Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D21/00—Measuring or testing not otherwise provided for
  • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/16—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
  • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
  • G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
  • G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
  • G01K7/36—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using magnetic elements, e.g. magnets, coils
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R33/00—Arrangements or instruments for measuring magnetic variables
  • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
  • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
  • G01R33/09—Magnetoresistive devices
  • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R33/00—Arrangements or instruments for measuring magnetic variables
  • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
  • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
  • G01R33/09—Magnetoresistive devices
  • G01R33/096—Magnetoresistive devices anisotropic magnetoresistance sensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
  • G01R17/10—AC or DC measuring bridges
  • G01R17/105—AC or DC measuring bridges for measuring impedance or resistance

Definitions

• the present invention relates in general to magnetic field sensors. More
• the present invention relates to using magneto-resistive sensors as multi ⁇
• Magnetoresistive sensors are examples of sensing small magnetic fields and their perturbations.
• nickel-iron (permalloy) thin film deposited on a silicon wafer or other types of
• the resistance of the strip depends on the angle between the magnetization and the direction of the applied current, and is maximized when the
• the field influences the magnetization, rotating it and thereby
• the maximum change in resistance due to rotation of the magnetic field is two to three percent of the nominal resistance.
• the easy axis (a preferred direction of magnetization) is set
• magnetic field is typically applied to restore, or set, the sensor's characteristics.
• large external magnets can be placed to reset the sensor's settings.
• set-reset straps and offset straps may be used to restore the sensor's characteristics.
• set-reset straps and offset straps may be used to restore the sensor's characteristics.
• current straps in a magnetic field sensing device is discussed
• giant magnetoresistive (“GMR”) sensors are often used in many applications that require measurements of a relatively small
• GMR sensors are composed of a
• substrate or any other substrate, can be configured as resistors, resistor pairs, half
• GMR sensors often do
• LCD LCD
• consumer and recreation products such as a compass or
• GPS global positioning system
• temperature sensors play a key role in maintaining the reliability of the
• RTDs resistive temperature detectors
• thermocouples thermocouples, and sensor integrated circuits (“ICs”). Resistive temperature sensors
• a sensing element whose resistance varies with temperature.
• a sensing element whose resistance varies with temperature.
• a sensing element whose resistance varies with temperature.
• platinum resistive temperature detector consists of a platinum wire coil that is wound
• thermocouple around a film of platinum deposited on a substrate.
• magnetoresistive element has a first sensing terminal and a second sensing terminal.
• the first magnetoresistive element is connected to a first sensing terminal associated
• the first sensing terminal associated with the second magnetoresistive element associated with the second magnetoresistive element.
• the first sensing element is further connected to a power source.
• the integrated dual purpose sensing device is adaptable to
• Figure 1 is an electrical schematic diagram illustrating a sensor in a Wheatstone
• Figure 2 is an integrated circuit layout for the sensor illustrated in Figure 1 ;
• Figure 3 is an electrical schematic diagram illustrating a multi-purpose sensor
• Figure 4 is an electrical schematic diagram illustrating a multi-purpose sensor
• Figure 5 is an electrical schematic diagram illustrating a multi-purpose sensor
• Figure 6 is an electrical schematic diagram illustrating a multi-purpose sensor
• Figure 7 is a block diagram illustrating an exemplary cross-section for a layer
• Figure 8 is an electrical schematic diagram illustrating a current strap
• Figure 9 is an electrical schematic diagram illustrating a current strap
• Figure 1 is an electrical schematic diagram illustrating a sensor 100 that may be
• the sensor 100 is used in accordance with one embodiment of the present invention.
• the sensor 100 is a sensor used in accordance with one embodiment of the present invention.
• sensing terminals 110, 112, 116, and 118 With a bridge power
• output of the bridge may be measured between te ⁇ ninals 112 and 118.
• the senor consists of four magnetoresistive elements having the same resistance R, and the bridge supply voltage causes a current to flow through the
• resistance in the magnetoresistive elements 104 and 108 may increase to R+ ⁇ R.
