EP0169388A1 - Integrated constant-current source - Google Patents

Integrated constant-current source Download PDF

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Publication number
EP0169388A1
EP0169388A1 EP85107776A EP85107776A EP0169388A1 EP 0169388 A1 EP0169388 A1 EP 0169388A1 EP 85107776 A EP85107776 A EP 85107776A EP 85107776 A EP85107776 A EP 85107776A EP 0169388 A1 EP0169388 A1 EP 0169388A1
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Prior art keywords
current
stage
output
transistor
coupled
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EP85107776A
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German (de)
French (fr)
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EP0169388B1 (en
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Ulrich Lachmann
Erwin Krug
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Siemens AG
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Siemens AG
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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
    • 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
    • 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
    • G05F1/561—Voltage to current converters

Definitions

  • the present invention relates to an integrated constant current source according to the preamble of patent claim 1.
  • FIG. 1 shows a basic circuit diagram of an integrated constant current source of the generic type.
  • a constant current source contains an operational amplifier UP which compares a reference voltage U ref fed in at its inverting input with a voltage dropping across a reference resistor R Ref .
  • a transistor stage T 1 is coupled to the output of the operational amplifier OP, which converts the output voltage of the operational amplifier into a corresponding current.
  • a collector current of this transistor stage T 1 designated I c1 flows through the reference resistor R ref , across which a voltage drops due to the current I c1 flowing through it, which voltage is fed into the non-inverting input of the operational amplifier OP.
  • the transistor stage T 1 On the basis of the comparison carried out by the operational amplifier OP, the transistor stage T 1 is driven such that the reference voltage U ref and the voltage drop across the reference resistor R ref are the same.
  • the product of the collector current I c1 of the transistor stage T 1 and the value of the reference resistor R ref is thus equal to the reference voltage U ref . This means that the collector current Ic 1 is also constant.
  • the further transistor stage T 2 is coupled to the output of the operational amplifier OP, in the circuit of whose collector-emitter path there is a current mirror formed by transistors T 3 , T 4 against the reference potential (ground).
  • This current mirror is formed by a lying in the collector-emitter circuit of the transistor stage T2, diode reference transistor T 3 as well as a switch controlled by this transistor T 4, wherein about the last-mentioned transistor T 4 and an output A of the constant current source, a constant output current I a on a consumer, not shown, coupled to the output A flows.
  • the constancy of the currents and in particular of the output current I a applies only to a first approximation. If one looks more closely at the current ratio, for example in the per mille range, it becomes apparent that the constancy of the output current I a is not precise enough for many applications. A portion of the collector current I c2 supplied by the transistor stage T 2 is lost, which is used as the drive current in the form of base currents I B3 and I B4 for driving the current mirror transistors T 3 , T 4 is required.
  • the base currents mentioned depend on the current amplifications of the current mirror transistors T 3 , T 4 , which can vary widely, this variation correspondingly being included in the output current I a .
  • an emitter and / or collector area ratio of 1: n is selected for setting a predetermined output current I a in the current mirror for the transistors T 3 and T 4 , ie the emitter and / or collector area of the transistor T 4 n times larger than the emitter and / or collector area of the transistor T 3 .
  • the output current constancy is also adversely affected by the so-called early effect, which is that in the active part of the characteristic field of a transistor the collector current is not independent of the collector-emitter voltage, i.e. runs horizontally in the characteristic field, but also increases with increasing collector-emitter voltage.
  • the present invention is therefore based on the object of specifying a circuit for compensating for fluctuations in the output current caused by the base currents in the current mirror in the case of an integrated constant current source of the type explained above, this circuit also being able to be used to compensate for the early effect.
  • FIG. 2 shows a circuit diagram of an integrated constant current source according to FIG. 1 which has been expanded in accordance with the invention, the same elements being provided with the same reference symbols in FIGS. 1 and 2.
  • the circuit arrangement according to FIG. 2 corresponds to the circuit arrangement according to FIG. 1, so that here the corresponding statements regarding the circuit arrangement according to FIG. 1 can be referenced.
  • the circuit arrangement according to FIG. 2 contains a further current mirror T 7 , T 8 , a transistor T 6 being located in the collector-emitter circuit of the controlled transistor T 7 of this current mirror, which transistor is coupled with its base to the reference resistor R ref .
  • the current mirror T 7 , T 8 fetches a current in which the error caused by the base currents of the transistors T 7 , T 8 likewise occurs comes in.
  • This fault current is designated I F in FIG. 2.
  • the second current mirror T 71 T 8 produces the same error caused by the base currents as that by the Base currents IB 3 , IB 4 in the first current mirror T 3 , T 4 is conditional.
  • the properties of the transistors mentioned essentially match one another. At least, however, it is possible with very good yield to switch off those specimens in which the transistors T 3 , T 4 of the first current mirror or T 7 , T 8 of the second current mirror are not sufficiently "paired".
  • the transistor stage T 4 which carries the constant output current I, which still has errors due to the early effect, is coupled via a further operational amplifier OP connected as a voltage follower, to the transistor stage T 6 coupled to the reference resistor R ref .
  • This transistor T 6 lies with its collector-emitter path in the circuit of the transistor stage T 7 carrying the mirrored current of the second current mirror T 6 , T 7 and with its base on the reference resistor R rer .
  • T 4 is selected in which the diode-connected reference transistor T 3 and from this Controlled, the (mirrored) constant output current I a leading transistor T 4 have an emitter and / or collector area ratio of 1: n
  • the reference resistor R ref and the further operational amplifier OP 1 coupled transistor T 6 based on the emitter and / or collector area of the reference transistor T 3 of the first current mirror T 3 , T 4 an n-fold emitter and / or collector area and the transistor T 8 acting as a diode and acting as a reference transistor the mirrored current leading transistor T 7 of the second current mirror T 7 , T 8 an emitter and / or collector area ratio of 1: (n + 1).
  • the compensating effect is thus retained even for an output current I a determined by the ratio n.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
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Abstract

