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WO1991007713A1 - Alimentation de transducteur - Google Patents

Alimentation de transducteur Download PDF

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Publication number
WO1991007713A1
WO1991007713A1 PCT/GB1990/001744 GB9001744W WO9107713A1 WO 1991007713 A1 WO1991007713 A1 WO 1991007713A1 GB 9001744 W GB9001744 W GB 9001744W WO 9107713 A1 WO9107713 A1 WO 9107713A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
temperature
circuit
amplifier
output
Prior art date
Application number
PCT/GB1990/001744
Other languages
English (en)
Inventor
John Philip Lincoln Binns
Original Assignee
British Technology Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB898925578A external-priority patent/GB8925578D0/en
Priority claimed from GB909016434A external-priority patent/GB9016434D0/en
Priority claimed from GB909017573A external-priority patent/GB9017573D0/en
Application filed by British Technology Group Ltd filed Critical British Technology Group Ltd
Priority to JP90515206A priority Critical patent/JPH05505894A/ja
Publication of WO1991007713A1 publication Critical patent/WO1991007713A1/fr

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Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current 
    • G05F1/46—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC
    • G05F1/56—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC using semiconductor devices in series with the load as final control devices
    • G05F1/565—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
    • G05F1/567—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2268—Arrangements for correcting or for compensating unwanted effects
    • G01L1/2281—Arrangements for correcting or for compensating unwanted effects for temperature variations
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current 
    • G05F1/46—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC
    • G05F1/462—Regulating voltage or current  wherein the variable actually regulated by the final control device is DC as a function of the requirements of the load, e.g. delay, temperature, specific voltage/current characteristic
    • G05F1/463—Sources providing an output which depends on temperature

