| Title |
A Smart Interface Circuit for Detecting Capacitance Difference |
| Authors |
박준민(Jun-Min Park) ; 박춘상(Chun-Sang Park) ; 정원섭(Won-Sup Chung) ; 양오(Oh Yang) |
| DOI |
https://doi.org/10.5573/ieie.2021.58.2.82 |
| Keywords |
interface circuit; detecting capacitance difference; switched-capacitor; relaxation oscillator |
| Abstract |
In this paper we proposes a high-speed capacitance difference-to-period converter for interfacing capacitance transducers with digital systems. It consist of a switched-capacitor input stage, a sample-and-hold circuit followed by a voltage-to-current converter, and a current-controlled relaxation oscillator. A prototype circuit built using discrete components exhibits conversion sensitivity amounting to 4.049μs/pF and linearity error as low as ±0.03% in the range of capacitance difference 0-270pF. The maximum conversion time is about 1.8ms when capacitance difference is 270pF. |