A Readout Circuit Based on Zero Potential Crosstalk Suppression for a Large Piezoresistive Sensor Array: Case Study Based on a Resistor Model

Although large piezoresistive sensor arrays are vital in obtaining 2D pressure distributions in many applications, they suffer from crosstalk forming parasitic parallel paths as a result of their generic shared row-column architecture. Existing software based algorithms and post processing is the industrially utilized crosstalk suppression mechanism which is below par in meeting the desired measurement accuracy and shape accuracy requirements. However, several hardware based implementations based on the zero potential method have been proposed in literature to mitigate crosstalk and deliver reasonable measurements with repressed crosstalk. Nevertheless, they are often confined to smaller sensor array sizes meeting the requirements of low density applications like robotics where power consumption, design complexity, magnitude of external dimensions, cost of implementation and higher scanning rates are not the governing constraints during the design process. Adopting existing mechanisms directly into scanning large sensor arrays violate the aforementioned design constraints, thus, a novel approach is required. Here, we have proposed and implemented a readout circuit based on zero potential crosstalk suppression, with an improved decoder-transistor based scanning architecture, for a large piezoresistive sensor array containing 30000 sensels meeting the design constraints. The developed circuit was validated using a miniaturized resistor model in conjunction with circuit simulations in PSPICE to determine the propensity of the readout circuit to deliver a measurement accuracy (error less than 1%) while maintaining shape accuracy at the hardware level.