GB2140588A - Temperature-controlled electronic devices - Google Patents
Temperature-controlled electronic devices Download PDFInfo
- Publication number
- GB2140588A GB2140588A GB08413510A GB8413510A GB2140588A GB 2140588 A GB2140588 A GB 2140588A GB 08413510 A GB08413510 A GB 08413510A GB 8413510 A GB8413510 A GB 8413510A GB 2140588 A GB2140588 A GB 2140588A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- elements
- sensitive
- strain gauge
- measurement
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
Classifications
-
- 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
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0051—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance
- G01L9/0052—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements
- G01L9/0054—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements integral with a semiconducting diaphragm
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
- G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Measuring Fluid Pressure (AREA)
- Measurement Of Force In General (AREA)
Abstract
In an electronic device, e.g. a resistive strain gauge bridge mounted on a silicon diaphragm, the temperature of which is to be controlled, the resistance of elements 14,16,18,20 of the bridge is to be varied, in use, in dependence upon the magnitude of a physical parameter, e.g. pressure or force applied to the diaphragm. Resistors 44,46 sense the temperature of the resistive elements 14,16,18,20 and control the temperature of a heating resistor 42 electrically isolated from the resistive elements 14,16,18,20 but in heat-transferring relation thereto such that the temperature of the resistive elements is maintained substantially constant. <IMAGE>
Description
SPECIFICATION
Temperature-controlled electronic devices
This invention relates to temperature-controlled electronic devices such as temperature-controlled resistance strain gauge bridges.
The concept of controlling the temperature of an electronic device to minimize a change in the characteristics of the device with temperature, hereinafter referred to as thermal shifts, is well known.
A known pressure transducer comprises a silicon diaphragm having a four-arm, active, resistance strain gauge bridge formed thereon, the four resistors of the bridge being diffused into the silicon diaphragm at the areas of maximum strain. A constant current, or a current fed by way of a resistor from a source of a constant voltage is applied to opposed first and second junctions of the bridge. If the resistance of the resistors in the bridge remains constant the voltage between the first and second junctions also remains constant. A strain in the diaphragm due to an applied pressure or force results in a change in the resistance of the bridge resistors and this change is detected by detection means coupled to the third and fourth opposed junctions.The detection means would often include an amplifier and the output of the bridge could be expressed in a current per unit pressure or force.
If the temperature of the device remains constant then the resistance of the resistors and hence the output of the bridge for a given strain in the transducer would remain constant provided that the strain coefficients of the bridge strain gauge resistors are matched.
However, if the temperature of the diaphragm changes due to changes in operating and/or ambient temperature then the values of the bridge resistors will change with a corresponding change in the voltage across the first and second junctions of the bridge and this is manifested as an error in the measured output signal.
Any change in temperature could also affect the operation of other associated devices, such as the measuring amplifier which would result in a change in the amplifier offset voltage, drift in the amplifier output signal and the like.
It is therefore important to maintain constant the temperature of such electronic devices or to provide some means of compensating for temperature change.
One known pressure transducer comprising a silicon diaphragm and a four arm active bridge as hereinbefore mentioned includes two other sets of silicon resistors deposited on the substrate in a non-active area. One temperature measuring set of the resistors is arranged to provide a signal representative of the temperature of the diaphragm to the input of an amplifier, the output of which is arranged to provide an output current to the other, heating set of resistors thereby to heat the diaphragm and to maintain it at a predetermined temperature. A control feedback loop is provided in known manner between the output and input of the amplifier to
maintain the temperature substantially constant and
to prevent fluctuations about the predetermined temperature.
This known arrangement maintains the temperture of the diaphragm approximately constant and
reduces errors in the output of the bridge. However,
as the temperature control is determined by the temperature sensing resistors on the non-active area
of the diaphragm, temperature gradients across the
silicon substrate and variations of these temperature
gradients with ambient temperature limit the accuracy to which the temperature of the active area of the diaphragm can be controlled.
it is a general object of this invention to overcome the problems and meet the needs expressed or implicit in the above background of the invention or in other parts hereof.
