WO1994017365A1 - Circuit for amplifying the output signal of a sensor - Google Patents

Circuit for amplifying the output signal of a sensor Download PDF

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Publication number
WO1994017365A1
WO1994017365A1 PCT/EP1994/000128 EP9400128W WO9417365A1 WO 1994017365 A1 WO1994017365 A1 WO 1994017365A1 EP 9400128 W EP9400128 W EP 9400128W WO 9417365 A1 WO9417365 A1 WO 9417365A1
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WO
WIPO (PCT)
Prior art keywords
output signal
amplifier
sensor
microcontroller
amplifying
Prior art date
Application number
PCT/EP1994/000128
Other languages
German (de)
French (fr)
Inventor
Roland Burghardt
Original Assignee
Itt Automotive Europe Gmbh
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
Application filed by Itt Automotive Europe Gmbh filed Critical Itt Automotive Europe Gmbh
Publication of WO1994017365A1 publication Critical patent/WO1994017365A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H03F1/303—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters using a switching device
    • H03F1/304—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters using a switching device and using digital means
    • 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
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/02—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/09—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by piezoelectric pick-up

Definitions

  • the invention relates to a circuit for amplifying the electrical output signal of a sensor with a high zero-point error, in particular for amplifying such sensor output signals with very low-frequency alternating components, with a feedback DC voltage amplifier.
  • the quality and the manufacturing outlay of control systems are largely influenced by the sensors and by the electronics required for the preparation and processing of the sensor signals.
  • the electrical signals of the individual specimens vary within wide limits.
  • the so-called Offset or the zero point error can be a multiple of the total output signal or the useful signal width.
  • the zero point deviations of the amplifier electronics are also not negligible. As a result of these specimen variations and temperature dependencies, complex calibration and temperature compensation measures and circuits are often required.
  • the present invention is therefore based on the object to develop a circuit of the type mentioned, which can be produced with little effort and which also . large specimen scatter does not require individual calibration measures.
  • this object can be achieved in that, in the case of a circuit for amplifying such a sensor signal, the amplifier output signal with the aid of a microcontroller control loop, which by feedback of the amplifier output signal via an analog / digital converter, via the Microcontroller, via a digital / analog converter and via an adder to the amplifier input, is compared to zero or to another specific value, the time behavior or the time constant of the comparison being predetermined by the data processing in the microcontroller.
  • the amplifier circuit according to the invention thus avoids the problems which are inevitably associated with the use of a capacitively coupled amplifier with a very low cut-off frequency, by using a simple DC voltage amplifier whose output signal is controlled by a microcontroller. loop is constantly adjusted to a certain value, preferably to "zero". With this microcontroller or with the microcontroller control loop, limit frequencies of 0.01 Hz or even smaller can be realized without difficulty. All zero-point errors of the sensor and the amplifier, whether they are caused by specimen scatter or by temperature response, are automatically compensated for via the control loop.
  • the circuit according to the invention is used to amplify the output signal of a piezoresistive acceleration sensor which is provided for motor vehicle control systems.
  • Fig. 1 shows in principle the most important components of a circuit arrangement according to the invention
  • a sensor S the output signal of which is to be amplified by a circuit according to the invention, is denoted by 1 in FIG. 1.
  • a DC voltage amplifier 3 here a simple operational amplifier.
  • the output signal of the amplifier 3 is transmitted via a series circuit consisting of an analog / digital tal converter 4, a microcontroller 5 (MC) and a digital / analog converter 6, and via the adder 2, in which the sensor output signal and the signal component derived from the amplifier output signal are superimposed, to the input of the amplifier 3 returned.
  • a control loop is formed, via which the output signal of the DC voltage amplifier 3 is constantly adjusted to "zero" with a predetermined time constant or a predetermined time behavior.
  • a control loop is formed, via which the output signal of the DC voltage amplifier 3 is constantly adjusted to "zero" with a predetermined time constant or a predetermined time behavior.
  • the lower limit frequency of the amplifier circuit according to FIG. 1 is 0.01 Hz. Slow changes in the sensor output signal, which are still above this very low frequency, lead to a clear, evaluable change in the Amplifier output signal. Even slower changes are completely compensated for by the microcroller roller.
  • the timing of the control loop can be determined in a very simple manner by appropriate training and programming of the microcontroller 5, 5 'and can be adapted very quickly to the respective requirements by changing the programming. For this reason, the amplifier circuit according to the invention is suitable for processing or conditioning the output signals of different sensor types.
  • the use of a microcontroller to form the control loop does not lead to an increase in the manufacturing outlay in the very common cases in which a microcomputer is available for signal processing anyway.
  • FIG. 2 shows the course of the amplifier output signal (FIG. 2C) as a function of the sensor output signal (FIG. 2A) in one exemplary embodiment.
  • the offset that is to say the potential present at the sensor output in the idle state
  • An acceleration process results in an approximately abrupt voltage increase of 0. 1 V.
  • This signal change leads to an amplified, evaluable signal at the output C of the amplifier 3; this is shown in Fig. 2C.
  • the potential jump at time t 1 at sensor output A of 0.1 V. to a potential jump of 1 V at the amplifier output C.
  • the microcontroller control loop with which the amplifier output signal is constantly adjusted according to the invention, has the effect that the potential of 1 V decays with the time constant specified by the programming of the microcontroller; the time constant is, for example, on the order of 10-60 seconds.
  • FIG. 2B illustrates the course of the compensation or output signal of the digital / analog converter 6 or the microcontroller 5 ', which is superimposed on the sensor output signal in the adder stage 2.
  • the diagrams according to FIG. 2 are of course an idealized representation; the zero point error of the amplifier 3 has been neglected; the potential change at the sensor output was assumed to be an ideal jump. It should also be noted that the compensation signal is generally generated by averaging a pulse-shaped signal formed in the control loop.

