Temperature compensation circuit

TL;DR: In this paper, the authors proposed a method to obtain a compensation voltage excellent in linearity for temperature by only setting a circuit constant at a proper value, where the compensation voltage at a certain temperature at the terminal 55 and a temperature coefficient thereof are set at a desired value.

Abstract: PURPOSE:To enable the obtaining of a compensation voltage excellent in linearity for temperature, by only setting a circuit constant at a proper value. CONSTITUTION:An output voltage obtained at an output terminal 55 of an operational amplifier 30 is the sum of a first term K1V2 as forward voltage drop V2 of a diode 12 multiplied by a constant K1 and a second term K2 (V2-V1) as a difference (V2-V1) in forward voltage drop between diodes 12 and 11 multiplied by a constant K2. Here, as the voltage drop V2 decrease linearly together with temperature, the first term has a negative temperature coefficient and as the difference (V2-V1) in voltage drop is proportional to an absolute temperature, the second term has a positive temperature coefficient. Then, with the capacity of a capacitor 33 as unit capacity, K1 of the capacitors are connected in parallel to form a capacitor 31 while K2 thereof are connected in parallel to form a capacitor 32, which facilitates the selection of the constants K1 and K2 as proper values with the alteration of an integrated circuit pattern. Thus, a compensation voltage at a certain temperature at the terminal 55 and a temperature coefficient thereof are set at a desired value, thereby enabling the obtaining of a compensation voltage excellent in linearity.