High-Accuracy, Compact Scanning Method and Circuit for Resistive Sensor Arrays.

Jong-Seok Kim,Byong-Deok Choi,Dae-Yong Kwon

doi:10.3390/s16020155

Jong-Seok Kim, Byong-Deok Choi + Show 1 more

Open Access

https://doi.org/10.3390/s16020155

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Abstract

The zero-potential scanning circuit is widely used as read-out circuit for resistive sensor arrays because it removes a well known problem: crosstalk current. The zero-potential scanning circuit can be divided into two groups based on type of row drivers. One type is a row driver using digital buffers. It can be easily implemented because of its simple structure, but we found that it can cause a large read-out error which originates from on-resistance of the digital buffers used in the row driver. The other type is a row driver composed of operational amplifiers. It, very accurately, reads the sensor resistance, but it uses a large number of operational amplifiers to drive rows of the sensor array; therefore, it severely increases the power consumption, cost, and system complexity. To resolve the inaccuracy or high complexity problems founded in those previous circuits, we propose a new row driver which uses only one operational amplifier to drive all rows of a sensor array with high accuracy. The measurement results with the proposed circuit to drive a 4 × 4 resistor array show that the maximum error is only 0.1% which is remarkably reduced from 30.7% of the previous counterpart.

Highlights

Resistive sensors, such as piezoresistive tactile sensors [1,2,3,4,5,6], infrared sensors [7,8,9,10], and light-dependent resistors [11,12], have been widely used for measurement or instrumentation in a variety of fields
When we use resistive sensor arrays, we should consider the crosstalk current between each sensor element in the array [13,14,15,16]
In order to resolve the inaccuracy and high complexity problems found in the previous row drivers, we propose a new row driver circuit which uses only one operational amplifier to drive all

Summary

Introduction

Resistive sensors, such as piezoresistive tactile sensors [1,2,3,4,5,6], infrared sensors [7,8,9,10], and light-dependent resistors [11,12], have been widely used for measurement or instrumentation in a variety of fields. The crosstalk currents can flow through the unintended current paths when we read the voltage of the resistive sensor element of interest in a selected row of the array. Flow through the resistive sensor elements in the selected row without crosstalk currents. The zero-potential scanning method can be classified into two groups based on type of a row driver:. Itoin paper) and a rowAlthough driver composed operational amplifiers (which is referred asthis both of theof types were proposed to remove the crosstalk current, we found that Type I row driver still suffers from the inaccuracy problem and Type II row referred to we as Type in this paper). 2, we a new zero-potential scanning compact row thatand alleviates theprinciple drawbacks of the analyze the previous circuits method to revealwith theiralimitations.

Analysis of Previous Row Drivers for Resistive Sensor Arrays

Row Driver

The on-resistance of the selection switch in Figure

Results and Discussion

The proposed

Conclusions