WO1999019958A1 - Protective circuit with n-channel mos fet for an electronic circuit - Google Patents

Protective circuit with n-channel mos fet for an electronic circuit Download PDF

Info

Publication number
WO1999019958A1
WO1999019958A1 PCT/EP1998/006419 EP9806419W WO9919958A1 WO 1999019958 A1 WO1999019958 A1 WO 1999019958A1 EP 9806419 W EP9806419 W EP 9806419W WO 9919958 A1 WO9919958 A1 WO 9919958A1
Authority
WO
WIPO (PCT)
Prior art keywords
fet
circuit
mos
channel mos
protection circuit
Prior art date
Application number
PCT/EP1998/006419
Other languages
German (de)
French (fr)
Inventor
Eberhard HÖGLER
Original Assignee
Swf Auto-Electric Gmbh & Co. Kg
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 Swf Auto-Electric Gmbh & Co. Kg filed Critical Swf Auto-Electric Gmbh & Co. Kg
Publication of WO1999019958A1 publication Critical patent/WO1999019958A1/en

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
    • H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection
    • H02H11/003—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection using a field effect transistor as protecting element in one of the supply lines

Definitions

  • the invention relates to a protective circuit for an electronic circuit provided with electronic components.
  • a reverse polarity diode In order to protect an electronic circuit against reverse polarity or interference voltages of the supply voltage, a reverse polarity diode is connected in series with the supply branch in most cases. If the polarity is reversed, no current can flow due to the high blocking resistance of the diode and the electronics cannot be destroyed.
  • diodes for large currents must be used for reverse polarity protection. This has the disadvantage that great power and a high voltage drop occur at the diode or diodes, which can lead to problems. In most cases, cooling is required to dissipate the power at the diode. Furthermore, the diodes, which allow high power to pass and are able to block sufficient voltages in the reverse direction, are comparatively expensive.
  • the invention consists in principle in the protection circuit against reverse polarity protection, a MOS-FET
  • all MOS-FET circuits are suitable for this.
  • an N-channel MOS-FET in a further development of the invention A provided with an n-channel MOS FET circuit has a very low on-state resistance (QS o n) 'was i- n forward to a particularly low power dissipation and a very low voltage drop results.
  • the N-channel MOS FET is preferably operated inversely to implement reverse polarity protection.
  • the MOS-FET In normal operation, the MOS-FET is switched on via its gate and thus its forward resistance R DS on is connected in parallel to the inverse diode (Q). This leads to a reduction in the power loss and the voltage drop.
  • reverse polarity operation both the MOS-FET, in particular the N-channel MOS-FET, is switched off or blocked and the inverse diode (Q) works in the reverse direction.
  • the drawing shows a voltage source B, one end point of which is at ground M and the other point of which is at the supply voltage terminal V.
  • the electronic circuit E to be protected is connected to ground via points S, D of an N-CHANNEL-MOS-FET F, while the
  • Electronic circuit E is present with its other voltage connection on the supply voltage terminal V.
  • the drain-source path (DS) of the N-CHANNEL-MOS-FET is protected by a first protection circuit S1, which at the connection point Pl between the electronic circuit and the N-CHANNEL-MOS-FET and with its other end at the point D of the N-CHANNEL MOS FET is present, which is connected to the ground terminal of the voltage source.
  • the MOS-FET is controlled by a terminal V of the supply voltage via a voltage divider R1, R2, the gate G of the N-CHANNEL MOS-FET being connected to a connection point P2 of the two serial resistors R1, R2.
  • the gate of the N-CHANNEL MOS FET is protected by a second protective circuit S2, the protective circuit being connected in parallel with the resistor R2.
  • the drain-source path (D, S) can also be protected by a first protective circuit S1, which is connected in parallel with the inverse-operated diode Q of the N-CHANNEL MOSFET.
  • a P-CHANNEL-MOS-FET or N-CHANNEL-MOS-FET can be connected between point V and the electronics E to be protected.

Abstract

The invention relates to an inexpensive, low-power protective circuit for electronic circuits (E) in which a destruction of the electronic circuit should be reliably prevented during polarity reversal of the supply voltage. To this end, the invention uses the application of a MOS FET, especially n-channel MOS FET. Such a component enables a low-power switching of large output in a conducting direction.

