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 9,429,479 B2
• Filed: 07/18/2012
• Issued: 08/30/2016
• Est. Priority Date: 07/18/2012
• Status: Active Grant

• Current Assignee: Millar Instruments
• Original Assignee: Millar Instruments
• Inventors: Millar, Huntly D., Thornton, Richard T., Pauly, Robert L.
• Primary Examiner(s): KAPLAN VERBITSKY, GAIL
• Application Number:
  US13/551,811
• Publication Number:
  US 20140023112A1
• Time in Patent Office: 1,504 Days
• Field of Search: 374/100, 374/163, 374/185, 374/114, 374/141, 374/143, 374/183, 374/179, 374/45, 600/474, 600/549, 702/130, 702/131, 702/133
• 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 temperature using a resistive sensor having a Wheatstone bridge circuit with at least two variable resistors, wherein the method comprises:

positioning the resistive sensor such that the at least two variable resistors of the Wheatstone bridge circuit are arranged in an environment in which temperature is to be determined;

measuring, while the two variable resistors are arranged in the environment, a temperature detection voltage derived from the Wheatstone bridge circuit which correlates to a common mode signal of the Wheatstone bridge circuit;

determining, from the temperature detection voltage, a temperature of the environment;

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

determining, from the differential voltage, a pressure of the environment, wherein at least one of the steps of measuring the differential voltage and determining the pressure is performed simultaneously with at least one of the steps of measuring the temperature detection voltage and determining the temperature.

2. The method of claim 1, wherein the method of determining the temperature comprises computing the temperature from a polynomial equation having the temperature detection voltage as a variable.

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

4. The method of claim 1, wherein the at least two variable resistors respectively comprise opposing sides of the Wheatstone bridge circuit during the steps of measuring the differential voltage and measuring the temperature detection voltage.

5. The method of claim 1, wherein the resistive sensor is disposed within a medical probe.

6. An electronic signal monitoring device for monitoring and processing signals received from a balanced circuit of a medical probe, wherein the electronic signal monitoring device comprises:

a first means for receiving output signals from the balanced circuit;

a second means for determining from one or more of the received output signals a voltage which correlates to a common mode signal of the balanced circuit;

a third means for measuring a differential mode voltage of the balanced circuit, wherein the electronic signal monitoring device is configured to utilize the third means and the second means to measure the differential voltage and the voltage correlating to a common mode signal of the balanced circuit substantially simultaneously; and

program instructions which are executable by a processor for;

determining, from the voltage which correlates to a common mode signal of the balanced circuit, a temperature of an environment in which a tip of the medical probe is arranged; and

determining, from the differential voltage, a pressure of the environment.