An integrated constant-current source having an operational amplifier with an inverting input to which a reference voltage is feedable, and an output; a first stage to which the output is coupled and by which the output voltage of the operational amplifier is converted to a first current, the first stage being in a circuit wherein a reference resistor is connected from which, for coupling a voltage dropping across the reference resistor, the reference resistor is coupled to a non-inverting input of the operational amplifier; and a second stage coupled to the output of the operational amplifier for converting the output voltage of the operational amplifier to a second current, the second stage being in a circuit wherein a current reflector is connected for supplying an output current which is constant in a first approximation, the integrated constant current source includes a third stage coupled to the output of the operational amplifier and converting the output voltage thereof into another current, the third stage being in a circuit wherein another current reflector is connected, and another stage coupled to the reference resistor, the other current reflector conducting reflected current and having a stage thereof connected in a circuit wherein the other stage coupled to the reference resistor is also connected.

Description

Die vorliegende Erfindung betrifft eine integrierte Konstantstromquelle nach dem Oberbegriff des Patentanspruchs 1.The present invention relates to an integrated constant current source according to the preamble of patent claim 1.

Fig. 1 zeigt ein Prinzipschaltbild einer integrierten Konstantstromquelle der gattungsgemäßen Art. Ein derartige Konstantstromquelle enthält einen Operationsverstärker UP, der eine an seinem invertierenden Eingang eingespeiste Referenzspannung Uref mit einer an einem Referenzwiderstand RRef abfallenden Spannung vergleicht. Zur Erzeugung dieser Spannung ist an den Ausgang des Operationsverstärkers OP eine Transistorstufe T1 angekoppelt, welche die Ausgangsspannung des Operationsverstärkers in einen entsprechenden Strom überführt. Ein mit Ic1 bezeichneter.Kollektorstrom dieser Transistorstufe T1 fließt über den Referenzwiderstand Rref, an dem aufgrund des ihn durchfließenden Stromes Ic1 eine Spannung abfällt, die in den nichtinvertierenden Eingang des Operationsverstärkers OP eingespeist wird. Aufgrund des durch den Operationsverstärker OP durchgeführten Vergleichs wird die Transistorstufe T1 so angesteuert, daß die Referenzspannung Uref und die am Referenzwiderstand Rref abfallende Spannung gleich sind. Damit ist das Produkt aus dem Kollektorstrom Ic1 der Transistorstufe T1 und dem Wert des Referenzwiderstandes Rref gleich der Referenzspannung Uref. Das bedeutet, daß auch der Kollektorstrom Ic1 konstant ist.1 shows a basic circuit diagram of an integrated constant current source of the generic type. Such a constant current source contains an operational amplifier UP which compares a reference voltage U ref fed in at its inverting input with a voltage dropping across a reference resistor R Ref . To generate this voltage, a transistor stage T 1 is coupled to the output of the operational amplifier OP, which converts the output voltage of the operational amplifier into a corresponding current. A collector current of this transistor stage T 1 designated I c1 flows through the reference resistor R ref , across which a voltage drops due to the current I c1 flowing through it, which voltage is fed into the non-inverting input of the operational amplifier OP. On the basis of the comparison carried out by the operational amplifier OP, the transistor stage T 1 is driven such that the reference voltage U ref and the voltage drop across the reference resistor R ref are the same. The product of the collector current I c1 of the transistor stage T 1 and the value of the reference resistor R ref is thus equal to the reference voltage U ref . This means that the collector current Ic 1 is also constant.