Definitions

  • This invention relates to power supply circuits for ratiometrlc transducers, such as strain gauge transducers of resistive-bridge or piezoresistive type, and more particularly to such power supply circuits providing a temperature-dependent supply voltage In order to compensate for temperature-dependent changes in the output sensitivity of such transducers.
  • Circuits according to the invention are particularly useful when the supply voltage to the circuit is low, but are of general application.
  • Most strain gauge transducers have four terminals and can be represented as a resistor bridge circuit. In use a d.c. supply voltage is applied across two of the terminals and a much smaller differential output voltage may be measured across the other two terminals.
  • X-ducer is a trade mark of Motorola Inc.
  • the normal method of span temperature compensation is to change the supply voltage so as to compensate for the change in sensitivity.
  • the X-ducer series has a sensitivity which drops with temperature. It has been designed so that if the supply voltage applied across it is raised linearly at typically 0.19%/°C then the increase in sensitivity due to increased supply voltage exactly compensates for the decrease in sensitivity due to the rise in temperature.
  • the usual way of producing the required transducer supply voltage characteristic involves a technique called 'self temperature compensation 1 .
  • One version of this method uses a constant current supply to the transducer. As the transducer's resistance increases with temperature so the voltage across it rises in the required manner.
  • Another version uses a constant voltage supply with series resistors or thermistors. As the transducer's resistance rises so the voltage across 1t rises 1n the required manner. Both these methods can have combinations of components such as diodes, resistors and thermistors in series or parallel with the transducer and each other which can render improvements to the voltage characteristic obtained.
  • a power supply circuit for applying a temperature-compensating supply voltage across a temperature-sensitive transducer, the circuit comprising : a first operational amplifier; means for applying an output level determining voltage to one Input of the amplifier; means for applying a temperature-dependent output slope determining voltage to the other Input of the amplifier; and means for applying the resultant temperature-dependent output voltage of the amplifier to the transducer.
  • the output level determining voltage and the output slope determining voltage are applied respectively to the positive and to the negative inputs of the amplifier.
  • the output slope determining voltage is, or is derived from, the output of a differential amplifier having a temperature-sensitive feedback element (which may be a semiconductor diode or a temperature-sensitive resistor) connected between Its output and Its negative Input.
  • a temperature-sensitive feedback element which may be a semiconductor diode or a temperature-sensitive resistor
  • Figure 1 shows a first circuit according to the invention, connected to supply a bridge-circuit transducer
  • FIG 2 shows temperature-dependent output voltages ' of operational amplifiers comprised by the circuit shown in Figure 1 ;
  • Figure 3 shows a second circuit according to the invention, similarly connected to supply a bridge-circuit transducer
  • Figure 4 shows temperature-dependent output voltages of operational amplifiers comprised by the circuit shown in Figure 3;
  • Figure 5 shows a third circuit, closely similar to that shown in Figure 1 or Figure 3, but differently connected to supply a bridge-circuit transducer and appropriately modified;
  • Figure 6 shows a fourth circuit, combining the circuits of Figure 1 or 3, and Figure 5, connected to supply a bridge- circuit transducer;
  • FIG 7 shows temperature-dependent output voltages of operational amplifiers comprised by the circuit shown in Figure 6, and Figures 8, 9 and 10 show embodiments of simplified circuits according to the invention.
  • the transducer circuit 1 is represented as four resistors (RG1 to RG4) in a Hheatstone bridge configuration.
  • the span temperature compensation circuit comprises level setting voltage generating circuit 2 and temperature dependent voltage generating circuit 3 feeding into the positive and negative inputs respectively of an inverting amplifier 4 which supplies the output to the transducer 1.
  • the level setting voltage generating circuit 2 comprises resistors Rl and R2 connected in series between a regulated supply Vr and ground (GND). The node between resistors Rl and R2 is the output.
  • the temperature dependent voltage generating circuit 3 comprises resistors R3 and R4 in series between the regulated supply Vr and ground (GND), with the node therebetween connected to the non-inverting (+) input of an operational amplifier Ul .
  • the output of amplifier Ul is connected via a diode Dl to its inverting (-) input.
  • the inverting (-) input is also connected via a resistor R5 to ground (GND).
  • the amplifier Ul supplies the required temperature dependent voltage V2 at its output.