• magnetoresistive elements 102 and 106 rotates away from the current and results in a
• Figure 2 illustrates a layout for an integrated circuit 200 that may be employed as
• the integrated circuit 200 includes a substrate 202, a sensing structure 204, and sensing terminals 206,
• the sensing structure 204 may be configured as a resistance bridge such as the Wheatstone bridge 100 illustrated in Figure 1.
• Figure 2 also
• set-reset strap 216 illustrates a set-reset strap 216 and an offset strap 218. Also illustrated are set-reset
• the magnetic flux generated around the set-reset strap 216 may reset the
• sensing structure 204 into a single magnetic domain.
• the sensing structure 204 may bias the sensing structure 204 to compensate for background magnetic fields.
• the current in the offset strap 218 may generate a magnetic flux that is
• the offset strap 218 may be also configured to
• a sensing device such as a sensing device having a
• Figure 3 is an electrical schematic diagram illustrating a multi-purpose sensor
• magnetoresistive elements 304 and 308 in the presence of an applied magnetic field
• Each magnetoresistive element 306 may decrease to R - ⁇ R.
• Each magnetoresistive element includes a first sensing
• magnetoresistive elements could also be used in exemplary embodiments, and the
• exemplary embodiments are not limited to magnetoresistive elements. Further,
• the 300 includes four sensing terminals 310, 312, 314, and 316.
• the sensing terminals 310, 312, 314, and 316 are connected to The sensing terminals 310, 312, 314, and 316.
• 312, 314 and 316 are formed by connecting a second sensing terminal associated with
• the element 306 to a first sensing terminal associated with the element 308, and, further,
• the sensing terminal 310 is connected to a power
• the power source 318 includes a current source that supplies a
• the senor 300 provides two output
• the multi-purpose sensor readings include a magnetic sensor reading and a
• the Noutl provides a magnetic
• ⁇ R is a magnetoresistance
• S is a bridge sensitivity related to magnetoresistive
• the Noutl value is used to determine
• a temperature sensor reading According to an exemplary embodiment,
• magnetoresistive or giant magnetoresistive materials that are employed for dual-purpose
• a temperature sensor reading may be determined by measuring the value of the resistance.
• the Nout2 may be computed using the following equation:
• Eq. 2 for Noutl, Eq. 5 for Nout2 may be employed to determine a temperature sensor
• a temperature sensor reading may be calculated as
• the sensing functionality of the bridge may be controlled by
• two output channels may be
• microprocessor may employ a look-up table or a polynomial that may be used to
• two outputs from the sensor can be input to a
• A/D analog to digital
• the sensing element may be implemented using hardware, software, firmware elements,
• Figure 4 is an electrical schematic diagram illustrating a multi-purpose sensor
• a power supply of the bridge includes a voltage source 324 connected to
• power sources may be external or internal.
• the voltage source may be any type of power sources.
• the resistive element may be incorporated into the sensor, or may be external to the sensor.
• the resistive element may be incorporated into the sensor, or may be external to the sensor.
• resistor having a very low temperature coefficient, or being insensitive to
• resistive elements described herein may be internal resistive elements
• the senor 350 provides two
• S is a bridge sensitivity related to the magnetoresistive ratio
• H is a bridge sensitivity related to the magnetoresistive ratio
• V is the voltage of the constant voltage source 324
• the first output voltage may be
• Nout3 (N-Nout4)x SxH Eq. 8
• Nout4 may be computed using the following equation:
• N - Nout4 Nout4xR/r
• N-Nout4 Nout4xRox (l+CxT)/r Eq. 10
• Eq. 10 may be employed to determine a temperature sensor's reading. Referring
• the logical sensing element may be employed to determine the temperature
• sensors including only two magnetoresistive elements, or a half Wheatstone bridge
• Figure 5 is an electrical schematic diagram illustrating a dual-purpose sensor 400
• the output voltage Nout5 may be computed using the
• the sensing terminals 310 and 314. the sensing terminals 310 and 314.
• Nout6 value is employed to determine a temperature sensor reading.