According to one aspect of the invention there is provided an electronic device comprising at least one resistive element the temperature of which is to be controlled and the value of which is to be varied in use, in dependence upon the magnitude of a physical parameter, other than temperature, referred to herein as "non-thermal parameter" applied to the device, means for sensing the temperature of the resistive element or elements and arranged to control the temperature of a heating resistor electrically isolated from said resistive element or elements but in heat-transferring relation thereto such that the temperature of said resistive element or elements is maintained substantially constant.
The resistive elements may be a resistance bridge, such as a resistance strain gauge bridge.
The strain gauge bridge may be on the active part of a diaphragm to which a pressure or force to be measured is applied. The heating resistor may be on a non-active part of the diaphragm such that it is not subject to strain due to the applied pressure or force which might change its resistance value.
The diaphragm may be a silicon diaphragm with the strain gauge resistive elements diffused into the silicon at areas of maximum strain and they may be arranged as a four-arm active bridge.
The silicon diaphragm may be made from a base material with a central, square portion reduced in thickness to form the diaphragm with a relatively thick annular, peripheral portion. The strain gauge resistors would be positioned on the diaphragm at areas of maximum strain, that is near the junction of the diaphragm with the thick annular portion and the heating resistor would be positioned on the annular portion. The heating resistor may be a single resistor which may extend around a substantial part of the annular portion or it may comprise a plurality of discrete resistors arranged around the annular portion and connected together in series.
From another aspect thereof, the subject invention resides in a method of measuring a non-thermal physical parameter with temperature-sensitive means, and, more specifically, resides in the improvement comprising the steps of imparting a predetermined temperature to the temperaturesensitive means, measuring the physical parameter with the temperature-sensitive means, subjecting the temperature-sensitive means to environmental temperature variation affecting the mentioned predetermined temperature, employing the temperature-sensitive means themselves for effecting a measurement of environmental temperature variation, and restoring the temperature-sensitive means to their predetermined temperature in response to the measurement of environmental temperature variation effected with the temperature-sensitive means themselves.
From a related aspect thereof, the subject invention resides in apparatus for mesuring a non-thermal physical parameter with temperature-sensitive means, and, more specifically, resides in the improvement comprising, in combination, first means connected to the temperature-sensitive means for measuring the physical parameter with such temperature-sensitive means, second means for imparting a predetermined temperature to the temperaturesensitive means, such temperature-sensitive means being subject to environmental temperature variation affecting the mentioned predetermined temperature, third means connected to the temperaturesensitive means for effecting a measurement of environmental temperature variation with such temperature-sensitive means, and fourth means connected to the second and third means for restoring the temperature-sensitive means to their predetermined temperature in response to measurement of environmental temperature variation effected with that temperature-sensitive means.
The invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a block circuit diagram of one embodiment of the invention in the form of a four-arm active bridge and part of its control circuit;
Figure 2 is a diagrammatic plan view of a silicon diaphragm for use as part of a pressure or force transducer showing the bridge resistors and heating resistor of Figure 1;
Figure 3 is a section taken on the line 3-3 in Figure 2; and,
Figure 4shows a modification of part of the circuit of Figure 1.
Referring to the drawings, there is shown an electronic device 10 comprising a four-arm active strain gauge bridge 12 consisting of resistors 14, 16, 18,20. The resistors 14,16,18,20 are diffused into one surface 22a of a silicon diaphragm 22 at areas of maximum strain in the diaphragm 22 when it is stressed by a pressure or force applied, for example, to its other surface 22b.
A constant current is applied to first and second junctions 12a, 12b of the bridge 12 by way of resistors 24, 26 from an operational amplifier 28 having one, negative or inverting input 28a coupled to the negative power bus 30 by way of a resistor 32 and its other, positive or non-inverting input 28b coupled to a source of a reference voltage developed across a zener or band gap reference diode 34. The diode 34 is coupled as a potential divider with a resistor 36 between the negative power bus 30 and the positive power bus 38. A band gap diode, having a nominal 1.2 volts developed thereacross, has a very low temperature coefficient of voltage so that the potential applied to the input 28b of the amplifier 28 is substantially constant.If the temperature of the amplifier is maintained constant, then the current applied to the bridge by way of opposed junctions 1 2a, 122 will be maintained substantially constant provided the resistanceof resistor 32 is maintained constant.
