WO1987000700A1 - Over-voltage protection circuit - Google Patents

Over-voltage protection circuit Download PDF

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Publication number
WO1987000700A1
WO1987000700A1 PCT/DE1986/000095 DE8600095W WO8700700A1 WO 1987000700 A1 WO1987000700 A1 WO 1987000700A1 DE 8600095 W DE8600095 W DE 8600095W WO 8700700 A1 WO8700700 A1 WO 8700700A1
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WO
WIPO (PCT)
Prior art keywords
transistor
emitter
protection circuit
overvoltage protection
resistor
Prior art date
Application number
PCT/DE1986/000095
Other languages
German (de)
French (fr)
Inventor
Dieter Clement
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to JP85504326A priority Critical patent/JPS63500770A/en
Publication of WO1987000700A1 publication Critical patent/WO1987000700A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/042—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage comprising means to limit the absorbed power or indicate damaged over-voltage protection device
    • 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
    • H02H3/02—Details
    • H02H3/06—Details with automatic reconnection
    • H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection

Definitions

  • the invention relates to an overvoltage protection circuit according to the preamble of the main claim.
  • Such an overvoltage protection circuit is known from the company publication: Bosch Technical Instruction, Electronics (2) Application in Motor Vehicles, page 10 to page 12, Robert Bosch GmbH, 1st edition, February 28, 1978.
  • the overvoltage protection in the on-board electrical system of motor vehicles is carried out using a power limiter diode which is connected in the reverse direction in parallel to the battery terminals.
  • the voltage in the vehicle electrical system is limited to the breakdown voltage of the power limiting diode.
  • the overvoltage in the vehicle electrical system can have various causes: controller failure, ignition, switching off consumers with a predominantly inductive load, loose contact, Short to ground, all types of polarity reversal and generator operation without a car battery.
  • a disadvantage of using the power limiting diode is that it can absorb interference with only a small amount of pulse energy. If the battery is accidentally disconnected while the generator is running, a high-energy overvoltage pulse occurs, which in the best case scenario only leads to the destruction of the power limiting diode.
  • This pulse (load-dump) has a duration of up to one second, whereby the voltage can be up to about 250 volts and the maximum possible generator current flows.
  • the overvoltage protection circuit according to the invention has the advantage that the pulse energy can be unlimitedly high.
  • the fault itself can last as long as you like.
  • a semiconductor power component is required that can withstand a voltage equal to the overvoltage to be expected and is only supplied with the operating current of the electronic circuit to be protected.
  • Oversized heat sinks are not necessary, since there is only a small power loss in normal operation and in the event of a fault.
  • a particular advantage of the overvoltage protection circuit according to the invention is the automatic reclosure after the fault.
  • the overvoltage protection circuit can be used wherever an electronic circuit must be protected against high-energy overvoltage pulses. However, it is particularly suitable for overvoltage protection in the vehicle electrical system.
  • the invention Voltage protection circuit contains only a few components and it can be manufactured in the form of an integrated circuit. It is therefore particularly suitable for series production in automotive applications.
  • the figure shows a circuit diagram of the overvoltage protection circuit according to the invention.
  • the figure shows an energy source 10, the positive pole of which is connected to a first input terminal 11 and the negative pole of which is connected to a second input terminal 12 of the overvoltage protection circuit.
  • a positive connecting line 13 of an electronic circuit 14 to be protected is connected to a collector terminal 15 of a first transistor 16.
  • a negative connecting line 17 of the electronic circuit to be protected is connected to the connecting terminal 12 and thus directly to the negative pole of the energy source 10.
  • a resistor 19 is located between the emitter terminal 13 of the first transistor 16 and the input terminal 11.
  • the emitter Terminal 18 of the first transistor 16 is also connected to the emitter terminal 20 of a second transistor 21.
  • the collector terminal 22 of the second transistor 21 is connected to the base terminal 23 of the first transistor 16 and via a resistor 24 to the second input terminal 12.
  • Between the first input terminal 11 and the base terminal 25 of the second transistor 21 there is a resistor 26.
  • a resistor 27 Between the base terminal 25 and the second input terminal 12 is a resistor 27 connected in series with a limiting dio
  • the overvoltage protection circuit according to the invention acts as follows:
  • the second transistor 21 is blocked and there is no connection between the collector terminal 22 and the emitter terminal 20 of the second transistor 21.
  • the first transistor 16 receives a base current via the resistor 24 and is fully controlled. Between the collector terminal 15 and the emitter terminal 18 of the first transistor 16 there is a voltage which is equal to the saturated residual voltage of the fully controlled transistor 16.
  • the second transistor 21 begins to conduct after the breakdown voltage of the limiting diode 28 has been reached, thereby reducing the base current of the second transistor 22.
  • the first transistor 16 begins to lock and thereby reduces the voltage at the electronic circuit 14 to be protected. This results in a reduction in the current flow in the positive supply line 13 and thus a reduction in the voltage drop across the resistor 19.
  • the turning on of the second transistor 21 is' increased, a tilting process begins until the second transistor 21 is turned on completely and the first transistor 16 is completely blocked.
  • the electronic circuit 1 4 to be protected is then completely separated from the energy source. A further increase in the input voltage does not change anything in this state.
  • the second transistor 21 begins to block at the response threshold minus the hysteresis caused by the resistor 19.
  • the first e Trans is or 1 6 receives a base current again and begins to conduct. The voltage drop across the resistor 19 increases and the circuit tilts into the conductive state. The electronic circuit 1 4 to be protected is then again connected to the energy source 10.
  • a PNP Darlington transistor is preferably used for the first transistor 16. It consists of an interconnection of an NPN transistor with a PNP transistor, behaves overall like a PNP transistor and is characterized by a very large current gain. If the first transistor 16 and the second transistor 21 are silicon transistors, then the voltage drop between the collector terminal 15 and the emitter terminal 18 of the first transistor 16 is approximately normal operation 1.2 volts. If, on the other hand, the first transistor 16 and the second transistor 21 are each a germanium transistor, then a voltage drop on the collector-emitter path of the switched-on first transistor 16 can achieve a voltage drop of below 0.5 volts. Thus, a low power loss occurs at the first transistor 16 in normal operation.
  • the low-resistance resistor 19 located between the input terminal 11 and the emitter terminal 18 of the transistor 16 ensures hysteresis between the switch-on and switch-off voltage thresholds. A hysteresis is necessary in order to prevent the circuit from oscillating between the switch-off and the switch-on state when the overvoltage increases slowly.