  • the amplifier 4 comprises an operational amplifier U2 with its output connected via a feedback resistor R7 to its inverting
  • the temperature-dependent output voltage of circuit 3 is connected via an input resistor R6 of the amplifier 4 to the inverting (-) input of amplifier U2.
  • the level setting output of the circuit 2 is connected to the non-inverting (+) input of amplifier U2.
  • the output of amplifier U2 provides the required temperature compensated voltage V3 which is applied to the transducer 1.
  • this circuit 1 The operation of this circuit 1s as follows: Suppose the transducer 1 requires a voltage supply (V3) of 3.0v at 20°C with a linear slope of 4.5mv/ ⁇ C.
  • the voltage level is set to 3.0v by adjusting the resistor ratio R1/R2 1n the level setting circuit 2 so that its output (VI) is 3.0v and by adjusting the ratio R3/R4 1n the temperature dependent voltage generating circuit 3 so that Its output (V2) 1s the same at 20 ⁇ C.
  • This circuit 3 is an operational amplifier in a non-inverting configuration with a temperature dependent component (diode Dl) in the feedback circuit which therefore has a constant current through it.
  • FIG. 3 An embodiment of the invention with enhancements for low voltage operation is shown in Figure 3, in which the transducer circuit 1, the level setting voltage generating circuit 2, the temperature dependent voltage generating circuit 3, and the output amplifier 4 in inverting configuration, are as described with reference to Figure 1.
  • the circuit shown in Figure 3 comprises, additionally, inverting gain stages 5 and 6 with an associated false ground generating circuit 7, and a pull-up circuit 8.
  • the inverting gain stage 5 comprises an operational amplifier
  • the inverting gain stage 6 comprises an operational amplifier
  • the output of the false ground generating circuit 7 is connected to the non-inverting (+) input of amplifier U4.
  • the false ground generating circuit 7 comprises resistors R12 and R13 in series between regulated supply Vr and ground (GND). The node therebetween is the output and is connected to the non-inverting (+) inputs of amplifiers U3 and U4.
  • the pull-up circuit 8 comprises a resistor R14 connected between the regulated supply voltage Vr and the output of the amplifier U2. To provide the same temperature-dependent voltage V3 as described above in the case of Figure 1, this circuit operates as follows:
  • the temperature dependent voltage generating circuit 3 generates a voltage (V2) with a slope of about -2mv/°C but the resistor ratio R3/R4 is set in this case so as to give an output voltage of only 1.2v at 20°C, as shown in Figure 4A.
  • the resistor ratio R12/R13 in the false ground generating circuit 7 is also set so as to give a false ground voltage (V4) of 1.2v.
  • stage 5 The gain of stage 5 is set by the resistor ratio R8/R9 at -2.25.
  • the output voltage as shown in Figure 4B, has a slope of +4.5mv/°C and is applied to the inverting amplifier stage 6 which (its resistors RIO and Rll being made equal) has a gain of -1 and inverts the signal relative to false ground to give a falling output as shown in Figure 4C. This is so that the final output voltage (V3) will be a rising output as required. If a falling output were required then this stage would be omitted.
  • inverting amplifier stage 6 1s fed Into the negative side of the output stage 4.
  • This stage in this instance, has its resistors R6 and R7 equal and gives a gain of -1 and thus an output voltage with a slope of +4.5mv/ ⁇ C as required.
  • the output level requirement of 3.0v at 20 ⁇ C is met by adjusting the level setting voltage (VI) to 2.1v. This output 1s shown in Figure 4D.
  • the input common mode voltage (at 2.1v) is lower than before and Implies a supply voltage of no more than 4.1v if LM124 operational amplifiers are used.
  • the output stage 4 is unable to source current at the required output voltage whilst Its supply is at only 4.1v, this requirement is met by the pull-up circuit 8, shown as a resistor R14, which is chosen to supply more current than the bridge requires at any temperature. The output stage 4 1s then able to determine the voltage V3 as required, by sinking the excess current.
  • the transducer 1 has one supply voltage terminal connected to ground and the temperature- dependent voltage V3 is applied to its other supply voltage terminal.
  • one supply voltage terminal of the transducer bridge 1 is again held at fixed voltage, but by being connected to the regulated voltage Vr rather than to ground. Accordingly the temperature- compensated V3 which is to be applied to the other supply voltage terminal of the bridge 1 is required, in this case, to be close to ground potential.
  • voltage supply circuitry comprising circuit units 2, 3 and 4 which are the same as in Figure 1, except for appropriate changes in the values of the resistors Rl , R2 etc., and the provision in the output stage 4 of an additional inverting amplifier U5 to reverse the direction of slope of the voltage V3.
  • the circuit shown in Figure 5 may have a pull-down resistor R' connected between ground and the bridge supply voltage terminal to which the voltage V3 is applied.