Abstract

A circuit for amplifying the electric output signal of a sensor (1) affected by high residual deflection has a direct voltage amplifier (3) and a microcontroller regulating loop (4 to 6, 5'). By feeding back the amplifier output signal through the regulating loop, the output signal of the amplifier (3) is compensated by a time constant predetermined by means of the microcontroller (5, 5').

Description

Schaltung zur Verstärkung des AusgangsSignals eines SensorsCircuit for amplifying the output signal of a sensor
Die Erfindung bezieht sich auf eine Schaltung zur Verstärkung des elektrischen Ausgangssignals eines mit hohem Nullpunkt¬ fehler behafteten Sensors, insbesondere zur Verstärkung von solchen Sensor-Ausgangssignalen mit sehr niedrigfrequenten Wechselanteilen, mit einem rückgekoppelten Gleichspannungs- verstärker.The invention relates to a circuit for amplifying the electrical output signal of a sensor with a high zero-point error, in particular for amplifying such sensor output signals with very low-frequency alternating components, with a feedback DC voltage amplifier.
Die Qualität und der Herstellungsaufwand von Regelungssyste¬ men werden weitgehend von den Sensoren und von der erforder¬ lichen Elektronik zur Aufbereitung und Verarbeitung der Sen¬ sorsignale beeinflußt. Bei manchen Sensortypen, z.B. bei Sen¬ soren auf Halbleiterbasis, variieren die elektrischen Signale der einzelnen Exemplare in weiten Grenzen. Hinzu kommt eine hohe Temperaturabhängigkeit. Der sogen. Offset oder der Null¬ punktfehler kann ein Vielfaches des gesamten Ausgangssignals bzw. der Nutzsignalbreite betragen. Bei den benötigten hohen Verstärkungen der schwachen Sensorsignale sind auch die Null¬ punkt-Abweichungen der Verstärkerelektronik nicht zu vernach¬ lässigen. Als Folge dieser Exemplarstreuungen und Temperatur¬ abhängigkeiten werden häufig aufwendige Kalibier- und Tempe¬ raturkompensationsmaßnahmen und -Schaltungen erforderlich. Zum Eliminieren des Nullpunktfehlers ist es natürlich mög¬ lich, dem Verstärker kapazitiv an den Sensorausgang anzukop¬ peln, sofern Gleichanteile des Sensorausgangssignals nicht interessieren. Bei Verstärkerschaltungen mit sehr niedrigen unteren Grenzfrequenzen (< 1Hz) werden solche Schaltungen je¬ doch recht aufwendig, da Kondensatoren hoher Kapazität benö¬ tigt werden.The quality and the manufacturing outlay of control systems are largely influenced by the sensors and by the electronics required for the preparation and processing of the sensor signals. With some sensor types, for example with sensors based on semiconductors, the electrical signals of the individual specimens vary within wide limits. In addition, there is a high temperature dependency. The so-called Offset or the zero point error can be a multiple of the total output signal or the useful signal width. With the required high amplifications of the weak sensor signals, the zero point deviations of the amplifier electronics are also not negligible. As a result of these specimen variations and temperature dependencies, complex calibration and temperature compensation measures and circuits are often required. To eliminate the zero point error, it is of course possible to capacitively couple the amplifier to the sensor output, provided that the DC components of the sensor output signal are not of interest. In the case of amplifier circuits with very low lower limit frequencies (<1 Hz), however, such circuits are quite complex since capacitors of high capacitance are required.
Der vorliegenden Erfindung liegt daher die Aufgabe zugrunde, eine Schaltung der eingangs genannten Art zu entwickeln, die sich mit geringem Aufwand herstellen läßt und die auch bei . großen Exemplarstreuungen ohne individuelle Kalibriermaßnah¬ men auskommt.The present invention is therefore based on the object to develop a circuit of the type mentioned, which can be produced with little effort and which also . large specimen scatter does not require individual calibration measures.
