Circuit Design A CMOS-based I / F Conversion

Current/frequency converter can make current which is the analog signaltransforms pulse frequency which is the digital signal, and the output frequency isdirectly proportional to the input current. Because of the transmission and measure offrequency signal is more accuracy than the current, and better for transmission in longdistance line and less susceptible to interference. So I/F converter as a cell is theoptimized for the digital output, which has become widely used in electronic circuitfields.This project is intend to design an oscillation current frequency converter circuitwhich is based on0.5μm CMOS technology. The structure is mainly includes four parts,integrator, switch, comparator and trigger part. In the design processing, using theCadence spectre software draw the circuit diagram, finish the simulation and use thevertuso to draw the layout. The project proposes that under the power of3.3V thecurrent to frequency converter can resolve4-20μA to the rate2.25-6MHz with2.6mWpower.And the result gets a linear relationship between each other.