| 摘要 |
PROBLEM TO BE SOLVED: To correctly test a function of an irregularity detection circuit.SOLUTION: A semiconductor device is a semiconductor device that has a function detecting irregularity of a clock frequency, and comprises: a detection circuit; switching means; a frequency dividing circuit; and input means. In the detection circuit, an amount of delay of an output signal relative to an input signal is equal to an amount of delay in a critical path of the semiconductor device. The switching means is configured to input the output signal from the detection circuit to the detection circuit, thereby forming a ring oscillation circuit. The frequency dividing circuit is configured to divide a frequency of the output signal output from the detection circuit when a close circuit is formed by the switching means. The input means is configured to input the output signal having the frequency divided by the frequency dividing circuit to a PLL circuit generating a clock signal of the semiconductor device as a reference signal.SELECTED DRAWING: Figure 1 |