  • Figure 6 shows a voltage supply circuit which is essentially a combination of the circuits shown in Figures 1 and 5, in that the temperature-compensating variations in the voltage which it provides are applied, preferably equally, to both the supply voltage terminals of the transducer bridge 1 which it supplies.
  • the bridge circuit 1 has temperature- compensated voltages V3 and V5, respectively, applied to its supply voltage terminals, the voltages V3 and V5 being provided as the outputs of operational amplifiers U2 and U5 comprised by parallel output stages 4 and 11 of the compensated voltage supply circuit.
  • Level-setting voltage generating circuits 2 and 10 respectively provide steady voltages to the positive inputs of the amplifiers U2 and U5.
  • the temperature-dependent voltage generating circuit 3 is like that shown in Figures 1 and 3 except that its temperature-sensitive component, instead of being a diode, is shown as a platinum resistor Rt (though it might equally well be a diode as in Figures 1 and 3); and its output voltage V2 is applied to the output stage 4 not directly but through an inverting gain stage 5 including an amplifier U3 and provided with an associated false-ground generating circuit 7.
  • the temperature-dependent component of the voltage V2 is applied to the output stage 11 not directly but via the amplifiers U3 and U2, as is further described below.
  • the supply voltage terminals of the bridge circuit 1 to which the voltages V3 and V5 are applied are connected respectively to the regulated voltage Vr and to ground by pull-up and pull-down circuits 8 and 9, respectively, constituted by resistors R14 and R15 which correspond to the resistors R14 and R' 1n Figures 3 and 6 respectively.
  • Transducer 1 is a foil-based transducer of 350 ⁇ resistance which requires a voltage supply (V3-V5) of 9.0v at 20 ⁇ C with a linear slope of 5.7 mv/°C. With a supply voltage Vr of lOv this is achieved by setting voltage V3 to 9.5v with a slope of +2.85mv/°C and voltage V5 to 0.5v with a slope of -2.85mv/ ⁇ C. The method of achieving this will be described with additional references to Figure 7.
  • Temperature-dependent voltage generating circuit 3 has a platinum resistor Rt with a resistance of 100 ⁇ at 20"C and a slope of 0.385 ⁇ / ⁇ C.
  • the resistor ratio R3/R4 is set to give a voltage of 2.75v at the non-inverting (+) input of operational amplifier Ul .
  • Resistor R5 is set to 1K ⁇ to give an output voltage V2 of 3.0v at 20 ⁇ C with a slope of 1.06mv/ ⁇ C as shown in Figure 7A. This voltage is fed Into the negative input of inverting gain stage 5.
  • the resistor ratio R12/R13 1s set to give a false ground V4 of 3.0v, and this voltage Is fed into the positive input of amplifier U3 of inverting gain stage 5.
  • Inverting gain stage 5 has resistor ratio R9/R8 set to 2.69 to give a gain of -2.69 and hence an output voltage with a slope of - 2.85mv/ ⁇ C as Illustrated in Figure 7B.
  • the output of inverting amplifier stage 5 is fed into the negative side of output stage 4.
  • This stage gives a gain of -1 and thus a slope of +2.85mv/ ⁇ C as required.
  • the output level requirement of 9.5v at 20°C is met by adjusting the level setting voltage VI to 6.25v.
  • This output (V3) is shown in Figure 7C.
  • the output voltage V3 is also fed into the negative side of output stage 11.
  • This stage also has a gain of -1, giving a slope of -2.85mv/°C as required.
  • output stage 4 is unable to source current at the required output voltage whilst its supply is at only lOv, this requirement is met by the pull-up resistor R14 which is chosen to supply more current than the transducer 1 requires at any temperature and then the output stage 4 is able to determine the voltage by sinking the excess current.
  • output stage 11 is unable to sink much current at the required output voltage of about 0.5v, this requirement is met by the pull-down resistor R17 which is chosen to sink more current than the bridge sources at any temperature and then the output stage 11 can control the voltage by sourcing the excess current required.
  • This circuit with dual output stages 4 and 11 has advantages over the use of a single output stage in certain applications. It is common for bridge transducers to be packaged separately from the associated power supply and amplification electronics.
  • the output voltage from this type of transducer is a small differential voltage resting on a large common mode voltage. Normally this common mode voltage would be half-way between the two voltages on the supply terminals.
  • This type of transducer would thus be connected to an amplifier circuit which requires a common mode voltage to be approximately half-way between the supply voltages.
  • the use of dual output stages in the temperature compensation circuit allows compatibility with external amplifier circuits to be maintained, i.e. the transducer common mode voltage can be set half way between the supply rails whereas the use of a single output amplifier would not allow this.
  • any change in the common mode voltage during operation could cause common mode errors in the associated amplifier.