The output span of the bridge 12 can be adjusted by adjustment of the value of resistor 32 and the zero output of the bridge at junctions 12cud can be adjusted by adjusting resistors 24 and 26.
If the temperature of the amplifier 28 and bridge resistors 14,16,18,20 are maintained constant, then the output signal appearing at junctions 12c, 12dwill depend on the strain induced in the bridge resistors by a pressure or force appliedtothe diaphragm 22.
The junctions will usually be coupled to an amplifier circuit having operational amplifiers 41a and 41b and output resistors 41c and 41 d connected in an instrumentation amplifier configuration between bridge terminals 1 2c and 1 2d and output terminals 40a and 40b, hereinafter collectively referred to as output terminal 40a supplying what may be considered as the bridge output.
The device 10 can be subject to temperature change, dueforexampleto changes in ambient temperature or to the power dissipated in the device.
If the temperature of the diaphragm 22 changes then the concomitant change in the resistance of the bridge resistors will result in an error in the output of the bridge at output terminal 40a of the amplifier 40 and a change in the potential difference between terminals 12a and 12b. Likewise changes in the temperature of the amplifiers will result in drift and changes in their offset voltage and current temperature coefficients which will degrade the accuracy of the output of the bridge seen at terminal 40a.
A resistor 42, shown in Figure 2 as four resistors connected in series, is mounted on the non-active, outer peripheral area of the square diaphragm 22 and is coupled as a controlled heater for the diaphragm.
Any change in the resistance of the resistors 14, 16,18,20 due to change in temperature will change the potential difference across the bridge measured between the terminals 12a and 12b. This change is sensed by a potential divider comprising resistors 44, 46 connected in series between the output of amplifier 28 and the negative bus 30. The values of the resistors 44,46 are so chosen that the voltage at their junction 47 at a predetermined temperature is approximately equal to the voltage across diode 34, say about 1.2 volts.
The voltages across diode 34 and across resistors 46 are coupled to the positive or non-inverting and negative or inverting inputs 48a and 48b respectively of an operational amplifier 48. The output 48c of amplifier 48 is coupled to the base of an NPN transistor 50. A resistor 52 is connected in the collector circuit and the heating resistor 42 is connected in the emitter circuit of the transistor 50. A feedback resistor 54 is coupled between the emitter of transistor 50 and the negative input 486 of amplifier 48. This forms a temperature control circuit for the substrate. The feedback resistor 54 controls the loop gain around the temperature control circuit to maintain the temperature of the substrate substantially constant.
In operation, the value of the potential at junction 47, input 48b, is made such that the output of amplifier 48 causes the current flowing through transistor 50 to be controlled at such a value that a predetermined ambient temperature, of say 20"C, the heat generated by the diffused resistor 42 on the silicon diaphragm maintains the bridge 12 resistors substantially constant at, say 80"C.
The bridge resistors 14, 16, 18,20 have a positive temperature coefficient of resistance such that any increase in ambient temperature will increase the potential across the bridge 12 and hence across the resistor 46. This will reduce the potential difference at the input terminals 48a, 48b of the amplifier 48, and therefore the current through resistor 42. The heat generated by resistor 42 is thus reduced until the temperature of the bridge resistors and sensed by resistors 44, 46 and amplifier 48 is again at the required temperature of 80"C.
Conversely, if the ambient temperature drops below the predetermined value of 20"C, the amplifier 48 causes an increase in the current flow through transistor 50 to increase the heat generated by resistor 42 until the bridge resistor temperature is again at the required value of 80"C.
Thus by sensing the resistance change ofthe bridge resistors 14, 16, 18, 20 due to temperature change, the maintenance of their actual temperature at a predetermined value can be achieved so much more precisely than if a separate temperature sensing resistor is used.
As aforementioned, the gain of the feedback loop around the amplifier is controlled by the value of the resistance of resistor 54.
Also as aforementioned, temperature changes in the amplifiers 28,40,48 can result in changes in the amplifiers' offset voltages, currents and drift which degrade the accuracy of the output of the bridge appearing at terminal 40a. The effects of these changes in ambient temperature can be reduced by using the temperature dissipated by the resistor 52.
