Classifications

• • 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
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
  • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
  • B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
  • H02J2310/40—The network being an on-board power network, i.e. within a vehicle
  • H02J2310/46—The network being an on-board power network, i.e. within a vehicle for ICE-powered road vehicles

Definitions

• the present invention relates to a voltage transformer of the kind described in the precharacterising part of claim 1.
• Such a device is already known for use in connection with an air bag protection device in a motor vehicle.
• the energy store is used for providing energy to detonate one or more air bag gas capsules for inflating the air bag or bags in the event of loss of battery power during a collision condition. It is also necessary to provide energy during such conditions for driving additional electronic circuitry of the motor vehicle and the usual practice has been to provide a separate voltage charging source for this purpose since the energy store for driving the electronics is generally to be charged to a smaller voltage than that for detonating the air bag capsules.
• i is an object of the present invention to provide a voltage transformer which overcomes this disadvantage of the known arrangement.
• the voltage transformer shown in the drawing operates on the known conversion principle of the so-called "flyback regulator” wherein energy is stored in a coil coupled to the battery voltage supply and a higher voltage is generated by periodically shorting the coil to earth by means of a controlled power stage.
• the battery voltage U BA ⁇ protected from interference pulses, is supplied by way of a diode D- ⁇ to one end of a coil L.
• the diode Di protects the circuit against reverse connection of the battery.
• the opposite end of the coil L is connected by way of a diode D£ to the one ends of a pair of storage capacitors CT , C2 whose other ends are earthed and which, together, form a first energy store 1 whose purpose is to provide energy for detonating one or more inflation capsules of air bags, used for the protection of the occupants of motor vehicles in a collision condition, in the event of loss of battery power.
• the diode D ⁇ and coil L, together with a capacitor C ⁇ form an inductive energy-storing device 2.
• each of the capacitors C ⁇ , C2 has a capacity of 4700 ⁇ F and is rated at 63V.
• the combined capacity is therefore 9.4 mF.
• a resistor R ⁇ and further diode D3 lead from the battery input to the capacitors C* ⁇ , C2 and form an auxiliary charging circuit 3 in a conventional manner.
• a MOSFET transistor Ti Coupled to the point P at the s.econd end of the coil L is a MOSFET transistor Ti forming a power output stage 4. When rendered conductive, the transistor T acts to connect the point P to ground.
• the controlling terminal of the transistor T* ⁇ is connected in a known manner to the output F of an astable multivibrator device 5 which is of known construction and is therefore not described further herein.
• the output F of the astable multivibrator 5 is also connected to a regulating device 6 which is described in more detail hereinafter but which acts under certain specified conditions to suppress the controlling action of the astable multivibrator 5 and prevents switching of the MOSFET transistor T ⁇ •
• a second energy store 7, consisting of a further capacitor C ⁇ , is coupled to the first energy store 1 by way of a charge control circuit 8 which only allows the second energy store 7 to be charged when the charging voltage of the first energy store 1 has reached a predetermined level, in this case 30 volts.
• the capacitor C forming the second energy store 7 has a capacity of 6.8mF and a rated voltage of 40 volts.
• the battery voltage (typically 12-16 volts) protected against spikes, is applied to the coil L.
• the astable multivibrator 5 operates continuously and acts to cause the transistor T j to repeatedly connect and disconnect the point P to earth, thereby causing a high voltage to be induced across the coil L.
• This high voltage is rectified by the diode D and begins to charge the capacitors C ⁇ , C£- Initially, the charging voltage on the capacitors C ⁇ » c 2 cannot reach the second energy storing capacitor C ⁇ since the transistor T2 is in a non-conductive state.
• a Zener diode Z breaks down, thereby switching on a transistor T3 and thence switching on the transistor T£. With the transistor T2 conductive, the capacitor C can then charge via a resistor R . Charging of the capacitor C above a further voltage level (in this case 24V) is, however, prevented by the presence of a
• the regulator 6 includes a comparator 10 which compares a signal developed from the charging signal on the first capacitors C--_, C£.
• the upstream capacitors C ⁇ , C first charge to 30 volts; then the capacitor C4 begins to charge to 24 volts and only then does the charging of the first capacitor Ci , C2 continue to rise to the maximum permitted level of 38 volts.
• the overall charging time to reach the specified charging levels can be achieved in a time t ⁇ seven seconds.
• the first capacitors C*-_, C are charged in a time Ti three seconds. This, after battery failure, is still sufficient to detonate the inflation capsule(s) with a steady discharge of 10mA after t - seven seconds.

Applications Claiming Priority (1)

Publications (1)

Family

ID=8165312

Family Applications (1)

Country Status (3)

Families Citing this family (7)

Family Cites Families (2)

• 1988
  • 1988-08-17 JP JP63506909A patent/JPH04500147A/ja active Pending
  • 1988-08-17 EP EP19880907279 patent/EP0433281A1/de not_active Withdrawn
  • 1988-08-17 WO PCT/EP1988/000728 patent/WO1990002440A1/en not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events