Abstract:
An amplifying circuit includes a feedback resistor (RA), and amplifies a voltage that is proportional to a current detected by a current detection resistor (R1) with a gain depending on the feedback resistor (RA). A current control circuit (IC) controls the current flowing through a Peltier element in such a manner that the amplified voltage (VA) output by the amplifying circuit is kept constant. The feedback resistor (RA) includes a thermistor and a fixed resistor (R2) connected to the thermistor in series.