In accordance with one embodiment of this aspect of the invention and as indicated by dotted lines 56, the amplifiers are incorporated in a single chip, such as one known as a "quad-op amplifier" and the chip is mounted in heat-transfer relationship on a thick film resistor 52. As described in relation to heating resistor 42, the current through, and the heat dissipated by, resistor 52 increases and decreases as the ambient temperature decreases and increases respectively. Thus the range of the temperature changes of the amplifiers with changes in ambient temperature can be substantially reduced with a corresponding reduction in their offset voltages and current drifts. If the thermal characteristics of the resistor 52 and the amplifiers were the same as the substrate diaphragm 22 then the temperature control of the amplifiers would match that of the bridge resistors.However, this is unlikely but nevertheless some measure of temperature control will be achieved.
Figure 4 shows a modification of the circuit of
Figure 1, wherein the resistor 52 is coupled in parallel with the heating resistor 42 in the emitter circuit of transistor 50. This circuit allows more flexibility in the control of the temperature of resistor 52 and therefore of the amplifiers 28,40,48 as it is possible to select its value.
The value of resistor 52 in Figure 4 can be so selected that when the ambient temperature is, say 20"C, the current trough resistor 52 is such that the temperature of the amplifiers is maintained at the same value as the bridge resistors, say 80"C. The amplifiers' drifts, offsets and the like will be known or determinable.
If the ambient temperature increases the current through transistor 50 and resistor 52 decreases so that the temperature of the amplifiers decreases. If the ambient temperature increases to the preferred value of 80"C then the current through transistor 50 is reduced effectively to zero so that there is no heat transfer from resistor 52 to the amplifiers and they are at a temperature of 80"C. Thus at two widely spaced ambient temperatures, in this example 20"C and 80"C, the amplifiers will be 80"C so that their gains, offsets and the like are the same.Between, and beyond, the two selected temperatures of 20"C and 80"C, the amplifier characteristics may not track the ambient temperature but they can be made to track within quite acceptable limits which are a substantial improvement over a circuit in which there is no temperature control of the amplifiers.
According to an embodiment of the invention there is provided an electronic device 10 comprising at least one resistive element 14,16, 18,20 the temperature of which is to be controlled and the value of which is to be varied, in use, in dependence upon the magnitude of a physical parameter, other than temperature (referred to herein as "nonthermal parameter"), applied to the device, means 44,46,48, 50, for sensing the temperature of the resistive element or elements 14,16, 18,20 and arranged to control the temperature of a heating resistor 42 electrically isolated from said resistive element or elements but in heat-transferring relation thereto such that the temperature of said resistive element or elements is maintained substantially constant.
The resistive elements may be a resistance bridge 12, such as a resistance strain gauge bridge.
The strain gauge bridge 12 may be on the active part of a diaphragm 22 to which a pressure or force to be measured is applied. The heating resistor 42 may be on a non-active part of the diaphragm such that it is not subject to strain due to the applied pressure or force which might change its resistance value.
The diaphragm 22 may be a silicon diaphragm with the strain gauge resistive elements 14, 16, 18, 20 diffused into the silicon at areas of maximum strain and they may be arranged as a four-arm active bridge.
The silicon diaphragm 22 may be made from a base material with a central, square portion reduced in thickness to form the diaphragm with a relatively thick annular, peripheral portion 23. The strain gauge resistors would be positioned on the
diagraphm at areas of maximum strain, that is near the junction of the diaphragm with the thick annular
portion and the heating resistor 42 would be positioned on the annular portion 23. The heating
resistor may be a single resistor, as shown in Figure
1 at 42, which may extend around a substantial part
of the annular portion or it may comprise a plurality
of discrete resistors 42 arranged around the annular
portion and connected together in series, as seen in
Figure 3.
From one aspect thereof, the subject invention
resides in a method of measuring a non-thermal
physical parameter with temperature-sensitive
means, comprising, in combination, the steps of
imparting a predetermined temperature to the tem
perature-sensitive means, measuring said physical
parameter with said temperature-sensitive means to
environmental temperature variation affecting the
mentioned predetermined temperature, employing
an input, (12at 1 2b) of the temperature sensitive
means 14,16, 18, 20 themselves for effecting a
measurement of environmental temperature variation and restoring the temperature-sensitive means to their predetermined temperature in response to the measurement of environmental temperature variation effected with an input of the temperaturesensitive means themselves.
