EP1126350A1 - Voltage-to-current converter - Google Patents

Voltage-to-current converter Download PDF

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Publication number
EP1126350A1
EP1126350A1 EP00103077A EP00103077A EP1126350A1 EP 1126350 A1 EP1126350 A1 EP 1126350A1 EP 00103077 A EP00103077 A EP 00103077A EP 00103077 A EP00103077 A EP 00103077A EP 1126350 A1 EP1126350 A1 EP 1126350A1
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EP
European Patent Office
Prior art keywords
current
voltage
transistor
transistors
current mirror
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Granted
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EP00103077A
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German (de)
French (fr)
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EP1126350B1 (en
Inventor
Hans-Heinrich Viehmann
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Infineon Technologies AG
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Infineon Technologies AG
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Priority to AT00103077T priority Critical patent/ATE328311T1/en
Application filed by Infineon Technologies AG filed Critical Infineon Technologies AG
Priority to EP00103077A priority patent/EP1126350B1/en
Priority to DE50012856T priority patent/DE50012856D1/en
Priority to CN01805037.9A priority patent/CN1401099A/en
Priority to PCT/DE2001/000333 priority patent/WO2001061430A1/en
Priority to JP2001560758A priority patent/JP3805678B2/en
Priority to TW090103231A priority patent/TW595078B/en
Publication of EP1126350A1 publication Critical patent/EP1126350A1/en
Priority to US10/219,601 priority patent/US6586919B2/en
Application granted granted Critical
Publication of EP1126350B1 publication Critical patent/EP1126350B1/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
    • 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
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is dc
    • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/26—Current mirrors
    • G05F3/262—Current mirrors using field-effect transistors only