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  • Emergency Protection Circuit Devices (AREA)

Abstract

The circuit protects an electronic circuit (14) from high-current overvoltage pulses. Connected to the positive current supply line (13) of the electronic circuit (14) to be protected is the emitter-collector section of a first transistor (16). In the event of an overvoltage, the emitter-base section of the first transistor (16) is short-circuited by means of an emitter-collector section of a second transistor (21), the first transistor (16) is blocked and the electronic circuit (14) to be protected is thus isolated from the energy source (10). If the overvoltage disappears, the protection circuit automatically returns to normal operation. Between the cut-off voltage threshold and the re-setting voltage threshold, hysteresis is provided in order to prevent oscillation of the circuit between the cut-off state and the re-setting state.

Description

Überspannungs-SchutzschaltungSurge protection circuit
Stand der Technik.State of the art.
Die Erfindung geht aus von einer Überspannungs-Schutzschaltung nach der Gattung des Hauptanspruches. Eine derartige Überspannungs-Schutzschaltung ist aus der Firmenschrift: Bosch Technische Unterrichtung, Elektronik (2) Anwendung im Kraftfahrzeug, Seite 10 bis Seite 12, Robert Bosch GmbH, 1. Ausgabe, 28. Februar 1978, bekannt. Der Überspannungs schütz im Bordnetz von Kraftfahrzeugen erfolgt mit einer Leistungs-Begrenzer-Diode, die in Sperrichtung parallel zu den Batterieklemmen geschaltet ist. Die Spannung im Bordnetz wird begrenzt auf die Durchbruchspannung der Leistungs-Begrenzungs-Diode.The invention relates to an overvoltage protection circuit according to the preamble of the main claim. Such an overvoltage protection circuit is known from the company publication: Bosch Technical Instruction, Electronics (2) Application in Motor Vehicles, page 10 to page 12, Robert Bosch GmbH, 1st edition, February 28, 1978. The overvoltage protection in the on-board electrical system of motor vehicles is carried out using a power limiter diode which is connected in the reverse direction in parallel to the battery terminals. The voltage in the vehicle electrical system is limited to the breakdown voltage of the power limiting diode.
Die Überspannung im Bordnetz kann verschiedene Ursachen haben: Reglerausfall, Zündung, Abschalten von Verbrauchern mit vorwiegend induktiver Last, Wackelkontakt, Masseschluß, Verpolungen aller Art und Generatorbetrieb ohne Kfz-Batterie.The overvoltage in the vehicle electrical system can have various causes: controller failure, ignition, switching off consumers with a predominantly inductive load, loose contact, Short to ground, all types of polarity reversal and generator operation without a car battery.
Ein Nachteil bei der Verwendung der Leistungs-BegrenzungsDiode besteht nun darin, daß sie Störungen mit nur geringer Impulsenergie absorbieren kann. Wird bei laufendem Generator versehentlich die Batterie abgeklemmt, dann entsteht ein energiereicher Überspannungsimpuls, der im günstigsten Fall nur zur Zerstörung der Leistungs-Begrenzungs-Diode führt. Dieser Impuls (load-dump) weist eine Zeitdauer bis zu einer Sekunde auf, wobei die Spannung bis zu etwa 250 Volt betragen kann und der maximal mögliche Generatorstrom fließt.A disadvantage of using the power limiting diode is that it can absorb interference with only a small amount of pulse energy. If the battery is accidentally disconnected while the generator is running, a high-energy overvoltage pulse occurs, which in the best case scenario only leads to the destruction of the power limiting diode. This pulse (load-dump) has a duration of up to one second, whereby the voltage can be up to about 250 volts and the maximum possible generator current flows.