Wie in Fig. 1 schematisch dargestellt, sind der Emitter der Transistorstufe T1 sowie der Emitter einer im folgenden noch zu erläuternden Transistorstufe T2 mit weiterer Lz 1 EM /9.7.1984 Beschaltung an eine Versorgungsspannung geführt. An der insoweit beschriebenen Konstantstromquelle wäre ein konstanter Strom bezogen auf die Versorgungsspannung abnehmbar. Für viele Anwendungsfälle einer in Rede stehenden Konstantstromquelle ist es jedoch erwünscht, den konstanten Strom gegen Bezugspotential (Masse) abzunehmen.As shown schematically in Fig. 1, the emitter of the transistor stage T 1 and the emitter of a transistor stage T 2 to be explained below with further Lz 1 EM / July 9, 1984 Wiring to a supply voltage. At the constant current source described so far, a constant current based on the supply voltage would be removable. For many applications of a constant current source in question, however, it is desirable to decrease the constant current against the reference potential (ground).

Zu diesem Zweck ist an den Ausgang des Operationsverstärkers OP die weitere Transistorstufe T2 angekoppelt, im Kreis von deren Kollektor-Emitter-Strecke ein durch Transistoren T3, T4 gebildeter Stromspiegel gegen Bezugspotential (Masse) liegt. Dieser Stromspiegel wird durch einen im Kollektor-Emitterkreis der Transistorstufe T2 liegenden, als Diode geschalteten Bezugstransistor T3 sowie einen von diesem gesteuerten Transistor T4 gebildet, wobei über den letztgenannten Transistor T4 und einen Ausgang A der Konstantstromquelle ein konstanter Ausgangsstrom Ia über einen nicht dargestellten, an den Ausgang A angekoppelten Verbraucher fließt.For this purpose, the further transistor stage T 2 is coupled to the output of the operational amplifier OP, in the circuit of whose collector-emitter path there is a current mirror formed by transistors T 3 , T 4 against the reference potential (ground). This current mirror is formed by a lying in the collector-emitter circuit of the transistor stage T2, diode reference transistor T 3 as well as a switch controlled by this transistor T 4, wherein about the last-mentioned transistor T 4 and an output A of the constant current source, a constant output current I a on a consumer, not shown, coupled to the output A flows.

Für den mit Ic2 bezeichneten Kollektorstrom der Transistorstufe T2 und damit - aufgrund der bekannten Funktion des Stromspiegels T3, T4 - für den Ausgangsstrom Ia gelten die gleichen Zusammenhänge, wie dies oben für den Kollektorstrom Ic1 der Transistorstufe T1 erläutert wurde.For the designated I c2 collector current of the transistor stage T 2 and thus - due to the well-known function of S t roms pi e g T3 els, T4 - for the output current I a, the same connections, as described above for the collector current I c1 of transistor stage are T 1 was explained.

Die Konstanz der Ströme und insbesondere des Ausgangsstroms Ia gilt jedoch nur in erster Näherung. Betrachtet man das Stromverhältnis beispielsweise im Promillebereich genauer, so zeigt sich, daß die Konstanz des Ausgangsstroms Ia für viele Anwendungsfälle nicht genau genug ist. Von dem von der Transistorstufe T2 gelieferten Kollektorstrom Ic2 geht nämlich ein Anteil verloren, der als Ansteuerstrom in Form von Basisströmen IB3 und IB4 für die Ansteuerung der Stromspiegel-Transistoren T3, T4 erforderlich ist. Insbesondere hängen die genannten Basisströme von den Stromverstärkungen der Stromspiegel-Transistoren T3,T4 ab, welche stark streuen können, wobei diese Streuung entsprechend in den Ausgangsstrom Ia eingeht. Dieser Effekt verstärkt sich noch, wenn zur Einstellung eines vorgegebenen Ausgangsstroms Ia im Stromspiegel für die Transistoren T3 und T4 ein Emitter-und/oder Kollektorflächenverhältnis von 1:n gewählt wird, d.h. die Emitter- und/oder Kollektorfläche des Transistors T4 n-mal größer als die Emitter- und/oder Kollektorfläche des Transistors T3 ist.However, the constancy of the currents and in particular of the output current I a applies only to a first approximation. If one looks more closely at the current ratio, for example in the per mille range, it becomes apparent that the constancy of the output current I a is not precise enough for many applications. A portion of the collector current I c2 supplied by the transistor stage T 2 is lost, which is used as the drive current in the form of base currents I B3 and I B4 for driving the current mirror transistors T 3 , T 4 is required. In particular, the base currents mentioned depend on the current amplifications of the current mirror transistors T 3 , T 4 , which can vary widely, this variation correspondingly being included in the output current I a . This effect is further enhanced if an emitter and / or collector area ratio of 1: n is selected for setting a predetermined output current I a in the current mirror for the transistors T 3 and T 4 , ie the emitter and / or collector area of the transistor T 4 n times larger than the emitter and / or collector area of the transistor T 3 .