Definitions

  • the invention relates to a voltage-current converter with a first current mirror, which has two transistors, the are designed so that with the same control current flowing through the first transistor by a predetermined Factor greater than that through the second transistor flowing current is the output current of the voltage-current converter represents.
  • Voltage-to-current converters are well known in the art and serve to convert an input voltage into a proportional Convert output current. This is for example for the voltage controlled oscillator (also called VCO for short) in a phase locked loop (also called PLL for short) needed.
  • VCO voltage controlled oscillator
  • PLL phase locked loop
  • the known voltage-current converter mentioned at the beginning is shown in FIG. 2 shown. It has a current mirror 10 with two normally-off n-channel MOSFETs 12, 14 (abbreviation for the English term "metal-oxide-semiconductor field-effect transistor").
  • the current mirror 10 is programmed via a series resistor 16, which is connected in series with the drain terminal of the first transistor 12 to the input voltage U E and defines the drain current I 12 of the first transistor 12, which is the input current I E of the current mirror 10 represents.
  • the gate connections of the two transistors 12, 14 are connected to one another and to the drain connection of the first transistor 12, so that both transistors 12, 14 are driven equally.
  • the source connection of the first transistor 12 is grounded.
  • the source connection of the second transistor 14 is grounded, and the output current I A of the voltage-current converter is taken from its drain connection.
  • the current mirror 10 is disclosed in the book SEIFART, MANFRED, "Analoge GmbH - 5th Edition", 1996, Verlagtechnik GmbH, Berlin, DE (ISBN 3-341-01175-7), Figure 6.21.
  • the circuit shown there is modified in that the input voltage U E is connected to the series resistor 16 instead of the supply voltage U DD . Consequently, the input voltage U E is proportional to the input current I E in accordance with the resistance value of the series resistor 16.
  • the series resistor 16 Since the input voltage U E is usually present in the range between 2 and 5 volts and the desired output current strength I A should be in the range of a few nano amperes in the above-mentioned applications of the phase locked loop, the series resistor 16 must have a resistance value in the range of a few megohms. Resistors of this size, however, require a very large area in integrated circuits, which is a major disadvantage since the cost of integrated circuits is mainly influenced by the area requirement.
  • This voltage-current converter is consequently based on the previous series resistor required in the known voltage-current converter 16 waived, and since the now provided MOSFET compared to a resistor a much smaller one Having space in an IC will save a significant amount of space achieved, although compared to the known Voltage-current converter more components are provided.
  • the first current mirror If the first current mirror is considered alone, would different due to its two transistors with the same control large streams flow, more precisely, they are cheats the current through the first transistor according to the factor ten times the current through the second transistor.
  • the first transistor has a conductance based on the factor ten times the conductance of the second transistor.
  • this first current mirror is not alone, but in Row with the second current mirror to the supply voltage, which like the input voltage mostly in the range between 2 and 5 volts is connected, the one being the two first and second the two second transistors in Are connected in series and so to speak the input current path or form the output current path of the voltage-current converter.
  • the two identical transistors of the second current mirror now ensure that the two are unequal Transistors of the first transistor have equal currents flow.
  • a voltage drops across the first transistor, the corresponding to the factor only a tenth of that over the second Transistor dropping voltage.
  • the residual tension that is the difference between these two tensions finally over that connected in series with the first transistor MOSFET and thus sets its drain-source voltage represents.
  • This drain-source voltage remains constant to a good approximation and is, for example, 60 mV.
  • This value is in consideration to the aforementioned range of input voltage between 2 and 5 volts selected and sufficient to make it smaller than the gate drive of the MOSFET, i.e. the difference between the gate-source voltage applied to it, yes is formed by the input voltage and its threshold voltage.
  • the MOSFET is operated in strong inversion, so that it is in the resistance range of the output characteristic which is also called “linear range” or "more active Area ".
  • the drain current is a good approximation in the resistance range proportional to the drain-source voltage. Because of this proportionality can give the channel of the MOSFET a resistance value or conductance. This conductance is in turn proportional to gate control. An enlargement the input voltage and thus the gate control a proportional increase in the conductance and thus also the drain current. Because the drain current is the first current mirror is therefore programmed by the second Current flowing transistor, which is the output current of the Voltage-current converter, also enlarged proportionally, but only stays with one according to the factor Tenth of the current through the first transistor. So is the output current proportional to the input voltage as it is expected from a voltage-current converter.
  • the first current mirror is a has a third transistor connected to ground is, now the current flowing through it and nothing more the current flowing through the second transistor is the output current represents the voltage-current converter.
  • This third transistor thus serves as a decoupling transistor, so that the input voltage is not loaded with the output current becomes. This creates a high input resistance of the voltage-current converter achieved. You can also use this third Transistor the output current regardless of the second Transistor can be scaled to the desired size.
  • the current flowing through the first transistor current flowing through the second transistor is equal.
  • the first transistor and the second transistor in weak inversion. This leaves the Drain-source voltage over a wider range of several Decades constant, so the accuracy of the voltage-current converter is improved.
  • FIG. 1 shows a voltage-current converter in a preferred embodiment, which has a first current mirror 18, a second current mirror 20 and a MOSFET 22.
  • this MOSFET 22 has a normally-off n-channel. Its source connection is grounded, and the input voltage U E of the voltage-current converter is connected to its gate connection and therefore forms the gate-source voltage U GS .
  • the first current mirror 18 shown has three transistors 24, 26, 28 which, in the embodiment shown, are likewise self-blocking n-channel MOSFETs which are operated in the saturation range. Their gate connections are connected to one another and to the drain connection of the first transistor 24, so that all three transistors 24, 26, 28 are driven equally.
  • the source of the first transistor 24 is connected to the drain of the MOSFET 22 so that the first transistor 24 and the MOSFET 22 are connected in series.
  • the source connection of the second transistor 26 is grounded.
  • the source terminal of the third transistor 28 is grounded and the output current I A of the voltage-current converter is taken from its drain terminal.
  • the first current mirror 18 is thus programmed by the channel resistance of the MOSFET 22.
  • the second current mirror 20 shown has two transistors 30, 32 which, in the embodiment shown, are normally-off p-channel MOSFETs which are operated in the saturation range. Their gate connections are connected to one another and to the drain connection of the second transistor 32, so that both transistors 30, 32 are driven equally. Their source connections are connected to the supply voltage U DD .
  • the drain of the first transistor 30 is connected to the drain of the first transistor 24 of the first current mirror 18, while the drain of the second transistor 32 is connected to the drain of the second transistor 26 of the first current mirror 10, so that the two first transistors 24, 30 and the two second transistors 26, 32 are each connected in series to the supply voltage U DD .
  • the three transistors 24, 26, 28 are formed in the first current mirror 18 in such a way that, with the same activation, the drain current I 24 flowing through the first transistor 24 is larger by a predetermined first factor K 1 than that through the second Transistor 26 flowing drain current I 26 and larger by a predetermined second factor K 2 than the drain current I 28 flowing through the third transistor 28.
  • the first transistor 24 has a channel conductance G 24 which is K 1 times the channel conductance G 26 of the second transistor 26 and K 2 times the channel conductance G 28 of the third transistor 28.
  • the two transistors 30, 32 are formed identically in the above sense, so that with the same control, the drain current I 30 flowing through the first transistor 30 is equal to the drain flowing through the second transistor 32 Current I 32 is. Consequently, their channel conductance values G 30 , G 32 are also the same. This can be achieved simply by suitable selection of the geometrical dimensions of the two transistors 30, 32 with the same parameters remaining, so that their geometrical quotients ⁇ 30 , ⁇ 32 are also the same.
  • the operation of the voltage-current converter shown is described below.
  • the course of the supply voltage U DD via the first transistor 30 of the second current mirror 20, the first transistor 24 of the first current mirror 18 and the MOSFET 22 to ground is referred to as the "input current path" of the voltage-current converter
  • the course of the Supply voltage UDD via the second transistor 32 of the second current mirror 20 and the second transistor 26 of the first current mirror 18 to ground is referred to as the "output current path" of the voltage-current converter.
  • the second current mirror 20 with its identical transistors 30, 32 ensures that the current I E in the input current path and the current I 1 in the output current path are the same size.
  • K 1 U 26 / U 24th
  • the first factor K 1 is now selected with the aid of the geometry quotients ⁇ 24 , ⁇ 26 such that the MOSFET 22 is operated in the resistance range.
  • the following must therefore apply: U DS ⁇ U GS - U T ⁇ U eff
  • U GS is the gate-source voltage that is formed by the input voltage U E
  • U T is the threshold voltage
  • U eff is the gate drive.
  • the channel current G 22 of the MOSFET 22 since it lies in the input current path, programs the first current mirror 18, that is to say that the current I E also flowing through the MOSFET 22 in the input current path causes the drain current I 26 through its second transistor 26 , and thus also the current I 1 in the output current path, and the drain current I 28 through its third transistor 28.
  • This drain current I 28 through the third transistor 28 represents the output current I A of the voltage-current converter, so that the second geometry quotient K 2 can be chosen such that the output current I A is of the desired order.
  • the transistors 30, 32 of the second current mirror must also be used 20 may not be identical, rather they can be, for example similar to transistors 24, 26, 28 of the first Current level 18 differentiated by a factor.
  • transistors 24, 26, 28, 30, 32 is the two current mirrors 18, 20 not on the described MOSFETs limited, rather they can, for example, MOSFETs with different polarity and / or doping, but also JFETs or be bipolar transistors.

Abstract

The invention relates to a voltage current transformer comprising a first current mirror (18) which is provided with two transistors (24, 26) that are embodied in such a way that, when said transistors are driven in the same way, the current which flows through the first transistor (24) and represents the output current of the voltage current transformer is greater than the current (I1) which flows through the second transistor (26) by a predetermined factor (K1). The aim of the invention is to reduce the surface in integrated circuits, whereby said surface that is required in known voltage current converters is very big. According to the invention, a second current mirror (20) which is provided with two transistors (30, 32) is provided. The two current mirrors (18, 20) are connected in series and to a supply voltage (UDD) in such a way that the two first transistors (24, 26) and the two second transistors (30, 32) are connected in series respectively. A MOSFET (22) is provided that is connected in series in relation to the first transistor (24) of the first current mirror (18) and is connected to the input voltage (UE) with the gate terminal thereof.

Description

Die Erfindung betrifft einen Spannungs-Strom-Wandler mit einem ersten Stromspiegel, der zwei Transistoren aufweist, die derart ausgebildet sind, daß bei gleicher Ansteuerung der durch den ersten Transistor fließende Strom um einen vorbestimmten Faktor größer als der durch den zweiten Transistor fließende Strom ist, der den Ausgangsstrom des Spannungs-Strom-Wandlers darstellt.The invention relates to a voltage-current converter with a first current mirror, which has two transistors, the are designed so that with the same control current flowing through the first transistor by a predetermined Factor greater than that through the second transistor flowing current is the output current of the voltage-current converter represents.

