DE102008003342A1 - Device with a differential capacitor and an evaluation circuit - Google Patents
Device with a differential capacitor and an evaluation circuit Download PDFInfo
- Publication number
- DE102008003342A1 DE102008003342A1 DE102008003342A DE102008003342A DE102008003342A1 DE 102008003342 A1 DE102008003342 A1 DE 102008003342A1 DE 102008003342 A DE102008003342 A DE 102008003342A DE 102008003342 A DE102008003342 A DE 102008003342A DE 102008003342 A1 DE102008003342 A1 DE 102008003342A1
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- evaluation circuit
- voltage
- differential capacitor
- voltage source
- voltages
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/945—Proximity switches
- H03K17/955—Proximity switches using a capacitive detector
-
- 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
- G01D5/24—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 capacitance
- G01D5/241—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 capacitance by relative movement of capacitor electrodes
- G01D5/2412—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 capacitance by relative movement of capacitor electrodes by varying overlap
-
- 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
- G01D5/24—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 capacitance
- G01D5/241—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 capacitance by relative movement of capacitor electrodes
- G01D5/2417—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 capacitance by relative movement of capacitor electrodes by varying separation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Amplifiers (AREA)
Abstract
Die Erfindung betrifft eine Vorrichtung mit einem Differenzkondensator (100) und einer Auswerteschaltung (1000), wobei die Auswerteschaltung (1000) ein Ausgangssignal (Ui) und eine spannungsgesteuerte Spannungsquelle (500) aufweist. Das Ausgangssignal (Ui) der Auswerteschaltung (1000) ist dabei zur Steuerung der spannungsgesteuerten Spannungsquelle (500) vorgesehen. Durch die spannungsgesteuerte Spannungsquelle (500) sind vier elektrische Spannungen erzeugbar. Dabei sind Schaltmittel (600) vorgesehen, derart, daß in einem ersten Betriebszustand zwei erste Spannungen (U1 und U4) und in einem zweiten Betriebszustand zwei zweite Spannungen (U2 und U3) der spannungsgesteuerten Spannungsquelle (500) an den Differenzkondensator (100) anlegbar sind.The invention relates to a device with a differential capacitor (100) and an evaluation circuit (1000), wherein the evaluation circuit (1000) has an output signal (Ui) and a voltage-controlled voltage source (500). The output signal (Ui) of the evaluation circuit (1000) is provided for controlling the voltage-controlled voltage source (500). By the voltage-controlled voltage source (500) four electrical voltages can be generated. In this case, switching means (600) are provided such that in a first operating state two first voltages (U1 and U4) and in a second operating state two second voltages (U2 and U3) of the voltage-controlled voltage source (500) to the differential capacitor (100) can be applied ,
Description
Stand der TechnikState of the art
Die Erfindung betrifft eine Vorrichtung mit einem Differenzkondensator und einer Auswerteschaltung.The The invention relates to a device with a differential capacitor and an evaluation circuit.
Bei kapazitiven Sensoren wird die Kapazität durch eine Veränderung der Lage von meist plattenförmigen Elektroden zueinander verändert. Entweder wird dabei der Plattenabstand um eine Auslenkung x variiert (Fall 1), oder die Größe des Bereiches, in dem sich zwei gegenüberstehende Platten überlappen (Fall 2), ändert sich. Dies kann beispielsweise durch Parallelverschiebung der Platten um eine Auslenkung x zueinander erfolgen.at Capacitive sensors will increase capacity through a change the location of mostly plate-shaped Changed electrodes to each other. Either the plate spacing is varied by one deflection x (case 1), or the size of the area, in which two opposite Overlap plates (Case 2), changes yourself. This can be done, for example, by parallel displacement of the plates to make a deflection x each other.
Im Fall 1 erhält man folgende Gesetzmäßigkeit: In case 1, the following law is obtained:
Hierbei ist x die Auslenkung, C0 die Grundkapazität, d0 der Plattenabstand (jeweils bei Auslenkung x = 0).Here, x is the deflection, C 0 is the basic capacitance, d 0 is the plate spacing (in each case with deflection x = 0).
Im Fall 2 erhält man: In case 2 you get:
Hierbei ist x die Auslenkung, C0 die Grundkapazität, x0 die Grundüberlapplänge (jeweils bei Auslenkung x = 0).Here, x is the deflection, C 0 is the basic capacitance, x 0 is the basic overlap length (in the case of displacement x = 0).