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Überspannungs-Schutzschaltung hat den Vorteil, daß die Impulsenergie unbegrenzt hoch sein kann. Die Störung selbst kann beliebig lange andauern. Zur Realisierung der Schaltung wird ein Halbleiter-LeistungsBauelement benötigt, das eine Spannung in Höhe der zu erwartenden Überspannung verträgt und lediglich mit dem Betriebsstrom der zu schützenden elektronischen Schaltung beaufschlagt wird. Überdimensionierte Kühlkörper sind nicht erforderlich, da sowohl im Normalbetrieb als auch im Störungsfall nur eine geringe Verlustleistung auftritt.The overvoltage protection circuit according to the invention has the advantage that the pulse energy can be unlimitedly high. The fault itself can last as long as you like. To implement the circuit, a semiconductor power component is required that can withstand a voltage equal to the overvoltage to be expected and is only supplied with the operating current of the electronic circuit to be protected. Oversized heat sinks are not necessary, since there is only a small power loss in normal operation and in the event of a fault.
Ein besonderer Vorteil der erfindungsgemäßen Überspannungs-Schutzschaltung liegt in der automatischen Wiedereinschaltung nach dem Störungsfall. Die Überspannungs-Schut zschaltung kann überall dort eingesetzt werden, wo eine elektronische Schaltung vor energiereichen Überspannungsimpulsen geschützt werden muß. Sie eignet sich jedoch insbesondere zum ÜberspannungsSchutz im Kfz-Bordnetz. Die erfindungsgemäße Über spannungs-Schutzschaltung enthält nur wenige Bauteile und sie läßt sich in Form einer integrierten Schaltung herstellen. Sie ist deshalb für die Serienproduktion in der Kfz-Anwendung besonders geeignet.A particular advantage of the overvoltage protection circuit according to the invention is the automatic reclosure after the fault. The overvoltage protection circuit can be used wherever an electronic circuit must be protected against high-energy overvoltage pulses. However, it is particularly suitable for overvoltage protection in the vehicle electrical system. The invention Voltage protection circuit contains only a few components and it can be manufactured in the form of an integrated circuit. It is therefore particularly suitable for series production in automotive applications.
Weitere Einzelheiten der erfindungsgemäßen ÜberspannungsSchut zschaltung ergeben sich aus den Unteransprüchen in Verbindung mit der folgenden Beschreibung. Vorteilhaft ist eine Hysterese zwischen der Aschalt- und der Wiedereinschaltschwelle, deren Betrag von dem Wert eines Bauelementes abhängt. Damit wird ein Schwingen zwischen dem Abschalt- und Einschalt zustand vermieden. Die Verlustleistung der Schaltung im Normalbetrieb bleibt niedrig, wenn als Leistungsstufe ein PNP-Darlington-Transistor verwendet wird.Further details of the overvoltage protection circuit according to the invention result from the subclaims in conjunction with the following description. A hysteresis between the switch-on and the switch-on threshold is advantageous, the amount of which depends on the value of a component. An oscillation between the switch-off and switch-on state is thus avoided. The power loss of the circuit in normal operation remains low if a PNP Darlington transistor is used as the power stage.
Zeichnungdrawing
Die Figur zeigt ein Schaltbild der erfindungsgemäßen Überspannungs-Schutzschaltung.The figure shows a circuit diagram of the overvoltage protection circuit according to the invention.
Beschreibung des AusführungsbeispielesDescription of the embodiment
Die Figur zeigt eine Energiequelle 10, deren Pluspol an einer ersten Eingangsklemme 11 und deren Minuspol an einer zweiten Eingangsklemme 12 der ÜberspannungsSchutzschaltung angeschlossen ist. Eine positive Anschlußleitung 13 einer zu schützenden Elektronikschaltung 1 4 ist mit einem Kollektoranschluß 15 eines ersteh Transistors 16 verbunden. Eine negative Anschlußleitung 17 der zu schützenden Elektronikschaltung ist mit der Anschlußklemme 12 und damit unmittelbar mit dem negativen Pol der Energiequelle 10 verbunden. Zwischen dem Emitteranschluß 13 des ersten Transistors 16 und der Eingangsklemme 11 liegt ein Widerstand 19. Der Emitter anschluß 18 des ersten Transistors 16 ist auch noch mit dem Emitteranschluß 20 eines zweiten Transistors 21 verbunden. Der Kollektoranschluß 22 des zweiten Transistors 21 liegt an dem Basisanschluß 23 des ersten Transistors 16 und über einen Widerstand 24 an der zweiten Eingangsklemme 12. Zwischen