EP0414319B1 - Circuit for supplying a reference voltage - Google Patents
Circuit for supplying a reference voltage Download PDFInfo
- Publication number
- EP0414319B1 EP0414319B1 EP90202235A EP90202235A EP0414319B1 EP 0414319 B1 EP0414319 B1 EP 0414319B1 EP 90202235 A EP90202235 A EP 90202235A EP 90202235 A EP90202235 A EP 90202235A EP 0414319 B1 EP0414319 B1 EP 0414319B1
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- European Patent Office
- Prior art keywords
- transistor
- whose
- circuit
- emitter
- collector
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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
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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
- G05F1/565—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 sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S323/00—Electricity: power supply or regulation systems
- Y10S323/901—Starting circuits
Definitions
- the invention relates to a circuit for supplying a reference voltage, comprising a voltage generator having a supply terminal and an output for delivering a voltage of given nominal value and comprising a differential amplifier presenting a supply terminal for a source. supply voltage, a non-inverting input connected to the output of the voltage generator, an inverting input and an output as well as a first output follower stage, the output of which delivers said reference voltage is retro-coupled to the inverting input of the amplifier via a divider bridge.
- the voltage generator is liable, when it is switched on, to give rise to instabilities.
- the invention relates to a circuit making it possible to avoid this drawback.
- the basic idea of the invention consists in transmitting the voltage generator signal only when the supply voltage is sufficient for the region of possible instabilities to be exceeded.
- the circuit according to the invention is for this purpose characterized in that the output of the differential amplifier is connected to the input of the first follower stage through a controlled switching device, the first follower stage having its input connected to terminal d power supply through a first resistor, and having its output connected to the supply terminal of the voltage generator and in that it comprises a circuit for controlling the switching device arranged to receive at least the supply voltage so that the switching device is closed when the first supply voltage reaches a threshold for which both the voltage generator and the differential amplifier are in a nominal operating zone .
- the voltage generator is supplied by the reference voltage produced by the circuit, and the reference voltage, once the switching device is closed, is 1 / k times higher than the voltage produced by the voltage generator, k being the division ratio of the first divider bridge.
- the first supply voltage has a low value, insufficient for the switching device to be closed, the voltage at the output of the circuit, which also supplies the voltage generator, varies with the same slope as the first supply voltage, at a constant close.
- the output voltage curve as a function of the first supply voltage therefore no longer presents a risk of instability.
- control circuit and the controlled switching circuit cooperate directly with the differential amplifier. This makes it possible to simplify the electronic diagram.
- the differential amplifier may include a first branch, the input of which is said non-inverting input and a second branch, the input of which is said inverting input
- the control circuit may be arranged to inhibit the passage of current through the second branch when the supply voltage is lower than said threshold
- the controlled switching circuit may include a second follower stage which is arranged to be conductive only when current flows through the second branch.
- the first branch may include the emitter-collector path of a first transistor of a first type, the base and the collector of which are connected respectively to the emitter and to the base of a second transistor of the first type whose collector is connected to a second supply voltage source, the collector of the first transistor being connected to that of a third transistor of the second type opposite to the first, the emitter of which is connected to the second voltage source d 'power supply through a second resistor and whose base constitutes the non-inverting input of the differential amplifier.
- Such a branch has a structure such that it derives from the current from low levels of the first supply voltage.
- the second branch may include the emitter-collector path of a fourth transistor of the first type, the base of which is connected to that of the first transistor, the collector of the fourth transistor being connected to that of a fifth transistor of the second type, the emitter of which is connected to that of the third transistor and whose base constitutes the inverting input of the differential amplifier.
- Such a branch has a structure such that it derives from the current only from a relatively high significant level of the first supply voltage.
- the fourth transistor can have its emitter connected to that of the first transistor.
- control circuit is advantageously common to the two branches.
- the control circuit may include a sixth transistor of the second type, the collector of which is connected to the first supply voltage source, the emitter of which is connected to the emitters of the first and fourth transistors, and the base of which is connected to the terminal of the first resistor which is not connected to the first source of supply voltage.
- the voltage on the basis of the sixth transistor determines the threshold from which the differential amplifier produces an output signal.
- the second follower stage may include a seventh transistor whose base is connected to the collector of the fifth transistor, whose collector is connected to the second supply voltage source and whose emitter is connected to the input of the first follower stage, possibly via a live diode.
- the value of said threshold can be chosen more precisely by having a second resistance between the first resistance and the input of the first follower stage.
- the first follower stage advantageously comprises an eighth transistor with two emitters, the base of which constitutes the input, the collector of which is connected to the first supply voltage source, the first emitter of which is connected to one end of the bridge and the second of which transmitter constitutes the output of the first follower stage.
