A Low-Power Sensing System Architecture With Mott Memristor and Time-to-Digital Converter for Large-Scale Sensor-Array Application

In this brief, we present a novel low-power sensing system architecture with the Mott memristor array and time-to-digital converter (TDC). The Mott memristor array and resistive or capacitive sensors are used as sensor interface, to convert external stimuli directly into frequency signals, and then the multi-channel TDC is employed to quantize the frequency signals without conventional analog-to-digital converter (ADC) and analog front-end (AFE) modules. The sensing system can be adapted to various types of sensor, and has been demonstrated by using piezoresistive sensor array, Mott memristor array and FPGA. Measured results show that Mott memristor can sense the resistance change of the piezoresistive sensor and then convert it to the change of frequency. The proposed multi-channel TDC has been fabricated using a standard $0.18~\mu \text{m}$ CMOS process with $0.05~mm^{2}$ area cost per channel. The only analog block is comparator array with $5.61~\mu \text{W}$ per channel and the digital TDC only consumes $16.57~\mu \text{W}$ to realize 16-bit output. The resolution of 31.25 Hz and conversion time of 32 ms at 1 kHz $f_{ref}$ indicate that the proposed system is a good alternative to conventional sensing architecture and much more suitable for digital integration and large-scale sensor application.