| 摘要 |
PURPOSE:To detect more faults even if the number of test patterns is small by setting variably the number of pieces of simultaneously active product term lines to be decided to be a fault in accordance with each product term line. CONSTITUTION:When an input 00001010b is given to inputs in 7-0 at the time of a fault, a product term line p63 is selected, therefore, 111b is about to be outputted to outputs sel2-0 of a detection use OR plane 101. In this case, 100b is about to be outputted already to the outputs sel2-0, but as for the outputs sel2-0, an output 1 is provided preferentially by input OR gates 120-122, therefore, 111b is generated. In this case, detector 302-304 output signals ERR2-ERR4, respectively. Since a fault deciding device 102 satisfies a truth table, the ERROR signal becomes '1', and a fault can be detected. On the other hand, in the case of a normal operation, the ERROR signal becomes '0'. |
