| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid runaway of an internal circuit of a semiconductor integrated circuit device when a frequency of a clock signal supplied to the internal circuit becomes higher than that at a normal time. <P>SOLUTION: A semiconductor integrated circuit device (1) comprises : an internal circuit (17); a crystal oscillation circuit (11) creating a clock signal by an oscillation operation using a crystal oscillator; a built-in oscillator (14) creating a clock signal of a frequency by which the internal circuit can normally operate; an abnormal high-speed oscillation detection circuit (13) capable of detecting increase of the frequency of the clock signal created in the crystal oscillation circuit out of a frequency range of a normal operation of the internal circuit; and a control circuit (16) for supplying a clock signal created in the built-in oscillator, instead of the clock signal created in the crystal oscillation circuit, to the internal circuit, on the basis of the detection result in the abnormal high-speed oscillation detection circuit. By this configuration, the semiconductor integrated circuit device avoids runaway of the internal circuit. <P>COPYRIGHT: (C)2013,JPO&INPIT |