According to a preferred embodiment of the invention, energizable means distinct from the temperature-sensitive means 14, 16, 18,20 are provided for imparting the predetermined temperature to such temperature-sensitive means, and such distinct
means 42 are energized in response to the measurement of environmental temperature variation effected with the temperature-sensitive means 14, 16,18, 20 themselves to restore such temperature- sensitive means to their predetermined temperature.
As seen in Figure 3, the energizable distinct means 42 preferably are provided around the temperaturesensitive means 14, 16, 18, 20.
As disclosed above with the aid of Figures 2 and 3, the non-thermal physical parameter is applied to the temperature-sensitive means within a predetermined region 22b, and the energizable distinct means 42 are placed into heat-transfer relationship with the temperature-sensitive means, but outside the predetermined region 22b.
According to the illustrated preferred embodiment of the subject invention, the disclosed temperaturesensitive means have or are provided with electrically energizable elements 14, 16, 18,20 having a temperature coefficient, and the desired predetermined temperature is imparted to these elements. A constant energizing input is applied to the elements 14, 16, 18,20 or on bridge 12, such as shown at 28,34, in Figure 1. The non-thermal physical parameter is applied to, and an output reflecting such physical parameter is derived from, the elements 14, 16, 18, 20. The desired measurement of environmental temperature variation is effected with the aid of an input voltage of the elements 14, 16,18,20 having the above mentioned constant energizing input applied thereto.As disclosed above, a voltage divider 44, 46 and amplifier 48 may be employed for that purpose. The elements 14, 16, 18,20 are
restored to their derived predetermined temperature
in response to the latter measurement of environ
mental temperature variation effected with the aid of the input or input voltage across input terminals 12a
and 12b.
In principle, the means for imposing a predeter
mined temperature may be heating or cooling
means. According to the illustrated embodiment, the temperature-sensitive means 12 are heated to a
predetermined temperature, and the non-thermal
physical parameter is measured with such heated temperature-sensitive means 12. Also, such heated temperature-sensitive means are subjected to environmental temperature variation affecting the desired predetermined temperature, and such heated temperature-sensitive means themselves are employed for effecting a measurement of environmental temperature variation. These temperaturesensitive means 12 are then restored to their predetermined temperature in response to measurement of environmental temperature variation effected with these heated temperature-sensitive means themselves.
As seen in Figure 2, the distinct heater means 42 are provided around or encompass the temperaturesensitive means 12 or 14, 16, 18,20.
As disclosed above with the aid of Figures 2 and 3, the strain gauge bridge 12 is located on areas of maximum strain of a diaphragm 22 for receiving the non-thermal physical parameter, and the heater elements 42 or other means for imparting the predetermined temperature to the strain gauge bridge are located outside of the maximum strain areas.
The means for restoring the temperature-sensitive elements 14,16, 18, 20 or bridge 12 to their predetermined temperature may include an amplifier 48 connected between the means 44,46 for effecting the measurement of environmental temperature variation with the aid of the bridge input voltage and the heater 42 or other means for imparting the predetermined temperature to the strain gauge bridge 12. That amplifier 48 serves to energize the heater 42 or other means into restoration of the strain gauge bridge 12 to its predetermined temperature. As disclosed with the aid of transistor 50 and resistor 52 the preferred apparatus 10 includes means, such as that resistor 52 connected as shown in Figure 1 or preferably as shown in Figure 4, for exerting a temperature control on the amplifier means 48.
Where second amplifier means 40 are connected to the strain gauge bridge 12 for providing an output signal reflecting the non-thermal physical parameter, the apparatus 10 preferably includes means such as the second heating resistor 52 for exerting a temperature control on the first and second amplifier means 40 and 48. Such exerting means are in heat-transfer relationship with said amplifier means as indicated by dotted lines 56 for imparting an optimum temperature to such amplifier means, and means 50 are connected between the first amplifier means 48 and the energizable means 52 for regulating energization of such energizable means to maintenance of the optimum temperature.