  • the use of a single output stage means that the common mode voltage would change with temperature whereas the use of two output stages means that although the voltage across the transducer changes with temperature the common mode output voltage need not.
  • Another feature of this circuit, as described above, is the use of a temperature sensitive resistor instead of a diode in the temperature dependent voltage generating circuit 3. The voltage across the resistor 1s proportional to the current through it whereas the voltage across the diode 1s highly insensitive to the current through It. Hence, the use of the resistor allows the construction of a circuit which is ratiometrlc.
  • the amplifier U2 (or U5) has an output level determining voltage applied to Its positive Input and an output slope determining voltage applied to Its negative input. If the amplifier has a gain of 1, however, a satisfactory circuit can also be achieved by applying the output level determining voltage to the negative input and the output slope determining voltage to the positive input.
  • the output level determining voltage generating circuit 2 is a pair of resistors whose output is fed into the positive input of the inverting amplifier 4, which is the high impedance input, whereas in the alternative circuit, the output of the circuit 2 would be fed into the negative side of the inverting amplifier circuit 4 which has a relatively low impedance determined by the value of resistor R6.
  • This buffer would normally be an operational amplifier, and the alternative circuit would thus require one more operational amplifier than the preferred circuit configuration; but it may well be, since operational amplifiers are packaged four to a chip, that there is a spare amplifier available and so the alternative circuit need not be more expensive.
  • pull-up and pull-down circuits 8 and 9 can be any component or combination of components that will supply or sink most or all of the current required by the transducer 1. Typical examples would be a current circuit or one or more diodes in series with a resistor.
  • the diode Dl or temperature sensitive resistor Rt of the temperature-dependent voltage generating circuits 3 as above described may be replaced by another temperature sensitive component or a network incorporating at least one temperature sensitive component, and that this component or network could replace one or more of the components in the circuit in order to achieve various different temperature-dependent voltage characteristics.
  • some known voltage regulators and voltage reference supply circuits supply a straight line temperature-dependent voltage as an auxiliary output, and if a straight line characteristic is satisfactory then these may be used to replace the temperature dependent voltage generating circuit 3.
  • the output voltage V2 of the temperature-dependent voltage generating circuits 3 are suitable for direct application to the transducer 1, and examples are described below with reference to Figures 8 to 10.
  • a transducer circuit 1 is again represented as four resistors (RG1 to RG4) in a Wheatstone Bridge configuration.
  • the temperature- dependent voltage generating circuit 3 itself constitutes the output stage of the supply circuit for the transducer 1.
  • the temperature dependent voltage generating circuit 3 comprises, as in the earlier described embodiments, resistors R3 and R4 in series between a regulated supply voltage Vr and ground (GND), with the node therebetween connected to the non-inverting (+) input to an operational amplifier Ul .
  • the output of operational amplifier Ul 1s connected via a temperature dependent feedback element, 1n this instance a temperature-sensitive resistor Rt as 1n Figure 6, to its inverting (-) input.
  • the inverting (-) input is also connected via a resistor R5 to ground (GND).
  • the desired temperature dependent voltage, V2 is provided at the output of amplifier Ul , which is connected to the positive supply side of transducer 1.
  • the negative supply side of transducer 1 is connected to ground (GND).
  • Transducer 1 requires a temperature compensated voltage supply (V2) of 3.0V at 20°C, with a linear slope of 4.5 mV/ ⁇ C.
  • Temperature dependent voltage generating circuit 3 Is an operational amplifier in non-inverting amplifier configuration with the temperature dependent component (resistor Rt) in the feedback circuit which therefore has a constant current through it. Resistor Rt has a resistance of 1077 ⁇ at 20°C and a temperature coefficient of 3.85 ⁇ /°C. In order to provide for a voltage change of 4.5 mV/°C it requires a constant current of
  • the positive supply side of transducer circuit 1 is connected to ground (GND) and the output voltage V2 of the temperature-dependent voltage generating circuit 3 as described above with reference to Figure 8 is connected to the negative supply side of the transducer 1 which, optionally, is connected to ground (GND) by a pull-down device 9 which will usually be a resistor.
  • a pull-down device 9 which will usually be a resistor.
