DE2056502A1 - Power source for supplying a load with constant current - Google Patents
Power source for supplying a load with constant currentInfo
- Publication number
- DE2056502A1 DE2056502A1 DE19702056502 DE2056502A DE2056502A1 DE 2056502 A1 DE2056502 A1 DE 2056502A1 DE 19702056502 DE19702056502 DE 19702056502 DE 2056502 A DE2056502 A DE 2056502A DE 2056502 A1 DE2056502 A1 DE 2056502A1
- Authority
- DE
- Germany
- Prior art keywords
- transistor
- current
- load
- operational amplifier
- voltage source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/12—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to underload or no-load
-
- 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
- G05F1/569—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 for protection
-
- 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
- G05F1/569—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 for protection
- G05F1/573—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 for protection with overcurrent detector
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Control Of Voltage And Current In General (AREA)
Description
"Stromquelle zur Speisung einer Last mit konstanter Strom Die Erfindung bezieht sioh auf eine Stromquelle zur Speisung einer Last mit konstantes Strom mit einer Schaltung, die beim Unterschreiten des Stroms unter einen bestimmten Wert anspricht, z. B. Alarm gibt, ..obei eine Spannungsquelle, ein erster Widerstand, die Lat und ein Transistor in Reihe liegen, ein Potentiometer parallel zur Spannungsquelle liegt, ein erster Operationsverstärker mit seinem einen Eingang an den Mittelabgriff des Potentiometers liegt, mit dem anderen Eingang, die über dem ersten Wi-Widerstand abfallende Spannung erfaßt und mit seinem Ausgang an der Basis des Transistors liegt, der innerhalb eines bestimmten Bereichs Änderungen des Widerstands der Last unter Konstanthaltung des Stroms kompensiert, und wobei ein zweiter Operationsverstärker vorgesehen ist, dessen Ausgang mit einem Relais od. dgl. "Current source for feeding a load with constant current The invention refers to a current source for supplying a load with constant current a circuit that when the current falls below a certain value responds, e.g. B. gives an alarm ... with a voltage source, a first resistor, the lat and a transistor are in series, a potentiometer parallel to the voltage source is a first operational amplifier with its one input to the center tap of the potentiometer lies with the other input, which is above the first Wi resistor falling voltage is detected and its output is at the base of the transistor, the within a certain Area changes in resistance the load is compensated while keeping the current constant, and using a second operational amplifier is provided, the output of which with a relay or the like.
verbunden ist, dessen Schaltzustand sich ändert, wenn der Versorgungsstrom fiir die Last einen eingestellten Wert unter schreitet.is connected, the switching state of which changes when the supply current for the load falls below a set value.
In Pigur 1 ist eine derartige Schaltung dargestellt, wobei die Spannungsquelle mit 1, der erste Widerstand mit 2, die Last mit der Transistor mit 3, das Potentiometer mit 4, der erste Operationsterstärker mit 5, der zweite Operationsverstärker mit 6 und das Relais mit 7 bezeichnet sind. Eine solche Schaltung wird beispielsweise benutzt, um ein Gerät zur Anzeige der Kosentration eines in einer Atmosphäre enthaltenden Gases mit Hilfe einer Wheatstone'schen Brücke mit einem konstanten Versorgungsstrom zu beaufschlagen und um ferner anzuzeigen, wenn der Versorgungsstrom einen bestimmten Wert unterschreitet. Ändert sioh der Widerstand der Last, dann wird diese Änderung vo n dem ersten Operationsverstärker 5 festgestellt, der dann die Basis des Transistors 3 mit einem solchen Strom versorgt, daß dessen Kollektor-Emitter-Widerstand sich indert, wobei die Widerstandiänderung des Transistors 3 die Widerstandsänderung der Last L konpensiert.Such a circuit is shown in Pigur 1, with the voltage source with 1, the first resistor with 2, the load with the transistor with 3, the potentiometer with 4, the first operational amplifier with 5, the second operational amplifier with 6 and the relay with 7 are designated. Such a circuit is for example used to be a device for displaying the cosentration of a contained in an atmosphere Gases using a Wheatstone bridge with a constant supply current to apply and also to indicate when the supply current is a certain Value falls below. If the resistance of the load changes, this change occurs vo n found the first operational amplifier 5, which is then the base of the transistor 3 supplied with such a current that its collector-emitter resistance indert, wherein the change in resistance of transistor 3 is the change in resistance the load L is compensated.
