FUNCTION GENERATING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To reduce the causes of dispersion in temperature compensation characteristic and to attain an operation at a low voltage at the same time by compositing three control currents forming a group consecutively linearly changed and applying current-voltage conversion to the composed current so as to output a control voltage for compensating an oscillated frequency temperature characteristic of a crystal oscillator. SOLUTION: The function generating circuit is provided with: a MAX circuit 3 for selecting a current with a maximum current value in received currents IT1, IT2 and providing an output of the selected current as a current IT3; a MIN circuit 4 for selecting a current with a minimum current value in a current IT4 equivalent to the received current IT3 and a current IT5 and providing an output of the selected current as a current IT6; and a current voltage conversion circuit 11 for inversely amplifying the current IT6, converting the amplified current into a voltage and providing an output of the voltage as an electric signal Vc1. COPYRIGHT: (C)2004,JPO&NCIPI