EP0462314B1 - Circuit arrangement to supply an earthed load with load independent current - Google Patents

Circuit arrangement to supply an earthed load with load independent current Download PDF

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Publication number
EP0462314B1
EP0462314B1 EP90120362A EP90120362A EP0462314B1 EP 0462314 B1 EP0462314 B1 EP 0462314B1 EP 90120362 A EP90120362 A EP 90120362A EP 90120362 A EP90120362 A EP 90120362A EP 0462314 B1 EP0462314 B1 EP 0462314B1
Authority
EP
European Patent Office
Prior art keywords
load
voltage
circuit arrangement
independent current
earthed
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.)
Revoked
Application number
EP90120362A
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German (de)
French (fr)
Other versions
EP0462314A2 (en
EP0462314A3 (en
Inventor
Helmut Dr. Brock
Wolfgang Freitag
Reinhard Dr. Vogt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Training Center GmbH and Co KG
Original Assignee
Hartmann and Braun AG
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Publication date
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Application filed by Hartmann and Braun AG filed Critical Hartmann and Braun AG
Publication of EP0462314A2 publication Critical patent/EP0462314A2/en
Publication of EP0462314A3 publication Critical patent/EP0462314A3/en
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Publication of EP0462314B1 publication Critical patent/EP0462314B1/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices

Definitions

  • the invention relates to a circuit arrangement for supplying an earthed consumer with an impressed current representing a measured value according to the preamble of the claim.
  • DD PS 240 086 describes a circuit arrangement for supplying a consumer in accordance with the preamble of the claim.
  • the inputs of a control amplifier are supplied with the setpoint voltage forming a measured value and an actual value voltage, the actual value voltage being tapped at a current measuring resistor through which the impressed current flows.
  • FIG. 1 An arrangement known from "Semiconductor Circuit Technology", 1971, page 340 from Tietze / Schenk is shown in FIG. 1. It consists of a control amplifier with a differential stage 2 and a controllable current source 1. The control amplifier supplies an impressed current I which is dependent on a setpoint voltage 3 and flows through the load 5 of a consumer.
  • the circuit arrangement forms a control circuit in which the actual value voltage 7 is used at a current measuring resistor 4 as a feedback control variable. For consumers which are connected to earth 8 on one side, there is the problem that the actual value voltage 7 representing the measured value is superimposed by a common mode signal which can fluctuate over a wide voltage range.
  • the invention has for its object to design the circuit arrangement of the type mentioned in such a way that the reaction of the common mode voltage caused by the burden on the consumer to the control amplifier is minimized.
  • the object is achieved according to the invention in a circuit arrangement of the type mentioned at the outset with the measures specified in the characterizing part of the claim.
  • the principle of the floating reference point is used here.
  • the reference potential for the setpoint voltage and the control amplifier is adjusted so that it corresponds to the voltage drop across the consumer burden. Due to this virtual reference potential, the actual value voltage 7 is free of common mode via the measuring resistor for the control amplifier.
  • the floating power supply is realized by a voltage regulator, the reference potential of which is the voltage at the load of the consumer.
  • FIG. 2 shows the basic circuit diagram of an embodiment of the invention.
  • a differential stage 2 and a voltage-controlled current source 1 together form a control amplifier.
  • the control amplifier supplies an impressed current I which is dependent on a setpoint voltage 3 and which flows through the load 5 of a consumer and causes a voltage drop U there.
  • the consumer is connected to ground 8 on one side.
  • a current measuring resistor 4 is connected electrically in series with the burden 5.
  • the current I causes a voltage drop across the current measuring resistor 4, the actual value voltage 7, which is supplied to the non-inverting input of the differential stage 2.
  • the voltage U falling across the load 5 of the consumer is fed to the input of a high-impedance impedance converter 6 with the gain one.
  • the potential at the output of the impedance converter 6 at the switching point 9 is led to the inverting input of the differential stage 2 and it also serves as a reference potential for the setpoint voltage 3.
  • This circuit-technical measure has the effect that the potential at the switching point 9 for the closed control loop and the setpoint voltage 3 , which represents the respective measured value, corresponds to the voltage U at the load 5 of the consumer.
  • the potential at the node 9 is always tracked by the impedance converter 6 so that the differential voltage 2 of the actual value voltage 7 is not superimposed by common mode signals.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Amplifiers (AREA)
  • Control Of Voltage And Current In General (AREA)

Description

Die Erfindung betrifft eine Schaltungsanordnung zur Speisung eines geerdeten Verbrauchers mit einem einen Meßwert darstellenden eingeprägten Strom nach dem Oberbegriff des Anspruches.The invention relates to a circuit arrangement for supplying an earthed consumer with an impressed current representing a measured value according to the preamble of the claim.

In der DD PS 240 086 ist eine Schaltungsanordnung zur Speisung eines Verbrauchers gemäß dem Oberbegriff des Anspruches beschrieben. Den Eingängen eines Regelverstärkers werden die einen Meßwert bildende Sollwertspannung und eine Istwertspannung zugeführt, wobei die Istwertspannung an einem vom eingeprägten Strom durchflossenen Strommeßwiderstand abgegriffen wird.DD PS 240 086 describes a circuit arrangement for supplying a consumer in accordance with the preamble of the claim. The inputs of a control amplifier are supplied with the setpoint voltage forming a measured value and an actual value voltage, the actual value voltage being tapped at a current measuring resistor through which the impressed current flows.

Eine aus "Halbleiter-Schaltungstechnik", 1971, Seite 340 von Tietze/Schenk bekannte Anordnung ist in Fig. 1 dargestellt. Sie besteht aus einem Regelverstärker mit einer Differenzstufe 2 und einer steuerbaren Stromquelle 1. Der Regelverstärker liefert einen von einer Sollwertspannung 3 abhängigen eingeprägten Strom I, der die Bürde 5 eines Verbrauchers durchfließt. Die Schaltungsanordnung bildet einen Regelkreis, in dem die Istwertspannung 7 an einem Strommeßwiderstand 4 als rückgeführte Regelgröße genutzt wird. Für Verbraucher, die einseitig an Erde 8 angebunden sind, besteht das Problem, daß die den Meßwert repräsentierende Istwertspannung 7 von einem Gleichtaktsignal überlagert ist, welches über einen weiten Spannungsbereich schwanken kann.An arrangement known from "Semiconductor Circuit Technology", 1971, page 340 from Tietze / Schenk is shown in FIG. 1. It consists of a control amplifier with a differential stage 2 and a controllable current source 1. The control amplifier supplies an impressed current I which is dependent on a setpoint voltage 3 and flows through the load 5 of a consumer. The circuit arrangement forms a control circuit in which the actual value voltage 7 is used at a current measuring resistor 4 as a feedback control variable. For consumers which are connected to earth 8 on one side, there is the problem that the actual value voltage 7 representing the measured value is superimposed by a common mode signal which can fluctuate over a wide voltage range.

In "Halbleiter-Schaltungstechnik", 1980, Seite 667 bis 670 von Tietze/Schenk werden die durch unerwünschte Gleichtaktsignale hervorgerufenen Probleme diskutiert und als Abhilfe ist in Abschnitt 25.1.3 "Trennverstärker" vorgeschlagen, die Signal- und Masseverbindung zwischen dem Sender und dem Empfänger aufzutrennen und den Senderteil mit einer schwimmenden Masseverbindung zu versehen."Semiconductor circuit technology", 1980, pages 667 to 670 by Tietze / Schenk discusses the problems caused by undesired common-mode signals and, as a remedy, section 25.1.3 "Isolation amplifier" proposes the signal and ground connection between the transmitter and the receiver to separate and to provide the transmitter part with a floating ground connection.

Der Erfindung liegt die Aufgabe zugrunde, die Schaltungsanordnung der eingangs genannten Art so auszubilden, das die Rückwirkung der von der Bürde des Verbrauchers hervorgerufenen Gleichtaktspannung auf den Regelverstärker minimiert wird.The invention has for its object to design the circuit arrangement of the type mentioned in such a way that the reaction of the common mode voltage caused by the burden on the consumer to the control amplifier is minimized.

Die Aufgabe wird bei einer Schaltungsanordnung der eingangs genannten Art erfindungsgemäß mit den im Kennzeichen des Anspruches angegebenen Maßnahmen gelöst. Um das Problem der Gleichtaktunterdrückung zu umgehen, wird hier das Prinzip des schwebenden Bezugspunktes angewendet. Das Bezugspotential für die Sollwertspannung und den Regelverstärker wird so nachgeführt, daß es dem Spannungsabfall über die Verbraucherbürde entspricht. Durch dieses virtuelle Bezugspotential ist die Istwertspannung 7 über den Meßwiderstand für den Regelverstärker gleichtaktfrei. Die schwebende Stromversorgung wird durch einen Spannungsregler realisiert, dessen Bezugspotential die Spannung an der Bürde des Verbrauchers ist.The object is achieved according to the invention in a circuit arrangement of the type mentioned at the outset with the measures specified in the characterizing part of the claim. To avoid the problem of common mode rejection, the principle of the floating reference point is used here. The reference potential for the setpoint voltage and the control amplifier is adjusted so that it corresponds to the voltage drop across the consumer burden. Due to this virtual reference potential, the actual value voltage 7 is free of common mode via the measuring resistor for the control amplifier. The floating power supply is realized by a voltage regulator, the reference potential of which is the voltage at the load of the consumer.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der folgenden Beschreibung näher erläutert. Die Fig. 2 zeigt das Prinzipschaltbild einer Ausgestaltung der Erfindung.An embodiment of the invention is shown in the drawing and explained in more detail in the following description. 2 shows the basic circuit diagram of an embodiment of the invention.

Eine Differenzstufe 2 und eine spannungsgesteuerte Stromquelle 1 bilden zusammen einen Regelverstärker. Der Regelverstärker liefert einen von einer Sollwertspannung 3 abhängigen eingeprägten Strom I, der die Bürde 5 eines Verbrauchers durchfließt und an ihr einen Spannungsabfall U hervorruft. Der Verbraucher ist einseitig an die Masse 8 angeschlossen. Elektrisch in Reihe mit der Bürde 5 ist ein Strommeßwiderstand 4 geschaltet. Der Strom I verursacht an dem Strommeßwiderstand 4 einen Spannungsabfall, die Istwertspannung 7, die dem nichtinvertierenden Eingang der Differenzstufe 2 zugeführt ist.A differential stage 2 and a voltage-controlled current source 1 together form a control amplifier. The control amplifier supplies an impressed current I which is dependent on a setpoint voltage 3 and which flows through the load 5 of a consumer and causes a voltage drop U there. The consumer is connected to ground 8 on one side. A current measuring resistor 4 is connected electrically in series with the burden 5. The current I causes a voltage drop across the current measuring resistor 4, the actual value voltage 7, which is supplied to the non-inverting input of the differential stage 2.

Die an der Bürde 5 des Verbrauchers abfallende Spannung U ist dem Eingang eines hochohmigen Impedanzwandlers 6 mit der Verstärkung eins zugeführt. Das am Ausgang des Impedanzwandlers 6 anstehende Potential am Schaltungspunkt 9 ist an den invertierenden Eingang der Differenzstufe 2 geführt und es dient gleichzeitig als Bezugspotential für die Sollwertspannung 3. Diese schaltungstechnische Maßnahme bewirkt, daß das Potential am Schaltungspunkt 9 für den geschlossenen Regelkreis und die Sollwertspannung 3, die den jeweiligen Meßwert repräsentiert, der Spannung U an der Bürde 5 des Verbrauchers entspricht. Das Potential am Schaltungspunkt 9 wird durch den Impedanzwandler 6 stets so nachgeführt, daß an der Differenzstufe 2 der Istwertspannung 7 nicht von Gleichtaktsignalen überlagert ist.The voltage U falling across the load 5 of the consumer is fed to the input of a high-impedance impedance converter 6 with the gain one. The potential at the output of the impedance converter 6 at the switching point 9 is led to the inverting input of the differential stage 2 and it also serves as a reference potential for the setpoint voltage 3. This circuit-technical measure has the effect that the potential at the switching point 9 for the closed control loop and the setpoint voltage 3 , which represents the respective measured value, corresponds to the voltage U at the load 5 of the consumer. The potential at the node 9 is always tracked by the impedance converter 6 so that the differential voltage 2 of the actual value voltage 7 is not superimposed by common mode signals.

Claims (1)

  1. Circuit arrangement for supplying an earthed consumer unit with a load-independent current (I) representing a measured value
    - with a regulating amplifier (1, 2), the inputs of which are acted upon by a reference voltage (3) forming the measured value and by an actual voltage (7), and
    - with a current measuring resistor (4) through which the load-independent current (I) flows and at which the actual voltage (7) is picked off,
    characterised in that the voltage (U) dropping across the load (5) of the consumer unit is delivered to the input of a high-resistance impedance transformer (6), and that the potential (9) present at the output of the impedance transformer (6) forms the reference potential for the regulating amplifier (1, 2) and the reference voltage (3).
EP90120362A 1989-11-20 1990-10-24 Circuit arrangement to supply an earthed load with load independent current Revoked EP0462314B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3938460A DE3938460C1 (en) 1989-11-20 1989-11-20
DE3938460 1989-11-20

Publications (3)

Publication Number Publication Date
EP0462314A2 EP0462314A2 (en) 1991-12-27
EP0462314A3 EP0462314A3 (en) 1992-01-29
EP0462314B1 true EP0462314B1 (en) 1994-09-28

Family

ID=6393844

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Application Number Title Priority Date Filing Date
EP90120362A Revoked EP0462314B1 (en) 1989-11-20 1990-10-24 Circuit arrangement to supply an earthed load with load independent current

Country Status (5)

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US (1) US5138248A (en)
EP (1) EP0462314B1 (en)
JP (1) JPH0612498B2 (en)
CN (1) CN1025082C (en)
DE (2) DE3938460C1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5604430A (en) * 1994-10-11 1997-02-18 Trw Inc. Solar array maximum power tracker with arcjet load
US6239997B1 (en) * 2000-09-01 2001-05-29 Ford Motor Company System for connecting and synchronizing a supplemental power source to a power grid
US6919650B2 (en) * 2002-05-31 2005-07-19 Ballard Power Systems Corporation Hybrid synchronization phase angle generation method
DE10257632B4 (en) * 2002-12-09 2005-03-03 Zentrum Mikroelektronik Dresden Ag Method for signal output by AS-i transmitters in As-i units of an AS-i bus system
CN103294090A (en) * 2013-05-24 2013-09-11 南京化工职业技术学院 Direct-current signal generator

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3546564A (en) * 1968-11-25 1970-12-08 Us Air Force Stabilized constant current apparatus
US3735240A (en) * 1971-10-15 1973-05-22 Motorola Inc Integrated circuit current regulator with differential amplifier control
JPS603098A (en) * 1983-06-20 1985-01-09 株式会社日立製作所 Voltage-current conversion circuit
DD240086A1 (en) * 1985-08-05 1986-10-15 Berlin Treptow Veb K VOLTAGE POWER CONVERTER
GB2182788B (en) * 1985-11-08 1989-12-28 Plessey Co Plc Voltage regulator circuit
DE3715886A1 (en) * 1987-05-13 1988-11-24 Philips Patentverwaltung Controllable constant current source
JP2710326B2 (en) * 1988-01-31 1998-02-10 日本電気株式会社 Drive circuit
DE3815979A1 (en) * 1988-05-10 1989-11-23 Philips Patentverwaltung Current supply apparatus

Also Published As

Publication number Publication date
JPH03175511A (en) 1991-07-30
CN1025082C (en) 1994-06-15
DE3938460C1 (en) 1991-02-07
DE59007348D1 (en) 1994-11-03
US5138248A (en) 1992-08-11
JPH0612498B2 (en) 1994-02-16
EP0462314A2 (en) 1991-12-27
CN1051990A (en) 1991-06-05
EP0462314A3 (en) 1992-01-29

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