Description

Schutzschaltung mit N-KANAL-MOS FET für eine ElektronikschaltungProtection circuit with N-CHANNEL MOS FET for an electronic circuit
Die Erfindung betrifft eine Schutzschaltung für eine mit elektronischen Bauelementen versehene Elektronik-Schaltung.The invention relates to a protective circuit for an electronic circuit provided with electronic components.
Um eine elektronische Schaltung gegen Verpolung oder auch Störspannungen der Versorgungsspannung zu schützen, wird in den meisten Fällen eine Verpoldiode in Reihe mit dem Versorgungszweig geschaltet. Bei Verpolung kann wegen des hohen Sperrwiderstands der Diode kein Strom fließen und die Elektronik kann somit nicht zerstört werden.In order to protect an electronic circuit against reverse polarity or interference voltages of the supply voltage, a reverse polarity diode is connected in series with the supply branch in most cases. If the polarity is reversed, no current can flow due to the high blocking resistance of the diode and the electronics cannot be destroyed.
Werden in einer Elektronikschaltung, insbesondere einer elektronischen Steuerung, hohe Ströme benötigt (z.B. zum Schalten großer Lasten), so müssen für den Verpolschutz Dioden für große Ströme verwendet werden. Dies hat den Nachteil, daß hier eine große Leistung und ein hoher Spannungsabfall an der bzw. den Dioden auftritt, was zu Problemen führen kann. Für die Abführung der an der Diode anfallenden Leistung ist somit in den meisten Fällen eine Kühlung erforderlich. Weiterhin sind die Dioden, die große Leistungen durchlassen und in Sperrichtung hinreichende Spannungen zu sperren vermögen, vergleichsweise teuer.If high currents are required in an electronic circuit, in particular an electronic control (e.g. for switching large loads), diodes for large currents must be used for reverse polarity protection. This has the disadvantage that great power and a high voltage drop occur at the diode or diodes, which can lead to problems. In most cases, cooling is required to dissipate the power at the diode. Furthermore, the diodes, which allow high power to pass and are able to block sufficient voltages in the reverse direction, are comparatively expensive.
Die Erfindung besteht im Prinzip darin, in die Schutzschaltung gegen Verpolungsschutz eine MOS-FET-The invention consists in principle in the protection circuit against reverse polarity protection, a MOS-FET
BESϊSπGUNßSKDPlE Schaltung einzufügen, die eine Zerstörung der Elektronikschaltung bei Verpolung verhindert. Hierfür eignen sich im Prinzip alle MOS-FET-Schaltungen. Um einen möglichst geringen Spannungsabfall bei niedriger Verlustleistung und bei einem vergleichsweise niedrigen Preis zu erhalten, empfiehlt sich in Weiterbildung der Erfindung einen N-Kanal- MOS-FET zu verwenden. Eine mit einem N-KANAL-MOS FET versehen Schaltung hat einen besonders niedrigen Durchlaßwiderstand ( QS on)' was i-n Durchlaßrichtung zu einer besonders niedrigen Verlustleistung bzw. einem besonders niedrigen Spannungsabfall führt.BESϊSπGUNßSKDPlE Insert a circuit that prevents the electronic circuit from being destroyed if the polarity is reversed. In principle, all MOS-FET circuits are suitable for this. In order to obtain the lowest possible voltage drop with low power loss and at a comparatively low price, it is advisable to use an N-channel MOS-FET in a further development of the invention. A provided with an n-channel MOS FET circuit has a very low on-state resistance (QS o n) 'was i- n forward to a particularly low power dissipation and a very low voltage drop results.
Bevorzugt wird der N-Kanal-MOS-FET zur Realisierung eines Verpolschutzes invers betrieben. Im Normalbetrieb wird der MOS-FET über sein Gate eingeschaltet und somit sein Durchlaßwiderstand RDS on parallel zur Inversdiode (Q) geschaltet. Dies führt zu einer Verringerung der Verlustleistung und des Spannungsabfalls. Im Verpolbetrieb ist sowohl der MOS-FET insbesondere N-Kanal-MOS-FET ausgeschaltet bzw. gesperrt und die Inversdiode (Q) arbeitet in Sperrichtung.The N-channel MOS FET is preferably operated inversely to implement reverse polarity protection. In normal operation, the MOS-FET is switched on via its gate and thus its forward resistance R DS on is connected in parallel to the inverse diode (Q). This leads to a reduction in the power loss and the voltage drop. In reverse polarity operation, both the MOS-FET, in particular the N-channel MOS-FET, is switched off or blocked and the inverse diode (Q) works in the reverse direction.