Es hat sich gezeigt, daß diese Aufgabe dadurch gelöst werden kann, daß bei einer Schaltung zur Verstärkung eines solchen Sensorsignals das Verstärkerausgangssignal mit Hilfe einer MicrocontroUer-Regelschleife, die durch Rückführung des Ver¬ stärker-Ausgangssignals über einen Analog/Digital-Wandler, über den Microcontroller, über einen Digital/Analog-Wandler und über eine Addierstufe zu dem Verstärkereingang gebildet wird, auf Null oder auf einen anderen bestimmten Wert abge¬ glichen wird, wobei das Zeitverhalten bzw. die Zeitkonstante des Abgleichs durch die Datenverarbeitung im Microcontroller vorgegeben ist.It has been shown that this object can be achieved in that, in the case of a circuit for amplifying such a sensor signal, the amplifier output signal with the aid of a microcontroller control loop, which by feedback of the amplifier output signal via an analog / digital converter, via the Microcontroller, via a digital / analog converter and via an adder to the amplifier input, is compared to zero or to another specific value, the time behavior or the time constant of the comparison being predetermined by the data processing in the microcontroller.
Die erfindungsgemäße Verstärkerschaltung umgeht also die mit der Verwendung eines kapazitiv gekoppelten Verstärkers sehr niedriger Grenzfrequenz zwangsläufig verbundenen Probleme, indem ein einfacher Gleichspannungsverstärker verwendet wird, dessen Ausgangssignal mit Hilfe einer Microcontroller-Regel- schleife ständig auf einen bestimmenten Wert, vorzugsweise auf "Null", abgeglichen wird. Mit diesem Microcontroller bzw. mit der MicrocontroUer-Regelschleife können ohne Schwierig¬ keiten Grenzfrequenzen von 0,01 Hz oder noch kleinere reali¬ siert werden. Sämtliche Nullpunktfehler des Sensors und des Verstärkers, seien sie durch Exemplarstreuung oder durch Tem¬ peraturgang verursacht, werden automatisch über die Regel¬ schleife kompensiert.The amplifier circuit according to the invention thus avoids the problems which are inevitably associated with the use of a capacitively coupled amplifier with a very low cut-off frequency, by using a simple DC voltage amplifier whose output signal is controlled by a microcontroller. loop is constantly adjusted to a certain value, preferably to "zero". With this microcontroller or with the microcontroller control loop, limit frequencies of 0.01 Hz or even smaller can be realized without difficulty. All zero-point errors of the sensor and the amplifier, whether they are caused by specimen scatter or by temperature response, are automatically compensated for via the control loop.
Nach einem vorteilhaften Ausführungsbeispiel wird die erfin¬ dungsgemäße Schaltung zur Verstärkung des AusgangsSignals ei¬ nes piezoresistiven Beschleunigungsaufnehmers, der für Kraft¬ fahrzeug-Regelungssysteme vorgesehen ist, verwendet.According to an advantageous exemplary embodiment, the circuit according to the invention is used to amplify the output signal of a piezoresistive acceleration sensor which is provided for motor vehicle control systems.
Weitere Merkmale, Vorteile und Anwendungsmöglichkeiten gehen aus der folgenden Beschreibung eines Ausführungsbeispiels an¬ hand der beigefügten Abbildungen hervor. Es zeigenFurther features, advantages and possible uses are evident from the following description of an exemplary embodiment with reference to the attached figures. Show it
Fig. 1 in Prinzipdarstellung die wichtigsten Komponenten einer Schaltungsanordnung nach der Erfindung undFig. 1 shows in principle the most important components of a circuit arrangement according to the invention and
Fig. 2 Diagramme zur Veranschaulichung der Arbeitsweise der Schaltung nach Fig. 1.2 diagrams to illustrate the operation of the circuit of FIG .. 1
Ein Sensor S, dessen Ausgangssignal durch eine Schaltung nach der Erfindung verstärkt werden soll, ist in Fig. 1 mit 1 be¬ zeichnet. Über eine Addierstufe 2, in der zur Nullpunkt-Kor¬ rektur eine bestimmte Spannungskomponente überlagert wird, wird das Ausgangssignal des Sensors 1 einem Gleichspannungs- verstärker 3, hier einem einfachen Operationsverstärker, zu¬ geführt. Erfindungsgemäß wird das Ausgangssignal des Verstär¬ kers 3 über eine Serienschaltung, die aus einem Analog/Digi- tal-Wandler 4, einem Microcontroller 5 (MC) und einem Digi¬ tal/Analog-Wandler 6 besteht, und über die Addierstufe 2, in der das Sensorausgangssignal und die von dem Verstärkeraus¬ gangssignal abgeleitete Signalkomponente