Weiterhin wird die Ausgangsstromkonstanz auch durch den sogenannten Early-Effekt nachteilig beeinflußt, wobei es sich darum handelt, daß im aktiven Teil des Kennlinienfeldes eines Transistors der Kollektorstrom nicht unabhängig von der Kollektor-Emitterspannung ist, d.h. im Kennlinienfeld horizontal verläuft, sondern mit zunehmender Kollektor-Emitterspannung ebenfalls ansteigt.Furthermore, the output current constancy is also adversely affected by the so-called early effect, which is that in the active part of the characteristic field of a transistor the collector current is not independent of the collector-emitter voltage, i.e. runs horizontally in the characteristic field, but also increases with increasing collector-emitter voltage.

Der vorliegenden Erfindung liegt daher die Aufgabe zugrunde, bei einer integrierten Konstantstromquelle der vorstehend erläuterten Art eine Schaltung zur Kompensation von durch die Basisströme im Stromspiegel bedingten Schwankungen des Ausgangsstroms anzugeben, wobei diese Schaltung auch gleichzeitig zur Kompensation des Early-Effektes herangezogen werden kann.The present invention is therefore based on the object of specifying a circuit for compensating for fluctuations in the output current caused by the base currents in the current mirror in the case of an integrated constant current source of the type explained above, this circuit also being able to be used to compensate for the early effect.

Diese Aufgabe wird bei einer integrierten Konstantstromquelle der eingangs genannten Art erfindungsgemäß durch die Merkmale des kennzeichnenden Teils des Patentanspruchs 1 gelöst.This object is achieved according to the invention in an integrated constant current source of the type mentioned at the outset by the features of the characterizing part of patent claim 1.

Weiterbildungen des Erfindungsgedankens sind in Unteransprüchen gekennzeichnet.Further developments of the inventive concept are characterized in the subclaims.

Die Erfindung wird im folgenden anhand eines in Fig. 2 der Zeichnung dargestellten Ausführungsbeispiels näher erläutert. Fig. 2 zeigt dabei ein Schaltbild einer erfindungsgemäß erweiterten integrierten Konstantstromquelle nach Fig. 1, wobei in den Figuren 1 und 2 gleiche Elemente mit gleichen Bezugszeichen versehen sind.The invention is explained below with reference to an embodiment shown in Fig. 2 of the drawing. FIG. 2 shows a circuit diagram of an integrated constant current source according to FIG. 1 which has been expanded in accordance with the invention, the same elements being provided with the same reference symbols in FIGS. 1 and 2.

Hinsichtlich des Operationsverstärkerteils, des Referenzkreises T1, Rref und des Stromspiegelkreises T2,T3,T4 stimmt die Schaltungsanordnung nach Fig.2 mit der Schaltungsanordnung nach Fig. 1 überein, so daß hier auf die entsprechenden Ausführungen zur Schaltungsanordnung nach Fig. 1 verwiesen werden kann.With regard to the operational amplifier part, the reference circuit T 1 , R ref and the current mirror circuit T 2 , T 3 , T 4 , the circuit arrangement according to FIG. 2 corresponds to the circuit arrangement according to FIG. 1, so that here the corresponding statements regarding the circuit arrangement according to FIG. 1 can be referenced.

Die Schaltungsanordnung nach Fig. 2 enthält einen weiteren Stromspiegel T7,T8, wobei im Kollektor-Emitterkreis des gesteuerten Transistors T7 dieses Stromspiegels ein Transistor T6 liegt, der mit seiner Basis an den Referenzwiderstand Rref angekoppelt ist. Ober diesen Transistor T6, der die am Widerstand Rref stehende Spannung in einen entsprechenden Strom überführt, "holt" sich der Stromspiegel T7,T8 einen Strom, in den ebenfalls der durch die Basisströme der Transistoren T7,T8 bedingte Fehler eingeht. Dieser Fehlerstrom ist in Fig. 2 mit IF bezeichnet. Unter der Voraussetzung, daß sich die Transistoren T3,T4 des ersten Stromspiegels und die Transistoren T7, T8 in ihren Eigenschaften entsprechen, entsteht also im zweiten Stromspiegel T71 T8 der gleiche durch die Basisströme bedingte Fehler, wie dies durch die Basisströme IB3,IB4 im ersten Stromspiegel T3,T4 bedingt ist. In monolithisch integrierter Technik ist praktisch immer erfüllt, daß die Eigenschaften der genannten Transistoren im wesentlichen miteinander übereinstimmen. Mindestens ist es jedoch mit sehr guter Ausbeute möglich, durch entsprechend schafte Messungen diejenigen Exemplare auszuschalten, in denen die Transistoren T3,T4 des ersten Stromspiegels bzw. T7, T8 des zweiten Stromspiegels nicht ausreichend gut "gepaart" sind.The circuit arrangement according to FIG. 2 contains a further current mirror T 7 , T 8 , a transistor T 6 being located in the collector-emitter circuit of the controlled transistor T 7 of this current mirror, which transistor is coupled with its base to the reference resistor R ref . Via this transistor T 6 , which converts the voltage across the resistor R ref into a corresponding current, the current mirror T 7 , T 8 fetches a current in which the error caused by the base currents of the transistors T 7 , T 8 likewise occurs comes in. This fault current is designated I F in FIG. 2. Provided that the transistors T 3 , T 4 of the first current mirror and the transistors T 7 , T 8 correspond in their properties, the second current mirror T 71 T 8 produces the same error caused by the base currents as that by the Base currents IB 3 , IB 4 in the first current mirror T 3 , T 4 is conditional. In monolithically integrated technology, it is practically always the case that the properties of the transistors mentioned essentially match one another. At least, however, it is possible with very good yield to switch off those specimens in which the transistors T 3 , T 4 of the first current mirror or T 7 , T 8 of the second current mirror are not sufficiently "paired".