der ersten Eingangsklemme 11 und dem Basisanschluß 25 des zweiten Transistors 21 liegt ein Widerstand 26. Zwischen den Basisanschluß 25 und die zweite Eingangsklemme 12 ist ein Widerstand 27 in Reihe mit einer Begrenzungs-Diode 28 geschaltet.The figure shows an energy source 10, the positive pole of which is connected to a first input terminal 11 and the negative pole of which is connected to a second input terminal 12 of the overvoltage protection circuit. A positive connecting line 13 of an electronic circuit 14 to be protected is connected to a collector terminal 15 of a first transistor 16. A negative connecting line 17 of the electronic circuit to be protected is connected to the connecting terminal 12 and thus directly to the negative pole of the energy source 10. A resistor 19 is located between the emitter terminal 13 of the first transistor 16 and the input terminal 11. The emitter Terminal 18 of the first transistor 16 is also connected to the emitter terminal 20 of a second transistor 21. The collector terminal 22 of the second transistor 21 is connected to the base terminal 23 of the first transistor 16 and via a resistor 24 to the second input terminal 12. Between the first input terminal 11 and the base terminal 25 of the second transistor 21 there is a resistor 26. Between the base terminal 25 and the second input terminal 12 is a resistor 27 connected in series with a limiting diode 28.
Die erfindungsgemäße Überspannungs-Schutzschaltung wirkt folgendermaßen:The overvoltage protection circuit according to the invention acts as follows:
Liegt die Spannung der Energiequelle 10 zwischen den Eingangsklemmen 11 und 12 unterhalb der durch den Widerstand 19, den Widerstand 26, den Widerstand 27, der Begrenzungsspannung der Begrenzungs-Diode 28 und der durch die zur Durchsteuerung des zweiten Transistors 21 erforderliehe Emitter-Basis-Spannung festgelegten Ansprechschwelle, so ist der zweite Transistor 21 gesperrt und es besteht keine Verbindung zwischen dem Kollektoranschluß 22 und dem Emitteranschluß 20 des zweiten Transistors 21. Der erste Transistor 16 erhält über den Widerstand 24 einen Basisstrom und ist voll durchgesteuert. Zwischen dem Kollektoranschluß 15 und dem Emitteranschluß 18 des ersten Transistors 16 liegt eine Spannung, die gleich der Satt igungs-Rest Spannung des voll durchgesteuerten Transistors 16 ist. Steigt nun die Eingangsspannung zwischen der ersten Eingangsklemme 11 und der zweiten Eingangsklemme 12 über die Ansprechschwelle, so beginnt nach Erreichen der Durchbruchspannung der Begrenzungs-Diode 28 der zweite Transistor 21 zu leiten und verkleinert dadurch den Basisstrom des zweiten Transistor 22. Der erste Transistor 16 beginnt zu sperren und verringert dadurch die Spannung an der zu schützenden Elektronikschaltung 14 . Dies hat eine Verringerung des Stromflusses in der positiven Versorgungsleitung 13 und damit eine Verkleinerung des Spannungsabfalls an dem Widerstand 19 zur Folge. Das Durchsteuern des zweiten Transistors 21 wird' verstärkt, es setzt ein Kippvorgang ein, bis der zweite Transistor 21 vollständig durchgesteuert und der erste Transistor 16 vollständig gesperrt ist. Die zu schützende Elektronikschaltung 1 4 ist dann vollständig von der Energiequelle getrennt. Ein weiteres Ansteigen der Eingangsspannung ändert an diesem Zustand nichts mehr.If the voltage of the energy source 10 between the input terminals 11 and 12 is below that of the resistor 19, the resistor 26, the resistor 27, the limiting voltage of the limiting diode 28 and the emitter-base voltage required to control the second transistor 21 set response threshold, the second transistor 21 is blocked and there is no connection between the collector terminal 22 and the emitter terminal 20 of the second transistor 21. The first transistor 16 receives a base current via the resistor 24 and is fully controlled. Between the collector terminal 15 and the emitter terminal 18 of the first transistor 16 there is a voltage which is equal to the saturated residual voltage of the fully controlled transistor 16. If the input voltage between the first input terminal 11 and the second input terminal 12 now rises above the