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

• Main Authors: Jong-Seok Kim, Dae-Yong Kwon, Byong-Deok Choi
• Format: Article
• Language: English
• Published: MDPI AG 2016-01-01
• Series: Sensors
• Subjects: resistive sensor; sensor array; crosstalk; read-out circuit; row driver
• Online Access: http://www.mdpi.com/1424-8220/16/2/155

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.