JP2872053B2 - Squib ignition circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squib ignition circuit, and more particularly to a squib ignition circuit having a structure in which a plurality of squibs are connected in parallel.

[0002]

2. Description of the Related Art In recent years, automobiles are often provided with airbags and seatbelt pretensioners for protecting occupants. It is necessary to install a squib for ignition.

[0003] Therefore, a configuration in which a plurality of squibs are connected in parallel to a vehicle-mounted battery is used. However, since the DC resistance of each squib varies, when the vehicle-mounted battery and the squib are directly connected, most squibs have a small DC resistance. Therefore, reliable ignition of all the squibs cannot be guaranteed. In order to solve the above problem, a squib connected to a vehicle-mounted battery via a current limiting circuit has been proposed (see Japanese Patent Application Laid-Open No. 4-321454).

[0004]

However, in the ignition circuit according to the above proposal, it is necessary to install a current limiting circuit for each squib, which not only complicates the circuit but also impairs economic efficiency. The present invention has been made in view of the above problems, and has as its object to provide a squib ignition circuit that can reliably ignite a plurality of squibs and has a simple configuration.

[0005]

A squib ignition circuit according to the present invention comprises a plurality of squibs and a plurality of squibs.
A plurality of screens each having its positive terminal connected to its negative terminal
A plurality of switching elements installed corresponding to Eve,
Each positive terminal of the plurality of switching elements and the ground
Between the multiple squibs
Capacitor and all negative terminals of multiple squibs
And its positive terminal is connected in common, and its negative terminal is grounded.
Squib ignition, comprising:
In a circuit, each positive
Between the pole terminals and the power supply for multiple squibs.
A plurality of connection resistors.

[0006]

In the squib ignition circuit according to the present invention,
When some of the squibs are short-circuited to the ground side, the backup capacitors installed corresponding to the other squibs are grounded via the connection resistors.

[0007]

FIG. 1 is a circuit diagram of an embodiment of a squib ignition circuit according to the present invention, in which an airbag and a seatbelt pretensioner are installed in a driver seat and a passenger seat, respectively. The positive electrode of the vehicle-mounted battery 11 is connected to the power bus 13 via the main backflow prevention diode 12.

The driver airbag squib circuit 14, the driver seatbelt pretensioner 15, the passenger airbag squib circuit 16 and the passenger seatbelt pretensioner squib circuit 17 have the same configuration. For example, the squib circuit of the driver's seat airbag 14 includes a squib 141, a switching element 142 connected in series to the positive electrode side of the squib 141, and a backup capacitor 143 connected in parallel to the squib 141 * switching element 142.

The negative electrodes of the four squibs 141, 151, 161 and 171 are connected in common and are grounded via the safing sensor 18. The gates of the four switching elements 142, 152, 162 and 172 are connected in common, and the control unit 19 is connected via a drive transistor 191.
2 is connected. Also, four squib circuits 14, 15,
16 and 17 are four connection resistors 144, 15 respectively.
4, 164 and 174 are connected to the power supply bus 13.

The four connection resistors 144, 154, 16
4 and 174 have four squibs 141, 1
51, 161 and 171 have substantially the same value as the DC resistance R _S. A backup capacitor 132 for the control unit is connected to the downstream of the main backflow prevention diode 13 via a backflow prevention diode 131 for the control unit, and supplies power to the control unit 192.

In this configuration, when a collision signal is detected from the control unit 192, the drive transistor 191 is turned on and the four switching elements 142, 152, 162
And 172 are turned on. Further, when the safing sensor 18 is mechanically turned on, the four squibs 141, 151, 161 and 171 are in an ignition state.

FIG. 2 shows an airbag squib 141 for a driver's seat.
Is an equivalent circuit when a short circuit occurs on the ground side or when the upstream terminal and the downstream terminal short-circuit. That is, although the driver airbag backup capacitor 143 is in a short-circuit state, the other backup capacitors 153 and 163 are in a short-circuit state.
And 173 are grounded via two connection resistors connected in series, so that power stored in other backup capacitors 153, 163 and 173 is supplied to corresponding squibs 151, 161 and 171. You.

When the connection between the vehicle-mounted battery 11 and the power supply bus 13 is disconnected, the electric power stored in the four backup capacitors 143, 153, 163 and 173 is supplied via the control unit backflow prevention diode 131. It is supplied to the control unit 192 and drives the control unit 192 to drive the four backup capacitors 143, 153, 163 and 1
73 is discharged.

This discharge makes it possible to omit the operation of discharging the backup capacitor after the power is turned off.

[0015]

According to the squib ignition circuit of the present invention, it is possible to omit the current limiting circuit in the squib ignition circuit for igniting a plurality of squibs with one vehicle-mounted battery, and to simplify the circuit. . Furthermore, when some of the squibs are short-circuited to the ground side, the backup capacitor installed corresponding to the other squibs is grounded via the connection resistor, so that a short-circuit condition is prevented, and the other squibs are reliably ignited. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment.

FIG. 2 is an equivalent circuit when a squib is short-circuited.

DESCRIPTION OF SYMBOLS 11: Inter-battery battery 12 ... Main backflow prevention diode 13 ... Power supply bus 131 ... Backflow prevention diode for control unit 132 ... Backup capacitor for control unit 141, 151, 161, 171 ... Squib 142, 152, 162, 172: Sinching element 143, 153, 163, 173: Backup capacitor 144, 154, 164, 174: Connection resistance 18: Safing sensor 191: Driving transistor 192: Control unit

Claims (1)

(57) [Claims] A plurality of squibs and a negative electrode connected to a positive electrode terminal of each of the plurality of squibs.
Terminals are installed corresponding to the plurality of squibs to be connected.
A plurality of switching elements to be connected to the respective positive terminals of the plurality of switching elements.
Multiple squibs installed between the ground and the ground
Number of backup capacitors and all the negative terminals of the plurality of squibs have their positive terminals
Are connected in common and the negative terminal is grounded.
And a positive electrode terminal of each of the plurality of switching elements.
A plurality of squibs between the source and the squib
A squib ignition circuit with a number of connection resistors.