überlagert werden, zum Eingang des Verstärkers 3 zurückgeführt.A sensor S, the output signal of which is to be amplified by a circuit according to the invention, is denoted by 1 in FIG. 1. Via an adder stage 2, in which a certain voltage component is superimposed for the zero point correction, the output signal of the sensor 1 is fed to a DC voltage amplifier 3, here a simple operational amplifier. According to the invention, the output signal of the amplifier 3 is transmitted via a series circuit consisting of an analog / digital tal converter 4, a microcontroller 5 (MC) and a digital / analog converter 6, and via the adder 2, in which the sensor output signal and the signal component derived from the amplifier output signal are superimposed, to the input of the amplifier 3 returned.
Mit Hilfe des Microcontrollers 5 wird eine Regelschleife ge¬ bildet, über die das Ausgangssingal des Gleichspannungsver¬ stärkers 3 mit einer vorgegebenen Zeitkonstante bzw. einem vorgegebenen Zeitverhalten ständig auf "Null" abgeglichen wird. Auf diese Weise wird automatisch, d.h. ohne jegliche Kalibrierung - ein Offset des Sensors 1 bzw. das in der Ruhe¬ lage des Sensors 1 anliegende Ausgangspotential, ebenso wie ein Offset oder Nullpunktfehler des Verstärkers 3, durch Tem¬ peraturänderungen bedingte Verschiebungen des Nullpunktes usw. ausgeglichen. Schnelle, d.h. oberhalb einer vorgegebenen Grenzfrequenz liegende Änderungen des Ausgangssignals des Sensors 1 werden dagegen in dem Gleichspannungsverstärker 3 verstärkt und stehen dann als weiterverarbeitbares, analoges Signal an dem Analogausgang des Verstärkers 3 und als digita¬ les Signal an dem Digitalausgang des Microcontrollers 5 zur Verfügung.With the help of the microcontroller 5, a control loop is formed, via which the output signal of the DC voltage amplifier 3 is constantly adjusted to "zero" with a predetermined time constant or a predetermined time behavior. In this way, automatically, i.e. without any calibration - an offset of the sensor 1 or the output potential present in the rest position of the sensor 1, as well as an offset or zero point error of the amplifier 3, compensated for shifts in the zero point, etc. caused by temperature changes. Fast, i.e. In contrast, changes in the output signal of the sensor 1 which lie above a predetermined limit frequency are amplified in the DC voltage amplifier 3 and are then available as a further processable, analog signal at the analog output of the amplifier 3 and as a digital signal at the digital output of the microcontroller 5.
Nach einem Ausführungsbeispiel der Erfindung, bei dem als Sensor 1 ein piezoresistiver Beschleunigungsaufnehmer vorge¬ sehen ist, der zur Messung von Aufbaubeschleunigungen als Re¬ gelgröße eines Fahrwerkregelungssystems für Kraftfahrzeuge dient, liegt die untere Grenzfrequenz der Verstärkerschaltung nach Fig. 1 bei 0,01 Hz. Langsame, aber noch über dieser sehr niedrigen Frequenz liegende Änderungen des Sensor-Ausgangssi¬ gnals führen zu einer deutlichen, auswertbaren Änderung des Verstärker-Ausgangssignals. Noch langsamere Änderungen werden durch die Microcrontoller-Regelschleife vollständig kompen¬ siert.According to one embodiment of the invention, in which a piezoresistive acceleration sensor is provided as sensor 1, which serves to measure body accelerations as the control variable of a chassis control system for motor vehicles, the lower limit frequency of the amplifier circuit according to FIG. 1 is 0.01 Hz. Slow changes in the sensor output signal, which are still above this very low frequency, lead to a clear, evaluable change in the Amplifier output signal. Even slower changes are completely compensated for by the microcroller roller.
Durch die Zusammenfassung in einem gestrichelt umrandeten Baustein 5' ist symbolisch angedeutet, daß die beiden Wandler 4 und 6 mit dem Microcontroller 5 zu einer baulichen Einheit zusammengefaßt werden können.The combination in a dashed-edged module 5 'symbolically indicates that the two converters 4 and 6 can be combined with the microcontroller 5 to form a structural unit.