Da also von den über den Referenzwiderstand Rref fließenden Kollektorstrom Ic1 der Transistorstufe T1, d.h.,vom Referenzstrom, der Fehlerstrom entsprechend den Basisströmen im Stromspiegel T7,T8 subtrahiert wird, ergibt sich, wenn überhaupt, ein sehr kleiner resultierender Fehler im Ausgangsstrom Ia. Aus den vorstehenden Ausführungen folgt, daß für die durch die Basisströme in einem Stromspiegel bedingten Fehler eine Kompensation allein dadurch durchgeführt werden könnte, daß der Transistor T6 ebenso wie die Transistoren T1,T2,T5 an die Versorgungsspannung geführt würde. Die erfindungsgemäße Schaltungsanordnung nach Fig. 2 besitzt jedoch den weiteren Vorteil, daß mit der Kompensation der genannten, durch die Basisströme in einem Stromspiegel bedingten Fehler in einfacher Weise auch gleichzeitig eine Kompensation von durch den Early-Effekt der Stromspiegel-Transistoren bedingten Fehler möglich ist. Dieser Fehler ergibt sich dadurch, daß die Kollektoren der Transistoren T3,T4 des ersten Stromspiegels aufgrund des Early-Effektes unterschiedliche Potentiale haben können.So since the fault current corresponding to the base currents in the current mirror T 7 , T 8 is subtracted from the collector current I c1 of the transistor stage T 1 , ie, from the reference current, flowing through the reference resistor R ref , a very small resulting error results, if at all Output current I a . From the foregoing, it follows that for the errors caused by the base currents in a current mirror, compensation could be carried out solely by leading the transistor T 6 to the supply voltage just like the transistors T 1 , T 2 , T 5 . However, the circuit arrangement according to the invention according to FIG. 2 has the further advantage that with the compensation of the errors mentioned, which are caused by the base currents in a current mirror, it is also possible in a simple manner to compensate for errors caused by the early effect of the current mirror transistors. This error results from the fact that the collectors of the transistors T 3 , T 4 of the first current mirror can have different potentials due to the early effect.

Um diesen Fehler gleichzeitig zu kompensieren, ist die den konstanten, aber noch mit Fehlern aufgrund des Early-Effektes behafteten Ausgangsstrom I, führende Transistorstufe T4 über einen als Spannungsfolger geschalteten weiteren Operationsverstärker OP, an die an den Referenzwiderstand Rref angekoppelte Transistorstufe T6 gekoppelt. Dieser Transistor T6 liegt dabei mit seiner Kollektor-Emitter-Strecke im Kreis der den gespiegelten Strom führenden Transistorstufe T7 des zweiten Stromspiegels T6, T7 und mit seiner Basis am Referenzwiderstand Rrer. Da ein als Spannungsfolger (durch Rückkopplung seines Ausgangs auf den invertierenden Eingang) geschalteter Operationsverstärker die Spannungsverstärkung 1 besitzt, liegt am Kollektor des Transistors T6 die gleiche Spannung wie am Kollektor des den Ausgangsstrom Ia führenden Transistors T4 des ersten Stromspiegels T3,T4, so daß am Transistor T6 der gleiche Early-Effekt wirksam ist, wodurch eine Kompensation von durch den Early-Effekt im Ausgangsstrom Ia bedingten Fehlern realisiert ist.In order to compensate for this error at the same time, the transistor stage T 4 , which carries the constant output current I, which still has errors due to the early effect, is coupled via a further operational amplifier OP connected as a voltage follower, to the transistor stage T 6 coupled to the reference resistor R ref . This transistor T 6 lies with its collector-emitter path in the circuit of the transistor stage T 7 carrying the mirrored current of the second current mirror T 6 , T 7 and with its base on the reference resistor R rer . Since an operational amplifier connected as a voltage follower (by feedback of its output to the inverting input) has voltage gain 1, is at the collector of the transistor T 6 the same voltage as at the collector of the transistor T 4 leading the output current I a of the first current mirror T3, T4, so that the same early effect is effective at the transistor T 6 , whereby compensation by the early -Effect in the output current Ia-related errors is realized.