Claims (31)
1. An electronic device comprising at least one resistive element the temperature of which is to be controlled and the value of which is to be varied, in use, in dependence upon the magnitude of a physical parameter, other than temperature, applied to the device, means for sensing the temperature of the resistive element or elements and arranged to control the temperature of a heating resistor electrically isolated from said resistive element or elements but in heat-transferring relation thereto such that the temperature of said resistive element or elements is maintained substantially constant.
2. A device according to claim 1, in which the resistive elements are connected to form a resistance bridge.
3. A device according to claim 2, in which the resistive elements form a resistance strain gauge bridge, such as a four-arm active bridge.
4. A device according to claim 3, in which the strain gauge bridge is on the active part of a diaphragm to which a pressure or force to be measured can be applied.
5. A device according to claim 4, in which the heating resistor is on a non-active part of the diaphragm such that it is not subject to strain due to the applied pressure or force.
6. A device according to claims 4 or 5, in which the diaphragm is a silicon diaphragm with the strain gauge resistive elements diffused into the silicon at areas of maximum strain.
7. A device according to claim 6, in which the silicon diaphragm is made from a base material with a central, circular portion reduced in thickness to form the diaphragm with a relatively thick annular, peripheral portion.
8. A device according to claim 7, in which the strain gauge resistive elements are positioned on the diaphragm at areas of maximum strain near the junction of the diaphragm with the thick annular portion and the heating resistor is positioned on the annular portion.
9. A device according to claim 8, in which the heating resistor is a single resistor which extends around a substantial part of the annular portion of the diaphragm.
10. A device according to claim 8, in which the heating resistor comprises a plurality of discrete resistors arranged around the annular portion of the diaphragm and connected together.
11. A device according to any one of the preceding claims, in which the means for sensing the temperature of the resistive element or elements comprises amplifier means having an input coupled to said resistive element or elements for deriving an input signal dependent upon the temperature thereof and an output coupled to said heating resistor to control the heating current therethrough.
12. A device according to claim 11, comprising a further heating resistor coupled to an output of said amplifying means and arranged in heat-transfer relationship with an active element or elements of said amplifying means whereby the temperature of said further heating resistor increases and decreases with decrease and increase in the ambient temperature thereby to minimise temperature changes in said active element or elements due to changes in ambient temperature.
13. A device according to claim 12, in which said resistive element or elements are coupled to further amplifying means and wherein the active element of said further amplifying means is coupled in heat transfer relationship with said further heating resistor (52).
14. An electronic device substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 or Figures 1 to 3 as modified by
Figure 4 of the accompanying drawings.
15. A method of measuring a non-thermal physical parameter with temperature-sensitive means, comprising in combination the steps of: imparting a predetermined temperature to said temperaturesensitive means; measuring said physical parameter with said temperature-sensitive means; subjecting said temperature-sensitive means to environmental temperature variation affecting said predetermined temperature; employing said temperature-sensitive means themselves for effecting a measurement of said environmental temperature variation; and restoring said temperature-sensitive means to said predetermined temperature in response to said measurement of said environmental temperature variation effected with said temperature-sensitive means themselves.
16. A method as claimed in claim 15, including the steps of: providing energizable means distinct from said temperature-sensitive means for imparting said predetermined temperature to said temperature-sensitive means; and energizing said distinct means in response to said measurement of said environmental temperature variation effected with said temperature-sensitive means themselves to restore said temperature-sensitive means to said predetermined temperature.
17. A method as claimed in claim 15 or 16 including the steps of: providing said temperaturesensitive means with electrically energizable elements having a temperature coefficient; imparting said predetermined temperature to said elements; applying a constant energizing input to said elements; applying said non-thermal physical parameter to said elements; deriving from said elements an output reflecting said physical parameter; effecting said measurement of said environmental temperature variation with the aid of an input voltage of said elements having said constant energizing input applied thereto; and restoring said elements to said predetermined temperature in response to the latter measurement of said environmental temperature variation effected with the aid of said input voltage.
18. A method as claimed in claim 16 or 17 as dependent on claim 16, including the steps of: applying said physical parameter to said temperature-sensitive means within a predetermined region; and placing said energizable distinct means into heat transfer relationship with said temperature-sensitive means, but outside said predetermined region.
19. A method as claimed in claim 16 or claim 17 or 18 as dependent on claim 16, wherein: said energizable distinct means is provided around said temperature-sensitive means.