- a voltage generator REF delivers a voltage V R which is applied to the non-inverting input of a differential amplifier A supplied with a supply voltage V cc .
- the output S of the amplifier A drives a follower circuit T whose output, which delivers a regulated reference voltage V O is retro-coupled to the inverting input of the amplifier A via a resistive divider bridge R3, R4.
- the REF voltage generator is supplied by the supply voltage V cc .
- the voltage generator REF delivers a voltage V at the output + i which is applied to the non-inverting input of the differential amplifier A supplied with a supply voltage V cc .
- the output S of the amplifier A is connected via a controlled switching device 1 to the input S 'of the follower circuit.
- a resistance R1 is arranged between the input S 'and the supply voltage source V cc .
- the output of the follower circuit delivers the regulated reference voltage V O. This output is looped over the inverting input of amplifier A (signal V - i ) using a divider bridge comprising resistors R3 and R4.
- the signal V - i is present at the common point (or mid point) of the divider bridge.
- the other end of the divider point is connected to a second source of supply voltage (here the common mode pole).
- the follower circuit is represented as a transistor T whose base is the point S ', whose emitter delivers the signal V O and whose collector is connected to the supply voltage source V cc .
- the signal V O is applied to the supply terminal of the voltage generator REF.
- a control circuit C which receives the supply voltage V cc (and optionally the voltage V O ) is arranged so as to close the switching device 1 when the supply voltage V cc exceeds a given threshold for which the voltage V + i delivered by the REF voltage generator has exceeded the portion of its characteristic in which instabilities may occur.
- the supply voltage V cc starts from the value 0 and increases to reach its nominal value.
- the switching current 1 is open and the voltage V O changes in proportion to the instantaneous value of the voltage V cc and independently of the voltage V + i .
- the input S 'of the follower stage is referenced to the potential V cc through the resistor R1.
- the switching circuit 1 is closed, and the voltage V O then has the value: For a certain value of V cc , V + i reaches its nominal value V REF .
- a voltage generator (said to be of the "band gap" type) described in the aforementioned work p.295, comprises a transistor T11 of the npn type whose collector is connected to the aforementioned point B and which has a resistance R15, acting as a current source, between its collector and its base.
- the emitter of the transistor T11 which delivers the voltage V + i is connected to a diode (npn transistor T12 mounted as a diode by base-collector short-circuit) through a resistor R11.
- the emitter of transistor T12 is connected to the common mode pole, and its base to that of a transistor T14 whose emitter is connected to the common mode pole through a resistor R14 and whose collector is firstly connected to the transistor emitter T11 through a resistor R16 and on the other hand connected to the base of an npn transistor T15 whose emitter is connected to the common mode pole, and whose collector is connected to the transistor base T11.
- Amplifier A comprises a first branch having a transistor T type of the pnp type whose emitter is connected to a point F, whose base is connected to the emitter of a transistor T transistor of the pnp type, whose collector is connected to the common mode pole and whose base is connected to the transistor collector T5.
- the collector of transistor T5 is connected to that of a transistor T8 of the npn type, the base of which is attacked by the voltage V + i available on the emitter of transistor T11, and whose emitter is connected to the common mode pole through a resistor R8.
- the transistors T5 and T7 have two emitter-base junctions in series, which means that a current is likely to flow in the first branch even for a low potential value at point F.
- the second branch has a pnp transistor T6 whose emitter is connected to point F, whose base is connected to that of transistor T du and whose collector (point S) is connected to that of an npn transistor T9 whose emitter is connected to the common mode pole through the resistor R8.
- the control circuit comprises an npn transistor T3 whose collector is connected to the supply voltage source V cc , whose emitter is connected to said point F and whose base is preferably connected to the mid point H of a bridge divider R1, R2 having two resistors R1 and R2 in series between the supply voltage source V cc and the point S ′, or else directly at the point S ′, the resistance R2 being omitted.
- the switching circuit comprises a pnp transistor T10 whose base is connected to point S (output of amplifier A), whose collector is connected to the common mode pole and whose emitter is connected to point S ′ through a live diode D.
- the output follower stage comprises a transistor (T1, T2) with two emitters (or two transistors T1 and T2 mounted as a follower emitter), the emitter of T1 connected to the divider bridge (R3, R4) and that of T2 delivering the voltage V o at point B.
- T1, T2 with two emitters (or two transistors T1 and T2 mounted as a follower emitter), the emitter of T1 connected to the divider bridge (R3, R4) and that of T2 delivering the voltage V o at point B.
- V cc When V cc has a value below the given threshold, the first branch of the amplifier is likely to be crossed by a current, but the second branch is not crossed by any current. The transistor T10 is then blocked. The base of the transistors T1 and T2 is then at a potential very close to the instantaneous value of V cc .
- V cc When V cc reaches the given threshold, the second branch of the amplifier is crossed by a current sufficient for the transistor T10 to be in conduction state.