Wenn, wie eingangs anhand der Schaltungsanordnung nach Fig. 1 ausgeführt wurde, zur Einstellung eines vorgegebenen Wertes des Ausgangsstroms Ia ein erster Stromspie- gel T3,T4 gewählt wird, in dem der als Diode geschaltete Bezugstransistor T3 und der von diesem gesteuerte, den (gespiegelten) konstanten Ausgangsstrom Ia führende Transistor T4 ein Emitter- und/oder Kollektorflächenverhältnis von 1:n besitzen, so ist in Weiterbildung der Erfindung zur Berücksichtigung dieses Flächenverhältnisses vorgesehen, daß der an den Referenzwiderstand Rref und den weiteren Operationsverstärker OP1 gekoppelte Transistor T6 bezogen auf die Emitter- und/oder Kollektorfläche des Bezugstransistors T3 des ersten Stromspiegels T3,T4 ein n-fache Emitter- und/oder Kollektorfläche und der als Diode geschaltete als Bezugstransistor wirkende Transistor T8 sowie der den gespiegelten Strom.führende Transistor T7 des zweiten Stromspiegels T7,T8 ein Emitter- und/ oder Kollektorflächenverhältnis von 1:(n+1) besitzen. Damit bleibt die kompensierende Wirkung auch für einen durch das Verhältnis n festgelegten Ausgangsstrom Ia erhalten.If, as already explained above, with reference to the circuit arrangement of FIG. 1, for setting a predetermined value of the output current I a a first Stromspie- g el T 3, T 4 is selected in which the diode-connected reference transistor T 3 and from this Controlled, the (mirrored) constant output current I a leading transistor T 4 have an emitter and / or collector area ratio of 1: n, it is provided in a further development of the invention to take this area ratio into account that the reference resistor R ref and the further operational amplifier OP 1 coupled transistor T 6 based on the emitter and / or collector area of the reference transistor T 3 of the first current mirror T 3 , T 4 an n-fold emitter and / or collector area and the transistor T 8 acting as a diode and acting as a reference transistor the mirrored current leading transistor T 7 of the second current mirror T 7 , T 8 an emitter and / or collector area ratio of 1: (n + 1). The compensating effect is thus retained even for an output current I a determined by the ratio n.

Claims (4)