20. A method of measuring a non-thermal physical parameter substantially as hereinbefore described with reference to the accompanying drawings.
21. Apparatus for measuring a non-thermal physical parameter with temperature-sensitive means, the improvement comprising in combination: first means connected to said temperature-sensitive means for measuring said physical parameter with said temperature-sensitive means; second means for imparting a predetermined temperature to said temperature-sensitive means, said temperaturesensitive means being subject to environmental temperature variation affecting said predetermined temperature; third means connected to said temperature-sensitive means for effecting a measurement of said environmental temperature variation with said temperature-sensitive means; and fourth means connected to said second and third means for restoring said temperature-sensitive means to said predetermined temperature in response to said measurement of said environmental temperature variation effected with said temperature-sensitive means.
22. Apparatus as claimed in claim 21, wherein: said second means include energizable means distint from said temperature-sensitive means for imparting said predetermined temperature to said temperature-sensitive means, and means connected to said second means for energizing said distinct means in response to said measurement of said environmental temperature variation effected with said temperature-sensitive means to restore said temperature-sensitive means to said predetermined temperature.
23. Apparatus as claimed in claim 22, wherein: said first means include means for applying said physical parameter to said temperature-sensitive means within a predetermined region, and said energizable distinct means are located outside said predetermined region in heat-transfer relationship with said temperature-sensitive means.
24. Apparatus as claimed in claim 23, wherein: said energizable distinct means encompass said temperature-sensitive means.
25. Apparatus as claimed in claim 21,22,23 or 24, wherein: said temperature-sensitive means include electrically energizable elements having a temperature coefficient, and means for applying said non-thermal physical parameter to said elements; said second means include means coupled to said elements for imparting said predetermined temperature to said elements; said first means include means connected to said elements for applying a constant energizing input to said elements, and means for deriving from said elements an output reflecting said physical parameter; said third means include means connected to said elements for effecting said measurement of said environmental temperature variation with the aid of an input voltage of said elements having said constant energizing input applied thereto; and said fourth means include means connected to said means for imparting said predetermined temperature to said elements, and to said means for effecting said measurement with the aid of said input voltage, for restoring said elements to said predetermined temperature in response to said measurement of said environmental temperature variation effected with the aid of said input voltage.
26. Apparatus as claimed in claim 25, wherein: said second means include means for heating said temperature-sensitive means to said predetermined temperature; and said fourth means include means for energizing said heating means to restore said temperature-sensitive means to said predetermined temperature in response to said measurement of said environmental temperature variation effected with said heated temperature-sensitive means.
27. Apparatus as claimed in claim 21, wherein: said temperature-sensitive means include a resistance strain gauge bridge, and means for applying said non-thermal physical parameter to said strain gauge bridge; said second means include means in heat-transfer relationship with said strain gauge bridge for imparting said predetermined temperature to said strain gauge bridge; said first means include means connected to said strain gauge bridge for applying a constant energizing input to said strain gauge bridge, and means for deriving from said strain gauge bridge, an output reflecting said physical parameter; said third means include means connected to said strain gauge bridge for effecting said measurement of said environmental temperature variation with the aid of an input voltage of said strain gauge bridge having said constant energizing input applied thereto; and said fourth means include means connected to said means for imparting said predetermined temperature to said strain gauge bridge, and to said means for effecting said mea surement with the aid of said input voltage for restoring said strain gauge bridge to said predetermined temperature in response to said measurement of said environmental temperature variation effected with the aid of said input voltage.
28. Apparatus as claimed in claim 27, wherein: said strain gauge bridge is located on areas of maximum strain of a diaphragm for receiving said non-thermal physical parameter; and said means for imparting said predetermined temperature to said strain gauge bridge are located outside of said maximum strain areas.
29. Apparatus as claimed in claim 27, wherein: said fourth means include amplifier means between said means for effecting said measurement with the aid of said input voltage and said means for imparting said predetermined temperature to said strain gauge bridge, for energizing the latter means into restoration of said strain gauge bridge to said predetermined temperature; and said apparatus include means for exerting a temperature control on said amplifier means.