- the amplifier is in its operating region and we have: V S ′ denoting the voltage at point S ′.
- V + i ⁇ V REF that is to say that for the calculation, it is considered that the voltage threshold corresponds practically to the correct operating threshold of the voltage generator. He comes : For the amplifier described, correct operation requires that V H is at least equal to 5V D (in fact it is necessary that V H is significantly greater than this value). We then have: The report It therefore makes it possible to determine the threshold V ccO of V cc from which the switching circuit is closed. If the resistance R2 is omitted, the points H and S 'are merged, and and the resistance R1 is no longer involved in determining the threshold.
- the base of transistor T3 is connected to the midpoint H 'of a divider bridge R'1 and R'2 disposed between the voltage source V cc and the common mode pole.
- the base of the transistor T1 is connected to the voltage source V cc through the resistor R1.
- the emitter of transistor T3 is connected to point C, that of transistor T1 is connected to point A through resistor R3, and that of transistor T2 is connected to point B.
- the rest of the circuit is as in Figure 3.
- the threshold condition is then: V H ' > 5V D
- the report determines the threshold V cco of V cc from which the switching circuit is closed.
- the voltages V + i , V - i and V0 increase as soon as V cc reaches V D (0.7 V), the regulation being obtained from 6 V D (approximately 4.2 V).
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Description
L'invention concerne un circuit destiné à fournir une tension de référence, comportant un générateur de tension présentant une borne d'alimentation et une sortie pour délivrer une tension de valeur nominale donnée et comportant un amplificateur différentiel présentant une borne d'alimentation pour une source de tension d'alimentation, une entrée non inverseuse connectée à la sortie du générateur de tension, une entrée inverseuse et une sortie ainsi qu'un premier étage suiveur de sortie, dont la sortie qui délivre ladite tension de référence est rétro-couplée à l'entrée inverseuse de l'amplificateur par l'intermédiaire d'un pont diviseur.The invention relates to a circuit for supplying a reference voltage, comprising a voltage generator having a supply terminal and an output for delivering a voltage of given nominal value and comprising a differential amplifier presenting a supply terminal for a source. supply voltage, a non-inverting input connected to the output of the voltage generator, an inverting input and an output as well as a first output follower stage, the output of which delivers said reference voltage is retro-coupled to the inverting input of the amplifier via a divider bridge.
Un tel circuit est connu de "Analysis and Design of Analog Integrated Circuits" de Paul R. GRAY et ROBERT G. MEYER (John Wiley and Sons - New-York 1977) fig.d.37 p.516 Voltage regulator.Such a circuit is known from "Analysis and Design of Analog Integrated Circuits" by Paul R. GRAY and ROBERT G. MEYER (John Wiley and Sons - New-York 1977) fig.d.37 p.516 Voltage regulator.
Le générateur de tension est susceptible, lors de sa mise sous tension de donner lieu à des instabilités.The voltage generator is liable, when it is switched on, to give rise to instabilities.
L'invention a pour objet un circuit permettant d'éviter cet inconvénient.The invention relates to a circuit making it possible to avoid this drawback.
L'idée de base de l'invention consiste à ne transmettre en sortie le signal du générateur de tension que lorsque la tension d'alimentation est suffisante pour que la région d'instabilités possibles soit dépassée.The basic idea of the invention consists in transmitting the voltage generator signal only when the supply voltage is sufficient for the region of possible instabilities to be exceeded.
Le circuit selon l'invention est dans ce but caractérisé en ce que la sortie de l'amplificateur différentiel est reliée à l'entrée du premier étage suiveur à travers un dispositif de commutation commandé, le premier étage suiveur ayant son entrée reliée à borne d'alimentation à travers une première résistance, et ayant sa sortie reliée à la borne d'alimentation du générateur de tension et en ce qu'il comporte un circuit de commande du dispositif de commutation agencé pour recevoir au moins la tension d'alimentation de manière que le dispositif de commutation soit fermé lorsque la première tension d'alimentation atteint un seuil pour lequel à la fois le générateur de tension et l'amplificateur différentiel sont dans une zone de fonctionnement nominal.The circuit according to the invention is for this purpose characterized in that the output of the differential amplifier is connected to the input of the first follower stage through a controlled switching device, the first follower stage having its input connected to terminal d power supply through a first resistor, and having its output connected to the supply terminal of the voltage generator and in that it comprises a circuit for controlling the switching device arranged to receive at least the supply voltage so that the switching device is closed when the first supply voltage reaches a threshold for which both the voltage generator and the differential amplifier are in a nominal operating zone .