1. Integrierte Konstantstromquelle mit einem Operationsverstärker (OP), dem an seinem invertierenden Eingang (-) eine Referenzspannung (Uref) führbar ist und an dessen Ausgang ein seine Ausgangsspannung in einen Strom (Ic1) überführende erste Stufe (T1) angekoppelt ist, einem im Kreis der ersten Stufe (T1) liegenden Referenzwiderstand (Rref), von dem zur Kopplung der an ihm abfallenden Spannung eine Kopplung auf den nichtinvertierenden Eingang des Operationsverstärkers (OP) vorgesehen ist, einer zweiten an den Ausgang des Operationsverstärkers (OP) angekoppelten, dessen Ausgangsspannung in einen Strom (Ic2) überführenden Stufe (T2) und einem ersten, einen in erster Näherung konstanten Ausgangstrom (Ia) liefernden Stromspiegel (T3,T4) im Kreis der zweiten Stufe (T2)'
gekennzeichnet durch eine dritte an den Ausgang des Operationsverstärkers (OP) angekoppelte, dessen Ausgangsspannung in einen Strom (Ic5) überführende Stufe (T5), einen zweiten im Kreis der dritten Stufe (TS) liegenden Stromspiegel (T7,T8) und eine an den Referenzwiderstand (Rref) gekoppelte Stufe (T6), die im Kreis der Stufe (T7) des zweiten.Stromspiegels (T7,T8)liegt, welcher den gespiegelten Strom führt. 1. Integrated constant current source with an operational amplifier (OP), to which a reference voltage (U ref ) can be conducted at its inverting input (-) and to whose output a first stage (T 1 ) which converts its output voltage into a current (I c1 ) is coupled, a reference resistor (R ref ) located in the circuit of the first stage (T 1 ), from which a coupling to the non-inverting input of the operational amplifier (OP) is provided for coupling the voltage drop across it, a second to the output of the operational amplifier (OP) coupled, the output voltage of which converts into a current (I c2 ) stage (T 2 ) and a first current mirror (T 3 , T 4 ) delivering a constant output current (I a ) in the circuit of the second stage (T 2 ) '
marked by a third coupled to the output of the operational amplifier (OP), the output voltage of which converts into a current (I c5 ) stage (T 5 ), a second current mirror (T 7 , T 8 ) lying in the circuit of the third stage (T S ) and a stage (T 6 ) coupled to the reference resistor (R ref ), which lies in the circle of stage (T 7 ) of the second current mirror (T 7 , T 8 ), which carries the mirrored current. 2. Integrierte Konstantstromquelle nach Anspruch 1, dadurch gekennzeichnet,
daß die den konstanten Ausgangsstrom (Ia) führende Stufe (T4) des ersten Stromspiegels (T3,T4) über einen als Spannungsfolger geschalteten weiteren Operationsverstärker (OP1) an die an dem Referenzwiderstand (Rref) angekoppelte Stufe (T6) gekoppelt ist.2. Integrated constant current source according to claim 1, characterized in that
that the stage (T 4 ) of the first current mirror (T 3 , T 4 ) carrying the constant output current (I a ) via a further operational amplifier (OP 1 ) connected as a voltage follower to the stage (T 6 ) coupled to the reference resistor (R ref ) ) is coupled. 3. Integrierte Konstantstromquelle nach Anspruch 1/oder 2, dadurch gekennzeichnet,
daß die an den Referenzwiderstand (Rref) gekoppelte Stufe (T6) durch einen Transistor gebildet ist, der mit seiner Kollektor-Emitter-Strecke im Kreis der den gespiegelten Strom führenden Stufe (T7) des zweiten Stromspiegels (T6, T7 ) und mit seiner Basis am Referenzwiderstand (Rref) liegt.3. Integrated constant current source according to claim 1 / or 2, characterized in
that the reference resistor (R ref) coupled stage (T 6) is formed by a transistor with its collector-emitter path of the circle of the mirrored current leading stage (T 7) of the second current mirror (T 6, T 7 ) and is based on the reference resistance (R ref ). 4. Integrierte Konstantstromquelle nach einem der Ansprüche 1 bis 3, mit einem ersten Stromspiegel (T3,T4), in dem ein als Diode geschalteter Bezugstransistor (T3) und der von diesem gesteuerte, den (gespiegelten) konstanten Ausgangsstrom (Ia) führende Transistor (T4) ein Emitter- und/oder Flächenverhältnis von 1:n besitzen, dadurch gekennzeichnet,
daß
der an den Referenzwiderstand (Rref) und den weiteren Operationsverstärker (OP1) gekoppelte Transistor (T6) bezogen auf die Emitter- und /oder Kollektorfläche des Bezugstransistors (T3) des ersten Stromspiegels (T3,T4) eine n-fache Emitter- und/oder Kollektorfläche und ein als Diode geschalteter Bezugstransistor (T8) sowie der den gespiegelten Strom führende Transistor (T7) des zweiten Stromspiegels (T7,T8) ein Emitter- und/oder Kollektorflächenverhältnis von 1:(n+1)
besitzen.4. Integrated constant current source according to one of claims 1 to 3, with a first current mirror (T 3 , T 4 ), in which a switched as a diode reference transistor (T 3 ) and the controlled by this, the (mirrored) constant output current (I a ) leading transistor (T 4 ) have an emitter and / or area ratio of 1: n, characterized in that
that
the transistor (T 6 ) coupled to the reference resistor (R ref ) and the further operational amplifier (OP 1 ) with respect to the emitter and / or collector area of the reference transistor (T 3 ) of the first current mirror (T 3 , T 4 ) an n- times the emitter and / or collector area and a reference transistor (T 8 ) connected as a diode as well as the transistor (T 7 ) of the second current mirror (T 7 , T 8 ) carrying the mirrored current an emitter and / or collector area ratio of 1: (n +1)
have.
EP85107776A 1984-07-16 1985-06-24 Integrated constant-current source Expired EP0169388B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85107776T ATE37619T1 (en) 1984-07-16 1985-06-24 INTEGRATED CONSTANT CURRENT SOURCE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3426166 1984-07-16
DE3426166 1984-07-16

Publications (2)

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EP0169388A1 true EP0169388A1 (en) 1986-01-29
EP0169388B1 EP0169388B1 (en) 1988-09-28

Family

ID=6240752

Family Applications (1)

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EP85107776A Expired EP0169388B1 (en) 1984-07-16 1985-06-24 Integrated constant-current source

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Country Link
US (1) US4651083A (en)
EP (1) EP0169388B1 (en)
JP (1) JPS6136816A (en)
KR (1) KR860001374A (en)
AT (1) ATE37619T1 (en)
DE (1) DE3565328D1 (en)

Cited By (5)

