Diagnostic waveform generator for a sensor
Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.
1. A method for controlling an electrochemical sensor, the method comprising:
receiving a supply voltage at power supply inputs of a control circuit;
in a diagnostic mode of operation, generating a sensor diagnostic signal at the control circuit using the supply voltage, wherein the sensor diagnostic signal is a periodic signal;
in a sensing mode, receiving a signal from a working electrode of the electrochemical sensor at the control circuit; and
providing an indication of a material concentration at an output of the control circuit using the signal;
wherein a peak-to-peak voltage of the sensor diagnostic signal is greater than the supply voltage.
2. The method of claim 1 , wherein the generating the sensor diagnostic signal includes generating a first waveform for a reference electrode of the electrochemical sensor using a first signal generator of the control circuit.
3. The method of claim 2 , wherein the generating a sensor diagnostic signal includes generating a second waveform for a diagnostic electrode of the electrochemical sensor using a second signal generator of the control circuit.
4. The method of claim 3 , wherein the generating a first waveform includes generating a first pattern of voltage ramps and voltage steps applied to one of the reference electrode or the diagnostic electrode.
5. The method of claim 4 , wherein the generating a second waveform includes generating a second pattern of voltage steps applied to the other one of the reference electrode or the diagnostic electrode.
6. The method of claim 3 , wherein generating the first waveform includes generating the first waveform at a first output of a dual output digital-to-analog converter DAC.
7. The method of claim 6 , wherein generating the second waveform includes generating the second waveform at a second output of the dual output digital-to-analog converter.
8. The method of claim 3 , wherein the supply voltage is provided by a battery.
9. A method for controlling an electrochemical sensor, the method comprising:
receiving a supply voltage;
in a diagnostic mode, generating a sensor diagnostic signal using the supply voltage, wherein the sensor diagnostic signal is a periodic signal and wherein a peak-to-peak voltage of the sensor diagnostic signal is greater than the supply voltage; and
in a sensing mode, based on a signal from a working electrode of the electrochemical sensor, generating an indication of a material concentration.
10. The method of claim 9 , wherein the generating the sensor diagnostic signal includes generating a first waveform for a reference electrode of the electrochemical sensor.
11. The method of claim 10 , wherein the generating a sensor diagnostic signal includes generating a second waveform for a diagnostic electrode of the electrochemical sensor.
12. The method of claim 11 , wherein the generating a first waveform includes generating a first pattern of voltage ramps and voltage steps applied to one of the reference electrode or the diagnostic electrode.
13. The method of claim 12 , wherein the generating a second waveform includes generating a second pattern of voltage steps applied to the other one of the reference electrode or the diagnostic electrode.
14. The method of claim 11 , wherein generating the first waveform includes generating the first waveform at a first output of a dual output digital-to-analog converter DAC.
15. The method of claim 14 , wherein generating the second waveform includes generating the second waveform at a second output of the dual output digital-to-analog converter.
16. The method of claim 11 , wherein the supply voltage is provided by a battery.
17. A method for operating an electrochemical sensor, the method comprising:
receiving a supply voltage;
receiving control information; and
during a diagnostic mode of operation:
based on the supply voltage and control information, applying a first waveform to a reference electrode of the electrochemical sensor and applying a second waveform to a diagnostic electrode of the electrochemical sensor; and
generating a diagnostic waveform at the reference electrode and the diagnostic electrode, the diagnostic waveform including a periodic signal having a peak-to-peak voltage greater than the supply voltage.
18. The method of claim 17 , further comprising:
during a sense mode of operation:
receiving sense information from the electrochemical sensor; and
providing an indication of a material concentration using the sense information.
19. The method of claim 17 , wherein the generating a first waveform includes generating a first pattern of voltage ramps and voltage steps applied to one of the reference electrode or the diagnostic electrode.
20. The method of claim 19 , wherein the generating a second waveform includes generating a second pattern of voltage steps applied to the other one of the reference electrode or the diagnostic electrode.