Das Zeitverhalten der Regelschleife läßt sich durch entspre¬ chende Ausbildung und Programmierung des Microcontrollers 5,5' in sehr einfacher Weise festlegen und durch Änderung der Programmierung sehr schnell den jeweiligen Forderungen anpas¬ sen. Aus diesem Grunde eignet sich die Verstärkerschaltung nach der Erfindung zur Verarbeitung bzw. Aufbereitung der Ausgangssignale unterschiedlicher Sensoren-Typen. Die Verwen¬ dung eines Microcontrollers zur Ausbildung der Regelschleife führt in den sehr häufigen Fällen, in denen ohnehin zur Si¬ gnalverarbeitung ein Microcomputer vorhanden ist, zu keiner Erhöhung des Herstellungsaufwandes.The timing of the control loop can be determined in a very simple manner by appropriate training and programming of the microcontroller 5, 5 'and can be adapted very quickly to the respective requirements by changing the programming. For this reason, the amplifier circuit according to the invention is suitable for processing or conditioning the output signals of different sensor types. The use of a microcontroller to form the control loop does not lead to an increase in the manufacturing outlay in the very common cases in which a microcomputer is available for signal processing anyway.
Fig. 2 zeigt in einem Ausführungsbeispiel den Verlauf des Verstärker-Ausgangssignals (Fig. 2C) in Abhängigkeit von dem Sensor-Ausgangssignal (Fig. 2A) . In diesem Ausführungsbei¬ spiel bzw. bei dem hier verwendeten Sensorexemplar beträgt der Offset, d.h. das im Ruhezustand an dem Sensorausgang an¬ stehende Potential, bereits 0,5 V. Durch einen Beschleuni¬ gungsvorgang wird hier eine annähernd sprungförmige Span¬ nungserhöhung um 0,1 V hervorgerufen. Diese Signaländerung führt zu einem verstärkten, auswertbaren Signal am Ausgang C des Verstärkers 3; dies gibt Fig. 2C wieder. Der Potential¬ sprung zum Zeitpunkt t1 am Sensorausgang A von 0,1 V führt zu einem Potentialsprung von 1 V am Verstärkerausgang C. Die MicrocontroUer-Regelschleife, mit der erfindungsgemäß das Verstärkerausgangssignal ständig abgeglichen wird, bewirkt, daß das Potential von 1 V mit der durch die Programmierung des Microcontrollers vorgegebenen Zeitkonstanten abklingt; die Zeitkonstante liegt beispielsweise in der Größenordnung von 10 - 60 Sekunden.FIG. 2 shows the course of the amplifier output signal (FIG. 2C) as a function of the sensor output signal (FIG. 2A) in one exemplary embodiment. In this exemplary embodiment or in the case of the sensor specimen used here, the offset, that is to say the potential present at the sensor output in the idle state, is already 0.5 V. An acceleration process results in an approximately abrupt voltage increase of 0. 1 V. This signal change leads to an amplified, evaluable signal at the output C of the amplifier 3; this is shown in Fig. 2C. The potential jump at time t 1 at sensor output A of 0.1 V. to a potential jump of 1 V at the amplifier output C. The microcontroller control loop, with which the amplifier output signal is constantly adjusted according to the invention, has the effect that the potential of 1 V decays with the time constant specified by the programming of the microcontroller; the time constant is, for example, on the order of 10-60 seconds.
Fig. 2B veranschaulicht den Verlauf des Ausgleichs- bzw. Aus¬ gangssignals des Digital/Analog-Wandlers 6 bzw. des Microcon¬ trollers 5', das in der Addierstufe 2 dem Sensor-Ausgangssi¬ gnal überlagert wird.FIG. 2B illustrates the course of the compensation or output signal of the digital / analog converter 6 or the microcontroller 5 ', which is superimposed on the sensor output signal in the adder stage 2.
Es handelt sich bei den Diagrammen nach Fig. 2 natürlich um eine idealisierte Darstellung, der Nullpunktfehler des Ver¬ stärkers 3 wurde vernachlässigt; die Potentialänderung am Sensorausgang wurde als idealer Sprung angenommen. Ferner ist zu beachten, daß im allgemeinen das Ausgleichssignal durch Mittelwertbildung eines in der Regelschleife gebildeten puls- förmigen Signals erzeugt wird. The diagrams according to FIG. 2 are of course an idealized representation; the zero point error of the amplifier 3 has been neglected; the potential change at the sensor output was assumed to be an ideal jump. It should also be noted that the compensation signal is generally generated by averaging a pulse-shaped signal formed in the control loop.