Le générateur de tension est alimenté par la tension de référence produite par le circuit, et la tension de référence, une fois le dispositif de commutation fermé, est 1/k fois plus élevée que la tension produite par le générateur de tension, k étant le rapport de division du premier pont diviseur. Lorsque la première tension d'alimentation a une valeur faible, insuffisante pour que le dispositif de commutation soit fermé, la tension en sortie du circuit, qui alimente également le générateur de tension varie avec la même pente que la première tension d'alimentation, à une constante près. La courbe de tension de sortie en fonction de la première tension d'alimentation ne présente donc plus de risque d'instabilité.The voltage generator is supplied by the reference voltage produced by the circuit, and the reference voltage, once the switching device is closed, is 1 / k times higher than the voltage produced by the voltage generator, k being the division ratio of the first divider bridge. When the first supply voltage has a low value, insufficient for the switching device to be closed, the voltage at the output of the circuit, which also supplies the voltage generator, varies with the same slope as the first supply voltage, at a constant close. The output voltage curve as a function of the first supply voltage therefore no longer presents a risk of instability.
Il est particulièrement avantageux que le circuit de commande et le circuit de commutation commandé coopèrent directement avec l'amplificateur différentiel. Ceci permet en effet de simplifier le schéma électronique.It is particularly advantageous that the control circuit and the controlled switching circuit cooperate directly with the differential amplifier. This makes it possible to simplify the electronic diagram.
Dans ce but, l'amplificateur différentiel peut comporter une première branche dont l'entrée est ladite entrée non inverseuse et une deuxième branche dont l'entrée est ladite entrée inverseuse, le circuit de commande peut être agencé pour inhiber le passage du courant dans la deuxième branche lorsque la tension d'alimentation est inférieure audit seuil, et le circuit de commutation commandé peut comporter un deuxième étage suiveur qui est agencé pour n'être conducteur que lorsque du courant traverse la deuxième branche.For this purpose, the differential amplifier may include a first branch, the input of which is said non-inverting input and a second branch, the input of which is said inverting input, the control circuit may be arranged to inhibit the passage of current through the second branch when the supply voltage is lower than said threshold, and the controlled switching circuit may include a second follower stage which is arranged to be conductive only when current flows through the second branch.
La première branche peut comporter le trajet émetteur-collecteur d'un premier transistor d'un premier type dont la base et le collecteur sont connectés respectivement à l'émetteur et à la base d'un deuxième transistor du premier type dont le collecteur est connecté à une deuxième source de tension d'alimentation, le collecteur du premier transistor étant connecté à celui d'un troisième transistor du deuxième type opposé au premier, dont l'émetteur est reliè à la deuxième source de tension d'alimentation à travers une deuxième résistance et dont la base constitue l'entrée non inverseuse de l'amplificateur différentiel. Une telle branche présente une structure telle qu'elle dérive du courant à partir de niveaux faibles de la première tension d'alimentation.The first branch may include the emitter-collector path of a first transistor of a first type, the base and the collector of which are connected respectively to the emitter and to the base of a second transistor of the first type whose collector is connected to a second supply voltage source, the collector of the first transistor being connected to that of a third transistor of the second type opposite to the first, the emitter of which is connected to the second voltage source d 'power supply through a second resistor and whose base constitutes the non-inverting input of the differential amplifier. Such a branch has a structure such that it derives from the current from low levels of the first supply voltage.
La deuxième branche peut comporter le trajet émetteur-collecteur d'un quatrième transistor de premier type dont la base est connectée à celle du premier transistor, le collecteur du quatrième transistor étant connecté à celui d'un cinquième transistor du deuxième type dont l'émetteur est connecté à celui du troisième transistor et dont la base constitue l'entrée inverseuse de l'amplificateur différentiel. Une telle branche présente une structure telle qu'elle dérive du courant seulement à partir d'un niveau significatif relativement élevé de la première tension d'alimentation.The second branch may include the emitter-collector path of a fourth transistor of the first type, the base of which is connected to that of the first transistor, the collector of the fourth transistor being connected to that of a fifth transistor of the second type, the emitter of which is connected to that of the third transistor and whose base constitutes the inverting input of the differential amplifier. Such a branch has a structure such that it derives from the current only from a relatively high significant level of the first supply voltage.
Le quatrième transistor peut avoir son émetteur connecté à celui du premier transistor.The fourth transistor can have its emitter connected to that of the first transistor.
Le circuit de commande est avantageusement commun aux deux branches. Dans ce but, le circuit de commande peut comporter un sixième transistor du deuxième type dont le collecteur est connecté à la première source de tension d'alimentation, dont l'émetteur est connecté aux émetteurs des premier et quatrième transistors, et dont la base est connectée à la borne de la première résistance qui n'est pas connectée à la première source de tension d'alimentation. La tension sur la base du sixième transistor détermine le seuil à partir duquel l'amplificateur différentiel produit un signal de sortie.The control circuit is advantageously common to the two branches. For this purpose, the control circuit may include a sixth transistor of the second type, the collector of which is connected to the first supply voltage source, the emitter of which is connected to the emitters of the first and fourth transistors, and the base of which is connected to the terminal of the first resistor which is not connected to the first source of supply voltage. The voltage on the basis of the sixth transistor determines the threshold from which the differential amplifier produces an output signal.
