Semiconductor integrated circuit device and microcomputer

摘要

A semiconductor integrated circuit comprises a logic circuit which is formed of p-channel MIS transistors and n-channel MIS transistors, a first oscillation circuit of variable oscillation frequency which is formed of p-channel MIS transistors and n-channel MIS transistors, a control circuit which produces a control signal for controlling the threshold voltage of the p-channel and n-channel MIS transistors, and a second oscillation circuit which produces multiple reference clock signals of different frequencies depending on the operation mode. The control circuit receives a reference clock signal and controls the first oscillation circuit with the control signal so that the oscillation frequency of the first oscillation circuit is correspondent to the frequency of the reference clock signal.