Claims

PatentansprücheClaims
Schaltung zur Verstärkung des elektrischen Ausgangssi¬ gnals eines mit hohem Nullpunktfehler behafteten Sensors, insbesondere zur Verstärkung von Signalen mit sehr nie- drigfrequenten Wechselanteilen, mit einem rückgekoppelten Gleichspannungsverstärker, dadurch g e k e n n ¬ z e i c h n e t , daß das Ausgangssignal des Verstärkers (3) mit Hilfe einer MicrocontroUer-Regelschleife (4 - 6,5'), die durch Rückführung des Verstärker-Aus- gangssignals über einen Analog/Digital-Wandler (4), über den Microcontroller (5), über einen Digital/Analog-Wand- ler (6) und über eine Addierstufe (2) zu dem Verstärker¬ eingang gebildet wird, mit einem durch die Datenverarbei¬ tung im Microcontroller vorgegebenen Zeitverhalten bzw. einer vorgegebenen Zeitkonstanten auf Null oder auf einen anderen bestimmten Wert abgeglichen wird.Circuit for amplifying the electrical output signal of a sensor with a high zero-point error, in particular for amplifying signals with very low-frequency alternating components, with a feedback DC voltage amplifier, characterized in that the output signal of the amplifier (3) using a microcontroller Control loop (4 - 6.5 '), which by feedback of the amplifier output signal via an analog / digital converter (4), via the microcontroller (5), via a digital / analog converter (6) and is formed via an adder stage (2) to the amplifier input, with a time behavior or a predetermined time constant predetermined by the data processing in the microcontroller or a predetermined time constant.
Schaltung nach Anspruch 1, dadurch g e k e n n ¬ z e i c h n e t , daß die untere Grenzfrequenz der Ver¬ stärkung in der Größenordnung von 0,1 oder 0,01 Hz liegt.Circuit according to claim 1, characterized in that the lower cut-off frequency of the amplification is of the order of 0.1 or 0.01 Hz.
Verwendung der Schaltung nach Anspruch 1 oder 2 zur Ver¬ stärkung des Ausgangssignals eines piezoresistiven Be¬ schleunigungssensors (1) für Kraftfahrzeug-Regelungssy¬ steme. Use of the circuit according to claim 1 or 2 for amplifying the output signal of a piezoresistive acceleration sensor (1) for motor vehicle control systems.
PCT/EP1994/000128 1993-01-27 1994-01-20 Circuit for amplifying the output signal of a sensor WO1994017365A1 (en)

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DE19934302184 DE4302184A1 (en) 1993-01-27 1993-01-27 Circuit for amplifying the output signal of a sensor

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