A 109.2dB-Dynamic-Range Fully Dynamic Dual-Mode Adjustable Gain Resistive Sensor Interface Circuit

In this work, we proposed a fully dynamic dual-mode adjustable-gain interface circuit for resistive sensors. This interface circuits are designed with a high input dynamic range (DR) to process general resistive sensors. By adjusting the modulation period of the excitation signal and feedback capacitance of the switched-capacitor circuit, its gain can be tuned accordingly, which thereby enhances the overall DR. By employing different sampling schemes, both bridge resistance and bridge voltage can be measured. A dynamic amplifier is implemented to efficiently enable the proposed dual-mode operations. The proposed circuit was designed, and simulated using 180 nm CMOS technology. The DR enhancement technique provides an additional input range of approximately 50 dB with high SNDR, and an expanded range of 60 to 80 dB with a measurement accuracy of 1%.