Spannungs-Strom-Wandler sind im Stand der Technik gut bekannt und dienen dazu, eine Eingangsspannung in einen proportionalen Ausgangsstrom umzuwandeln. Dies wird beispielsweise für den spannungsgesteuerten Oszillator (auch kurz mit VCO bezeichnet) in einem Phasenregelkreis (auch kurz mit PLL bezeichnet) benötigt.Voltage-to-current converters are well known in the art and serve to convert an input voltage into a proportional Convert output current. This is for example for the voltage controlled oscillator (also called VCO for short) in a phase locked loop (also called PLL for short) needed.

Der zu Beginn erwähnte bekannte Spannungs-Strom-Wandler ist in der FIG. 2 dargestellt. Er weist einen Stromspiegel 10 mit zwei selbstsperrenden n-Kanal-MOSFETs 12, 14 (Abkürzung für den englischen Begriff "metal-oxide-semiconductor field-effect transistor") auf. Der Stromspiegel 10 wird über einen Vorwiderstand 16 programmiert, der in Reihe mit dem Drain-Anschluß des ersten Transistors 12 an die Eingangsspannung UE angeschlossen ist und den Drain-Strom I12 des ersten Transistors 12 festlegt, der den Eingangsstrom IE des Stromspiegels 10 darstellt.The known voltage-current converter mentioned at the beginning is shown in FIG. 2 shown. It has a current mirror 10 with two normally-off n-channel MOSFETs 12, 14 (abbreviation for the English term "metal-oxide-semiconductor field-effect transistor"). The current mirror 10 is programmed via a series resistor 16, which is connected in series with the drain terminal of the first transistor 12 to the input voltage U E and defines the drain current I 12 of the first transistor 12, which is the input current I E of the current mirror 10 represents.

Die Gate-Anschlüsse der beiden Transistoren 12, 14 sind miteinander sowie mit dem Drain-Anschluß des ersten Transistors 12 verbunden, so daß beide Transistoren 12, 14 gleich angesteuert werden. Der Source-Anschluß des ersten Transistors 12 liegt an Masse. Der Source-Anschluß des zweiten Transistors 14 liegt an Masse, und an seinem Drain-Anschluß wird der Ausgangsstrom IA des Spannungs-Strom-Wandlers abgenommen.The gate connections of the two transistors 12, 14 are connected to one another and to the drain connection of the first transistor 12, so that both transistors 12, 14 are driven equally. The source connection of the first transistor 12 is grounded. The source connection of the second transistor 14 is grounded, and the output current I A of the voltage-current converter is taken from its drain connection.

Der Stromspiegel 10 ist in dem Buch SEIFART, MANFRED, "Analoge Schaltungen - 5. Auflage", 1996, Verlag Technik GmbH, Berlin, DE (ISBN 3-341-01175-7), Bild 6.21 offenbart. Gemäß der FIG. 2 ist bei dem bekannten Spannungs-Strom-Wandler die dort gezeigte Schaltung jedoch dadurch abgewandelt, daß die Eingangsspannung UE an Stelle der Versorgungsspannung UDD an den Vorwiderstand 16 angeschlossen ist. Folglich ist die Eingangsspannung UE entsprechend dem Widerstandswert des Vorwiderstands 16 proportional zu dem Eingangsstrom IE.The current mirror 10 is disclosed in the book SEIFART, MANFRED, "Analoge Schaltungen - 5th Edition", 1996, Verlag Technik GmbH, Berlin, DE (ISBN 3-341-01175-7), Figure 6.21. According to FIG. 2 in the known voltage-current converter, however, the circuit shown there is modified in that the input voltage U E is connected to the series resistor 16 instead of the supply voltage U DD . Consequently, the input voltage U E is proportional to the input current I E in accordance with the resistance value of the series resistor 16.

Da die Transistoren 12, 14 im Sättigungsbereich betrieben werden, sind ihre jeweiligen Drain-Ströme I12, I14 zueinander proportional. Diese Proportionalität kann einfach durch Auswahl der geometrischen Abmessungen der Transistoren 12, 14 bestimmt werden, wenn die übrigen Parameter, wie die Oberflächenbeweglichkeit der Ladungsträger im Kanal µ0, die Gate-Kapazität pro Fläche C0x und die Schwellspannung UT, für die Transistoren 12, 14 gleich sind. In diesem Fall gilt für die beiden Drain-Ströme I12 und I14: I14/I12 = β14/β12, wobei β=W/L der Geometriequotient eines Transistors mit der Kanalbreite W und der Kanallänge L ist.Since the transistors 12, 14 are operated in the saturation range, their respective drain currents I 12 , I 14 are proportional to one another. This proportionality can be determined simply by selecting the geometric dimensions of the transistors 12, 14 when the other parameters, such as the surface mobility of the charge carriers in the channel μ 0 , the gate capacitance per area C 0x and the threshold voltage U T , for the transistors 12 , 14 are the same. In this case, the following applies to the two drain currents I 12 and I 14 : I. 14 / I 12th = β 14 / β 12th , where β = W / L is the geometric quotient of a transistor with channel width W and channel length L.

Wenn folglich das Layout des ersten Transistors 12 und des zweiten Transistors 14 auf dem Chip geometrisch so dimensioniert wird, daß β12=10·β14 gilt, indem beispielsweise der Kanal des ersten Transistors 12 gleich lang, aber zehnmal breiter als der Kanal des zweiten Transistors 14 gemacht wird, dann gilt entsprechend auch I12=10·I14. Consequently, if the layout of the first transistor 12 and the second transistor 14 on the chip is geometrically dimensioned such that β 12 = 10 × β 14 applies, for example by making the channel of the first transistor 12 the same length but ten times wider than the channel of the second If transistor 14 is made, then I 12 = 10 * I 14 applies accordingly.

In diesem Fall ist also wegen der zuvor erwähnten Proportionalität zwischen Eingangsspannung UE und Eingangsstrom IE≡I12 auch der Drain-Strom I14 des zweiten Transistors 14, der den Ausgangsstrom IA des bekannten Spannungs-Strom-Wandlers darstellt, proportional zu der Eingangsspannung UE.In this case, because of the aforementioned proportionality between input voltage U E and input current I E ≡I 12 , the drain current I 14 of the second transistor 14, which represents the output current I A of the known voltage-current converter, is proportional to that Input voltage U E.

