EP0169388B1 - Integrated constant-current source - Google Patents

Integrated constant-current source Download PDF

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Publication number
EP0169388B1
EP0169388B1 EP85107776A EP85107776A EP0169388B1 EP 0169388 B1 EP0169388 B1 EP 0169388B1 EP 85107776 A EP85107776 A EP 85107776A EP 85107776 A EP85107776 A EP 85107776A EP 0169388 B1 EP0169388 B1 EP 0169388B1
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EP
European Patent Office
Prior art keywords
current
stage
transistor
output
operational amplifier
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Expired
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EP85107776A
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German (de)
French (fr)
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EP0169388A1 (en
Inventor
Ulrich Lachmann
Erwin Krug
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Siemens AG
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Siemens AG
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Priority to DE3426166 priority
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Publication of EP0169388A1 publication Critical patent/EP0169388A1/en
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    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05FSYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00Automatic 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
    • G05F1/10Regulating voltage or current
    • G05F1/46Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56Regulating 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
    • G05F1/561Voltage to current converters

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 T, angekoppelt, welche die Ausgangsspannung des Operationsverstärkers in einen entsprechenden Strom überführt. Ein mit Ic1 bezeichneter. Kollektorstrom dieser Transistorstufe T, 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 T, 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 T, 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 is coupled to the output of the operational amplifier OP, which converts the output voltage of the operational amplifier into a corresponding current. One labeled I c1 . Collector current of this transistor stage T flows through the reference resistor R ref , across which a voltage drops due to the current I c1 flowing through it. which 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 is driven such that the reference voltage U ref and the voltage dropping across the reference resistor R ref are the same. The product of the collector current I c1 of the transistor stage T and the value of the reference resistor R ref is thus equal to the reference voltage U ref . This means that the collector current I c1 is also constant.
  • Wie in Fig. 1 schematisch dargestellt, sind der Emitter der Transistorstufe T, sowie der Emitter einer im folgenden noch zu erläuternden Transistorstufe T2 mit weiterer 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 and the emitter of a transistor stage T 2, which will be explained below, are connected to a supply voltage with further wiring. 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 la gelten die gleichen Zusammenhänge, wie dies oben für den Kollektorstrom Ic1 der Transistorstufe T, erläutert wurde.For the collector current of the transistor stage T 2 designated I c2 and thus - due to the known function of the current mirror T 3 , T 4 - for the output current I a the same relationships apply as was explained above for the collector current I c1 of the transistor stage T .
  • Die Konstanz der Ströme und insbesondere des Ausgangstroms Ia gilt jedoch nur in erster Näherung. Betrachtet man das Stromverhältnis beispielsweise im Promillebereich genauer, so zeigt sich, daß die Konstanz des Ausgangstroms 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 Ausgangstrom Ia eingeht. Dieser Effekt verstärkt sich noch, wenn zur Einstellung eines vorgegebenen Ausgangsstroms la 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 you take a closer look at the current ratio, for example in the alcohol 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 being incorporated in the output current I a accordingly. 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. H. 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 der 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 Ti, 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 i , 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. Über diesen Transistor T6, der die am Widerstand Ref 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 T7, T8 der gleiche durch die Basisströme bedingte Fehler, wie dies durch die Basisströme lB3, lB4 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.2 contains a further current mirror T 7 , T 8 , in which Collector-emitter circuit of the controlled transistor T 7 of this current mirror is a transistor T 6 , which is coupled with its base to the reference resistor R ref . The current mirror T 7 is obtained via this transistor T 6 , which converts the voltage across the resistor R ef into a corresponding current. T 8 is a current which also includes the error caused by the base currents of the transistors T 7 , T 8 . 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 7 , T 8 produces the same error caused by the base currents as is caused by the base currents l B3 , l B4 in the first current mirror T 3 , T 4 . 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 yields 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 paired sufficiently well by corresponding measurements.
  • Da also von den über den Referenzwiderstand Rref fließenden Kollektorstrom lc1 der Transistorstufe T1, d. h., vom Referenzstrom, der Fehlerstrom entsprechend den Basisströmen im Stromspiegel T7, Ta subtrahiert wird, ergibt sich, wenn überhaupt, ein sehr kleiner resultierender Fehler im Ausgangsstrom la. 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 TI, 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.Since the fault current corresponding to the base currents in the current mirror T 7 , T a 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 in, if at all, results Output current l a . From the foregoing it follows that for the errors caused by the base currents in a current mirror, compensation could be carried out only by leading the transistor T 6 to the supply voltage just like the transistors T I , 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 der Early-Effektes behafteten Ausgangsstrom la führende Transistorstufe T4 über einen als Spannungsfolger geschalteten weiteren Operationsverstärker OP1 an die an den Referenzwiderständ 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 la 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 la bedingten Fehlern realisiert ist.In order to compensate for this error at the same time, the transistor stage T 4 carrying the constant output current l a , which still has errors due to the early effects, is coupled via a further operational amplifier OP 1 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 amplification 1, the same voltage is present at the collector of the transistor T 6 as at the collector of the transistor T 4 carrying the output current I a of the first current mirror T 3 , T 4 , so that the same early effect is effective at transistor T 6 , whereby a compensation of errors caused by the early effect in the output current I a is realized.
  • Wenn, wie eingangs anhand der Schaltungsanordnung nach Fig. 1 ausgeführt wurde, zur Einstellung eines vorgegebenen Wertes des Ausgangsstroms la ein erster Stromspiegel T3, T4 gewählt wird, in dem der als Diode geschaltete Bezugstransistor T3 und der von diesem gesteuerte, den (gespiegelten) konstanten Ausgangsstrom la 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, Ta ein Emitter- und/oder Kollektorflächenverhältnis von 1 : (n + 1) besitzen. Damit bleibt die kompensierende Wirkung auch für einen durch das Verhältnis n festgelegten Ausgangsstrom la erhalten.1 , a first current mirror T 3 , T 4 is selected to set a predetermined value of the output current I a , in which the reference transistor T 3 connected as a diode and the one controlled by this, 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 coupled to the reference resistor R ref and the further operational amplifier OP 1 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, has an n-fold emitter and / or collector area and the transistor T 8 which acts as a diode and acts as a reference transistor and the mirrored current leading transistor T 7 of the second current mirror T 7 , T a 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. An integrated constant current source comprising : an operational amplifier (OP) which, at its inverting input (-), can be supplied with a reference voltage (Uref), and whose output can be coupled to a first stage (T1) which converts its output voltage into a current (lcl), a reference resistor (Rref) located in the circuit of the first stage (T1) and which couples the voltage drop across said resistor to the non-inverting input (+) of the operational amplifier (OP), a second stage (T2) coupled to the output of the operational amplifier (OP) which converts the output voltage of the operational amplifier into a current (lc2), and a first current reflector (T3, T4) which supplies an output current (la, constant in first approximation, and located in the circuit of the second stage (T2), characterised by a third stage (T5) coupled to the output of the operational amplifier (OP) which converts the output voltage of the operational amplifier into a current (lc5). a second current reflector (T7, Ts) arranged in the circuit of the third stage (T5), and a stage (T6) coupled to the reference resistor (Rref) and located in the circuit of the stage (T7) of the second current reflector (T7, T8) which conducts the reflected current.
2. An integrated constant current source as claimed in Claim 1, characterised in that the stage (T4) of the first current reflector (T3, T4) which conducts the constant output current (la), is coupled via a further operational amplifier (OP1) connected as a voltage follower to the stage (T6) which is coupled to the reference resistor (Rref).
3. An integrated constant current source as claimed in Claim 1 and/or 2, characterised in that the stage (Ts) which is coupled to the reference resistor (Rref) is formed by a transistor whose collector-emitter path is located in the circuit of the stage (T7) of the second current reflector (T6, T7) which conducts the reflected current, and whose base is connected to the reference resistor (Rref).
4. An integrated constant current source as claimed in one of Claims 1 to 3, comprising a first current reflector (T3, T4) in which a reference transistor (T3) connected as a diode to control the transistor (T4) which conducts the (reflected) constant output current (la) possess an emitter and/or collector surface area ration of 1 : n, characterised in that, relative to the emitter and/or collector surface area of the reference transistor (T3) of the first current reflector (T3, T4), the transistor (T6) coupled to the reference resistor (Rref) and to the further operational amplifier (OP1) has an n-fold emitter and/or collector surface area, and a reference transistor (T8) connected as a diode, and the transistor (T7) of the second current reflector (T7, T8), which conducts the reflected current, possesses an emitter and/or collector surface area ratio of 1 : (n + 1).
EP85107776A 1984-07-16 1985-06-24 Integrated constant-current source Expired EP0169388B1 (en)

