SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device of which the reinforcement of a protecting feature is realized.

SOLUTION: A low frequency clock detection circuit detects whether a first clock has a frequency lower than a fixed frequency and forcibly stops or invalidates an operation of an internal circuit of the semiconductor integrated circuit device. The low frequency clock detection circuit is constituted of: a first circuit which is supplied with a first clock and forms a first signal to be regarded as different waveforms on the basis of the first clock depending on whether the first clock has a frequency lower than the fixed frequency or the first clock has a frequency higher than the fixed frequency: and a second circuit which forms a low frequency clock detection signal on the basis of the first signal and the first clock.

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