Da bei den genannten Anwendungsfällen des Phasenregelkreises die Eingangsspannung UE meist im Bereich zwischen 2 und 5 Volt vorliegt und die gewünschte Ausgangsstromstärke IA im Bereich von wenigen Nanoampere liegen soll, muß der Vorwiderstand 16 einen Widerstandswert im Bereich von einigen Megaohm aufweisen. Widerstände in dieser Größenordnung benötigen jedoch in integrierten Schaltungen eine sehr große Fläche, was einen großen Nachteil darstellt, da die Kosten von integrierten Schaltungen hauptsächlich durch den Flächenbedarf beeinflußt werden.Since the input voltage U E is usually present in the range between 2 and 5 volts and the desired output current strength I A should be in the range of a few nano amperes in the above-mentioned applications of the phase locked loop, the series resistor 16 must have a resistance value in the range of a few megohms. Resistors of this size, however, require a very large area in integrated circuits, which is a major disadvantage since the cost of integrated circuits is mainly influenced by the area requirement.

Es ist daher Aufgabe der Erfindung, einen Spannungs-Strom-Wandler der genannten Art zur Verfügung zu stellen, der weniger Fläche benötigt.It is therefore an object of the invention to provide a voltage-current converter of the type mentioned, the less Area needed.

Diese Aufgabe wird dadurch gelöst, daß:

  • ein zweiter Stromspiegel vorgesehen ist, der zwei Transistoren aufweist;
  • die beiden Stromspiegel derart in Reihe an eine Versorgungsspannung angeschlossen sind, daß die beiden ersten Transistoren und die beiden zweiten Transistoren jeweils in Reihe geschaltet sind; und
  • ein MOSFET vorgesehen ist, der in Reihe zu dem ersten Transistor des ersten Stromspiegels geschaltet und mit seinem Gate-Anschluß an die Eingangsspannung angeschlossen ist.
This problem is solved in that:
  • a second current mirror is provided which has two transistors;
  • the two current mirrors are connected in series to a supply voltage such that the two first transistors and the two second transistors are each connected in series; and
  • a MOSFET is provided which is connected in series with the first transistor of the first current mirror and is connected with its gate connection to the input voltage.

Bei diesem Spannungs-Strom-Wandler wird folglich auf den bisher in dem bekannten Spannungs-Strom-Wandler benötigten Vorwiderstand 16 verzichtet, und da der nunmehr vorgesehene MOSFET im Vergleich zu einem Widerstand eine erheblich kleinere Fläche in einem IC hat, wird eine erhebliche Flächenersparnis erzielt, obwohl im Vergleich zu dem bekannten Spannungs-Strom-Wandler mehr Bauteile vorgesehen sind.This voltage-current converter is consequently based on the previous series resistor required in the known voltage-current converter 16 waived, and since the now provided MOSFET compared to a resistor a much smaller one Having space in an IC will save a significant amount of space achieved, although compared to the known Voltage-current converter more components are provided.

Zur einfacheren Erläuterung der Funktionsweise dieses Spannungs-Strom-Wandlers wird im folgenden angenommen, daß in dem zweiten Stromspiegel die beiden Transistoren identisch sind, was hier bedeuten soll, daß durch sie bei gleicher Ansteuerung gleich große Ströme fließen, und daß zudem der Faktor gleich zehn ist.To simplify the explanation of how this voltage-current converter works It is assumed below that in the second current mirror the two transistors are identical which is supposed to mean here that with the same control equal currents flow, and that is also the factor is ten.

Falls der erste Stromspiegel allein betrachtet wird, würden durch seine beiden Transistoren bei gleicher Ansteuerung unterschiedlich große Ströme fließen, genauer gesagt betrüge der Strom durch den ersten Transistor entsprechend dem Faktor das Zehnfache des Stromes durch den zweiten Transistor. Anders ausgedrückt weist der erste Transistor einen Leitwert auf, der entsprechend dem Faktor das Zehnfache des Leitwertes des zweiten Transistors beträgt.If the first current mirror is considered alone, would different due to its two transistors with the same control large streams flow, more precisely, they are cheats the current through the first transistor according to the factor ten times the current through the second transistor. In other words, the first transistor has a conductance based on the factor ten times the conductance of the second transistor.

Dieser erste Stromspiegel ist jedoch nicht allein, sondern in Reihe mit dem zweiten Stromspiegel an die Versorgungsspannung, die wie die Eingangsspannung meist im Bereich zwischen 2 und 5 Volt liegt, angeschlossen, wobei zum einen die beiden ersten und zum anderen die beiden zweiten Transistoren in Reihe geschaltet sind und sozusagen den Eingangsstrompfad bzw. den Ausgangsstrompfad des Spannungs-Strom-Wandlers bilden. Die beiden identischen Transistoren des zweiten Stromspiegels sorgen nun dafür, daß auch durch die beiden ungleichen Transistoren des ersten Transistors gleich große Ströme fließen. Da deren Leitwerte aber hierdurch unverändert bleiben, fällt über dem ersten Transistor eine Spannung ab, die entsprechend dem Faktor nur ein Zehntel der über dem zweiten Transistor abfallenden Spannung beträgt. Die Restspannung, also die Differenz zwischen diesen beiden Spannungen, fällt schließlich über dem in Reihe zu dem ersten Transistor geschalteten MOSFET ab und stellt somit dessen Drain-Source-Spannung dar.However, this first current mirror is not alone, but in Row with the second current mirror to the supply voltage, which like the input voltage mostly in the range between 2 and 5 volts is connected, the one being the two first and second the two second transistors in Are connected in series and so to speak the input current path or form the output current path of the voltage-current converter. The two identical transistors of the second current mirror now ensure that the two are unequal Transistors of the first transistor have equal currents flow. However, since their guideline values remain unchanged, a voltage drops across the first transistor, the corresponding to the factor only a tenth of that over the second Transistor dropping voltage. The residual tension, that is the difference between these two tensions finally over that connected in series with the first transistor MOSFET and thus sets its drain-source voltage represents.