  • the circuit element shown as Rt is in this instance required to have a negative temperature coefficient of resistance. Assuming for purposes of explanation that it is again a resistance having a value of 1077 ⁇ at 20°C and a temperature coefficient, now, of -3.85 ⁇ /°C, it requires a constant current of 1.169 mA in order for the resistor Rt to provide for a voltage change of -4.5 mV/°C. At 20°C this constant current implies a potential difference of 1.26V across resistor Rt. The output voltage (V2) requirement of 2.0V at 20°C is met by dropping an additional 0.74V across resistor R5. With the constant current of 1.169 mA flowing through it this gives a required resistance value of 633 ⁇ for R5.
  • a circuit combining features of Figures 8 and 9 may be provided as illustrated in Figure 10.
  • the amplifier Ul of the temperature dependent voltage generating circuit 3 in Figure 10 supplies a temperature-dependent voltage V2 to the positive supply side of transducer 1 which, optionally, is connected by the pull-up device 8 to the regulated voltage supply Vr.
  • the output of operational amplifier Ul is also connected to the inverting input side of inverting amplifier circuit 11 which, as in the circuit shown in Figure 6, comprises an operational amplifier U5 with Its inverting input connected via a resistor (R6) to the output of operational amplifier Ul and its output connected to Its inverting input via a resistor (R7).
  • the positive input of operational amplifier U5 is connected to the output of level -setting voltage generating circuit 10.
  • the output of operational amplifier U5 is connected to the negative supply side of transducer 1 which, optionally, 1s connected by the pull-down device 9 to ground (GND).
  • the level setting voltage generating circuit 10 comprises, in this case, a pair of resistors connected in series between the regulated voltage supply Vr and ground (GND), and from the node between these resistors is taken an output voltage V6 which is applied to the positive input of the amplifier U5.
  • the circuit shown in Figure 10 enables this to be achieved by setting the voltage V2 on the positive supply side of the transducer to 4.0V at 20°C with a slope of +2.25 mV/°C and the voltage V3 on the negative supply side of the transducer 1 to 1.0V with a slope of -2.25 mV/°C.
  • resistor Rt has a resistance of 1077 ⁇ at 20°C and a temperature coefficient of 3.85 ⁇ /°C.
  • resistor Rt In order for the resistor Rt to provide for a voltage change of 2.25 mV/°C it requires a constant current of 0.584 mA. At 20°C this constant current implies a potential difference of 0.630V across resistor Rt. The requirement of 4.0V at 20°C for the output voltage V2 is met by dropping an additional 3.37V across resistor R5. This is done by setting the resistor ratio R3:R4 to give 3.37V at the non-inverting (+) input of operational amplifier Ul . The constant current requirement of 0.584 mA through resistor R5 which has a voltage of 3.37V across it determines its required resistance at 5770 ⁇ .
  • the level requirement of 1.0V at 20°C for the output voltage V3 is met by adjusting the resistor ratio in the level setting voltage generating circuit 10 to give an output voltage V6 of 2.5V.
  • the output of the temperature dependent voltage generating circuit 3 is applied to the positive supply side of the transducer and the output of inverting amplifier circuit 11 is applied to the negative supply side. It will be understood, however, that an equivalent circuit, equally in accordance with the invention, might have the temperature dependent voltage generating circuit 3 connected to the negative supply side and the inverting amplifier circuit 11 connected to the positive supply side, with optional pull-up and pull-down devices as necessary.
  • circuits described above employ in each case the minimum number of components necessary for a circuit functioning in the intended manner, circuits within the scope of the invention may nevertheless contain additional components such, for example, as extra amplifiers in various configurations, of which the functions reduce logically to those of the circuits illustrated.
  • Circuits in accordance with the invention may be made on a printed circuit board or on a thick film hybrid, though most if not all of such a circuit may alternatively be placed on a single piece of silicon.
  • the temperature dependent component in the circuit will normally be located physically close to the transducer itself and If the transducer is based on silicon then the temperature dependent circuit component may itself also be diffused into the silicon.
  • any of the above-described circuits according to the invention will usually be part of a larger sensor signal conditioning circuit, which may also include sensor output amplification, offset compensation, and temperature coefficient of offset compensation (with the temperature dependent voltage for this latter function being derived, preferably, from the output of one of the amplifiers in the circuit according to the Invention, as is described and claimed in our co-pending UK Patent Application No. 8925579.8.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Amplifiers (AREA)
  • Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
  • Continuous-Control Power Sources That Use Transistors (AREA)
  • Measurement Of Force In General (AREA)
  • Control Of Voltage And Current In General (AREA)