• Nout6 may be computed using the following
• a magnetic sensor reading may be computed using Eq. 13, and a magnetic sensor reading may be
• Figure 6 is an electrical schematic diagram 450 of a half Wheatstone bridge
• the half Wheatstone bridge configuration includes two magnetoresistive
• the source 324 is connected to the sensing terminal 310 via the resistive element 322 including for example, a resistor having a very low temperature coefficient or being
• the first voltage measurement (Nout7) is employed to determine a
• Vout7 may be computed using the following equation:
• the Nout8 measurement is taken across the resistive element 322 and may be computed using the following equation:
• a temperature (T) reading may be determined using Eq. 15, and a magnetic field sensor
• the logical element may be implemented using a
• processor and/or hardware, software, firmware elements, or a combination thereof.
• a sensor may include metal
• metal straps metal straps
• current straps known as set-reset and offset straps
• offset and set/reset straps are deposited as two metal layers in
• Figure 7 is a block diagram illustrating an exemplary cross-section 700 of the
• the senor includes a
• permalloy layer 712 composed of nickel and iron, for instance. Further, the sensor
• insulator layer 710 includes an insulator layer 710, and electrical conductors in the form of pads 718, 720
• the sensor 700 further includes an
• offset strap 714 placed between two dielectric layers 704 and 716. The sensor furthermore
• a Barber Pole/interconnect bar 704 arranged to provide barber pole biasing.
• the barber pole biasing may cause the current to flow at 45-degree angle in
• the sensor may further include a set/reset strap 708, and a passivation nitride
• metal straps deposited on an MR/GMR sensor such as the set/reset or
• FIG. 8 is an electrical schematic diagram of a metal (or current) strap configuration 800 that may be
• strap 806 such as a set/reset strap or an offset strap, is connected to two sensing
• the output voltage Vout9 may be computed according to the following equation:
• Eq. 16 may be used to determine the temperature sensor's reading, and the
• magnetic sensor reading may be determined using the methods described above.
• magnetoresistive elements included in
• multi-purpose sensors described in reference to the preceding figures may include
• anisotropic magnetoresistive elements or giant magnetoresistive elements for instance.
• Figure 9 is an electrical schematic diagram of a current strap configuration 900
• exemplary embodiment employing a constant voltage source.
• a current strap 910 such as a set/reset strap or an
• offset strap is connected to two sensing terminals 908 and 912, with the sensing
• the sensing terminal 908 is connected to a constant voltage source 902 via a resistive element 906 and a sensing terminal 904.
• the resistive element 906 may include a resistor having a very low
• measurements "NoutlO” and “Noutll” may be taken to determine a temperature sensor
• NoutlO and Noutl l may be computed using the following equations:
• Eq. 18 may be used to determine the temperature sensor's reading, and the magnetic
• sensor reading may be dete ⁇ nined using the methods described above.
• Magnetic sensors enable and enhance a wide variety of applications, including
• sensors such as tilt, accelerometer, gyro, angular rate, or pressure sensors. Most likely
• the range of the operating temperature is narrow, and the temperature change, rather than the absolute temperature, is often sufficient to implement the
• the constant current implementation of the dual-purpose sensor leads to a simplified form. For example, differentiating both
• configurations could be single-chip configuration or multi-chip configurations.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Nanotechnology (AREA)
• Crystallography & Structural Chemistry (AREA)
• Measuring Magnetic Variables (AREA)
• Testing Or Calibration Of Command Recording Devices (AREA)
• Hall/Mr Elements (AREA)

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• 2001
  • 2001-12-26 US US10/035,957 patent/US6667682B2/en not_active Expired - Lifetime
• 2002
  • 2002-12-03 KR KR1020047010217A patent/KR100983128B1/ko not_active Expired - Fee Related
  • 2002-12-03 JP JP2003558436A patent/JP4458849B2/ja not_active Expired - Fee Related
  • 2002-12-03 EP EP02794140.0A patent/EP1459038B1/en not_active Expired - Lifetime
  • 2002-12-03 CA CA002471864A patent/CA2471864A1/en not_active Abandoned
  • 2002-12-03 WO PCT/US2002/038698 patent/WO2003058173A1/en not_active Ceased
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