response threshold, the second transistor 21 begins to conduct after the breakdown voltage of the limiting diode 28 has been reached, thereby reducing the base current of the second transistor 22. The first transistor 16 begins to lock and thereby reduces the voltage at the electronic circuit 14 to be protected. This results in a reduction in the current flow in the positive supply line 13 and thus a reduction in the voltage drop across the resistor 19. The turning on of the second transistor 21 is' increased, a tilting process begins until the second transistor 21 is turned on completely and the first transistor 16 is completely blocked. The electronic circuit 1 4 to be protected is then completely separated from the energy source. A further increase in the input voltage does not change anything in this state.
Sinkt die Eingangsspannung wieder ab, so beginnt bei der Ansprechschwelle abzüglich der durch den Widerstand 19 hervorgerufenen Hysterese der zweite Transistor 21 zu sperren . Der erst e Trans ist or 1 6 erhält wieder einen Basisstrom und beginnt zu leiten. An dem Widerstand 19 erhöht sich der Spannungsabfall und die Schaltung kippt in den leitenden Zustand. Die zu schützende Elektronikschaltung 1 4 liegt dann wieder an der Energiequelle 10.If the input voltage drops again, the second transistor 21 begins to block at the response threshold minus the hysteresis caused by the resistor 19. The first e Trans is or 1 6 receives a base current again and begins to conduct. The voltage drop across the resistor 19 increases and the circuit tilts into the conductive state. The electronic circuit 1 4 to be protected is then again connected to the energy source 10.
In der praktischen Schaltungsausführung wird für den ersten Transistor 16 vorzugsweise ein PNP-DarlingtonTransistor eingesetzt. Er besteht aus einer Zusammenschaltung eines NPN-Transistors mit einem PNP-Transistor, verhält sich insgesamt wie ein PNP-Transistor und zeichnet sich durch eine sehr große Stromverstärkung aus. Handelt es sich bei dem ersten Transistor 16 und dem zweiten Transistor 21 um Silizium-Transistoren, dann beträgt der Spannungsabfall zwischen dem Kollektoranschluß 15 und dem Emitteranschluß 18 des ersten Transistors 16 im durchgeschalteten Normalbetrieb etwa 1,2 Volt. Ist der erste Transistor 16 und der zweite Transistor 21 dagegen jeweils ein Germanium-Transistor, dann läßt sich ein Spannungsabfall an der KollektorEmitter-Strecke des durchgeschalteten ersten Transistors 16 ein Spannungsabfall von unterhalb 0,5 Volt erreichen. Damit tritt im Normalbetrieb eine geringe Verlustleistung am ersten Transistor 16 auf.In the practical circuit design, a PNP Darlington transistor is preferably used for the first transistor 16. It consists of an interconnection of an NPN transistor with a PNP transistor, behaves overall like a PNP transistor and is characterized by a very large current gain. If the first transistor 16 and the second transistor 21 are silicon transistors, then the voltage drop between the collector terminal 15 and the emitter terminal 18 of the first transistor 16 is approximately normal operation 1.2 volts. If, on the other hand, the first transistor 16 and the second transistor 21 are each a germanium transistor, then a voltage drop on the collector-emitter path of the switched-on first transistor 16 can achieve a voltage drop of below 0.5 volts. Thus, a low power loss occurs at the first transistor 16 in normal operation.
Der zwischen der Eingangsklemme 11 und dem Emitteranschluß 18 des Transistors 16 liegende niederohmige Widerstand 19 sorgt für eine Hysterese zwischen der Einschalt- und Abschaltspannungsschwelle. Eine Hysterese ist notwendig, um bei langsam ansteigender Überspannung ein Schwingen der Schaltung zwischen dem Abschalt- und Wiedereinschaltzustand zu verhindern. The low-resistance resistor 19 located between the input terminal 11 and the emitter terminal 18 of the transistor 16 ensures hysteresis between the switch-on and switch-off voltage thresholds. A hysteresis is necessary in order to prevent the circuit from oscillating between the switch-off and the switch-on state when the overvoltage increases slowly.

