Methods, Devices And Systems Which Determine A Parameter Value Of An Object Or An Environment From A Voltage Reading Associated With A Common Mode Signal Of A Balanced Circuit

• US 20160349291A1
• Filed: 08/10/2016
• Published: 12/01/2016
• Est. Priority Date: 07/18/2012
• Status: Abandoned Application

• Current Assignee: Millar Instruments
• Original Assignee: Millar Inc.
• Inventors: Millar, Huntly D., Thornton, Richard T., Pauly, Robert L.
• Application Number:
  US15/233,426
• Publication Number:
  US 20160349291A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 2562/029 Humidity sensors
• CPC Class Codes: A61B 5/1073 Measuring volume, e.g. of limbs
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals
• CPC Class Codes: G01K 7/20 in a specially-adapted circuit, e.g. bridge circuit
• CPC Class Codes: G01L 1/2262 involving simple electrical bridges
• CPC Class Codes: G01L 1/2281 for temperature variations
• CPC Class Codes: G01L 9/045 with electric temperature compensating means non electric temperature compensating means G01L19/04
• CPC Class Codes: G01L 9/065 with temperature compensating means non electric temperature compensating means G01L19/04
• CPC Class Codes: G01R 17/10 AC or DC measuring bridges

Abstract

A method for determining a value of a parameter of an object or an environment includes positioning a device having a balanced circuit in or on an object or within a particular environment, wherein the balanced circuit comprises elements which are operationally sensitive to changes in a parameter of the object or the environment. The method further includes measuring a common mode signal of the balanced circuit and determining, from the common mode signal, a value of the parameter. An exemplary implementation of the method includes determining temperature using a resistive sensor having a Wheatstone bridge circuit with two variable resistors and two fixed resistors. Embodiments of systems and devices configured to employ such methods are provided, particularly medical probes, electronic signal monitoring devices, and systems employing such devices.

Claims

1. A method for determining values of parameters of an object or an environment, wherein the method comprises:

positioning a device in or on an object or within a particular environment, wherein the device comprises a balanced circuit, and wherein the balanced circuit comprises elements which are operationally sensitive to changes in a first parameter of the object or the environment;

measuring a common mode voltage derived from the balanced circuit which correlates to a common mode signal of the balanced circuit;

determining, from the measured common mode voltage, a value of the first parameter;

measuring a differential voltage between signal output nodes of the balanced circuit; and

determining, from the differential voltage, a value of a second parameter of the object or environment which is different from the first parameter, wherein at least one of the steps of measuring the differential voltage and determining the value of the second parameter is performed substantially simultaneously with at least one of the step of measuring the common mode voltage and determining the value of the first parameter.

2. The method of claim 1, wherein the first and second parameters are selected from a group consisting of temperature, pressure, volume, velocity, pH, oxygen concentration and humidity.

3. The method of claim 1, wherein the balanced circuit is a half-bridge Wheatstone bridge circuit.

4. The method of claim 3, wherein half-bridge Wheatstone bridge circuit comprises two variable resistors respectively comprising opposing sides of the Wheatstone bridge circuit.

5. The method of claim 1, wherein the device is a medical probe.

6. A system, comprising:

a device having a balanced circuit;

an electronic signal monitoring unit configured for electrical communication with the device to measure electrical parameters of the balanced circuit;

circuitry for coupling to the balanced circuit, wherein the circuitry, when coupled to the balanced circuit, is configured to;

generate a common mode voltage which correlates to a common mode signal of the balanced circuit; and

generate a differential voltage of the balanced circuit, wherein the electronic signal monitoring unit comprises means for measuring the differential voltage and the common mode voltage; and

a storage medium comprising program instructions which are executable by a processor for respectively determining, from the common mode voltage and the differential voltage, different parameters of an environment in which the device is arranged.

7. The system of claim 6, wherein the different parameters are selected from a group consisting of temperature, pressure, volume, velocity, pH, oxygen concentration and humidity.

8. The system of claim 6, wherein one of the different parameters is temperature, and wherein the device is absent a temperature sensor distinct from the balanced circuit.

9. The system of claim 6, wherein the circuitry is disposed between the device and the electronic signal monitoring unit.

10. The system of claim 6, wherein the circuitry is disposed within the device.

11. The system of claim 6, wherein the circuitry is disposed within the electronic signal monitoring unit.

12. The system of claim 6, wherein the device is a medical probe.

13. The system of claim 6, wherein the balanced circuit is a half-bridge Wheatstone bridge circuit.

14. A device, comprising:

a Wheatstone bridge circuit having two fixed resistors and two variable resistors;

compensation circuitry coupled to the Wheatstone bridge circuit which is configured to compensate for variations of a resistive coefficient of a conductive material comprising the Wheatstone bridge circuit due to ambient temperature changes of the conductive material; and

common mode signal circuitry coupled to the Wheatstone bridge circuit which generates a voltage correlating to a common mode signal of the Wheatstone bridge circuit.

15. The device of claim 14, wherein the compensation circuitry comprises one or more fixed resistors in parallel with at least one of the two variable resistors of the Wheatstone bridge circuit.

16. The device of claim 14, wherein the device is a medical probe.

17. The device of claim 16, wherein the common mode signal circuitry is disposed within an electrical connector of the medical probe.

18. The device of claim 16, wherein the common mode signal circuitry is disposed within a tip of the medical probe.

19. The device of claim 16, wherein the medical probe is a catheter.

20. The device of claim 14, further comprising reference voltage circuitry for generating a biased reference voltage relative to an excitation voltage applied to the Wheatstone bridge circuit.