Temperature sensing device semiconductor device having temperature sensing device installed therein and auto-focusing system using this semiconductor device

摘要

In view of the fact that in the prior art temperature variations in a monitored device installed on a chip could not be detected accurately, the present invention presents a system in which a MOS transistor (M0) is provided, there is also provided a potential control circuit (10) for sensing the potential in the case of depletion under the gate of a certain specified MOS transistor (M1) and for controlling the gate voltage of this specified MOS transistor while comparing the detected output with a reference voltage Vref, and a temperature is detected with reference to a variation in current of the MOS transistor (M0) while controlling the gate voltage of the MOS transistor by this potential control circuit (10).