Devices and methods for smart sensor application

1. A test circuit for an electronic sensor, the test circuit comprising:

a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and an internal impedance of the electronic sensor;

an excitation circuit configured to apply a predetermined voltage to a circuit element; and

a measurement circuit configured to:

initiate applying the predetermined voltage to the series resistance and determining the series resistance;

initiate applying the predetermined voltage to the load resistance and determining the load resistance; and

calculate the internal impedance of the electronic sensor using a difference of the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

2. The test circuit of claim 1 , wherein the excitation circuit is configured to apply a specified electrical signal having a signal amplitude less than twenty millivolts (20 m V) to the series resistance, and the internal impedance of the electronic sensor is less than ten ohms (10Ω).

3. The test circuit of claim 1 , wherein the electronic sensor is an electro-chemical sensor.

4. The test circuit of claim 1 , wherein the measurement circuit is configured to calibrate the predetermined voltage applied using the excitation circuit.

5. The test circuit of claim 1 , wherein the test circuit is configured to:

connect a calibration resistor of a predetermined resistance to an output of the test circuit;

adjust an excitation signal applied by the excitation circuit until the test circuit measures a specified current corresponding to the predetermined voltage; and

apply the predetermined voltage to the series resistance and the load resistance.

6. A method of monitoring an electronic sensor using a test circuit, the method comprising:

connecting a load resistance in series with the electronic sensor to form a series resistance of the load resistance and an internal impedance of the electronic sensor;

applying, using a measurement circuit, a predetermined voltage to the series resistance and determining the series resistance;

applying the predetermined voltage to the load resistance and determining the load resistance;

calculating the internal impedance of the electronic sensor using a difference of the determined series resistance and the load resistance; and

providing the calculated internal impedance to a user or process.

7. The method of claim 6 ,

wherein the applying the predetermined voltage includes applying a specified electrical signal having a signal amplitude less than twenty millivolts (20 m V) to the series resistance; and

wherein calculating the internal impedance of the electronic sensor includes calculating an internal impedance less than ten ohms (10Ω).

8. The method of claim 6 , wherein calculating the internal impedance of the electronic sensor includes calculating the internal impedance of an electro-chemical sensor.

9. The method of claim 6 , including calibrating the predetermined voltage.

10. The method of claim 9 , wherein calibrating the predetermined voltage includes:

electrically connecting, by the test circuit, a calibration resistor of a predetermined resistance to outputs of the test circuit;

adjusting, by the test circuit, an excitation signal until a specified current is measured corresponding to the predetermined voltage of the excitation signal; and

applying the predetermined voltage to the series resistance and the load resistance.

11. An integrated circuit comprising:

a sensor circuit having an impedance;

a load resistor connectable in series with the sensor circuit to form a series resistance of the load resistor and the internal impedance of the sensor circuit;

an excitation circuit configured to apply a predetermined voltage to a circuit element; and

a measurement circuit configured to:

initiate applying the predetermined voltage to the series resistance and determining the series resistance;

initiate applying the predetermined voltage to the load resistor and determining load resistance of the load resistor; and

calculate the impedance of the sensor circuit using a difference of the determined series resistance and the load resistance.

12. The integrated circuit of claim 11 , wherein the excitation circuit is configured to apply a specified electrical signal having a signal amplitude less than twenty millivolts (20 m V) to the series resistance, and the impedance of the sensor circuit is less than ten ohms (10Ω).

13. The integrated circuit of claim 11 , wherein the sensor circuit includes an electro-chemical sensor.

14. The integrated circuit of claim 11 , wherein the measurement circuit is configured to calibrate the predetermined voltage applied using the excitation circuit.

15. The integrated circuit of claim 11 , including:

a calibration resistor;

wherein the excitation circuit is configured to apply an excitation signal to the calibration resistor;

wherein the measurement circuit is configured to:

adjust the excitation signal applied to the calibration resistor until a specified current corresponding to the predetermined voltage is measured; and

initiate applying the predetermined voltage to the series resistance and the load resistance.