| 摘要 |
PURPOSE:To extend the operation area of the voltage control circuit, by increasing the threshold voltage of the ring oscillator used for the temperatue sensing to control the power supply voltage of the circuit in matching with the temperature change, in circuitwise. CONSTITUTION:In the measuring means 15 included in the circuit block 5 operated at a low voltage, the ring oscillator 20 in ring connection of the inverter circuit 62 consisting of CMOS-FET is provided, and the resistor 61 is connected between the source electrode and the power supply line, and the voltage in reverse bias is fed to the source and the bulk. With the connection of the resistor 61 fed to the reverse bias, the voltage between the gate and the source is given with the voltage subtracting the voltage drop due to resistor 61 from the gate potential, and substantially the threshold voltage is increased. Since the power supply voltage is controlled with the control means 19 so that the oscillation period of the ring oscillator 20 and the oscillator 1 stable in the oscillator frequency can be a constant relation, the operation area of the voltage control circuit 21 is extended and the power consumption can be reduced.
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