Approximate third-order function generator temperature compensation quartz oscillation circuit made by using the same, and temperature compensation method

摘要

An approximate third-order function generator that controls variables of different orders independently to generate only the third-order component, and a temperature compensation quartz oscillation circuit made by using the generator, wherein a temperature detection circuit (1) and an approximate third-order function generator (2) form a temperature compensation circuit, and the output of the temperature compensation circuit is supplied to the voltage-controlled quartz oscillation circuit (100) to perform temperature compensation of a quartz oscillator. The generator (2) has four differential amplifiers (15A-15D) each having an input signal (VSBIN/SB) supplied at one input and a fixed level signal at the other input, the three fixed level signals of the three differential amplifiers being different in level from each other. The differential amplifiers (15A-15C) are supplied with fixed level signals whose levels increase in this order, and the differential amplifier (15D) is supplied with a fixed level signal of the same level as the one for the differential amplifier (15B). The inverted output characteristic of the differential amplifier (15B) is made reverse to those of other differential amplifiers to generate the third-order component by the differential amplifiers (15A-15C). The first-order component contained in the third-order component is offset by the approximate first-order output generated by the differential amplifier (15D) to generate only the third-order component free from the first-order component. The third-order component, the first-order component generated separately from the third-order component, and a constant component are summed up to enable variables of different orders to be controlled independently.