In Weiterbildung der Erfindung empfiehlt es sich, eine Schutzbeschaltung (Sl, S2 ) gegen die Zerstörung des MOS-FETS vorzusehen. Dabei kann zum einen das Gate G des MOS-FET geschützt werden, zum anderen wahlweise die Drain-Source- Strecke (DS) (ggf. auch zusätzlich) durch eine weitere Schutzschaltung (S2) geschützt werden. Ein Ausführungsbeispiel der Erfindung wird nachfolgend anhand der Zeichnung erläutert.In a further development of the invention, it is advisable to provide a protective circuit (S1, S2) against the destruction of the MOS-FETS. On the one hand, the gate G of the MOS-FET can be protected, and on the other hand the drain-source path (DS) can be protected (if necessary also additionally) by a further protection circuit (S2). An embodiment of the invention is explained below with reference to the drawing.
Die Zeichnung zeigt eine Spannungsquelle B, deren einer Endpunkt an Masse M und deren anderer Punkt an der Versorgungsspannungsklemme V liegt. Die zu schützende Elektronikschaltung E ist über die Punkte S,D eines N-KANAL- MOS-FET F mit Masse verbunden, während dieThe drawing shows a voltage source B, one end point of which is at ground M and the other point of which is at the supply voltage terminal V. The electronic circuit E to be protected is connected to ground via points S, D of an N-CHANNEL-MOS-FET F, while the
Elektronikschaltung E mit ihrem anderen Spannungsanschluß an der Versorgungsspannungsklemme V anliegt. Die Drain-Source- Strecke (DS) des N-KANAL-MOS-FET wird über eine erste Schutzschaltung Sl geschützt, die an dem Verbindungspunkt Pl zwischen Elektronikschaltung und N-KANAL-MOS-FET und mit ihrem anderen Ende an dem Punkt D des N-KANAL-MOS-FET anliegt, welcher mit der Masseklemme der Spannungsquelle verbunden ist.Electronic circuit E is present with its other voltage connection on the supply voltage terminal V. The drain-source path (DS) of the N-CHANNEL-MOS-FET is protected by a first protection circuit S1, which at the connection point Pl between the electronic circuit and the N-CHANNEL-MOS-FET and with its other end at the point D of the N-CHANNEL MOS FET is present, which is connected to the ground terminal of the voltage source.
Der MOS-FET wird über einen Spannungsteiler Rl, R2 von der Klemme V der Versorgungsspannung angesteuert, wobei das Gate G des N-KANAL-MOS-FET mit einem Verbindungspunkt P2 der beiden seriellen Widerstände Rl, R2 verbunden ist.The MOS-FET is controlled by a terminal V of the supply voltage via a voltage divider R1, R2, the gate G of the N-CHANNEL MOS-FET being connected to a connection point P2 of the two serial resistors R1, R2.
Durch eine zweite Schutzschaltung S2 wird das Gatter des N- KANAL-MOS-FET geschützt, wobei die Schutzschaltung parallel zu dem Widerstand R2 geschaltet ist. Dementsprechend oder zusätzlich kann auch die Drain-Source-Strecke (D,S) durch eine erste Schutzschaltung Sl geschützt sein, welche der invers betriebenen Diode Q des N-KANAL-MOS-FET parallelgeschaltet ist. Um einen Verpolschutz über einen MOS-FET zu realisierern kann ein P-KANAL-MOS-FET oder N-KANAL-MOS-FET zwischen dem Punkt V und der zu schützenden Elektronik E geschaltet werden. Hier zu müßte aber bei der Verwendung eines N-KANAL- MOS-FET eine aufwendige Schaltung zur Ansteuerung des Gates G realisiert werden, um den N-KANAL-MOS-FET einschalten zu können und somit den geringen Durchlaßwiderstand zu erhalten. Die Verwendung eines P-KANAL-MOS-FET hat aufgrund des höheren Durchlaßwiderstandes (RDS,on) ein höhere Verlustleistung und einen höheren Spannungsabfall zu Folge. Außerdem werden diese beiden Lösungen teurer als die bereits beschriebene Verwendung eines N-Kanal-MOS-FWT in der erläuterten Lage. The gate of the N-CHANNEL MOS FET is protected by a second protective circuit S2, the protective circuit being connected in parallel with the resistor R2. Correspondingly or additionally, the drain-source path (D, S) can also be protected by a first protective circuit S1, which is connected in parallel with the inverse-operated diode Q of the N-CHANNEL MOSFET. In order to implement reverse polarity protection via a MOS-FET, a P-CHANNEL-MOS-FET or N-CHANNEL-MOS-FET can be connected between point V and the electronics E to be protected. Here, however, a complex circuit for controlling the gate G would have to be implemented when using an N-CHANNEL-MOS-FET in order to be able to switch on the N-CHANNEL-MOS-FET and thus to maintain the low forward resistance. The use of a P-CHANNEL MOS FET results in a higher power loss and a higher voltage drop due to the higher forward resistance (RDS, on). In addition, these two solutions are more expensive than the use of an N-channel MOS-FWT already described in the situation described.