Claims

Ansprüche Expectations
1. Überspannungs-Schutzschaltung mit einer in die Stromversorgungsleitung einer zu schützenden Elektronikschaltung geschalteten Emitter-Kollektor-Strecke eines ersten Transistors, dadurch gekennzeichnet, daß parallel zur Emitter-Basis-Strecke des ersten Transistors (16) die Emitter-Kollektor-Strecke eines zweiten Transistors (21) liegt und der Emitter-Anschluß (20) des zweiten Transistors (21) und der Emitter-Anschluß (18) des ersten Transistors (16) verbunden sind.1. Overvoltage protection circuit with an emitter-collector path of a first transistor connected to the power supply line of an electronic circuit to be protected, characterized in that the emitter-collector path of a second transistor is parallel to the emitter-base path of the first transistor (16) (21) and the emitter terminal (20) of the second transistor (21) and the emitter terminal (18) of the first transistor (16) are connected.
2. Überspannungs-Schutzschaltung nach Anspruch 1, dadurch gekennzeichnet, daß zwischen dem EmitterAnschluß (18, 20) des ersten und zweiten Transistors (iβ, 21) und einer ersten Eingangsklemme (11) ein Widerstand (19) liegt.2. Overvoltage protection circuit according to claim 1, characterized in that between the emitter connection (18, 20) of the first and second transistor (iβ, 21) and a first input terminal (11) there is a resistor (19).
3. Überspannungs-Schutzschaltung nach Anspruch 1, dadurch gekennzeichnet, daß zwischen der ersten Eingangsklemme (11) und dem Basis-Anschluß (25) des zweiten Transistors (21) ein Widerstand (26) geschaltet ist.3. Overvoltage protection circuit according to claim 1, characterized in that a resistor (26) is connected between the first input terminal (11) and the base terminal (25) of the second transistor (21).
4 . Überspannungs-Schutzschaltung nach Anspruch 1, dadurch gekennzeichnet, daß der Basis-Anschluß (25) des zweiten Transistors (21) über eine Reihenschaltung eines Widerstandes (27) und einer 3egrenzungs-Diode (23) mit einer zweiten Eingangsklemme (12) verbunden ist. 4th Overvoltage protection circuit according to Claim 1, characterized in that the base connection (25) of the second transistor (21) is connected to a second input terminal (12) via a series connection of a resistor (27) and a 3-delimitation diode (23).
5. Überspannungs-Schutzschaltung nach Anspruch 1, dadurch gekennzeichnet, daß der Kollektor-Anschluß (22) des zweiten Transistors (21) bzw. der Basis-Anschluß (23) des ersten Transistors (16) über einen Widerstand ( 24 ) an die zweite Eingangsklemme (12) geschaltet ist.5. Overvoltage protection circuit according to claim 1, characterized in that the collector connection (22) of the second transistor (21) or the base connection (23) of the first transistor (16) via a resistor (24) to the second Input terminal (12) is switched.
6. Überspannungs-Schut zschaltung nach Anspruch 1, dadurch gekennzeichnet, daß der erste Transistor (16) ein Transistor vom Leitfähigkeits-Typ PNP und der zweite Transistor (21) vom Leitfähigkeits-Typ PNP ist. 6. Overvoltage protection circuit according to claim 1, characterized in that the first transistor (16) is a transistor of the conductivity type PNP and the second transistor (21) of the conductivity type PNP.
PCT/DE1986/000095 1985-07-23 1986-03-07 Over-voltage protection circuit WO1987000700A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP85504326A JPS63500770A (en) 1985-07-23 1986-03-07 Overvoltage - protection circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853526177 DE3526177A1 (en) 1985-07-23 1985-07-23 R-VOLTAGE PROTECTION CIRCUIT
DEP3526177.3 1985-07-23