Häufig werden zwei Meßkondensatoren so verschaltet, daß sie eine gemeinsame Mittelelektrode besitzen (Differentialkondensator). In diesem Fall führt eine Auslenkung um den Weg x im ersten Kondensator zu einer Auslenkung –x im zweiten Kondensator. Die beiden Kapazitäten ändern sich dabei gegensinnig: Often two measuring capacitors are connected so that they have a common center electrode (differential capacitor). In this case, a deflection about the path x in the first capacitor leads to a deflection -x in the second capacitor. The two capacities change in opposite directions:
Mit solchen Anordnungen lassen sich zunächst Auslenkungen x messen. Wird die Mittelelektrode als mechanisches Feder-Masse-Dämpfersystem ausgebildet, läßt sich die Anordnung als Beschleunigungssensor einsetzen, bei dem die Beschleunigung in eine dazu proportionale Kraft und diese wiederum in eine dazu proportionale End-Auslenkung x umgesetzt wird. Typische Anwendungen sind Beschleunigungssensoren für die Crash-Erkennung (Airbagauslösung, Gurtstraffer), aber auch Messung der Fahrzeugneigung in Längs- und Querrichtung. Auch Coriolisbeschleunigungen lassen sich so bestimmen, mit deren Hilfe Drehraten gemessen werden können (Anwendung: z. B. Drehratensensor im ESP).With such arrangements can first measure deflections x. If the center electrode as a mechanical spring-mass damper system trained, can be use the arrangement as an acceleration sensor, in which the acceleration into a force proportional to it, and this in turn into a proportional force End deflection x is implemented. Typical applications are acceleration sensors for the Crash detection (airbag deployment, Belt tensioner), but also measurement of the vehicle inclination in the longitudinal and transverse direction. Coriolis accelerations can also be determined with their Help rotation rates can be measured (application: eg yaw rate sensor in the ESP).
Die heute in integrierten Schaltungen eingesetzten Meßverfahren sind meist Verfahren mit geschalteten Kondensatoren (switched-capacitor, SC), die mit hochfrequent getakteten Schaltern und festen Kondensatoren arbeiten, oft kombiniert mit Sigma-Delta-A/D-Wandlungstechniken.The today used in integrated circuits measuring method are mostly switched-capacitor methods (switched-capacitor, SC), with high frequency clocked switches and fixed capacitors often combined with sigma-delta A / D conversion techniques.
Offenbarung der ErfindungDisclosure of the invention
Aufgabetask
Die Aufgabe der Erfindung ist die Bestimmung der Auslenkung in einem Differenzkondensator nach den oben beschriebenen Fällen 1 und 2. Die Schaltung sollte einfach und robust sein. Das analoge Ausgangssignal sollte dabei proportional zur Auslenkung x sein. Diese Aufgabe wird durch die vorliegende Erfindung gelöst.The object of the invention is the determination of the deflection in a differential capacitor according to Cases 1 and 2 described above. The circuit should be simple and robust. The analog output signal should be proportional to the displacement x. This object is achieved by the present invention.
Vorteile der ErfindungAdvantages of the invention
Die Erfindung betrifft eine Vorrichtung mit einem Differenzkondensator und einer Auswerteschaltung, wobei die Auswerteschaltung ein Ausgangssignal Ui und eine spannungsgesteuerte Spannungsquelle aufweist. Das Ausgangssignal Ui der Auswerteschaltung ist dabei zur Steuerung der spannungsgesteuerten Spannungsquelle vorgesehen. Durch die spannungsgesteuerte Spannungsquelle sind vier elektrische Spannungen erzeugbar. Dabei sind Schaltmittel vorgesehen, derart daß in einem ersten Betriebszustand zwei erste Spannungen U1 und U4 und in einem zweiten Betriebszustand zwei zweite Spannungen U2 und U3 der spannungsgesteuerten Spannungsquelle an den Differenzkondensator anlegbar sind.The The invention relates to a device with a differential capacitor and an evaluation circuit, wherein the evaluation circuit is an output signal Ui and a voltage controlled voltage source. The output signal Ui the evaluation circuit is to control the voltage-controlled voltage source intended. There are four due to the voltage controlled voltage source electrical voltages can be generated. In this case, switching means are provided, such that in a first operating state, two first voltages U1 and U4 and in a second operating state, two second voltages U2 and U3 the voltage controlled voltage source to the differential capacitor can be applied.
Vorteilhaft ist, daß ein Taktgenerator vorgesehen ist, der mit den Schaltmitteln verbunden ist und mittels dessen der erste und zweite Betriebszustand schaltbar ist.Advantageous is that one Clock generator is provided, which is connected to the switching means is and by means of which the first and second operating state switchable is.
Besonders vorteilhaft ist, daß der Differenzkondensator eine um eine Auslenkung x auslenkbare Elektrode aufweist und das Ausgangssignal (Ui) der Auswerteschaltung proportional zur Auslenkung x ist.It is particularly advantageous that the differential capacitor has a deflectable by a deflection x electrode and the output signal (U i ) of the evaluation circuit is proportional to the deflection x.
Eine besonders vorteilhafte Ausgestaltung sieht vor, daß ein mikromechanischer Sensor die erfindungsgemäße Vorrichtung aufweist, wobei die auslenkbare Elektrode eine seismische Masse aufweist oder mit einer seismischen Masse verbunden ist. Hierdurch kann vorteilhaft ein mikromechanischer Beschleunigungssensor oder Drehratensensor geschaffen werden.A particularly advantageous embodiment provides that a micromechanical Sensor device of the invention wherein the deflectable electrode is a seismic mass or connected to a seismic mass. hereby can advantageously be a micromechanical acceleration sensor or Rotation rate sensor are created.