Claims

Patentansprüche claims
1. Schutzschaltung für eine mit elektronischen Bauelementen versehene Schaltung (E), dadurch gekennzeichnet, daß die Schutzschaltung mit einem MOS-FET (F) versehen ist, der mit der elektronischen Schaltung (E) in bezug auf die Anschlüsse (V,M) einer Versorgungsspannung (B) in Reihe geschaltet ist.1. Protection circuit for a circuit provided with electronic components (E), characterized in that the protection circuit is provided with a MOS-FET (F) with the electronic circuit (E) with respect to the connections (V, M) one Supply voltage (B) is connected in series.
2. Schutzschaltung nach Anspruch 1, dadurch gekennzeichnet, daß der MOS-FET ein N-Kanal-MOS-FET ist, der zwischen die Elektronikschaltung (E) und den Masseanschluß (M) der Spannungsquelle (B) geschaltet ist, während die Elektronikschaltung mit einem weiteren Anschluß der mit dem Versorgungsspannungsanschluß (V) verbunden ist.2. Protection circuit according to claim 1, characterized in that the MOS-FET is an N-channel MOS-FET, which is connected between the electronic circuit (E) and the ground terminal (M) of the voltage source (B), while the electronic circuit with another connection which is connected to the supply voltage connection (V).
3. Schutzschaltung nach Anspruch 2, dadurch gekennzeichnet, daß ein erster Verbindungspunkt (Pl) zwischen dem N- Kanal-MOS-FET (F) und der Elektronikschaltung (E) über eine Serienschaltung (R1,R2) mindestens zweier serieller Widerstände (R1,R2) mit dem Versorgungsspannungsanschluß (V) verbunden ist und daß ein zweiter Verbindungspunkt (P2) der beiden Widerstände (Rl, R2 ) zu dem Gate- Anschluß (G) des MOS-FET (F) geführt ist.3. Protection circuit according to claim 2, characterized in that a first connection point (Pl) between the N-channel MOS-FET (F) and the electronic circuit (E) via a series circuit (R1, R2) of at least two serial resistors (R1, R2) is connected to the supply voltage connection (V) and that a second connection point (P2) of the two resistors (Rl, R2) is led to the gate connection (G) of the MOS-FET (F).
4. Schutzschaltung nach Anspruch 3, dadurch gekennzeichnet, daß zwischen das dem ersten Verbindungspunkt (Pl) abgewendete Ende der seriellen Widerstandsschaltung (Rl, R2 ) und Gate (G) eine zweite Schutzschaltung (S2) eingefügt ist, welche den Gateanschluß (G) im Störfalle schützt.4. Protection circuit according to claim 3, characterized in that between the the first connection point (Pl) opposite end of the serial resistance circuit (Rl, R2) and gate (G) a second protection circuit (S2) is inserted, which protects the gate terminal (G) in the event of a fault.
5. Schutzschaltung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, die die Drain-Source-Strecke (DS) des N-Kanal-MOS-FET mittels einer ersten Schutzschaltung (Sl) schützt. 5. Protection circuit according to one of claims 1 to 3, characterized in that protects the drain-source path (DS) of the N-channel MOS-FET by means of a first protection circuit (Sl).
PCT/EP1998/006419 1997-10-11 1998-10-09 Protective circuit with n-channel mos fet for an electronic circuit WO1999019958A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19745074.1 1997-10-11
DE1997145074 DE19745074A1 (en) 1997-10-11 1997-10-11 Electronic circuit protection device

