US3803569A - Failure check circuit - Google Patents

Failure check circuit Download PDF

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Publication number
US3803569A
US3803569A US00238333A US23833372A US3803569A US 3803569 A US3803569 A US 3803569A US 00238333 A US00238333 A US 00238333A US 23833372 A US23833372 A US 23833372A US 3803569 A US3803569 A US 3803569A
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US
United States
Prior art keywords
resistors
check
diodes
circuit according
failure
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.)
Expired - Lifetime
Application number
US00238333A
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English (en)
Inventor
T Tanigami
T Iwasaki
S Watanabe
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.)
Hitachi Ltd
Nissan Motor Co Ltd
Original Assignee
Hitachi Ltd
Nissan Motor Co Ltd
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
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Publication of US3803569A publication Critical patent/US3803569A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/017—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
    • B60R21/0173—Diagnostic or recording means therefor
    • B60R21/0176—Diagnostic or recording means therefor for firing circuits using only mechanical switches as collision detecting means, in series with pyrotechnic fuses
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/005—Testing of electric installations on transport means
    • G01R31/006—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
    • G01R31/2832—Specific tests of electronic circuits not provided for elsewhere
    • G01R31/2836—Fault-finding or characterising

Definitions

  • ABSTRACT The failure state, due to disconnection or grounding of resistors connected in parallel, is checked in such a way that diodes are connected in series, respectively between the resistors and a common terminal for the parallel connection.
  • a check signal is supplied to the other common terminal for the parallel connection, and the signals appearing at the connection points between the resistors and the diode are compared with the supplied check signal by using a logic circuit such as an AND gate.
  • This invention relates to a failure checking circuit to detect an abnormal or state of failure in which at least one circuit element is open circuited or grounded comprising a plurality of circuit elements which are connected in parallel.
  • This invention particularly relates to a circuit for checking a failure due to disconnection or short-circuiting of elements in a firing circuit system for the protection of occupants of a vehicle in the event of a crash.
  • the air-bag system comprises detector means for detecting a crash, high-pressure gas cylinders, air-bags which are quickly enlarged in the crash to restrain the vehicle occupants, and firing means for destroying or removing the valves provided between the high-pressure gas cylinders and the air bags.
  • the firing means comprise circuit elements such as resistors of low resistance, so called firing balls, which are operated by output signals from a detector means in the event of a crash and fire or explode as a result of the heat which the electric current flowing through the resistors generates.
  • Four to eight of these air-bags are provided in a car and, therefore, four to eight firing means are electrically connected in parallel to the detector means.
  • each circuit line, including the circuit element must be electrically isolated as to a check signal other than its own signal, since a plurality of circuit elements, such as resistors, are connected in parallel in the airbag system. It is also noted that if the mean value of the electric current flowing through a resistor, as the check signal, is large, the heat generated in the resistor might blow up the explosives, whereby the air-bag system might operate and restrain the driver and possibly cause a traffic accident. Therefore, it is necessary to use an electric current having a small mean value, as the failure check signal.
  • An object of the present invention is to provide a failure check circuit in which the failure of each circuit element can be separately or independently checked in a circuit with a plurality of circuit elements connected in parallel.
  • Another object of this invention is to provide a failure check circuit in a circuit comprising a plurality of firing means connected in parallel, for checking the failure state of the firing means without actually operating them.
  • a further object of this invention is to provide a failure check circuit in a firing circuit comprising a plurality of resistors, having a low resistance, connected in parallel, wherein the mean value of the electric current, flowing through a resistor as a check signal, is small.
  • Still a further object of this invention is to provide a check system suitable for use in an air-bag protection system for vehicles.
  • the failure check circuit comprises a plurality of serial unit circuits each comprising a circuit element such as resistor and a diode connected in series; connection means for electrically connecting the serial unit circuits in parallel between a first and a second common terminal; signal supply means for supplying an electrical signal to the first common terminal; detecting means for detecting the failure state of the circuit elements having a plurality of input terminals and an output terminal; and connection means for electrically connecting the input terminals respectively with the connection points between the circuit elements and the diodes.
  • a failure check circuit comprises a plurality of serial unit circuits each comprising a first diode, a circuit element such as resistor and a second diode which are connected in series; and connection means for electrically connecting the serial unit circuits in parallel between a first and a second common terminal.
  • a check signal such as a pulse signal is supplied to the first common terminal and the output signals appearing at the connection points between the circuit elements and the second diodes are checked through a detector for detecting the failure of the circuit elements, and/or wherein check signals such as pulse signalsare supplied to the connection points between the'first diodes and the circuit elements and an output signal appearing at the second common terminal is checked, through a detector for detecting the failure of the circuit elements.
