US 11,714,063 B2
Systems and methods for determining the condition of a gas sensor
Michael Looney, Croagh (IE); and GuangYang Qu, Beijing (CN)
Assigned to Analog Devices International Unlimited Company, Limerick (IE)
Filed by Analog Devices International Unlimited Company, Limerick (IE)
Filed on Sep. 9, 2020, as Appl. No. 17/16,085.
Application 17/016,085 is a division of application No. 15/586,849, filed on May 4, 2017, granted, now 10,782,263.
Prior Publication US 2020/0408714 A1, Dec. 31, 2020
Int. Cl. G01N 27/416 (2006.01); G01N 27/404 (2006.01); G01N 27/12 (2006.01)
CPC G01N 27/4163 (2013.01) [G01N 27/122 (2013.01); G01N 27/404 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A sensor interface circuit for measuring a gas concentration and an impedance of an electrochemical gas sensor, the sensor interface circuit comprising:
an integrated circuit comprising a first node configured to be connected to a first electrode in the electrochemical gas sensor;
a first switch located within the integrated circuit, the first switch being configured to connect a first noise-suppression circuit from the first electrode to an electrical reference node in a gas sensing mode and disconnect the first noise-suppression circuit in an impedance testing mode; and
bias circuitry configured to provide a bias signal to an electrode in the electrochemical gas sensor, the bias circuitry configured to perform operations comprising:
applying a constant bias signal to the first node; and
in the impedance testing mode with the constant bias signal being applied, applying a time-varying excitation signal to the first node.