30. Apparatus as claimed in claim 27, wherein: said fourth means include first amplifier means between said means for effecting said measurement with the aid of said input voltage and said means for imparting said predetermined temperature to said strain gauge bridge, for energizing the latter means into restoration of said strain gauge bridge to said predetermined temperature; said means for deriving from said strain gauge bridge an output include second amplifier means connected to said strain gauge bridge for providing an output signal reflecting said physical parameter; and said apparatus include means for exerting a temperature control on said first and second amplifier means.
31. Apparatus as claimed in claim 30, wherein: said exerting means include energizable means in heat-transfer relationship with said amplifier means for imparting an optimum temperature to said amplifier means, and means connected between said first amplifier means and said energizable means for regulating energization of said energizable means to maintenance of said optimum tem erature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08413510A GB2140588A (en) | 1983-05-27 | 1984-05-25 | Temperature-controlled electronic devices |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB838314846A GB8314846D0 (en) | 1983-05-27 | 1983-05-27 | Temperature controlled electronic devices |
| GB08413510A GB2140588A (en) | 1983-05-27 | 1984-05-25 | Temperature-controlled electronic devices |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8413510D0 GB8413510D0 (en) | 1984-07-04 |
| GB2140588A true GB2140588A (en) | 1984-11-28 |
Family
ID=26286259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08413510A Withdrawn GB2140588A (en) | 1983-05-27 | 1984-05-25 | Temperature-controlled electronic devices |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2140588A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109374158A (en) * | 2018-12-14 | 2019-02-22 | 华景传感科技（无锡）有限公司 | A kind of pressure sensor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1267848A (en) * | 1968-12-25 | 1972-03-22 | Matsushita Electrical Ind Comp | An infrared radiation detector |
| GB1431039A (en) * | 1972-05-25 | 1976-04-07 | Emi Ltd | Pressure transducer arrangements |
-
1984
- 1984-05-25 GB GB08413510A patent/GB2140588A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1267848A (en) * | 1968-12-25 | 1972-03-22 | Matsushita Electrical Ind Comp | An infrared radiation detector |
| GB1431039A (en) * | 1972-05-25 | 1976-04-07 | Emi Ltd | Pressure transducer arrangements |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109374158A (en) * | 2018-12-14 | 2019-02-22 | 华景传感科技（无锡）有限公司 | A kind of pressure sensor |
| CN109374158B (en) * | 2018-12-14 | 2024-08-13 | 华景传感科技（无锡）有限公司 | Pressure sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8413510D0 (en) | 1984-07-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4592665A (en) | Temperature-controlled systems for non-thermal parameter measurements | |
| US5137370A (en) | Thermoresistive sensor system | |
| CA1048622A (en) | Transistor pair temperature sensor | |
| US4798093A (en) | Apparatus for sensor compensation | |
| US10656036B2 (en) | Self-heated pressure sensor assemblies | |
| EP0239094B1 (en) | Semiconductor strain gauge bridge circuit | |
| US4587842A (en) | Arrangement for measuring the mass flow-rate of a flowing medium | |
| US3967188A (en) | Temperature compensation circuit for sensor of physical variables such as temperature and pressure | |
| US5343755A (en) | Strain gage sensor with integral temperature signal | |
| US5686826A (en) | Ambient temperature compensation for semiconductor transducer structures | |
| JPS6116026B2 (en) | ||
| JPS6038619A (en) | Sensing circuit for quantity of air | |
| US4498330A (en) | Gas detecting and monitoring device | |
| US5072614A (en) | Temperature compensating circuit | |
| US3882728A (en) | Temperature sensing circuit | |
| US4672847A (en) | Hot-wire flow rate measuring apparatus | |
| WO1988006719A1 (en) | Transducer signal conditioner | |
| US5122756A (en) | Linearization of a sensing bridge circuit output | |
| US4198868A (en) | Strain gauge apparatus and means for treating temperature dependency | |
| GB2140588A (en) | Temperature-controlled electronic devices | |
| JPH07139985A (en) | Thermal air flow measuring instrument | |
| SU1029011A1 (en) | Device for measuring medium parameters | |
| SU732707A1 (en) | Pressure sensor with frequency output | |
| JPH0835898A (en) | Temperature characteristic regulating method for semiconductor type pressure sensor | |
| JP2616150B2 (en) | Thermal air flow meter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |