DE2917288A1 - Feedback amplifier system with transformer secondary output - obtains feedback signal from auxiliary transformer primary and passes it to inverting input of operational amplifier - Google Patents

Feedback amplifier system with transformer secondary output - obtains feedback signal from auxiliary transformer primary and passes it to inverting input of operational amplifier

Info

Publication number
DE2917288A1
DE2917288A1 DE19792917288 DE2917288A DE2917288A1 DE 2917288 A1 DE2917288 A1 DE 2917288A1 DE 19792917288 DE19792917288 DE 19792917288 DE 2917288 A DE2917288 A DE 2917288A DE 2917288 A1 DE2917288 A1 DE 2917288A1
Authority
DE
Germany
Prior art keywords
amplifier
output
feedback signal
inverting input
operational amplifier
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Withdrawn
Application number
DE19792917288
Other languages
German (de)
Inventor
Friedrich Dipl Ing Lembcke
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of DE2917288A1 publication Critical patent/DE2917288A1/en
Withdrawn legal-status Critical Current

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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
    • H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
    • H03F1/347—Negative-feedback-circuit arrangements with or without positive feedback using transformers

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)

Abstract

The amplifier has its feedback signal independent of the earth connection in its output circuit. The feedback signal is obtained using an auxiliary transformer connected to the output by its primary winding. The feedback signal is passed via a voltage divider to the inverting input of an operational amplifier connected to the input side of the amplifier. The input signal (1) is applied to the operational amplifier non-inverting input and via the voltage divider (7, 8) to the inverting input. The operational amplifier output is connected via a power amplifier (3) to the primary of the output transformer (5), whose secondary feeds the load (4) and is coupled to the auxiliary transformer (6) primary.

Description

RUckgekoD»elter VerstärkerRUckgekoD »Parent amplifier

Gegenstand der Erfindung ist ein rückgekoppelter Verstärker mit erdfreiem, von der Sekundärwicklung eines Ausgangstransformators gebildeten Ausgang, der bei symmetrischem Ausgang eine niedrige Ausgangsimpedanz aufweist und zufolge seins Störsicherheit besonders für die Anwendung bei integrierten Schaltungen geeignet ist.The subject of the invention is a feedback amplifier with floating, output formed by the secondary winding of an output transformer, which at symmetrical output has a low output impedance and as a result of its Interference immunity particularly suitable for use in integrated circuits is.

Bekanntlich werden Rückkoppelsignale bei Verstärkern meist mittels galvanisch leitender Rückkoppelnetzwerke über Erde vom Ausgang an den Eingang zurückgeführt. Wenn in den an den Verstärkerausgang angeschlossenen Geräten ebenfalls eine Verbindung zur Erde vorgesehen ist, dann können, vor allem bei grosser Entfernung zwischen Verstärker und Gerät, in die Erdverbindung Störspannungen eingestreut werden, die sich insbesondere bei integrierten Schaltungen sehr schädlich auswirken können.As is known, feedback signals are usually used in amplifiers Galvanically conductive feedback networks fed back via earth from the output to the input. If there is also a connection in the devices connected to the amplifier output is provided to the earth, then can, especially with great distance between Amplifier and device into the earth connection interference voltages are interspersed that can be very damaging, especially in the case of integrated circuits.

Daher hat sich die Erfindung die Aufgabe gestellt, ein von einer im Ausgangskreis befindlichen Erdverbindung unabhängiges Rückkoppelsignal zu erhalten und erzielt dies dadurch, daß das Rückkoppelsignal mittels eines mit seiner Primärwicklung an den Ausgang angeschlossenen Hilfstransformators gewonnen ist und über eine Spannungsteilerschaltung dem invertierenden Eingang eines dem Verstärker vorgeschalteten Operationsverstärkers zugeführt ist.Therefore, the invention has the task of providing one of an im Output circuit located ground connection to receive independent feedback signal and achieves this in that the feedback signal by means of a with its primary winding auxiliary transformer connected to the output is obtained and via a voltage divider circuit the inverting input of an operational amplifier connected upstream of the amplifier is fed.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt. Das einer Signalquelle 1 entspringende Eingangssignal liegt am nichtinvertierenden Eingang eines Operationsverstärkers 2, dessen Ausgang an den Eingang eines Leistungsverstärkers 3 angeschlossen ist.An embodiment of the invention is shown in the drawing. The input signal originating from a signal source 1 is due to the non-inverting one Input of an operational amplifier 2, the output of which is connected to the input of a power amplifier 3 is connected.

Der von der Verstärkerschaltung gespeiste Verbraucher 4 wird über einen Ausgangstransformator 5 gespeist.The consumer 4 fed by the amplifier circuit is over an output transformer 5 is fed.

Mittels eines Hilfstransformators 6, der an den Ausgang des Transformators 5 angeschlossen ist, wird ein RUckkoppelsignal aus dem Ausgangskreis ausgekoppelt. Im Ausgangskreis des Hilfstransformators 6 liegt ein aus den Widerständen 7 und 8 aufgebauter Spannungsteiler, dessen Mittenanzapfung mit dem invertierenden Eingang des Operationsverstärkers 2 verbunden ist.By means of an auxiliary transformer 6, which is connected to the output of the transformer 5 is connected, a feedback signal is decoupled from the output circuit. In the output circuit of the auxiliary transformer 6 is one of the resistors 7 and 8 built-up voltage divider, its center tap with the inverting input of the operational amplifier 2 is connected.

Da das rückgekoppelte Signal sehr schwach sein muß, genügt es, den Hilfstransformator 6 nur ganz schwach auszusteuern. Die Stärke des Rückkoppelsignals kann weiter durch die 3messung der Widerstände 7 und 8 des Spannungsteilers modifiziert werden. FUr die geforderte Verstärkung ist es belanglos, ob die Grösse des RUckkoppelsignales durch die Wahl des Übersetzungsverhältnisses des Hilfstransformators 6 oder durch Wahl des Spannungsteilungsverhältnisses des Spannungsteilers 7, 8 erzielt wird.Since the feedback signal must be very weak, it is sufficient to use the Auxiliary transformer 6 can only be controlled very weakly. The strength of the feedback signal can be further modified by measuring the resistors 7 and 8 of the voltage divider will. For the required gain it is irrelevant whether the size of the feedback signal by choosing the gear ratio of the auxiliary transformer 6 or by Choice of Voltage division ratio of the voltage divider 7, 8 is achieved.

Mit der erfindungsgemässen Schaltung lässt sich ein optimaler Frequenzgang bei nahezu verschwindendem Ausgangswiderstand erzielen. Vor allem werden sämtliche Verluste des Ausgangstransformators 5 (Wicklungswiderstand und Streuinduktivität) kompensiert. Schließlich ergibt sich ein von der Grösse des Lastwiderstandes des Verbrauchers 4 unabhängiger Betrieb.An optimal frequency response can be achieved with the circuit according to the invention achieve with almost vanishing initial resistance. Above all, all will Output transformer 5 losses (winding resistance and leakage inductance) compensated. Finally, there is one of the size of the load resistance of the Consumer 4 independent operation.

1 Patentanspruch 1 Figur1 claim 1 figure

Claims (1)

PatentansPruch Rückgekoppelter Verstärker mit erdfreiem, von der Sekundärwicklung eines Ausgangstransformators gebildeten Ausgang, d a d u r c h g e k e n n z e i c h n e t daß das Rückkoppelsignal mittels eines mit seiner Primärwicklung an den Ausgang angeschlossenen Hilf 5-transformators gewonnen ist und über eine Spannungsteilerschaltung dem invertierenden Eingang eines dem Verstärker vorgeschalteten Operationsverstärkers zugeführt ist.Patent claim feedback amplifier with floating, from the secondary winding an output transformer formed output, d u r c h e k e n n z e i c h n e t that the feedback signal by means of a with its primary winding to the Output connected auxiliary 5-transformer is obtained and via a voltage divider circuit the inverting input of an operational amplifier connected upstream of the amplifier is fed.
DE19792917288 1978-04-27 1979-04-27 Feedback amplifier system with transformer secondary output - obtains feedback signal from auxiliary transformer primary and passes it to inverting input of operational amplifier Withdrawn DE2917288A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT302678 1978-04-27

Publications (1)

Publication Number Publication Date
DE2917288A1 true DE2917288A1 (en) 1979-11-08

Family

ID=3544147

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19792917288 Withdrawn DE2917288A1 (en) 1978-04-27 1979-04-27 Feedback amplifier system with transformer secondary output - obtains feedback signal from auxiliary transformer primary and passes it to inverting input of operational amplifier

Country Status (1)

Country Link
DE (1) DE2917288A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0186073A2 (en) * 1984-12-17 1986-07-02 Honeywell Inc. Driver circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0186073A2 (en) * 1984-12-17 1986-07-02 Honeywell Inc. Driver circuit
EP0186073A3 (en) * 1984-12-17 1988-08-03 Honeywell Inc. Driver circuit

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