  • FIG. 1 is a circuit diagram of a failure check circuit according to an embodiment of this invention which is applied to an air-bag system; and 2 FIG. 2 shows waveforms of the output pulse signals of the pulse generator and the frequency dividers which are used in the circuit of FIG. 1.
  • reference numerals 1 and 2 show terminals which are connected to a power source (not shown), reference letters B, to B are circuit elements such as resistors of about 1 to 5 ohms for firing air bags (not shown), reference letters D to D are diodes, reference letters S and S are crash-detect switches comprising mechanical switches which close in the event of a crash of a vehicle and reference letter R is a load resistor of more than 500 k0, and wherein the frequency dividers respectively each comprises, for example, a flip-flop circuit.
  • the resistors for firing air bags (hereinafter referred as to fire-resistors B to B areeach respectively connected to one end of the diodes D, to D through terminals or connection points P to P and the other ends of the diodes D to D, are connected together to the crash-detect switch 8, through the first common connecting terminal P
  • the other ends of the fire-resistors B, to B are connected respectively to each one end of the diodes D to D through terminals or connection points P to P,,, and the other ends of the diodes D to D,., are connected to the crash-detect switch S through the second common connecting terminal P
  • a check signal is supplied from the pulse signal generator to the first common terminal P,, to the frequency dividers F, to F, and to an input terminal of the pulse detector A,.
  • Output terminals of the frequency dividers F, to F are respectively connected to the connecting terminals or points P to P between the fire-resistors B, to B, and thediodes D, to D
  • the input terminals of the pulse detector A are connected to the second common terminal P and to each output terminal of the frequency dividers F, to F
  • the input terminals of the pulse detector A are connected to each of the connecting terminals or points P to P between the fire-resistors B, to B, and the diodes D to D,.,.
  • These pulse detectors A, and A comprise logic circuits, for example, AND circuits in which an output signal appears at the output terminal only when input pulse signals are simultaneously supplied to the input terminals thereof.
  • the detector A operates to cause an output pulse signal to appear at the output terminal thereof only when the pulse signal transmitted from the pulse signal generator PG and the pulse signals transmitted through the connection points P to P, between the fire-resistors B, to B and the diodes D to D, are simultaneously applied to the input terminals of the detector A,.
  • Output terminals of the pulse detectors are connected with alarm circuits (not shown) such as a lamp and a buzzer circuit in order to provide a warning to the driver etc. of an abnormal state in the system.
  • reference letters V V V V and V show waveforms of the output signals from the pulse signal generator PG and frequency dividers F, to F respectively.
  • the axis of the abscissa is used to show time t.
  • the operation of the main circuit as shown in FIG. 1 is briefly explained as follows. Between the terminals 1 and 2, is connected a power source circuit such as a battery and a charged-up condensor, whereby a positive voltage is applied to the terminal 1 in case the diodes D, to D are connected with a polarity as shown in FIG. 1. If a crash occurs, the crash-detect switches 'S, and 5, close or are in the ON condition and a large amount of current flows through the fire-resistors B, to B, in order to operate the air-bag system. Under conditions other than a crash, however, the crash detect switches S, and S, are open or in the OFF" state. 7
  • the alarm or warning circuit may be set in such a way not to operate an alarm or a warning light.
  • the fire-resistors B If, for example, the fire-resistors B, is disconnected or grounded, namely, is in an abnormal state, and the others are in good condition, a pulse signal does not appear at the connection point I, even if a pulse signal is applied to the first common terminal P,. Therefore, to the input terminals of the detector A, only the pulse signals transmitted through the output terminal of the pulse generator PG and the connection points P P and P,,,' are applied and a pulse signal does not appear at the output terminal of the detector A, since the detector comprises an AND circuit. In this case the alarm or warning circuit may be set to operate, whereby failure of the fire-resistor can be detected.
  • Such a check can be effectively carried out by using the frequency dividers F, to F and the detector A,.
  • the pulse detector A checks the signal from the frequency divider F, and the signal from the terminal P In the absence of the signal from the terminal P the alarm circuit may be set to operate in order to notify the abnormal state to the driver.
  • the other circuits each comprising the fire-resistor of B to B and the diode of D to D are checked successively in the same way.
  • each of the terminals P, to P is electrically isolated by each of the diodes D, to D respectively, from the check signal transmitted through the other circuits.
  • the fire-resistors B, to 8. might be checked by applying pulse signals to the terminals P to P and by detecting the pulse signals which are to appear at the terminals P to P However, where at least one of the diodes D to D is defective, the circuit does not operate since the diodes D, to D are connected to the fire-resistors B, to B in series.
  • the circuit line comprising the fire-resistor B, and the diode D can be checked by applying a check signal to the terminal P, which is common to all the circuit lines and by detecting an output signal at the connecting terminal P between the fire-resistor B, and the diode D
  • the circuit line of the fire-resistor B and the diode D can be checked by applying a check signal to the connecting terminal P between the fire-resistor B and the diode D, and by detecting an output signal at the other common terminal P
  • Each circuit can be checked separately, since it is electrically isolated by the diodes from the check signal which is to be transmitted through the other circuits. Also, since the mean value of current which flows in the fireresistors during checking is very small, it hardly occurs that the fire-resistors are set in operation by the check signal.
  • the frequency dividers F, to F are employed in order to provide shifted pulse signals to each circuit