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WO1987000700A1 true WO1987000700A1 (en) 1987-01-29

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DE (1) DE3526177A1 (en)
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EP0349750A1 (en) * 1988-07-07 1990-01-10 Oerlikon-Knorr Eisenbahntechnik AG Protection circuit against compensation and overvoltages for electronic equipment
FR2634601A1 (en) * 1988-07-19 1990-01-26 Thomson Csf Electronic circuit for protection against overvoltages and current surges
GB2226196A (en) * 1988-12-15 1990-06-20 Philips Nv Excess voltage protection circuit
WO1990007213A1 (en) * 1988-12-12 1990-06-28 Standard Telephones And Cables Pty. Limited A protection circuit
EP0387108A1 (en) * 1989-03-10 1990-09-12 Nokia Mobile Phones Ltd. Eliminating the effects of voltage transients
AU634187B2 (en) * 1988-12-12 1993-02-18 Alcatel Australia Limited A protection circuit

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DE19645783A1 (en) * 1996-11-07 1998-05-20 Braun Ag Power supply circuit
DE19964097A1 (en) * 1999-12-31 2001-07-26 Nokia Mobile Phones Ltd Overvoltage protection circuit for electronic unit onboard automobile has integrator receiving switch signal from overvoltage indicator for opening switch to prevent overheating
DE10153158A1 (en) * 2001-10-27 2003-05-15 Conti Temic Microelectronic DC voltage supply circuit for consumers connected to at least one line
WO2004012317A2 (en) * 2002-07-29 2004-02-05 Raytheon Company Method and system for protecting a vehicle system from a load dump
JP2018057122A (en) * 2016-09-28 2018-04-05 株式会社ケーヒン Circuit protection device and power source monitoring device
DE102017123484A1 (en) 2017-10-10 2019-04-11 Danfoss Power Solutions Aps Overvoltage protection circuit
DE102020207430A1 (en) 2020-06-16 2021-12-16 Volkswagen Aktiengesellschaft Parking lock device for a motor vehicle and motor vehicle with a parking lock device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2808084A1 (en) * 1978-02-24 1979-08-30 Siemens Ag Overvoltage protection for power=pack voltage dropper - has first transistor switched on by rise in voltage and switching off second transistor to block output
DE3137176A1 (en) * 1981-09-18 1983-03-31 Robert Bosch Gmbh, 7000 Stuttgart On-board mains power supply protection device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2808084A1 (en) * 1978-02-24 1979-08-30 Siemens Ag Overvoltage protection for power=pack voltage dropper - has first transistor switched on by rise in voltage and switching off second transistor to block output
DE3137176A1 (en) * 1981-09-18 1983-03-31 Robert Bosch Gmbh, 7000 Stuttgart On-board mains power supply protection device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0349750A1 (en) * 1988-07-07 1990-01-10 Oerlikon-Knorr Eisenbahntechnik AG Protection circuit against compensation and overvoltages for electronic equipment
FR2634601A1 (en) * 1988-07-19 1990-01-26 Thomson Csf Electronic circuit for protection against overvoltages and current surges
WO1990007213A1 (en) * 1988-12-12 1990-06-28 Standard Telephones And Cables Pty. Limited A protection circuit
AU634187B2 (en) * 1988-12-12 1993-02-18 Alcatel Australia Limited A protection circuit
GB2226196A (en) * 1988-12-15 1990-06-20 Philips Nv Excess voltage protection circuit
EP0387108A1 (en) * 1989-03-10 1990-09-12 Nokia Mobile Phones Ltd. Eliminating the effects of voltage transients

Also Published As

Publication number Publication date
DE3526177A1 (en) 1987-02-05
JPS63500770A (en) 1988-03-17

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