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EP0268345A2 (en) * 1986-11-20 1988-05-25 Industrial Technology Research Institute Matching current source
EP0388802A2 (en) * 1989-03-24 1990-09-26 National Semiconductor Corporation Error amplifier for use with parallel operated autonomous current or voltage regulators using transconductance type power amplifiers
DE10145034A1 (en) * 2001-09-13 2003-04-03 Infineon Technologies Ag Current source/switch configuration has controller which ensures that potential established on current source side terminal of switch during open state of switch is similar to potential during closed state of switch
DE102005022612A1 (en) * 2005-05-10 2006-11-16 Atmel Germany Gmbh Driver circuit for electronic components e.g. laser diodes includes compensating circuit for generating and supplying correction signal to input of amplifier
US7740465B2 (en) 2005-03-03 2010-06-22 Atmel Automotive Gmbh Casting mold for producing an optical semiconductor module

Families Citing this family (12)

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US5021730A (en) * 1988-05-24 1991-06-04 Dallas Semiconductor Corporation Voltage to current converter with extended dynamic range
US5266887A (en) * 1988-05-24 1993-11-30 Dallas Semiconductor Corp. Bidirectional voltage to current converter
US5525897A (en) * 1988-05-24 1996-06-11 Dallas Semiconductor Corporation Transistor circuit for use in a voltage to current converter circuit
US5004938A (en) * 1989-03-03 1991-04-02 Acer Incorporated MOS analog NOR amplifier and current source therefor
IT1252324B (en) * 1991-07-18 1995-06-08 Sgs Thomson Microelectronics HIGH STABILITY VOLTAGE REGULATOR INTEGRATED CIRCUIT AND LOW CURRENT CONSUMPTION.
US5153499A (en) * 1991-09-18 1992-10-06 Allied-Signal Inc. Precision voltage controlled current source with variable compliance
JPH0635559A (en) * 1992-07-17 1994-02-10 Toko Inc Constant current circuit
DE4315296C2 (en) * 1993-05-07 2000-03-02 Siemens Ag Current source arrangement for generating multiple reference currents
DE4326282C2 (en) * 1993-08-05 1995-12-14 Telefunken Microelectron Power source circuit
US5519310A (en) * 1993-09-23 1996-05-21 At&T Global Information Solutions Company Voltage-to-current converter without series sensing resistor
US5661395A (en) * 1995-09-28 1997-08-26 International Business Machines Corporation Active, low Vsd, field effect transistor current source
JP3593396B2 (en) * 1995-11-17 2004-11-24 富士通株式会社 Current output circuit

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DE3136780A1 (en) * 1981-09-16 1983-03-31 Siemens AG, 1000 Berlin und 8000 München INTEGRATED SEMICONDUCTOR CIRCUIT

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
DE2844745A1 (en) * 1978-10-13 1980-04-24 Jurij Konstantinovits Kuschner Stabilised current sources network - has multiple collector transistors one with collector connected via load resistor to common bus
DE3136780A1 (en) * 1981-09-16 1983-03-31 Siemens AG, 1000 Berlin und 8000 München INTEGRATED SEMICONDUCTOR CIRCUIT

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0268345A2 (en) * 1986-11-20 1988-05-25 Industrial Technology Research Institute Matching current source
EP0268345A3 (en) * 1986-11-20 1988-10-12 Industrial Technology Research Institute Matching current source
EP0388802A2 (en) * 1989-03-24 1990-09-26 National Semiconductor Corporation Error amplifier for use with parallel operated autonomous current or voltage regulators using transconductance type power amplifiers
EP0388802A3 (en) * 1989-03-24 1991-04-24 National Semiconductor Corporation Error amplifier for use with parallel operated autonomous current or voltage regulators using transconductance type power amplifiers
DE10145034A1 (en) * 2001-09-13 2003-04-03 Infineon Technologies Ag Current source/switch configuration has controller which ensures that potential established on current source side terminal of switch during open state of switch is similar to potential during closed state of switch
US6657479B2 (en) 2001-09-13 2003-12-02 Infineon Technologies Ag Configuration having a current source and a switch connected in series therewith
DE10145034B4 (en) * 2001-09-13 2005-04-21 Infineon Technologies Ag Arrangement with a power source and a switch connected in series to this
US7740465B2 (en) 2005-03-03 2010-06-22 Atmel Automotive Gmbh Casting mold for producing an optical semiconductor module
DE102005022612A1 (en) * 2005-05-10 2006-11-16 Atmel Germany Gmbh Driver circuit for electronic components e.g. laser diodes includes compensating circuit for generating and supplying correction signal to input of amplifier

Also Published As

Publication number Publication date
DE3565328D1 (en) 1988-11-03
EP0169388B1 (en) 1988-09-28
ATE37619T1 (en) 1988-10-15
US4651083A (en) 1987-03-17
JPS6136816A (en) 1986-02-21
KR860001374A (en) 1986-02-26

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