Priority Applications (2)

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

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT85107776T AT37619T (en) 1984-07-16 1985-06-24 Integrated constant power source.

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

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US (1) US4651083A (en)
EP (1) EP0169388B1 (en)
JP (1) JPS6136816A (en)
KR (1) KR860001374A (en)
AT (1) AT37619T (en)
DE (1) DE3565328D1 (en)

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US4706013A (en) * 1986-11-20 1987-11-10 Industrial Technology Research Institute Matching current source
US5525897A (en) * 1988-05-24 1996-06-11 Dallas Semiconductor Corporation Transistor circuit for use in a voltage to current converter circuit
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
US5004938A (en) * 1989-03-03 1991-04-02 Acer Incorporated MOS analog NOR amplifier and current source therefor
US4920309A (en) * 1989-03-24 1990-04-24 National Semiconductor Corporation Error amplifier for use with parallel operated autonomous current or voltage regulators using transconductance type power amplifiers
IT1252324B (en) * 1991-07-18 1995-06-08 Sgs Thomson Microelectronics Integrated circuit voltage regulator with high stability 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
DE10145034B4 (en) * 2001-09-13 2005-04-21 Infineon Technologies Ag Arrangement with a power source and a switch connected in series to this
DE102005010311A1 (en) 2005-03-03 2006-09-14 Atmel Germany Gmbh Method and 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

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DE3136780A1 (en) * 1981-09-16 1983-03-31 Siemens Ag INTEGRATED SEMICONDUCTOR CIRCUIT

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US4651083A (en) 1987-03-17
JPS6136816A (en) 1986-02-21
DE3565328D1 (en) 1988-11-03
EP0169388A1 (en) 1986-01-29
KR860001374A (en) 1986-02-26
AT37619T (en) 1988-10-15

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