Le deuxième étage suiveur peut comporter un septième transistor dont la base est connectée au collecteur du cinquième transistor, dont le collecteur est connecté à la deuxième source de tension d'alimentation et dont l'émetteur est relié à l'entrée du premier étage suiveur, éventuellement par l'intermédiaire d'une diode en direct.The second follower stage may include a seventh transistor whose base is connected to the collector of the fifth transistor, whose collector is connected to the second supply voltage source and whose emitter is connected to the input of the first follower stage, possibly via a live diode.
La valeur dudit seuil pourra être choisi avec plus de précision en disposant une deuxième résistance entre la première résistance et l'entrée du premier étage suiveur.The value of said threshold can be chosen more precisely by having a second resistance between the first resistance and the input of the first follower stage.
Le premier étage suiveur comporte avantageusement un huitième transistor à deux émetteurs dont la base constitue l'entrée, dont le collecteur est connecté à la première source de tension d'alimentation, dont le premier émetteur est connecté à une extrémité du pont et dont le deuxième émetteur constitue la sortie du premier étage suiveur.The first follower stage advantageously comprises an eighth transistor with two emitters, the base of which constitutes the input, the collector of which is connected to the first supply voltage source, the first emitter of which is connected to one end of the bridge and the second of which transmitter constitutes the output of the first follower stage.
L'invention sera mieux comprise à la lecture de la description qui va suivre, donnée à titre d'exemple non limitatif, en liaison avec les dessins qui représentent :
- la figure 1, un circuit régulateur du type série selon l'art antérieur précité.
- la figure 2, un circuit selon l'invention.
- la figure 3, un mode préféré de réalisation de l'invention.
- la figure 4, une variante de la figure 3.
- et la figure 5, des courbes de tension en fonction de la tension d'alimentation selon la figure 3 ou 4.
- Figure 1, a series type regulator circuit according to the aforementioned prior art.
- Figure 2, a circuit according to the invention.
- Figure 3, a preferred embodiment of the invention.
- FIG. 4, a variant of FIG. 3.
- and FIG. 5, voltage curves as a function of the supply voltage according to FIG. 3 or 4.
Selon la figure 1, un générateur de tension REF délivre une tension VR qui est appliquée à l'entrée non inverseuse d'un amplificateur différentiel A alimenté à une tension d'alimentation Vcc. La sortie S de l'amplificateur A attaque un circuit suiveur T dont la sortie, qui délivre une tension de référence régulée VO est rétro-couplée à l'entrée inverseuse de l'amplificateur A par l'intermédiaire d'un pont diviseur résistif R₃, R₄. Le générateur de tension REF est alimenté par la tension d'alimentation Vcc. Lors de la mise sous tension, toute instabilité de la tension VR du générateur de tension REF se répercute directement sur la tension VO.According to FIG. 1, a voltage generator REF delivers a voltage V R which is applied to the non-inverting input of a differential amplifier A supplied with a supply voltage V cc . The output S of the amplifier A drives a follower circuit T whose output, which delivers a regulated reference voltage V O is retro-coupled to the inverting input of the amplifier A via a resistive divider bridge R₃, R₄. The REF voltage generator is supplied by the supply voltage V cc . When powering up, any instability of the voltage V R of the voltage generator REF has a direct impact on the voltage V O.
Selon la figure 2, le générateur de tension REF délivre en sortie une tension V
Pour une certaine valeur de Vcc, V
For a certain value of V cc , V
Selon la figure 3, un générateur de tension (dit du type "band gap") décrit dans l'ouvrage précité p.295, comporte un transistor T₁₁ de type npn dont le collecteur est connecté au point B précité et qui présente une résistance R₁₅, faisant office de source de courant, entre son collecteur et sa base. L'émetteur du transistor T₁₁ qui délivre la tension V
L'amplificateur A comporte une première branche présentant un transistor T₅ de type pnp dont l'émetteur est connecté à un point F, dont la base est connectée à l'émetteur d'un transistor T₇ de type pnp, dont le collecteur est connecté au pôle de mode commun et dont la base est connectée au collecteur de transistor T₅. Le collecteur du transistor T₅ est connecté à celui d'un transistor T₈ de type npn dont la base est attaquée par la tension V
L'étage suiveur de sortie comporte un transistor (T₁, T₂) à deux émetteurs (ou deux transistors T₁ et T₂ montés en émetteur suiveur), l'émetteur de T₁ connecté au pont diviseur (R₃, R₄) et celui de T₂ délivrant la tension Vo au point B. La présence de ce double émetteur (ou des deux transistors) permet classiquement un meilleur découplage vis à vis de l'impédance de charge.The output follower stage comprises a transistor (T₁, T₂) with two emitters (or two transistors T₁ and T₂ mounted as a follower emitter), the emitter of T₁ connected to the divider bridge (R₃, R₄) and that of T₂ delivering the voltage V o at point B. The presence of this double transmitter (or of the two transistors) conventionally allows better decoupling with respect to the load impedance.
Lorsque Vcc a une valeur inférieure au seuil donné, la première branche de l'amplificateur est susceptible d'être traversée par un courant, mais la deuxième branche n'est traversée par aucun courant. Le transistor T₁₀ est alors bloqué. La base des transistors T₁ et T₂ est alors à un potentiel très voisin de la valeur instantanée de Vcc.When V cc has a value below the given threshold, the first branch of the amplifier is likely to be crossed by a current, but the second branch is not crossed by any current. The transistor T₁₀ is then blocked. The base of the transistors T₁ and T₂ is then at a potential very close to the instantaneous value of V cc .
On a alors
et
avec VD = tension base-émetteur d'un transistor (environ 0,7V).We then have
and
with V D = base-emitter voltage of a transistor (approximately 0.7V).
Lorsque Vcc atteint le seuil donné, la deuxième branche de l'amplificateur est traversée par un courant suffisant pour que le transistor T₁₀ soit en état de conduction. L'amplificateur est dans sa région de fonctionnement et on a :
VS′ désignant la tension au point S′.When V cc reaches the given threshold, the second branch of the amplifier is crossed by a current sufficient for the transistor T₁₀ to be in conduction state. The amplifier is in its operating region and we have:
V S ′ denoting the voltage at point S ′.
Considérons V
Il vient :
Pour l'amplificateur décrit, un fonctionnement correct impose que VH soit au moins égal à 5VD (en fait il faut que VH soit sensiblement supérieur à cette valeur). On a alors :
Le rapport
Permet donc de déterminer le seuil VccO de Vcc à partir duquel le circuit de commutation est fermé. Si on omet la résistance R₂, les points H et S' sont confondus, et
et la résistance R₁ n'intervient plus dans la détermination du seuil.
Il faut alors :
Suivant la figure 4, la base du transistor T₃ est connectée au point milieu H' d'un pont diviseur R'₁ et R'₂ disposé entre la source de tension Vcc et le pôle de mode commun. La base du transistor T₁ est reliée à la source de tension Vcc à travers la résistance R₁. L'émetteur du transistor T₃ est connecté au point C, celui du transistor T₁ est relié au point A à travers la résistance R₃, et celui du transistor T₂ est connecté au point B. Le reste du circuit est comme à la figure 3.
On a
La condition de seuil est alors :
Le rapport
détermine le seuil Vcco de Vcc à partir duquel le circuit de commutation est fermé.Consider V
He comes :
For the amplifier described, correct operation requires that V H is at least equal to 5V D (in fact it is necessary that V H is significantly greater than this value). We then have:
The report
It therefore makes it possible to determine the threshold V ccO of V cc from which the switching circuit is closed. If the resistance R₂ is omitted, the points H and S 'are merged, and
and the resistance R₁ is no longer involved in determining the threshold.
It is then necessary:
According to Figure 4, the base of transistor T₃ is connected to the midpoint H 'of a divider bridge R'₁ and R'₂ disposed between the voltage source V cc and the common mode pole. The base of the transistor T₁ is connected to the voltage source V cc through the resistor R₁. The emitter of transistor T₃ is connected to point C, that of transistor T₁ is connected to point A through resistor R₃, and that of transistor T₂ is connected to point B. The rest of the circuit is as in Figure 3.
We have
The threshold condition is then:
The report
determines the threshold V cco of V cc from which the switching circuit is closed.
Suivant la figure 5, les tensions V
Claims (11)
- A circuit for supplying a reference voltage, comprising a voltage generator having a supply terminal and an output for supplying a voltage of given nominal value, a differential amplifier having a supply terminal for a first supply voltage source, a non-inverting input connected to the output of the voltage generator, an inverting input and an output, and a first output follower stage whose output, which supplies said reference voltage, provides feedback to the inverting input of the differential amplifier via a divider bridge, characterised in that the output of the differential amplifier (A) is coupled to the input of the first follower stage (T) via a controlled switching device (1), the first follower stage (T) having its input coupled to the supply terminal via a first resistor (R₁) and having its output, which supplies said reference voltage (Vo), coupled to the supply terminal of the voltage generator (REF), and in that it comprises a control circuit (C) for controlling the switching device (1), which control circuit is adapted to receive at least the supply voltage in such a manner that the switching device is closed when the supply voltage reaches a threshold for which both the voltage generator (REF) and the differential amplifier (A) are in a nominal operating range.