  • the invention is not limited thereto.
  • Other circuit means which can provide predetermined check-signals for example, pulse signal generators which can provide pulse signals having a predetermined waveforms and a predetermined interval can also be applied.
  • the pulse detectors of this invention comprise AND circuit, other circuits such as NAND circuits etc. which can detect check signals can also be applied.
  • the present invention provides a failure check circuit system in a circuit comprising a plurality of circuit elements such as resistors for firing means connected in parallel between a first and a second common terminal wherein a plurality of diodes are connected respectively in series between the circuit elements and the second common terminal, a check signal is applied to the first common terminal, failure of the circuit elements is checked by detecting the output signals appearing at the connection points between the circuit elements and the diodes.
  • a failure check circuit system in a circuit comprising a plurality of circuit elements such as resistors for firing means connected in parallel between a first and a second common terminal wherein a plurality of diodes are connected respectively in series between the circuit elements and the second common terminal, a check signal is applied to the first common terminal, failure of the circuit elements is checked by detecting the output signals appearing at the connection points between the circuit elements and the diodes.
  • the present invention further provides a failure check circuit system in a circuit having a plurality of serial unit circuits each comprising a first diode, a circuit element such as resistor used as a firing means and a second diode connected in parallel between a first and a second common terminal, wherein a check signal, such as a pulse signal, is applied to the first common terminal and the output signals appearing at the connection terminals between the circuit elements and the second diodes are detected, or wherein check signals such as pulse signals, are applied to the connection terminals between the first diodes and the circuit element and the output signals appearing at the second common terminal are detected.
  • a check signal such as a pulse signal
  • the existence of a failure in each unit circuit may be effectively checked and the mean value of signal current may be reduced by using a small signal such as a pulse signal, whereby misoperation of the firing means due to the signal current may be prevented.
  • a small signal such as a pulse signal
  • This invention may be applied not only to a failure check circuit system for an air-bag system for vehicles, but also to fire-alarm system, other firing means to simultaneously fire or blow-up many portions, etc.
  • a failure check circuit comprising:
  • connection means for connecting said unit circuits in parallel between a first and a second common terminal
  • detecting means for detecting the existence of signals transmitted from said check signal supplying means to the connection points between said resistors and the diodes.
  • said detecting means comprises a logic circuit and has a plurality of input terminals and an output terminal, said input terminals being respectively connected electrically to said connection points between said resistors and said diodes and to said first common terminal.
  • a failure check circuit comprising:
  • serial unit circuits each comprising a first diode, a resistor and a second diode which are connected in series;
  • connection means for connecting said serial unit circuits in parallel between a first and a second common terminal, so as to directly connect said first and second diodes with said first and second common terminals, respectively;
  • a failure check circuit according to claim 3, wherein said detecting means comprises a logic circit and has a plurality of input terminals and an output terminal, said input terminals being electrically connected to said connection points between said resistors and said second diodes and to said first common terminal.
  • a failure check circuit comprising a second means for supplying second check signals to the connection points between said first diodes and said resistors and a second detecting means for detecting the signal transmitted from said second means for supplying second check signals to said second common terminal.
  • a failure check circuit according to claim 5, wherein said second detecting means comprises a logic circuit and has a plurality of input terminals respectively connected to said common terminal and to said connection points between said first diodes and said resostors.
  • a failure check circuit according to claim 6, wherein said second check signals comprise pulse signals shifted in time with respect to each other.
  • a failure check circuit according to claim 3, wherein said first check signal supplying means cmprises means for generating a series of pulses.
  • said means for supplying second check signals comprises a plurality of frequency dividers, the inputs of which are connected in common to the output of said first check signal supplying means and the respective outputs of which are connected to respective connection points between said first diodes and resistors.
  • each of said frequency dividers has a different frequency division characteristic.
  • each of said first and second diodes is connected to pass current in the same direction between said first and second common terminals.
  • a failure check circuit according to claim 1, wherein said check signal is supplied to said first common terminal for checking the condition of said resistOl'S.
  • a failure check circuit according to claim 3, wherein said plurality of serial unit circuits serve for activating an occupant safety device of a vehicle, and said resistors of said unit circuits are firing resistors for activating the safety device.
  • a failure check circuit according to claim 5, wherein said plurality of unit circuits serve for activating an occupant protective safety device of a vehicle, and said resistor of said unit circuits are firing resistors for activating the occupant protective safety device.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Air Bags (AREA)
  • Alarm Systems (AREA)
US00238333A 1971-03-26 1972-03-27 Failure check circuit Expired - Lifetime US3803569A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1722271A JPS5616479B1 (enExample) 1971-03-26 1971-03-26

Publications (1)

Publication Number Publication Date
US3803569A true US3803569A (en) 1974-04-09

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ID=11937902

Family Applications (1)

Application Number Title Priority Date Filing Date
US00238333A Expired - Lifetime US3803569A (en) 1971-03-26 1972-03-27 Failure check circuit

Country Status (7)

Country Link
US (1) US3803569A (enExample)
JP (1) JPS5616479B1 (enExample)
AU (1) AU442040B2 (enExample)
CA (1) CA969619A (enExample)
DE (1) DE2213977C3 (enExample)
FR (1) FR2130694B1 (enExample)
GB (1) GB1390126A (enExample)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4007713A (en) * 1975-08-28 1977-02-15 Hydrolevel Corporation Test circuit
WO1983003142A1 (en) * 1982-03-08 1983-09-15 Stephen Robert Laughlin A circuit arrangement for enabling simultaneous operation of independent ac circuits
FR2632218A1 (fr) * 1988-06-03 1989-12-08 Lacoste Jean Procede de sertissage de pieces metalliques utilisant le formage par pression magnetique et articles issus de la mise en oeuvre du procede
US4945336A (en) * 1988-05-12 1990-07-31 Mitsubishi Denki Kabushiki Kaisha Trouble detection apparatus for automobile air-bag system
US4956631A (en) * 1989-03-20 1990-09-11 Mitsubishi Denki Kabushiki Kaisha Fault detector for vehicle safety system

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041374A (en) * 1976-03-15 1977-08-09 Rca Corporation Interelectrode open and short circuit tester
DE2808872C2 (de) * 1978-03-02 1986-01-23 Messerschmitt-Bölkow-Blohm GmbH, 8000 München Auslöseschaltung für eine Insassenschutzeinrichtung in Kraftfahrzeugen
DE8816606U1 (de) * 1988-03-22 1989-12-28 Robert Bosch Gmbh, 70469 Stuttgart Elektronische Einrichtung
DE3831335C1 (en) * 1988-09-15 1990-01-11 Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De Trigger circuit for a device for protecting occupants of a vehicle
KR102755524B1 (ko) * 2022-08-05 2025-01-14 고려대학교 산학협력단 수분흡수능력 및 기체투과도가 우수한 박테리아 셀룰로오스 및 이의 제조방법

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4007713A (en) * 1975-08-28 1977-02-15 Hydrolevel Corporation Test circuit
WO1983003142A1 (en) * 1982-03-08 1983-09-15 Stephen Robert Laughlin A circuit arrangement for enabling simultaneous operation of independent ac circuits
US4945336A (en) * 1988-05-12 1990-07-31 Mitsubishi Denki Kabushiki Kaisha Trouble detection apparatus for automobile air-bag system
FR2632218A1 (fr) * 1988-06-03 1989-12-08 Lacoste Jean Procede de sertissage de pieces metalliques utilisant le formage par pression magnetique et articles issus de la mise en oeuvre du procede
US4956631A (en) * 1989-03-20 1990-09-11 Mitsubishi Denki Kabushiki Kaisha Fault detector for vehicle safety system

Also Published As

Publication number Publication date
DE2213977C3 (de) 1975-07-17
CA969619A (en) 1975-06-17
DE2213977A1 (de) 1972-11-23
FR2130694A1 (enExample) 1972-11-03
FR2130694B1 (enExample) 1978-07-07
JPS5616479B1 (enExample) 1981-04-16
GB1390126A (en) 1975-04-09
AU442040B2 (en) 1973-11-15
AU4041172A (en) 1973-11-15
DE2213977B2 (de) 1974-12-05

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