Matürlich ist der Transistor 3 nur in der Lage, seinen Kollektor-Emitter-Widerstand bis annähernd Null zu ändern. Reicht dieses zur Widerstandskompensation der Last RL nicht aus (dies geschieht zum Beispiel dann, wenn sich ein Leitungsbruch eingestellt hat), dann indert sich der Strom im Versorgungskreis. Das erfaßt der zweite Operationsverstärker 6, der dann den Schaltstrom zu dem Belais 7 lieiert, welches seinerseits einen Alarm auslöst. Beispielsweise ist der Versorgungsstrom 100 mA, wobei bei Unterschreiten von 98 mA (Differenz 2 «) der Alarm ausgelöst wird.Of course, the transistor 3 is only capable of its collector-emitter resistance change to near zero. Is this enough to compensate for the resistance of the load RL not off (this happens, for example, when a line break occurs has), then the current in the supply circuit changes. The second operational amplifier detects this 6, which then passes the switching current to the Belais 7, which in turn generates an alarm triggers. For example, the supply current is 100 mA, with a value below this of 98 mA (difference 2 «) the alarm is triggered.
Die Schaltung erm@glicht es nun, den konstant zu haltenden Strom zu indern, beispielsweise auf 50 mA (das wird bei einem Gerät nur Anzeige der Konzentration eines in einer Atmosphäre enthal tenen Gases dann erforderlich, wenn anstelle eines ersten Gases ein zweites Gas hinsichtlich seiner Konzentration gemessen werden soll). Das geschieht durch Xnderung der Einstellung des Mittelabgriffs des Potentiometere 4. Zugleich suE aber auch der Mittelabgriff des Potentiometers 8 geändert werden, so daß bei Unterschreiten eines prozentual entsprechenden Wertes - beim Beispiel 49 mA, d. h. Differenz 2 « - der Alarm ausgelöst wird.The circuit now enables the current to be kept constant to change, for example to 50 mA (on a device this will only display the concentration a gas contained in an atmosphere required if instead of one first gas a second gas is to be measured with regard to its concentration). This is done by changing the setting of the center tap of the potentiometer 4. At the same time, however, the center tap of potentiometer 8 can also be changed, so that when falling below a corresponding percentage value - in the example 49 mA, i.e. H. Difference 2 «- the alarm is triggered.
Der Erfindung liegt die Aufgabe zugrunde, die Schaltung so auszulegen, daß man bei Knderung des Versorgungsstroms mit nur einer Einstellung auskommt.The invention is based on the object of designing the circuit in such a way that that you can manage with only one setting when changing the supply current.
Das gelingt erfindungsgemäß dadurch, daß der eine Eingang des zweiten Operationsverstärkers zwischen dem Ausgang des ersten Operationsverstärkers und einem zweiten Widerstand liegt.This is achieved according to the invention in that one input of the second Operational amplifier between the output of the first operational amplifier and a second resistor.
In diesem Palle ist es nur erforderlich, durch Änderung des Potentiometers den Wert des Sersorgungastrome einzustellen.In this case it is only necessary by changing the potentiometer to set the value of the supply astrome.
Wird der Yersorgungsstrom so klein, daß die Differenz aus dem Soll-Strom und dem Ist-Strom einen bestimmten Prozentwert des Soll-Stroms, z. B. 2 %, einnimmt, dann löst der zweite Operationsverstärker den Alarm aus.If the supply current is so small that the difference between the target current and the actual current a certain percentage of the target current, z. B. 2%, occupies, then the second operational amplifier triggers the alarm.
Ein Ausführungsbeispiel der Erfindung ist in der Pigur 2 dargestellt.One embodiment of the invention is shown in Pigur 2.
Die Bezugsziffern 1 bis 7 bezeichnen die gleichen Teile wie in Figur 1. Die telle, an der der eine Eingang des zwei ten Ope rationsverstärkers 6 angeschlossen ist, ist mit A bezeichnet.The reference numerals 1 to 7 denote the same parts as in the figure 1. The point at which one input of the second operational amplifier 6 is connected is denoted by A.
