed between the power supply circuit and the first circuit, wherein the first malfunction pre-detecting circuit includes a first selector that selects one of an output of the first logic circuit and a first test data, a first delay circuit that receives an output of the first selector, a second selector that selects one of the output of the first logic circuit and a second test data, and a first comparator that compares an output of the first delay circuit with an output of the second selector, and wherein when the first malfunction pre-detecting circuit detects a malfunction state based on a result of the first comparator, the first CPU turns off the first switch.