| 摘要 |
PROBLEM TO BE SOLVED: To provide a detection circuit capable of detecting a difference between minute capacity values with high accuracy. SOLUTION: The detection circuit detecting the difference between the capacity values of a first capacity and a second capacity of a sensor includes: an oscillator generating oscillation signals; a phase comparator combined with the oscillator and outputting signals according to a phase difference between oscillation signals delayed in the first capacity and oscillation signals delayed in the second capacity; an integrating circuit combined with the phase comparator and outputting signals integrated during the period of predetermined cycles of oscillation signals according to the phase difference; and a sample-hold circuit combined with the integrating circuit and outputting sample-held signals sampling the integrated signals at an end timing of the aforementioned period. COPYRIGHT: (C)2006,JPO&NCIPI
|