- A circuit as claimed in Claim 1, characterised in that the differential amplifier comprises a first branch, whose input constitutes said non-inverting input, and a second branch, whose input constitutes said inverting input, in that the control circuit is adapted to inhibit the flow of current in the second branch when the supply voltage is lower than said threshold, and in that the controlled switching circuit comprises a second follower stage, which is adapted to conduct only when current flows through the second branch.
- A circuit as claimed in Claim 2, characterised in that the first branch comprises an emitter-collector path of a first transistor (T₅) of a first type, whose base and collector are connected, respectively, to the emitter and the base of a second transistor (T₇) of the first type, whose collector is connected to a second supply voltage source, the collector of the first transistor (T₅) being connected to that of a third transistor (T₈) of the second type opposite to the first type, whose emitter is coupled to the second supply voltage source via a second resistor (R₈) and whose base constitutes the non-inverting input of the differential amplifier.
- A circuit as claimed in Claim 3, characterised in that the second branch comprises the emitter-collector path of a fourth transistor (T₆) of the first type, whose base is connected to that of the first transistor (T₅), the collector of the fourth transistor (T₆) being connected to that of a fifth transistor (T₉) of the second type, whose emitter is connected to that of the third transistor (T₈) and whose base constitutes the inverting input of the differential amplifier.
- A circuit as claimed in Claim 4, characterised in that the emitter of the fourth transistor (T₆) is connected to that of the first transistor (T₅).
- A circuit as claimed in Claim 5, characterised in that the control circuit comprises a sixth transistor (T₃) of the second type, whose collector is connected to the first supply voltage source, whose emitter is connected to the emitters of the first (T₅) and the fourth (T₆) transistor, and whose base is connected to that terminal of the first resistor (R₀) which is not coupled to the first supply voltage source (Vcc).
- A circuit as claimed in Claim 6, characterised in that the second follower stage comprises a seventh transistor (T₁₀), whose base is connected to the collector of the fifth transistor (T₉), whose collector is connected to the second supply voltage source and whose emitter is coupled to the input of the first follower stage.
- A circuit as claimed in Claim 7, characterised in that the emitter of the seventh transistor (T₁₀) is coupled to the input of the first follower stage via a diode poled in the forward direction.
- A circuit as claimed in Claim 7 or 8, characterised in that a second resistor (R₂) is disposed between the first resistor (R₁) and the input of the first follower stage.
- A circuit as claimed in any one of the Claims 7 to 9, characterised in that the first follower stage comprises an eighth transistor (T₁,T₂) having two emitters, whose base constitutes the input, whose collector is connected to the first supply voltage source, whose first emitter is connected to one end of the divider bridge and whose second emitter constitutes the output of the first follower stage.
- A circuit as claimed in any one of the Claims 7 to 10, characterised in that the divider bridge comprises a third (R₃) and a fourth (R₄) resistor.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8911114A FR2651343A1 (en) | 1989-08-22 | 1989-08-22 | CIRCUIT FOR PROVIDING REFERENCE VOLTAGE. |
FR8911114 | 1989-08-22 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0414319A1 EP0414319A1 (en) | 1991-02-27 |
EP0414319B1 true EP0414319B1 (en) | 1994-08-03 |
Family
ID=9384840
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90202235A Expired - Lifetime EP0414319B1 (en) | 1989-08-22 | 1990-08-20 | Circuit for supplying a reference voltage |
Country Status (6)
Country | Link |
---|---|
US (1) | US5079497A (en) |
EP (1) | EP0414319B1 (en) |
JP (1) | JP2790364B2 (en) |
KR (1) | KR0154335B1 (en) |
DE (1) | DE69011239T2 (en) |
FR (1) | FR2651343A1 (en) |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2727809B2 (en) * | 1991-08-26 | 1998-03-18 | 日本電気株式会社 | Semiconductor integrated circuit |
