A CMOS Soil Yeast Count to Frequency Converter for Sensing Yeast Count Applications

A CMOS soil yeast count converter with adjustment sensitivity circuits is newly used for applications of sensing yeast count in the soil. The proposed converter can linearly transform soil yeast count into frequency. Furthermore, the adjustment sensitivity circuits could regulate the sensitivities for different kinds of soil. Performing this functionality of adjustment sensitivity circuits, the sensitivity can be adjusted more sensitive under poor soil which is lack of nutrition is used. Without any sensitivity adjustments, the input voltage range of the proposed converter was from 0 to 2.2 V, and the corresponding output frequency range was 0 to 8.333 MHz. The varied sensitivities of the proposed converter were 5.3499, 4.5179, 3.7879, 3.0382, and 2.2631 MHz/V, respectively. The sensitivities of the entire system were 1.5824, 1.3553, 1.1302, 0.9113, and 0.675 MHz/108 CFU, respectively. The proposed chip could be used for sensing yeast count applications.