Publications (1)

Publication Number Publication Date
WO1999019958A1 true WO1999019958A1 (en) 1999-04-22

Family

ID=7845326

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/006419 WO1999019958A1 (en) 1997-10-11 1998-10-09 Protective circuit with n-channel mos fet for an electronic circuit

Country Status (2)

Country Link
DE (1) DE19745074A1 (en)
WO (1) WO1999019958A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9374435B2 (en) 1998-05-29 2016-06-21 Blackberry Limited System and method for using trigger events and a redirector flag to redirect messages

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19938403C2 (en) * 1999-08-13 2002-03-14 Micronas Gmbh circuit
DE102009019831A1 (en) * 2009-05-04 2010-11-11 Voltwerk Electronics Gmbh circuitry

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3535788A1 (en) * 1985-09-03 1986-02-20 Siemens AG, 1000 Berlin und 8000 München Incorrect polarity protection for circuit arrangements
DE3930896A1 (en) * 1989-09-15 1991-03-28 Vdo Schindling Polarisation protective circuit for DC consumer - has inversely operated MOSFET between earth input and output
DE19506074A1 (en) * 1995-02-22 1996-09-05 Telefunken Microelectron Circuit to protect vehicle components from inadvertent reversal of battery polarity or from negative voltage spikes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3535788A1 (en) * 1985-09-03 1986-02-20 Siemens AG, 1000 Berlin und 8000 München Incorrect polarity protection for circuit arrangements
DE3930896A1 (en) * 1989-09-15 1991-03-28 Vdo Schindling Polarisation protective circuit for DC consumer - has inversely operated MOSFET between earth input and output
DE19506074A1 (en) * 1995-02-22 1996-09-05 Telefunken Microelectron Circuit to protect vehicle components from inadvertent reversal of battery polarity or from negative voltage spikes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9374435B2 (en) 1998-05-29 2016-06-21 Blackberry Limited System and method for using trigger events and a redirector flag to redirect messages

Also Published As

Publication number Publication date
DE19745074A1 (en) 1999-04-15

Similar Documents

Publication Publication Date Title
DE69723415T2 (en) Protection of an integrated power supply
EP0572706B1 (en) Control circuit for a power-FET with a load connected to its source
DE4410978C2 (en) Circuit and method for improving the short circuit resistance of an insulated gate bipolar transistor (IGBT)
DE60130146T2 (en) ESD PROTECTION
WO2002082611A2 (en) Electric power supply with a safety cut-off
DE19603117A1 (en) Polarity reversal protection circuit e.g. for battery or other DC source
DE4316275A1 (en) MOS power switching circuit IC with short circuit protection - has current limiter between source of MOS power transistor and base of bipolar transistor
EP0790699A2 (en) DC motor control method and apparatus for operating the method
DE19838657B4 (en) Circuit arrangement for detecting the load current of a power field effect semiconductor device
DE4403375A1 (en) Device and method for controlling an inductive load
WO1999019958A1 (en) Protective circuit with n-channel mos fet for an electronic circuit
EP0495142B1 (en) Protection against inverted polarity and overvoltage for circuit arrangements
EP0560086B1 (en) Protection circuit for a power-MOSFET driving an inductive load
DE4428115A1 (en) Control unit with a circuit arrangement for protecting the control unit when the control unit mass is interrupted
EP0436778A2 (en) Circuit for the protection of a consumer
EP0993118A2 (en) Protection circuit for a power field-effect transistor
EP0876699B1 (en) Current limiting circuit
DE3834867C1 (en) Circuit arrangement for the parallel connection of power supply devices
EP0489935B1 (en) MOSFET switch for an inductive load
DE3505986A1 (en) SHORT-CIRCUIT-RESISTANT POWER SUPPLY, IN PARTICULAR FOR A TELEVISION RECEIVER
EP1193824A2 (en) Reverse battery protection circuit
DE4139378A1 (en) FET protective circuit against faulty polarisation - has diode incorporated between consumer junction point to DC voltage source and FET gate-terminal
EP1227562B1 (en) Electric circuit for protecting an electronic device connected to a dc power supply upon inverted polarity of the supply
EP0822661A2 (en) Drive circuit for a field effect controlled power semiconductor device
DE4321971A1 (en) Switching circuit for redundant automation system - has two switches operated by drive stage according to voltage drops across switches

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase