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WO1995001668A1 - Procede et systeme de protection de circuit electrique - Google Patents

Procede et systeme de protection de circuit electrique Download PDF

Info

Publication number
WO1995001668A1
WO1995001668A1 PCT/FI1994/000299 FI9400299W WO9501668A1 WO 1995001668 A1 WO1995001668 A1 WO 1995001668A1 FI 9400299 W FI9400299 W FI 9400299W WO 9501668 A1 WO9501668 A1 WO 9501668A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
interference
cutter
transistor
cutting
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.)
Ceased
Application number
PCT/FI1994/000299
Other languages
English (en)
Inventor
Jarmo Loukusa
Kauko Varanka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Oyj
Original Assignee
Nokia Telecommunications Oy
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 Nokia Telecommunications Oy filed Critical Nokia Telecommunications Oy
Priority to AU71255/94A priority Critical patent/AU7125594A/en
Publication of WO1995001668A1 publication Critical patent/WO1995001668A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • H02H9/043—Protection of over-voltage protection device by short-circuiting
    • 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
    • H02H9/045—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere
    • H02H9/046—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere responsive to excess voltage appearing at terminals of integrated circuits

Definitions

  • the present invention relates to a method for protecting an electric circuit against interference voltage with a voltage cutter, and corresponding appar ⁇ atus comprising a fuse component and a voltage cutter.
  • Electric circuits such as integrated circuits, are often sensitive to variations of the operating volt ⁇ age and other interference voltages. A sudden overvolt- age can easily cause disturbances in the operation of the circuit, damage the circuit or even completely des ⁇ troy the circuit. Therefore electric circuits are often provided with overvoltage protection to prevent AC in ⁇ terference voltages and surge voltages and to secure the operation of the circuit.
  • the object of the present invention is to pro ⁇ vide a method and apparatus, which can protect an elec- trie circuit against interference voltages simply and reliably and which can also protect itself from being destroyed.
  • the method according to the invention which is characterized in that the dura- tion and level of the interference voltage is monitored, and if the interference voltage persists longer than a predetermined period, the cutting voltage is lowered, and the remaining power in the voltage cutter is de ⁇ creased in proportion to the level of the interference voltage by cutting the input of the interference voltage to the voltage cutter and the protected circuit.
  • the apparatus according to the invention is characterized in that the voltage cutter comprises means for monitor ⁇ ing the duration and level of the interference voltage and decreasing the level of the cutting voltage and re ⁇ ducing the remaining power in the voltage cutter in pro ⁇ portion to the level of the interference voltage so as to activate the fuse component when the interference voltage persists longer than a predetermined period.
  • Figure 1 shows the above described example of a prior art interference voltage protecting device
  • Figure 2 shows the circuit diagram of an inter ⁇ ference voltage protecting device according to the in ⁇ vention.
  • the interference voltage protecting device can monitor the voltage over the protecting device, and if the interference voltage persists too long, the protecting device can cut the voltage to prevent the protecting device from being destroyed.
  • a fuse component PTC2 is series connected in the voltage line at the input of the protected circuit 21.
  • a voltage cutter 20 is connected in parallel with the input.
  • the voltage cutter comprises a forward-dir- ected diode D12 connected in series between the input of the protected circuit and the ground potential, a low ohmic resistor R13 and an NPN transistor Q6 in the col ⁇ lector-emitter direction.
  • the base of the transistor Q6 is connected to the collector of a PNP transistor Q10 by way of the series connection of resistors R4 and R3, which collector is connected to the emitter of the tran ⁇ sistor Q6 and to the ground potential by way of the par ⁇ allel connection of a resistor R5 and a capacitor Cl.
  • the base of the transistor Q10 is connected directly to the collector of the transistor Q6.
  • the cathode of a reverse-directed Zener diode Zl is connected to the junction of diode D12 with resistor R13, and the anode to the junction of resistors R3 and R4.
  • the cathode of the Zener diode Zl is also connected to the emitter of the transistor Q10 through a resistor R2.
  • the capacitor Cl is charged through the transistor Q10.
  • the tran- sistor Q10 becomes conductive and starts to feed base current to the transistor Q6.
  • the transistor Q6 goes to a saturation state and the cutting voltage of the voltage cutter 20 and the remaining power in the cutter are reduced.
  • the remaining power in the fuse component PTC2 increases and the fuse component cuts the incoming interference voltage.

Landscapes

  • Emergency Protection Circuit Devices (AREA)

Abstract

La présente invention concerne un procédé destiné à protéger un circuit électrique contre les tensions perturbatrices au moyen d'un dévolteur (20), ainsi qu'un et d'un système correspondant. Afin d'éviter la destruction du dévolteur, le système comprend des composants (C1 et Q10) qui permettent de surveiller la durée de la tension perturbatrice et de diminuer la tension de dévoltage de façon à activer un fusible (PTC2) quand la durée de la tension perturbatrice persiste jusqu'à dépasser une valeur prédéterminée.
PCT/FI1994/000299 1993-07-02 1994-06-29 Procede et systeme de protection de circuit electrique Ceased WO1995001668A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU71255/94A AU7125594A (en) 1993-07-02 1994-06-29 Method and apparatus for protecting an electric circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI933069A FI933069A7 (fi) 1993-07-02 1993-07-02 Menetelmä ja laitteisto sähköisen piirin suojaamiseksi
FI933069 1993-07-02

Publications (1)

Publication Number Publication Date
WO1995001668A1 true WO1995001668A1 (fr) 1995-01-12

Family

ID=8538268

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1994/000299 Ceased WO1995001668A1 (fr) 1993-07-02 1994-06-29 Procede et systeme de protection de circuit electrique

Country Status (3)

Country Link
AU (1) AU7125594A (fr)
FI (1) FI933069A7 (fr)
WO (1) WO1995001668A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004063708A1 (de) * 2004-12-28 2006-07-13 Endress + Hauser Flowtec Ag Schaltung zur Spannungsbegrenzung
US7231037B2 (en) 2002-03-20 2007-06-12 Sennheiser Communications A/S Active audio compressing in telecommunication

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3539865A (en) * 1968-11-12 1970-11-10 Roband Electronics Ltd Crowbar protection device
US3594612A (en) * 1970-02-24 1971-07-20 Forbro Design Corp Overvoltage protector for the load of fast-slewing regulated power supplies
US3686511A (en) * 1971-04-16 1972-08-22 Stanton Magnetics Speaker protective circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3539865A (en) * 1968-11-12 1970-11-10 Roband Electronics Ltd Crowbar protection device
US3594612A (en) * 1970-02-24 1971-07-20 Forbro Design Corp Overvoltage protector for the load of fast-slewing regulated power supplies
US3686511A (en) * 1971-04-16 1972-08-22 Stanton Magnetics Speaker protective circuit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7231037B2 (en) 2002-03-20 2007-06-12 Sennheiser Communications A/S Active audio compressing in telecommunication
EP1931171A3 (fr) * 2002-03-20 2008-10-22 Sennheiser Communications A/S Compression audio active dans le domaine des telecommunications
USRE42093E1 (en) * 2002-03-20 2011-02-01 Sennheiser Communications A/S Active audio compressing in telecommunication
DE102004063708A1 (de) * 2004-12-28 2006-07-13 Endress + Hauser Flowtec Ag Schaltung zur Spannungsbegrenzung
DE102004063708B4 (de) * 2004-12-28 2010-12-16 Endress + Hauser Flowtec Ag Schaltung zur Spannungsbegrenzung

Also Published As

Publication number Publication date
AU7125594A (en) 1995-01-24
FI933069L (fi) 1995-01-03
FI933069A7 (fi) 1995-01-03
FI933069A0 (fi) 1993-07-02

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