Systems and methods for determining the condition of a gas sensor

Patent metadata

Field	Value
Publication number	US-10782263-B2
Application number	US-201715586849-A
Country	US
Kind code	B2
Filing date	May 4, 2017
Priority date	May 4, 2017
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

An impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

First claim

The invention claimed is:

1. A method of measuring an impedance of an electrochemical gas sensor, the method comprising:
connecting at least one pin in an integrated circuit to at least one electrode in the electrochemical gas sensor;
using a first damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground;
applying a constant bias voltage to at least one electrode of the electrochemical gas sensor;
receiving a current from at least one electrode in the electrochemical gas sensor;
determining a measured gas amount from the received current;
activating a first switch located within the integrated circuit to isolate the first damping capacitor from the at least one pin in the integrated circuit;
while the first switch is activated and while the constant bias voltage is applied, applying a time-varying excitation signal to the at least one electrode of the electrochemical gas sensor; and
measuring an impedance of the electrochemical gas sensor based at least in part on a response of the electrochemical gas sensor to the constant bias voltage and the time-varying excitation signal.

2. The method of claim 1 further comprising connecting the first damping capacitor to the at least one electrode in the electrochemical gas sensor and further operating the electrochemical gas sensor in a gas detection mode.

3. The method of claim 1 comprising connecting a first pin of an integrated circuit to a working electrode of the electrochemical gas sensor, connecting a second pin of an integrated circuit to a reference electrode of the electrochemical gas sensor, and connecting a third pin of an integrated circuit to a counter electrode of the electrochemical gas sensor.

4. The method of claim 3 comprising using the first damping capacitor to connect the first pin in the integrated circuit to an electrical ground and using a second damping capacitor to connect the second pin in the integrated circuit to an electrical ground.

5. The method of claim 4 comprising activating the first switch located within the integrated circuit to disconnect the first damping capacitor from the first pin of the integrated circuit and activating a second switch located within the integrated circuit to disconnect the second damping capacitor from the second pin of the integrated circuit.

6. The method of claim 5 comprising activating a third switch located within the integrated circuit to deactivate filter circuitry located within the integrated circuit.

7. The method of claim 5 comprising using a third damping capacitor to connect a first biasing amplifier terminal to an electrical ground and using a fourth damping capacitor to connect a second biasing amplifier terminal to an electrical ground.

8. The method of claim 7 comprising activating a third switch located within the integrated circuit to disconnect the third damping capacitor from the first biasing amplifier terminal and activating a fourth switch located within the integrated circuit to disconnect the fourth damping capacitor from the second biasing amplifier terminal.

9. The method of claim 8 comprising measuring the impedance of the electrochemical gas sensor while the first, second, third, and fourth switches are activated.

10. A method of measuring an impedance of an electrochemical gas sensor, the method comprising:
applying a constant bias voltage to at least one electrode of the electrochemical gas sensor;
isolating at least one damping capacitor from at least one electrode in the electrochemical gas sensor;
while the constant bias voltage is applied and while the at least one damping capacitor is isolated, applying a time-varying excitation signal to the at least one electrode of the electrochemical gas sensor; and
measuring an impedance of the electrochemical gas sensor based at least in part on a response of the electrochemical gas sensor to the constant bias voltage and the time-varying excitation signal.

11. The method of claim 10 further comprising connecting the at least one damping capacitor to the at least one electrode in the electrochemical gas sensor for operating the electrochemical gas sensor in a gas detection mode.

12. The method of claim 11 comprising disconnecting the at least one damping capacitor from bias circuitry used to provide the bias voltage to the at least one electrode in the electrochemical gas sensor and then measuring the impedance of the electrochemical gas sensor while the at least one damping capacitor is disconnected from the bias circuitry.

13. The method of claim 11 further comprising measuring the impedance of the gas sensor using an excitation signal in a frequency range from 0.2 Hz to 200 kHz while the at least one damping capacitor is isolated from the at least one electrode of the electrochemical gas sensor.

14. A method of using an electrochemical gas sensor, comprising:
applying a constant bias voltage to at least one electrode of the electrochemical gas sensor;
receiving a current from the at least one electrode in the electrochemical gas sensor while the constant bias voltage is applied;
determining a measured gas amount from the received current;
isolating at least one damping capacitor from the at least one electrode of the electrochemical gas sensor;
while the constant bias voltage is applied and while the at least one damping capacitor is isolated, applying a time-varying excitation signal to the at least one electrode of the electrochemical gas sensor; and
measuring an impedance of the electrochemical gas sensor based at least in part on a response of the electrochemical gas sensor to the constant bias voltage and the time-varying excitation signal.

15. The method of claim 14 , wherein the current is received from the at least one electrode of the electrochemical gas sensor before the isolating of the at least one damping capacitor.

16. The method of claim 14 comprising connecting a first pin of an integrated circuit to a working electrode of the electrochemical gas sensor, connecting a second pin of an integrated circuit to a reference electrode of the electrochemical gas sensor, and connecting a third pin of an integrated circuit to a counter electrode of the electrochemical gas sensor.

17. The method of claim 16 comprising using a first damping capacitor to connect the first pin in the integrated circuit to an electrical ground and using a second damping capacitor to connect the second pin in the integrated circuit to an electrical ground.

18. The method of claim 17 comprising activating a first switch located within the integrated circuit to disconnect the first damping capacitor from the first pin of the integrated circuit and activating a second switch located within the integrated circuit to disconnect the second damping capacitor from the second pin of the integrated circuit.

19. The method of claim 14 comprising disconnecting the at least one damping capacitor from bias circuitry used to provide the constant bias voltage to the at least one electrode in the electrochemical gas sensor and then measuring the impedance of the electrochemical gas sensor while the at least one damping capacitor is disconnected from the bias circuitry.

20. The method of claim 14 further comprising measuring the impedance of the gas sensor using an excitation signal in a frequency range from 0.2 Hz to 200 kHz while the at least one damping capacitor is isolated from the at least one electrode of the electrochemical gas sensor.

Assignees

• Analog Devices Global

Inventors

• Looney Michael
• Qu GuangYang

Classifications

• G01N27/4163 Primary

  checking the operation of, or calibrating, the measuring apparatus (G01N27/3274, G01N27/4175 and G01N33/0006 take precedence) · CPC title

• G01N27/122

  Circuits particularly adapted therefor, e.g. linearising circuits · CPC title

• G01R27/02 Primary

  Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) · CPC title

• G01N27/404

  Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid {, e.g. Clark-type oxygen sensors} · CPC title