| 摘要 |
<p>PURPOSE: To reduce the scale of a semiconductor integrated circuit by generating a clock from the clocks of the 1st and 2nd oscillation circuits by a 3rd oscillation circuit and then outputting the generated clock. CONSTITUTION: The clocks outputted from the 1st and 2nd oscillation circuits 1 and 2 are inputted to a clock generation circuit 3, i.e., a 3rd oscillation circuit to generate a clock which actuates a clock monitor circuit 4 and the clock is outputted to the circuit 4. The circuit 4 monitors whether the outputs of both circuits 1 and 2 are normal or not, and when the operation of the circuit 1 stops and the circuit 2 is normal, a clock switching circuit 5 outputs a monitor signal to select the output of the circuit 2. Otherwise, the circuit 5 outputs a monitor signal to select the output of the circuit 1. Thereby, the 3rd oscillation circuit can omit the oscillators of both circuits 1 and 2 so that the scale of a semiconductor integrated circuit can be reduced.</p> |