Die Erfindung erzeugt zwei gegenphasige Rechtecksignale bei einer Frequenz von z. B. 20 kHz, deren Amplituden von einer Steuerspannung Ui linear, aber gegenläufig abhängen. Die Rechtecksignalerzeugung geschieht auf einfache Weise über zwei Analog-Umschalter, die z. B. als CMOS-Schalter realisierbar sind. Die beiden Rechtecksignale werden auf die beiden äußeren Elektroden gegeben. Die Amplituden der Rechtecksignale werden so eingestellt, daß das Signal an der Mittelelektrode Null wird. Dann ist vorteilhaft die Steuerspannung Ui ein direkt proportionales Maß für die Auslenkung. Eine weitere vorteilhafte Eigenschaft des Auswerteprinzips ist, daß die angelegten Rechtecksignale im eingeschwungenen Zustand im Fall 1 keine zusätzlichen Kräfte auf die Mittelelektrode ausüben. Weiterhin vorteilhaft beeinflussen parasitäre Kapazitäten gegen Masse den Endwert des Meßergebnisses nicht.The invention generates two antiphase rectangular signals at a frequency of z. B. 20 kHz, the amplitudes of a control voltage U i linear, but in opposite directions. The square wave signal generation is done in a simple way via two analogue switches, the z. B. can be realized as a CMOS switch. The two square-wave signals are applied to the two outer electrodes. The amplitudes of the square wave signals are adjusted so that the signal at the center electrode becomes zero. Then, advantageously, the control voltage U i is a directly proportional measure of the deflection. A further advantageous feature of the evaluation principle is that the applied rectangular signals in the steady state in case 1 exert no additional forces on the center electrode. Furthermore advantageously, parasitic capacitances to ground do not influence the final value of the measurement result.
Zeichnungdrawing
Ausführungsbeispielembodiment
Hierbei ist Ub die Betriebsspannung. Ui ist die Spannung zur Steuerung der spannungsgesteuerten Spannungsquelle.Here U b is the operating voltage. U i is the voltage for controlling the voltage-controlled voltage source.
Ist der Regelkreis eingeschwungen, so gilt für die Integratorausgangsspannung: If the control loop has settled, then the following applies to the integrator output voltage:
Durch Einsetzen der Gleichungen (3) bzw. (4) läßt sich zeigen, daß sich die Integratorausgangsspannung Ui in beiden Fällen linear zur Auslenkung x verhält.By substituting the equations (3) and (4), it can be shown that the integrator output voltage U i behaves linearly with respect to the deflection x in both cases.
Die
im eingeschwungenen Fall sich einstellenden Spannungen an den Meßelektroden
des Differenzkondensators
Claims (4)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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DE102008003342A DE102008003342A1 (en) | 2008-01-07 | 2008-01-07 | Device with a differential capacitor and an evaluation circuit |
PCT/EP2008/067603 WO2009087022A1 (en) | 2008-01-07 | 2008-12-16 | Device having a difference capacitor and an evaluation circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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DE102008003342A DE102008003342A1 (en) | 2008-01-07 | 2008-01-07 | Device with a differential capacitor and an evaluation circuit |
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DE102008003342A1 true DE102008003342A1 (en) | 2009-07-09 |
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DE102008003342A Withdrawn DE102008003342A1 (en) | 2008-01-07 | 2008-01-07 | Device with a differential capacitor and an evaluation circuit |
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WO (1) | WO2009087022A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102015216438A1 (en) * | 2015-08-27 | 2017-03-02 | Carl Zeiss Smt Gmbh | Sensor arrangement for a lithography system, lithography system and method for operating a lithography system |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4054833A (en) * | 1976-06-11 | 1977-10-18 | Setra Systems, Inc. | Capacitance measuring system |
DE19929767C2 (en) * | 1999-06-29 | 2002-06-13 | Litef Gmbh | Accelerometer |
WO2001016606A1 (en) * | 1999-08-31 | 2001-03-08 | Analog Devices, Inc. | Feedback circuit for micromachined accelerometer |
-
2008
- 2008-01-07 DE DE102008003342A patent/DE102008003342A1/en not_active Withdrawn
- 2008-12-16 WO PCT/EP2008/067603 patent/WO2009087022A1/en active Application Filing
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102015216438A1 (en) * | 2015-08-27 | 2017-03-02 | Carl Zeiss Smt Gmbh | Sensor arrangement for a lithography system, lithography system and method for operating a lithography system |
US10514619B2 (en) | 2015-08-27 | 2019-12-24 | Carl Zeiss Smt Gmbh | Sensor arrangement for a lithography system, lithography system, and method for operating a lithography system |
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WO2009087022A1 (en) | 2009-07-16 |
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