Patent attributes
The invention provides a logic circuit to identify time difference between signals having a variation in delay, and an integrated circuit which can evaluate variations in delay among internal signals. By using a logic circuit which outputs different number of pulse depending on a relationship of delay when a first signal and a second signal which are a pair of digital signals having a time difference are inputted, variations in delay of internal signals of an integrated circuit can be evaluated. Specifically, an output signal is generated by a logical operation of values of the first signal and second signal in a period in which the first signal is High and the second signal is Low, and values of a first signal and a second signal immediately before them by using a latch circuit. Further, by using a delay circuit which can set a delay time of an input signal, time difference between signals can be evaluated quantitatively.
