High-speed interface circuit for differential capacitance transducers

IEICE Electronics Express

Hoon Kim¹  Il-Ho Rho¹  Won-Sup Chung¹ 

[1] Dept. of Semiconductor Engineering, Cheongju University

关键词: differential capacitance transducer;    ratiometric operation;    relaxation oscillator;   

DOI  :  10.1587/elex.8.96

学科分类：电子、光学、磁材料

来源: Denshi Jouhou Tsuushin Gakkai

【 摘 要 】

References(11)A high-speed capacitance difference-to-sum ratio measurement circuit is presented for differential capacitance transducers. It consists of a switched-capacitor input stage, two sample-and-hold (S/H) circuits followed by voltage-to-current (V/I) converters, and a current-ratio-controlled relaxation oscillator. This circuit offers a square-wave output whose oscillation period is directly proportional to the capacitance difference-to-sum ratio of the transducers. A prototype circuit built using discrete components exhibits conversion sensitivity (period per unit capacitance difference-to-sum ratio) amounting to 400µs and linearity error as low as 0.037%. The maximum conversion time is about 160µs when the capacitance difference-to-sum ratio is 0.4.

【 授权许可】

Unknown