| 摘要 |
<p>PROBLEM TO BE SOLVED: To carry out high-speed operation even at low power-supply voltage, and to reduce power consumption by a leakage current at the time of a standby mode by lowering a threshold value at the time of operation and elevating the threshold value at the time of the standby mode. SOLUTION: A principal section is composed of a microprocessor-unit(MPU) 1, substrate bias circuits 2-1, 2-2 and a clock control circuit 3. The substrate bias circuits 2-1, 2-2 are stopped, MOS transistors MP, MN for the MPU 1 are set at low threshold values, a clock CKm at a high speed is supplied, and high-speed operation at low power-supply voltage is carried out at the time of operation. The clock CKm fed to the clock control circuit is stopped, while the substrate bias circuits 2-1, 2-2 are operated, and the threshold values of the MOS transistors MP, MN are elevated at the time of a standby mode. Sub-threshold characteristic is improved by increasing the threshold values, thereby reducing a leakage current and power consumption.</p> |
