SYSTEM AND METHOD FOR IDENTIFYING ISSUES IN CURRENT AND VOLTAGE MEASUREMENTS

• US 20100100345A1
• Filed: 10/20/2008
• Published: 04/22/2010
• Est. Priority Date: 10/20/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: LEUTHEUSER, ANDREW H., KATRAK, KERFEGAR K.
• Granted Patent: US 8,396,680 B2
• Time in Patent Office: Days
• US Class Current: 702/65
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

First and second reference voltages are applied to first and second terminals of a processor via voltage divider circuits. First and second signal conditioning circuits are coupled to third and fourth terminals of the processor, respectively, and voltage or current sensors are coupled to the first and second signal conditioning circuits. The processor measures the electrical characteristics at the third and fourth terminals and computes first and second ratiometric values of the electrical characteristics, wherein the first ratiometric value is based upon a measurement obtained from the third terminal and the first reference voltage and the second ratiometric value is based upon a measurement of obtained from the fourth terminal and the second reference voltage. The processor further identifies an issue if a ratio of the first ratiometric value to the second ratiometric value exceeds a ratio of the first reference value to the second reference value.

Claims

1. A method of identifying issues associated with sensing of electrical characteristics in a processor having first, second, third and fourth terminals, the method comprising:

receiving a first reference voltage at the first terminal and a second reference voltage at the second terminal;

obtaining first data about the electrical characteristics from the third terminal and second data about the electrical characteristics from the fourth terminal;

computing a first value of the electrical characteristics based upon the first data and the first reference voltage and a second value of the electrical characteristics based upon the second data and the second reference voltage;

determining a reference ratio of the first reference voltage to the second reference voltage and a value ratio of the first value to the second value; and

identifying an issue if the value ratio exceeds the reference ratio.

2. The method of claim 1 further comprising comparing the first and second values to each other, and identifying the issue if the first and second values differ.

3. The method of claim 2 further comprising comparing the first and second reference voltages to each other, and identifying the issue if the first and second values differ.

4. The method of claim 1 further comprising comparing the first and second reference voltages to each other, and identifying the issue if the first and second values differ.

5. The method of claim 1 wherein the identifying step comprises outputting a signal when the issue is identified.

6. The method of claim 1 wherein the first and second values of the electrical characteristics are computed ratiometrically.

7. The method of claim 1 wherein the electrical characteristics comprise a voltage measurement.

8. The method of claim 1 wherein the electrical characteristics comprise a current measurement.

9. The method of claim 8 wherein the first value of the current measurement and the second value of the current measurement are obtained from a common current sensor.

10. The method of claim 8 wherein the first value of the current measurement is obtained from a first current sensor and the second value of the current measurement is obtained from a second current sensor different from the first current sensor, wherein the first and second current sensors have different ranges of sensitivity.

11. The method of claim 10 wherein the determining of the value ratio comprises determining the ratio over the range of sensitivity associated with one of the first and second current sensors.

12. A method of diagnosing issues in electrical characteristics comprising a current and a voltage measured by a processor having a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal and a sixth terminal, the method comprising:

obtaining a first reference value on the first terminal, a second reference value on the second terminal, a first voltage measurement on the third terminal, a second voltage measurement on the fourth terminal, a first current measurement on the fifth terminal, and a second current measurement on the sixth terminal;

computing a first value of the voltage based upon the first voltage measurement and the first reference voltage, a second value of the voltage based upon the second voltage measurement and the second reference voltage, a first value of the current based upon the first current measurement and the first reference voltage, and a second value of the current based upon the second current measurement and the second reference voltage;

comparing the first reference value to the second reference value, and identifying an issue if the first and second reference values differ;

comparing the first and second values of the voltage, and identifying the issue if the first and second values of the voltage differ;

comparing the first and second values of the current, and identifying the issue if the first and second values of the current differ; and

comparing a value ratio of the first and second voltages to a reference ratio of the first and second reference voltages, and identifying the issue if the value ratio exceeds the reference ratio.

13. The method of claim 12 wherein the first value of the voltage and the first value of the current are each ratiometric values determined with respect to the first reference voltage, and wherein the second value of the voltage and the second value of the current are each ratiometric values determined with respect to the second reference voltage.

14. The method of claim 12 wherein the first and second values of are compared over a limited range.

15. A system for measuring an electrical characteristic, the system comprising:

a processor having a first terminal, a second terminal, a third terminal and a fourth terminal;

a first reference voltage circuit configured to apply a first reference voltage to the first terminal of the processor, wherein the first reference voltage circuit comprises a first reduction resistor and a first sensing resistor configured as a voltage divider;

a second reference voltage circuit configured to apply a second reference voltage to the second terminal of the processor, wherein the second reference voltage circuit comprises a second reduction resistor and a second sensing resistor configured as a voltage divider;

a first signal conditioning circuit coupled to the third terminal of the processor;

a second signal conditioning circuit coupled to the fourth terminal of the processor; and

a voltage sensor coupled to the first and second signal conditioning circuits;

wherein the processor is configured measure the electrical characteristics at the third and fourth terminals and to compute first and second ratiometric values of the electrical characteristics, wherein the first ratiometric value is based upon a measurement obtained from the third terminal and the first reference voltage and the second ratiometric value is based upon a measurement of obtained from the fourth terminal and the second reference voltage, and wherein the processor is further configured to identify an issue if a ratio of the first ratiometric value to the second ratiometric value exceeds a ratio of the first reference value to the second reference value.

16. The system of claim 15 wherein the resistances of the first and second reduction resistors are larger than the resistances of the first and second sensing resistors, respectively.

17. The system of claim 15 wherein the resistances of the first and second reduction resistors are at least twenty times greater than the resistances of the first and second sensing resistors, respectively.

18. The system of claim 15 further comprising a current sensor coupled to provide a current signal to the third and fourth terminals of the processor, and wherein the processor is further configured to measure the current signal at the third and fourth terminals and to compute first and second ratiometric values of the current signal, wherein the first ratiometric value of the current signal is based upon a measurement obtained from the third terminal and the first reference voltage and the second ratiometric value of the current signal is based upon a measurement of obtained from the fourth terminal and the second reference voltage, and wherein the processor is further configured to identify an issue if a ratio of the first ratiometric value of the current signal to the second ratiometric value of the current signal exceeds the ratio of the first reference value to the second reference value.

19. The system of claim 15 further comprising a first current sensor coupled to provide a first current signal to the third terminal of the processor and a second current sensor coupled to provide a second current signal to the fourth terminal of the processor, and wherein the processor is further configured to measure the first and second current signals at the third and fourth terminals, respectively, and to compute first and second ratiometric values of the current signal, wherein the first ratiometric value of the current signal is based upon a measurement obtained from the third terminal and the first reference voltage and the second ratiometric value of the current signal is based upon a measurement of obtained from the fourth terminal and the second reference voltage, and wherein the processor is further configured to identify an issue if a ratio of the first ratiometric value of the current signal to the second ratiometric value of the current signal exceeds the ratio of the first reference value to the second reference value.

20. The system of claim 19 wherein the first and second current signals are compared over a limited range.