Abstract

Circuit d'alimentation permettant d'appliquer une tension d'alimentation à compensation de température à un transducteur sensible à la température (tel qu'un transducteur de jauge de contrainte), le circuit comprenant un premier amplificateur opérationnel, un moyen d'application d'une tension de détermination d'un niveau de sortie à une entrée (de préférence négative) de l'amplificateur, un moyen d'application d'une tension de détermination d'une pente de sortie dépendant de la température à l'autre entrée (de préférence positive) de l'amplificateur, ainsi qu'un moyen d'application de la tension de sortie obtenue dépendant de la température de l'amplificateur au transducteur.
PCT/GB1990/001744 1989-11-13 1990-11-13 Alimentation de transducteur WO1991007713A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP90515206A JPH05505894A (ja) 1989-11-13 1990-11-13 トランスジューサ電源

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GB898925578A GB8925578D0 (en) 1989-11-13 1989-11-13 Power supply for strain gauge transducers
GB8925578.0 1989-11-13
GB9016434.4 1990-07-26
GB909016434A GB9016434D0 (en) 1990-07-26 1990-07-26 Power supply for ratiometric transducers
GB909017573A GB9017573D0 (en) 1990-08-10 1990-08-10 Power supply for ratiometric transducers
GB9017573.8 1990-08-10

Publications (1)

Publication Number Publication Date
WO1991007713A1 true WO1991007713A1 (fr) 1991-05-30

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PCT/GB1990/001744 WO1991007713A1 (fr) 1989-11-13 1990-11-13 Alimentation de transducteur

Country Status (3)

Country Link
EP (1) EP0500631A1 (fr)
JP (1) JPH05505894A (fr)
WO (1) WO1991007713A1 (fr)

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EP0631121A2 (fr) * 1993-06-24 1994-12-28 Nec Corporation Capteur semi-conducteur de tension avec compensation de la tension électrique d'entrée du circuit à pont wheatstone
EP0751451A1 (fr) * 1995-06-30 1997-01-02 STMicroelectronics S.r.l. Générateur de tension de référence ayant une caractéristique en température à double pente pour un régulateur de tension d'un alternateur d'automobile
EP0794477A1 (fr) * 1993-07-09 1997-09-10 Sgs-Thomson Microelectronics Pte Ltd. Circuit pour génération de tension
US5703476A (en) * 1995-06-30 1997-12-30 Sgs-Thomson Microelectronics, S.R.L. Reference voltage generator, having a double slope temperature characteristic, for a voltage regulator of an automotive alternator
US20210072145A1 (en) * 2019-09-05 2021-03-11 Dell Products, Lp System and Method for Sensing Corrosion in an Enclosure of an Information Handling System

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5396125A (en) * 1993-09-09 1995-03-07 Northern Telecom Limited Current injection logic

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EP0392746A2 (fr) * 1989-04-14 1990-10-17 LUCAS INDUSTRIES public limited company Circuit de compensation en température pour transducteur

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EP0631121A2 (fr) * 1993-06-24 1994-12-28 Nec Corporation Capteur semi-conducteur de tension avec compensation de la tension électrique d'entrée du circuit à pont wheatstone
EP0631121A3 (fr) * 1993-06-24 1995-09-20 Nec Corp Capteur semi-conducteur de tension avec compensation de la tension électrique d'entrée du circuit à pont wheatstone.
EP0794477A1 (fr) * 1993-07-09 1997-09-10 Sgs-Thomson Microelectronics Pte Ltd. Circuit pour génération de tension
EP0751451A1 (fr) * 1995-06-30 1997-01-02 STMicroelectronics S.r.l. Générateur de tension de référence ayant une caractéristique en température à double pente pour un régulateur de tension d'un alternateur d'automobile
US5703476A (en) * 1995-06-30 1997-12-30 Sgs-Thomson Microelectronics, S.R.L. Reference voltage generator, having a double slope temperature characteristic, for a voltage regulator of an automotive alternator
US20210072145A1 (en) * 2019-09-05 2021-03-11 Dell Products, Lp System and Method for Sensing Corrosion in an Enclosure of an Information Handling System
US11754490B2 (en) * 2019-09-05 2023-09-12 Dell Products L.P. System and method for sensing corrosion in an enclosure of an information handling system

Also Published As

Publication number Publication date
EP0500631A1 (fr) 1992-09-02
JPH05505894A (ja) 1993-08-26

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