Diese Drain-Source-Spannung bleibt in guter Näherung konstant und beträgt beispielsweise 60 mV. Dieser Wert ist in Hinblick auf den zuvor erwähnten Bereich der Eingangsspannung zwischen 2 und 5 Volt ausgewählt und reicht aus, damit sie kleiner ist als die Gate-Ansteuerung des MOSFET, also die Differenz zwischen der an ihn angelegten Gate-Source-Spannung, die ja durch die Eingangsspannung gebildet wird, und seiner Schwellspannung. Folglich wird der MOSFET in starker Inversion betrieben, so daß er sich im Widerstandsbereich der Ausgangskennlinie befindet, der auch als "linearer Bereich" oder "aktiver Bereich" bezeichnet wird.This drain-source voltage remains constant to a good approximation and is, for example, 60 mV. This value is in consideration to the aforementioned range of input voltage between 2 and 5 volts selected and sufficient to make it smaller than the gate drive of the MOSFET, i.e. the difference between the gate-source voltage applied to it, yes is formed by the input voltage and its threshold voltage. As a result, the MOSFET is operated in strong inversion, so that it is in the resistance range of the output characteristic which is also called "linear range" or "more active Area ".

Im Widerstandsbereich ist der Drain-Strom in guter Näherung proportional zur Drain-Source-Spannung. Wegen dieser Proportionalität kann also dem Kanal des MOSFET ein Widerstandswert oder Leitwert zugeordnet werden. Dieser Leitwert ist seinerseits proportional zur Gate-Ansteuerung. Eine Vergrößerung der Eingangsspannung und damit der Gate-Ansteuerung bewirkt also eine proportionale Vergrößerung des Leitwertes und damit auch des Drain-Stromes. Da der Drain-Strom den ersten Stromspiegel programmiert, wird folglich der durch den zweiten Transistor fließende Strom, der ja den Ausgangsstrom des Spannungs-Strom-Wandlers bildet, ebenfalls proportional vergrößert, bleibt aber entsprechend dem Faktor nur bei einem Zehntel des Stromes durch den ersten Transistor. Somit ist der Ausgangsstrom proportional zur Eingangsspannung, wie es von einem Spannungs-Strom-Wandler ja auch erwartet wird.The drain current is a good approximation in the resistance range proportional to the drain-source voltage. Because of this proportionality can give the channel of the MOSFET a resistance value or conductance. This conductance is in turn proportional to gate control. An enlargement the input voltage and thus the gate control a proportional increase in the conductance and thus also the drain current. Because the drain current is the first current mirror is therefore programmed by the second Current flowing transistor, which is the output current of the Voltage-current converter, also enlarged proportionally, but only stays with one according to the factor Tenth of the current through the first transistor. So is the output current proportional to the input voltage as it is expected from a voltage-current converter.

Vorteilharte Weiterbildungen der Erfindung sind in den Unteransprüchen beschrieben. Advantageous further developments of the invention are in the subclaims described.

Bevorzugt ist vorgesehen, daß der erste Stromspiegel einen dritten Transistor aufweist, der an die Masse angeschlossen ist, wobei nun der durch ihn fließende Strom und nicht mehr der durch den zweiten Transistor fließende Strom den Ausgangsstrom des Spannungs-Strom-Wandlers darstellt. Dieser dritte Transistor dient somit als Auskoppeltransistor, so daß die Eingangsspannung nicht mit dem Ausgangsstrom belastet wird. Dadurch wird ein hoher Eingangswiderstand des Spannungs-Strom-Wandlers erzielt. Außerdem kann mit diesem dritten Transistor der Ausgangsstrom unabhängig von dem zweiten Transistor auf die gewünschte Größenordnung skaliert werden.It is preferably provided that the first current mirror is a has a third transistor connected to ground is, now the current flowing through it and nothing more the current flowing through the second transistor is the output current represents the voltage-current converter. This third transistor thus serves as a decoupling transistor, so that the input voltage is not loaded with the output current becomes. This creates a high input resistance of the voltage-current converter achieved. You can also use this third Transistor the output current regardless of the second Transistor can be scaled to the desired size.

Bevorzugt ist weiter vorgesehen, daß in dem zweiten Stromspiegel der durch den ersten Transistor fließende Strom dem durch den zweiten Transistor fließenden Strom gleicht. Dadurch wird der Entwurf der Schaltung und des Layouts erleichtert.It is preferably further provided that in the second current mirror the current flowing through the first transistor current flowing through the second transistor is equal. Thereby the design of the circuit and the layout is facilitated.

Bevorzugt ist außerdem vorgesehen, daß in dem ersten Stromspiegel der erste Transistor und der zweite Transistor in schwacher Inversion betrieben werden. Dadurch bleibt die Drain-Source-Spannung über einen größeren Bereich von mehreren Dekaden konstant, so daß die Genauigkeit des Spannungs-Strom-Wandlers verbessert wird.It is also preferably provided that in the first current mirror the first transistor and the second transistor in weak inversion. This leaves the Drain-source voltage over a wider range of several Decades constant, so the accuracy of the voltage-current converter is improved.

Im folgenden werden bevorzugte Ausführungsbeispiele der Erfindung anhand der beigefügten Zeichnungen näher beschrieben.

Fig. 1
ist ein Schaltplan eines Spannungs-Strom-Wandlers in einer bevorzugten Ausführungsform; und
Fig. 2
ist ein Schaltplan eines bekannten Spannungs-Strom-Wandlers.
Preferred exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings.
Fig. 1
10 is a circuit diagram of a voltage-to-current converter in a preferred embodiment; and
Fig. 2
is a circuit diagram of a known voltage-current converter.

Die Fig. 1 zeigt einen Spannungs-Strom-Wandler in einer bevorzugten Ausführungsform, der einen ersten Stromspiegel 18, einen zweiten Stromspiegel 20 und einen MOSFET 22 aufweist. Bei der dargestellten Ausführungsform hat dieser MOSFET 22 einen selbstsperrenden n-Kanal. Sein Source-Anschluß liegt an Masse, und die Eingangsspannung UE des Spannungs-Strom-Wandlers ist an seinen Gate-Anschluß gelegt und bildet daher die Gate-Source-Spannung UGS.1 shows a voltage-current converter in a preferred embodiment, which has a first current mirror 18, a second current mirror 20 and a MOSFET 22. In the illustrated embodiment, this MOSFET 22 has a normally-off n-channel. Its source connection is grounded, and the input voltage U E of the voltage-current converter is connected to its gate connection and therefore forms the gate-source voltage U GS .