JP3337079B2 (en) * | 1991-11-26 | 2002-10-21 | ローム株式会社 | Power circuit |
JP2901434B2 (en) * | 1992-09-30 | 1999-06-07 | シャープ株式会社 | DC stabilized power supply |
WO1994012921A1 (en) * | 1992-12-03 | 1994-06-09 | Motorola, Inc. | Digital voltage regulator having capacitance selector |
US5604466A (en) * | 1992-12-08 | 1997-02-18 | International Business Machines Corporation | On-chip voltage controlled oscillator |
US5486778A (en) * | 1993-03-10 | 1996-01-23 | Brooktree Corporation | Input buffer for translating TTL levels to CMOS levels |
FR2709005B1 (en) * | 1993-08-13 | 1995-11-10 | Motorola Semiconducteurs | Circuit intended for use with a return arrangement. |
US5583442A (en) * | 1994-02-03 | 1996-12-10 | Harris Corporation | Differential voltage monitor using a bridge circuit with resistors on and off of an integrated circuit |
JPH09128080A (en) * | 1995-08-30 | 1997-05-16 | Sgs Thomson Microelectron Inc | Voltage regulator circuit |
FR2750240B1 (en) * | 1996-06-20 | 1998-07-31 | Sgs Thomson Microelectronics | VOLTAGE REFERENCE GENERATOR |
JP3322145B2 (en) * | 1996-12-26 | 2002-09-09 | 株式会社村田製作所 | Current control circuit |
KR100735440B1 (en) * | 1998-02-13 | 2007-10-24 | 로무 가부시키가이샤 | Semiconductor device and magnetic disk device |
KR100533389B1 (en) * | 1998-09-28 | 2006-02-08 | 매그나칩 반도체 유한회사 | Clock Synchronous Reference Voltage Generator |
JP4225630B2 (en) * | 1999-05-27 | 2009-02-18 | 株式会社ルネサステクノロジ | Voltage generation circuit |
US6175223B1 (en) * | 1999-09-04 | 2001-01-16 | Texas Instruments Incorporated | Controlled linear start-up in a linear regulator |
US6353310B1 (en) * | 2000-03-09 | 2002-03-05 | Tongt-Huei Wang | DC/DC charge and supply converting module |
US6528975B2 (en) * | 2000-12-15 | 2003-03-04 | Tropian Inc. | Saturation prevention and amplifier distortion reduction |
US7439718B2 (en) * | 2004-09-30 | 2008-10-21 | Freescale Semiconductor, Inc. | Apparatus and method for high speed voltage regulation |
JP5129149B2 (en) * | 2005-10-31 | 2013-01-23 | ザ リージェンツ オブ ザ ユニバーシティ オブ ミシガン | Compositions and methods for treating and diagnosing cancer |
US8331882B1 (en) | 2007-06-22 | 2012-12-11 | Panasonic Corporation | VSWR normalizing envelope modulator |
US7554395B1 (en) | 2007-06-28 | 2009-06-30 | Panasonic Corporation | Automatic low battery compensation scaling across multiple power amplifier stages |
US7702300B1 (en) | 2007-07-12 | 2010-04-20 | Panasonic Corporation | Envelope modulator saturation detection using a DC-DC converter |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3743923A (en) * | 1971-12-02 | 1973-07-03 | Rca Corp | Reference voltage generator and regulator |
JPS5543643A (en) * | 1978-09-21 | 1980-03-27 | Toshiba Corp | Constant voltage circuit |
US4270092A (en) * | 1979-05-18 | 1981-05-26 | International Business Machines Corporation | Current controlling circuitry for logical circuit reference electric level circuitry |
US4368420A (en) * | 1981-04-14 | 1983-01-11 | Fairchild Camera And Instrument Corp. | Supply voltage sense amplifier |
US4400661A (en) * | 1981-10-02 | 1983-08-23 | Ncr Corporation | Voltage regulation and battery dissipation limiter circuit |
JPS5999510A (en) * | 1982-11-30 | 1984-06-08 | Fujitsu Ltd | Constant voltage circuit |
WO1986005604A1 (en) * | 1985-03-13 | 1986-09-25 | Analog Devices, Inc. | Voltage/current source |
DE3540209A1 (en) * | 1985-11-13 | 1987-05-14 | Ako Werke Gmbh & Co | STABILIZING CIRCUIT FOR A MICROCOMPUTER |
-
1989
- 1989-08-22 FR FR8911114A patent/FR2651343A1/en active Pending
-
1990
- 1990-08-14 US US07/567,415 patent/US5079497A/en not_active Expired - Fee Related
- 1990-08-20 JP JP2217235A patent/JP2790364B2/en not_active Expired - Lifetime
- 1990-08-20 EP EP90202235A patent/EP0414319B1/en not_active Expired - Lifetime
- 1990-08-20 DE DE69011239T patent/DE69011239T2/en not_active Expired - Fee Related
- 1990-08-21 KR KR1019900012857A patent/KR0154335B1/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
DE69011239T2 (en) | 1995-02-23 |
KR910005125A (en) | 1991-03-30 |
EP0414319A1 (en) | 1991-02-27 |
FR2651343A1 (en) | 1991-03-01 |
DE69011239D1 (en) | 1994-09-08 |
US5079497A (en) | 1992-01-07 |
JP2790364B2 (en) | 1998-08-27 |
JPH03103908A (en) | 1991-04-30 |
KR0154335B1 (en) | 1998-12-15 |
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