Relaxation Oscillator Based Digital Interface Circuit for Resistive Sensors

A simple, relaxation oscillator based digital interface circuit for resistance measurement is reported in this paper. The proposed circuit uses a single reference voltage and it does not require any additional logic unit for its operation. The requirement of Op-amp is also reduced to two which reduces the power consumption of the circuit. The detailed analysis of the circuit and the effect of the error sources are also reported in this paper. Later, the performance of the proposed circuit is verified using simulation studies and 0.01 % is observed as a maximum nonlinearity error. Finally, the effect of the error sources is also verified using simulation studies. The details of these simulations are also present in this paper.