Der dargestellte erste Stromspiegel 18 weist drei Transistoren 24, 26, 28 auf, die bei der dargestellten Ausführungsform ebenfalls selbstsperrende n-Kanal-MOSFETs sind, die im Sättigungsbereich betrieben werden. Ihre Gate-Anschlüsse sind miteinander sowie mit dem Drain-Anschluß des ersten Transistors 24 verbunden, so daß alle drei Transistoren 24, 26, 28 gleich angesteuert werden. Der Source-Anschluß des ersten Transistors 24 ist mit dem Drain-Anschluß des MOSFET 22 verbunden, so daß der erste Transistor 24 und der MOSFET 22 in Reihe geschaltet sind. Der Source-Anschluß des zweiten Transistors 26 liegt an Masse. Der Source-Anschluß des dritten Transistors 28 liegt an der Masse, und an seinem Drain-Anschluß wird der Ausgangsstrom IA des Spannungs-Strom-Wandlers abgenommen. Der erste Stromspiegel 18 wird also durch den Kanalwiderstand des MOSFET 22 programmiert.The first current mirror 18 shown has three transistors 24, 26, 28 which, in the embodiment shown, are likewise self-blocking n-channel MOSFETs which are operated in the saturation range. Their gate connections are connected to one another and to the drain connection of the first transistor 24, so that all three transistors 24, 26, 28 are driven equally. The source of the first transistor 24 is connected to the drain of the MOSFET 22 so that the first transistor 24 and the MOSFET 22 are connected in series. The source connection of the second transistor 26 is grounded. The source terminal of the third transistor 28 is grounded and the output current I A of the voltage-current converter is taken from its drain terminal. The first current mirror 18 is thus programmed by the channel resistance of the MOSFET 22.

Der dargestellte zweite Stromspiegel 20 weist zwei Transistoren 30, 32 auf, die bei der dargestellten Ausführungsform selbstsperrende p-Kanal-MOSFETs sind, die im Sättigungsbereich betrieben werden. Ihre Gate-Anschlüsse sind miteinander sowie mit dem Drain-Anschluß des zweiten Transistors 32 verbunden, so daß beide Transistoren 30, 32 gleich angesteuert werden. Ihre Source-Anschlüsse liegen an der Versorgungsspannung UDD. Der Drain-Anschluß des ersten Transistors 30 ist mit dem Drain-Anschluß des ersten Transistors 24 des ersten Stromspiegels 18 verbunden, während der Drain-Anschluß des zweiten Transistors 32 mit dem Drain-Anschluß des zweiten Transistors 26 des ersten Stromspiegels 10 verbunden ist, so daß die beiden ersten Transistoren 24, 30 und die beiden zweiten Transistor 26, 32 jeweils in Reihe an die Versorgungsspannung UDD angeschlossen sind.The second current mirror 20 shown has two transistors 30, 32 which, in the embodiment shown, are normally-off p-channel MOSFETs which are operated in the saturation range. Their gate connections are connected to one another and to the drain connection of the second transistor 32, so that both transistors 30, 32 are driven equally. Their source connections are connected to the supply voltage U DD . The drain of the first transistor 30 is connected to the drain of the first transistor 24 of the first current mirror 18, while the drain of the second transistor 32 is connected to the drain of the second transistor 26 of the first current mirror 10, so that the two first transistors 24, 30 and the two second transistors 26, 32 are each connected in series to the supply voltage U DD .

In dieser bevorzugten Ausführungsform sind in dem ersten Stromspiegel 18 die drei Transistoren 24, 26, 28 derart ausgebildet, daß bei gleicher Ansteuerung der durch den ersten Transistor 24 fließende Drain-Strom I24 um einen vorbestimmten ersten Faktor K1 größer als der durch den zweiten Transistor 26 fließende Drain-Strom I26 und um einen vorbestimmten zweiten Faktor K2 größer als der durch den dritten Transistor 28 fließende Drain-Strom I28 ist. Anders ausgedrückt weist der erste Transistor 24 einen Kanalleitwert G24 auf, der das K1-fache des Kanalleitwertes G26 des zweiten Transistors 26 und das K2-fache des Kanalleitwertes G28 des dritten Transistors 28 beträgt. Dies kann einfach durch geeignete Auswahl der geometrischen Abmessungen der drei Transistoren 24, 26, 28 bei im übrigen gleichen Parametern erreicht werden, so daß auch ihre Geometriequotienten β24, β26, β28 die genannten proportionalen Verhältnisse einhalten. Es gilt demnach: K1 = I24/I26 = G24/G26 = β24/β26 und K2 = I24/I28 = G24/G28 = β24/β28 In this preferred embodiment, the three transistors 24, 26, 28 are formed in the first current mirror 18 in such a way that, with the same activation, the drain current I 24 flowing through the first transistor 24 is larger by a predetermined first factor K 1 than that through the second Transistor 26 flowing drain current I 26 and larger by a predetermined second factor K 2 than the drain current I 28 flowing through the third transistor 28. In other words, the first transistor 24 has a channel conductance G 24 which is K 1 times the channel conductance G 26 of the second transistor 26 and K 2 times the channel conductance G 28 of the third transistor 28. This can be achieved simply by suitable selection of the geometrical dimensions of the three transistors 24, 26, 28 with otherwise the same parameters, so that their geometrical quotients β 24 , β 26 , β 28 also comply with the proportional relationships mentioned. The following therefore applies: K 1 = I 24th / I 26 = G 24th /G 26 = β 24th / β 26 and K 2 = I 24th / I 28 = G 24th /G 28 = β 24th / β 28

Außerdem sind in dieser bevorzugten Ausführungsform in dem zweiten Stromspiegel 20 die beiden Transistoren 30, 32 identisch im oben genannten Sinne ausgebildet, so daß bei gleicher Ansteuerung der durch den ersten Transistor 30 fließende Drain-Strom I30 gleich dem durch den zweiten Transistor 32 fließende Drain-Strom I32 ist. Folglich sind auch ihre Kanalleitwerte G30, G32 gleich. Dies kann einfach durch geeignete Auswahl der geometrischen Abmessungen der beiden Transistoren 30, 32 bei im übrigen gleichen Parametern erreicht werden, so daß auch ihre Geometriequotienten β30, β32 gleich sind.In addition, in this preferred embodiment, in the second current mirror 20, the two transistors 30, 32 are formed identically in the above sense, so that with the same control, the drain current I 30 flowing through the first transistor 30 is equal to the drain flowing through the second transistor 32 Current I 32 is. Consequently, their channel conductance values G 30 , G 32 are also the same. This can be achieved simply by suitable selection of the geometrical dimensions of the two transistors 30, 32 with the same parameters remaining, so that their geometrical quotients β 30 , β 32 are also the same.

