| 摘要 |
PROBLEM TO BE SOLVED: To maintain linearity of output voltage, and accurately detect a temperature by connecting an electric current mirror circuit between a reference voltage generating circuit and an output circuit, preventing a change in reference voltage by increasing the input/output side electric current, and simultaneously preventing an increase in input voltage of the output circuit. SOLUTION: Voltage of a nonreversed input terminal of an operation amplifier 3 increases according to a temperature rise, so that output voltage similarly changes. However, when a temperature rises and exceeds a specific temperature in the vicinity where reference voltage starts to drop, on the input side of an electric current mirror circuit, an electric current supplied through a series circuit of resistances R1 , R4 and diodes D1 , D2 is added to an electric current supplied through a resistance R5 . Terminal voltage of a feedback resistance R1 of an operation amplifier 4 constituting a first resistance is increased to thereby prevent a drop in reference voltage. Since an electric current of diodes D3 , D4 connected to the output side also increases, a voltage drop by both diodes becomes large. Therefore, voltage of the nonreversed input terminal of the operation amplifier 3 is prevented from increasing by separating from a straight line to maintain linearity of output voltage to a temperature change so as to accurately detect a temperature. |