Der Punkt A liegt zwischen dem Ausgang des ersten Operationsverstärkers 5 und einem Widerstand 9. Mit 10 ist eine Versorgungsspannung für die Operationsverst:Srker (die der Einfachheit halber in Pigur 1 weggelas en worden ist) und mit 11 ein weiteres Potentiometer bezeichnet, mit dem der Prozentsatz eingestellt werdem kann, um den der Versorgungsstror. abfallen kann, ohne daß das Relais 7 anspricht. Solange die Summe aller Widerstände im Stromkreis kleiner ist als der Quotient U1 , wird an den I Soll Transistor 3 ein kleiner Basisstrom geliefert. Ebenso hat der Punkt A eine kleine Spannung gegenüber "0". Wird jedoch der Lastwi-Widerstand RL zu groß, so daß der Konstantstrom nicht mehr aufrechterhalten werden kann, so müßte der Transistor 3 Widerstandswerte <0 annehmen; dazu gehört ein unendlich großer Basisstrom durch den Widerstand 9. Damit steigt die Spannung am Punkt A. Der Operationsverstbrker 6 schaltet, wenn die Spannung am Punkt A die Spsnnung am Abgriff des Potentiometers 11 überschreitet.Point A lies between the output of the first operational amplifier 5 and a resistor 9. With 10 is a supply voltage for the operational terms (which have been left out in Pigur 1 for the sake of simplicity is) and with 11 another potentiometer is designated, with which the percentage is set who can to which the supply current. can drop without the relay 7 responding. As long as the sum of all resistances in the circuit is smaller than the quotient U1 , a small base current is supplied to the I Soll transistor 3. Likewise has the Point A a small voltage compared to "0". However, if the load wi resistance RL too large, so that the constant current can no longer be maintained, so would have to the transistor 3 assume resistance values <0; this includes an infinitely large one Base current through resistor 9. This increases the voltage at point A. The operational amplifier 6 switches when the voltage at point A exceeds the voltage at the potentiometer tap 11 exceeds.
Claims (4)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19702056502 DE2056502B2 (en) | 1970-11-12 | 1970-11-12 | CONTROL DEVICE FOR SUPPLYING A LOAD WITH CONSTANT CURRENT |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19702056502 DE2056502B2 (en) | 1970-11-12 | 1970-11-12 | CONTROL DEVICE FOR SUPPLYING A LOAD WITH CONSTANT CURRENT |
Publications (2)
Publication Number | Publication Date |
---|---|
DE2056502A1 true DE2056502A1 (en) | 1972-06-08 |
DE2056502B2 DE2056502B2 (en) | 1973-02-08 |
Family
ID=5788353
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19702056502 Granted DE2056502B2 (en) | 1970-11-12 | 1970-11-12 | CONTROL DEVICE FOR SUPPLYING A LOAD WITH CONSTANT CURRENT |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE2056502B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2626569A1 (en) * | 1976-06-14 | 1977-12-22 | Sachs Systemtechnik Gmbh | DEVICE FOR REGULATING AND MONITORING THE POWER SUPPLY OF A SUPPLY SYSTEM FOR DISINCLUDED LIQUIDS |
EP0472810A2 (en) * | 1990-08-27 | 1992-03-04 | Heraeus Elektrochemie GmbH | Device to regulate electrode current for electrolytic purposes |
-
1970
- 1970-11-12 DE DE19702056502 patent/DE2056502B2/en active Granted
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2626569A1 (en) * | 1976-06-14 | 1977-12-22 | Sachs Systemtechnik Gmbh | DEVICE FOR REGULATING AND MONITORING THE POWER SUPPLY OF A SUPPLY SYSTEM FOR DISINCLUDED LIQUIDS |
EP0472810A2 (en) * | 1990-08-27 | 1992-03-04 | Heraeus Elektrochemie GmbH | Device to regulate electrode current for electrolytic purposes |
EP0472810A3 (en) * | 1990-08-27 | 1992-10-21 | Heraeus Elektrochemie Gmbh | Device to regulate electrode current for electrolytic purposes |
Also Published As
Publication number | Publication date |
---|---|
DE2056502B2 (en) | 1973-02-08 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
C3 | Grant after two publication steps (3rd publication) | ||
E77 | Valid patent as to the heymanns-index 1977 | ||
EHJ | Ceased/non-payment of the annual fee |