Im folgenden wird die Funktionsweise des dargestellten Spannungs-Strom-Wandlers beschrieben. Hierzu wird der Verlauf von der Versorgungsspannung UDD über den ersten Transistor 30 des zweiten Stromspiegels 20, den ersten Transistor 24 des ersten Stromspiegels 18 und den MOSFET 22 zur Masse als "Eingangsstrompfad" des Spannungs-Strom-Wandlers bezeichnet, während der Verlauf von der Versorgungsspannung UDD über den zweiten Transistor 32 des zweiten Stromspiegels 20 und den zweiten Transistor 26 des ersten Stromspiegels 18 zur Masse als "Ausgangsstrompfad" des Spannungs-Strom-Wandlers bezeichnet wird.The operation of the voltage-current converter shown is described below. For this purpose, the course of the supply voltage U DD via the first transistor 30 of the second current mirror 20, the first transistor 24 of the first current mirror 18 and the MOSFET 22 to ground is referred to as the "input current path" of the voltage-current converter, while the course of the Supply voltage UDD via the second transistor 32 of the second current mirror 20 and the second transistor 26 of the first current mirror 18 to ground is referred to as the "output current path" of the voltage-current converter.

Der zweite Stromspiegel 20 sorgt mit seinen identischen Transistoren 30, 32 dafür, daß der Strom IE im Eingangsstrompfad und der Strom I1 im Ausgangsstrompfad gleich groß sind. In dem ersten Stromspiegel 18 verursachen jedoch diese gleichen Ströme IE, I1 gemäß der Gleichung U=R·I=I/G über dem ersten Transistor 24 einen Spannungsabfall U24, der entsprechend dem oben genannten Leitwertverhältnis K1=G24/G26 kleiner als der über dem zweiten Transistor 26 abfallende Spannungsabfall U26 ist. Es gilt folglich: K1 = U26/U24 The second current mirror 20 with its identical transistors 30, 32 ensures that the current I E in the input current path and the current I 1 in the output current path are the same size. In the first current mirror 18, however, these same currents I E , I 1 according to the equation U = R * I = I / G cause a voltage drop U 24 across the first transistor 24 which corresponds to the above-mentioned conductance ratio K 1 = G 24 / G 26 is smaller than the voltage drop U 26 falling across the second transistor 26. The following therefore applies: K 1 = U 26 / U 24th

Da beide Strompfade parallel von der Versorgungsspannung UDD zur Masse verlaufen, fällt über ihnen insgesamt dieselbe Spannung ab, nämlich die Versorgungsspannung UDD. Im Ausgangsstrompfad gilt also: UDD = U32 + U26 Since both current paths run in parallel from the supply voltage UDD to ground, the same voltage drops across them overall, namely the supply voltage U DD . In the output current path, the following therefore applies: U DD = U 32 + U 26

Hingegen muß im Eingangsstrompfad, obwohl U30=U32 gilt, wegen U24<U26 folgendes gelten: U30 + U24 < UDD On the other hand, the following must apply in the input current path, even though U 30 = U 32 , because of U 24 <U 26 : U 30th + U 24th <U DD

Dort ist aber vor der Masse noch der MOSFET 22 vorhanden, an dem die restliche Spannung als seine Drain-Source-Spannung UDS abfällt, so daß gilt: UDD = U30 + U24 + UDS There, however, the MOSFET 22 is still present in front of the ground, at which the remaining voltage drops as its drain-source voltage U DS , so that: U DD = U 30th + U 24th + U DS

Der erste Faktor K1 wird nun mit Hilfe der Geometriequotienten β24, β26 derart gewählt, daß der MOSFET 22 im Widerstandsbereich betrieben wird. Es muß also folgendes gelten: UDS < UGS - UT ≡ Ueff worin UGS die Gate-Source-Spannung ist, die durch die Eingangsspannung UE gebildet wird, UT die Schwellspannung ist, und Ueff die Gate-Ansteuerung ist.The first factor K 1 is now selected with the aid of the geometry quotients β 24 , β 26 such that the MOSFET 22 is operated in the resistance range. The following must therefore apply: U DS <U GS - U T ≡ U eff where U GS is the gate-source voltage that is formed by the input voltage U E , U T is the threshold voltage, and U eff is the gate drive.

Umgekehrt wird durch den Kanalleitwert G22 des MOSFET 22, da dieser im Eingangsstrompfad liegt, der erste Stromspiegel 18 programmiert, das heißt, daß der auch durch den MOSFET 22 fließende Strom IE im Eingangsstrompfad den Drain-Strom I26 durch seinen zweiten Transistor 26, und somit auch den Strom I1 im Ausgangsstrompfad, sowie den Drain-Strom I28 durch seinen dritten Transistor 28 festlegt. Es gilt somit wegen der oben erwähnten Gleichung K2=I24/I28: I28 = I24/K2 = IE/K2 Conversely, the channel current G 22 of the MOSFET 22, since it lies in the input current path, programs the first current mirror 18, that is to say that the current I E also flowing through the MOSFET 22 in the input current path causes the drain current I 26 through its second transistor 26 , and thus also the current I 1 in the output current path, and the drain current I 28 through its third transistor 28. The following applies because of the equation K 2 = I 24 / I 28 mentioned above: I. 28 = I 24th / K 2 = I E / K 2

Dieser Drain-Strom I28 durch den dritten Transistor 28 stellt den Ausgangsstrom IA des Spannungs-Strom-Wandlers dar, so daß der zweite Geometriequotient K2 derart gewählt werden kann, daß der Ausgangsstrom IA in der gewünschten Größenordnung liegt.This drain current I 28 through the third transistor 28 represents the output current I A of the voltage-current converter, so that the second geometry quotient K 2 can be chosen such that the output current I A is of the desired order.

