Digital temperature sensing device using temperature depending characteristic of contact resistance

A self-refresh driving device comprising:

• first reference voltage generating means for generating a reference voltage robust to temperature, the first reference voltage generating means being formed with a plurality of MOS transistors, the number of source contacts of the MOS transistors being adjusted such that variation of saturation current through source-drain is compensated for;
• second reference voltage generating means for generating a second reference voltage sensitive to temperature;
• level comparing means for comparing the first reference voltage with the second reference voltage;
• and
• oscillating means for generating a clock signals having one of a plurality periods depending on the output signal of the level comparing means.

A self-refresh driving device comprising:

• a plurality of first reference voltage generating means for generating respective reference voltages robust to temperature, each of the first reference voltage generating means being formed with a plurality of MOS transistors, the number of source contacts of the MOS transistors being adjusted such that variation of saturation current through source-drain is compensated for;
• second reference voltage generating means for generating a second reference voltage sensitive to temperature;
• a plurality of level comparing means for comparing the first reference voltages and the second reference voltage with each other;
• decoding means for decoding the outputs of the level comparing means;
• and
• oscillating means for generating a clock signals having one of various periods depending on the output signal of the decoding means.