Da im Widerstandsbereich die Gate-Ansteuerung Ueff≡UE-UT proportional zum Kanalleitwert G22 und dieser gemäß der Gleichung I=G·U wiederum proportional zum Drain-Strom IE ist, gilt für den MOSFET 22: UE ≈ IE Since the gate control U eff ≡U E -U T in the resistance range is proportional to the channel conductance G 22 and this is in turn proportional to the drain current I E according to the equation I = G · U, the following applies to the MOSFET 22: U E ≈ I E

Hieraus folgt wegen der Programmierung, gemäß der IE≈I28≡IA gilt, schließlich noch: UE ≈ IA also die für einen Spannungs-Strom-Wandler gewünschte Proportionalität zwischen dem Ausgangsstrom IA und der Eingangsspannung UE.Finally, because of the programming according to which I E ≈I 28 ≡I A applies: U E ≈ I A the desired proportionality between the output current I A and the input voltage U E for a voltage-current converter.

Auch müssen die Transistoren 30, 32 des zweiten Stromspiegels 20 nicht identisch sein, vielmehr können sie sich beispielsweise ähnlich wie die Transistoren 24, 26, 28 des ersten Stromspiegels 18 um einen Faktor unterschieden.The transistors 30, 32 of the second current mirror must also be used 20 may not be identical, rather they can be, for example similar to transistors 24, 26, 28 of the first Current level 18 differentiated by a factor.

Außerdem ist der Typ der Transistoren 24, 26, 28, 30, 32 der beiden Stromspiegel 18, 20 nicht auf die beschriebenen MOSFETs beschränkt, vielmehr können sie beispielsweise MOSFETs mit anderer Polarität und/oder Dotierung, aber auch JFETs oder Bipolar-Transistoren sein.In addition, the type of transistors 24, 26, 28, 30, 32 is the two current mirrors 18, 20 not on the described MOSFETs limited, rather they can, for example, MOSFETs with different polarity and / or doping, but also JFETs or be bipolar transistors.

Claims (4)

Spannungs-Strom-Wandler, mit: einem ersten Stromspiegel (18), der zwei Transistoren (24, 26) aufweist, die derart ausgebildet sind, daß bei gleicher Ansteuerung der durch den ersten Transistor (24) fließende Strom um einen vorbestimmten Faktor (K1) größer als der durch den zweiten Transistor (26) fließende Strom (I1) ist, der den Ausgangsstrom des Spannungs-Strom-Wandlers darstellt, dadurch gekennzeichnet, daß ein zweiter Stromspiegel (20) vorgesehen ist, der zwei Transistoren (30, 32) aufweist; die beiden Stromspiegel (18, 20) derart in Reihe an eine Versorgungsspannung (UDD) angeschlossen sind, daß die beiden ersten Transistoren (24, 26) und die beiden zweiten Transistoren (30, 32) jeweils in Reihe geschaltet sind; und ein MOSFET (22) vorgesehen ist, der in Reihe zu dem ersten Transistor (24) des ersten Stromspiegels (18) geschaltet und mit seinem Gate-Anschluß an die Eingangsspannung (UE) angeschlossen ist. Voltage-current converter, with: a first current mirror (18) which has two transistors (24, 26) which are designed such that, with the same control, the current flowing through the first transistor (24) is larger by a predetermined factor (K 1 ) than that through the second Transistor (26) flowing current (I 1 ), which represents the output current of the voltage-current converter, characterized in that a second current mirror (20) is provided, which has two transistors (30, 32); the two current mirrors (18, 20) are connected in series to a supply voltage (U DD ) such that the two first transistors (24, 26) and the two second transistors (30, 32) are each connected in series; and a MOSFET (22) is provided which is connected in series with the first transistor (24) of the first current mirror (18) and is connected with its gate connection to the input voltage (U E ). Spannungs-Strom-Wandler nach Anspruch 1, dadurch gekennzeichnet, daß in dem zweiten Stromspiegel (20) der durch den ersten Transistor (30) fließende Strom dem durch den zweiten Transistor (32) fließenden Strom gleicht.Voltage-current converter according to claim 1, characterized in that in the second current mirror (20) the current flowing through the first transistor (30) is equal to the current flowing through the second transistor (32). Spannungs-Strom-Wandler nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß in dem ersten Stromspiegel (18) der erste Transistor (24) und der zweite Transistor (26) in schwacher Inversion betrieben werden.Voltage-current converter according to one of the preceding claims, characterized in that in the first current mirror (18) the first transistor (24) and the second transistor (26) are operated in weak inversion. Spannungs-Strom-Wandler nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der MOSFET (22) eine Schwellenspannung aufweist, so daß die Spannungs-Strom-Kennlinie bei 0 beginnt.Voltage-current converter according to one of the preceding claims, characterized in that the MOSFET (22) has a threshold voltage, so that the voltage-current characteristic curve begins at 0.
EP00103077A 2000-02-15 2000-02-15 Voltage-to-current converter Expired - Lifetime EP1126350B1 (en)

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EP00103077A EP1126350B1 (en) 2000-02-15 2000-02-15 Voltage-to-current converter
DE50012856T DE50012856D1 (en) 2000-02-15 2000-02-15 Voltage-current converter
AT00103077T ATE328311T1 (en) 2000-02-15 2000-02-15 VOLTAGE-CURRENT CONVERTER
PCT/DE2001/000333 WO2001061430A1 (en) 2000-02-15 2001-01-26 Voltage current transformer
CN01805037.9A CN1401099A (en) 2000-02-15 2001-01-26 Voltage current transformer
JP2001560758A JP3805678B2 (en) 2000-02-15 2001-01-26 Voltage-current converter
TW090103231A TW595078B (en) 2000-02-15 2001-02-14 Spannungs-strom-wandler
US10/219,601 US6586919B2 (en) 2000-02-15 2002-08-15 Voltage-current converter

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US6586919B2 (en) 2003-07-01
JP2003523695A (en) 2003-08-05
CN1401099A (en) 2003-03-05
TW595078B (en) 2004-06-21
US20030020446A1 (en) 2003-01-30
ATE328311T1 (en) 2006-06-15
EP1126350B1 (en) 2006-05-31
DE50012856D1 (en) 2006-07-06
JP3805678B2 (en) 2006-08-02
WO2001061430A1 (en) 2001-08-23

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