JP2001191892A - Power supply unit for air bag system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use energy accumulated in backup power sources in a power supply unit in an air bag system supplying power from the power supply unit in a center ECU to a plurality of satellite units. SOLUTION: This power supply unit in the center ECU 20 is provided with a power control means for controlling a satellite power circuit 24 to stop power supply to satellite units requiring no power, in addition to backup power sources 22A, 22B charged by a battery power source 10 of a vehicle, and the satellite power circuit 24 for supplying power from the battery power source 10 and backup power sources 22A, 22B to a plurality of satellite units 52, 54, 56, 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for an airbag system having a plurality of satellite units each having a collision sensor.

[0002]

2. Description of the Related Art In recent years, in an airbag system for detecting a collision of a vehicle and deploying an airbag for protecting an occupant, a center electronic control unit (hereinafter, referred to as an electronic control unit) has been developed along with the diversification and high functionality of the system. Unit (electronic co
The control unit has been changed from a single configuration to a configuration having a plurality of satellite units.

Since power is generally supplied from the center ECU to such satellite units, the power consumption of the center ECU is increasing. On the other hand, the time that should be guaranteed as the time during which the airbag can be deployed by the backup power supply even after the power supply from the vehicle-mounted battery is interrupted due to a collision tends to increase with the sophistication of the system. It is in. To meet such demands, it is necessary to reduce the power consumption of the ECU, increase the capacity of the backup power supply, and the like. However, it is difficult to increase the capacity due to problems such as the limitation of the size of the ECU. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an airbag system for supplying power from a power supply device in a center ECU to a plurality of satellite units. Another object of the present invention is to make it possible to extend the airbag deployment guarantee time by effectively utilizing the energy stored therein without increasing the capacity of a backup power supply in the power supply device.

[0005]

In order to achieve the above object, according to the present invention, a plurality of satellite units each having a collision sensor and a corresponding air based on a collision detection signal from the plurality of satellite units are provided. A power supply device mounted in the center ECU, comprising: a center ECU that performs control to deploy the back; a backup power supply that is charged by a battery power supply of a vehicle; and the battery power supply and the backup power supply A power supply circuit for a satellite that supplies power from the plurality of satellite units, and a power supply control unit that controls the power supply circuit for a satellite so that power supply to a satellite unit that does not require power is stopped. A power supply device for an airbag system, comprising:

Further, according to the present invention, the power supply control means is configured to stop the power supply to all of the plurality of satellite units when the power supply from the battery power supply is cut off. It controls the circuit.

Further, according to the present invention, when the power supply from the battery power supply is cut off, the power supply control means controls the power supply to only one of the plurality of satellite units that has already transmitted a collision detection signal. The satellite power supply circuit is controlled so as to stop the supply.

Further, according to the present invention, the power supply control means deploys the airbag corresponding to the satellite unit that has transmitted the collision detection signal, and then stops the power supply to the satellite unit. It controls the power supply circuit.

Further, according to the present invention, each of the satellite units is configured to transmit an energization stop request signal after transmitting a collision detection signal, and the power supply control unit transmits the energization stop request signal. The satellite power supply circuit is controlled so as to stop power supply to the satellite unit.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram showing an embodiment of a power supply device of an airbag system according to the present invention. This airbag system includes a center ECU 20 and a plurality of satellite units 52, 54, 56, and 58. As shown in the in-vehicle layout diagram of FIG.
Numerals 2 and 54 are front collision detection satellite units, and units 56 and 58 are side collision detection satellite units. Each satellite unit is an acceleration sensor for detecting a collision, a microcomputer that determines the presence or absence of a collision based on the sensor output, a regulator that adjusts power received from the center ECU 20 via a power line,
And a transmission circuit for transmitting a signal current through the power supply line.

On the other hand, the center ECU 20 includes two backup capacitors 22A and 22B, a satellite power supply circuit 24, a microcomputer 26, an ignition circuit 28,
Etc. are provided. The backup capacitors 22A and 22B connected in parallel are a backup power supply that is charged by the battery power supply 10 mounted on the vehicle.

The satellite power supply circuit 24 includes a battery power supply 10 and backup capacitors 22A and 22B.
Is a circuit that supplies power from the satellites to the satellite units 52, 54, 56, and 58. The regulator, a switch for turning on or off the power supply for each satellite unit, and transmitted from each satellite unit via a power line. A receiving circuit for receiving the signal current and transmitting the signal current to the microcomputer 26 is provided.

The microcomputer 26 controls the ignition circuit 28 based on the collision detection signal received by the receiving circuit in the satellite power supply circuit 24. Ignition circuit 2
8 supplies a current to the corresponding squib 42, 44, 46 or 48 in order to deploy a necessary airbag among a plurality of airbags based on a command from the microcomputer 26. Also, the microcomputer 26 always
In addition to monitoring the voltage V _BAT of the power supply line from the battery 10, as described later, the power supplied from the satellite power supply circuit 24 to the satellite units 52, 54, 56 and 58 is controlled for each satellite unit.

Hereinafter, control of power supply to each satellite unit according to the present invention will be described. Normally, since the battery 10 is mounted on the front part of the vehicle, when the power supply from the battery 10 is cut off, it is considered that a frontal collision has occurred. Therefore, in that case, the satellite units 52, 54, 56 and 5
8 can be considered unnecessary, and there is no problem even if the power supply to each satellite unit is stopped. Therefore, in the first embodiment, when the power supply from the battery 10 is cut off, the power supply to each satellite unit is stopped and the backup capacitor 22 is turned off.
All the energy of A and 22B is directed to the center ECU 20.

FIG. 3 is a flow chart showing the processing procedure of the center ECU main routine according to the first embodiment. Among the processing repeatedly executed by the microcomputer 26 in the center ECU 20, the present invention is described. The relevant parts are extracted.

First, in step 102, the battery 10
It is determined whether or not the voltage V _BAT of the power supply line from is zero. If V _BAT = 0, that is, if the power supply from the battery 10 is cut off, step 104 is executed. In step 104, the microcomputer 2
6 controls the satellite power supply circuit 24 to stop power supply to all of the satellite units 52, 54, 56 and 58. Thus, as described above, all the energy stored in the backup power supply is
And is used effectively.

Next, a second embodiment will be described.
In the above-described first embodiment, when the power supply from the battery power supply 10 is cut off, the power supply to all the satellite units is stopped. However, in the second embodiment, the power supply from the battery power supply 10 is stopped. Are cut, the satellite units 52, 54, 56 and 5
8 is to stop the power supply to only the satellite units that have already transmitted the collision detection signal.

FIG. 4 is a flowchart showing a processing procedure of the center ECU main routine according to the second embodiment. Although steps 202, 204, and 206 in the figure are individually executed for each satellite unit, processing for one satellite unit will be described for simplicity.

First, at step 202, the battery 10
It is determined whether or not the voltage V _BAT of the power supply line from is zero. When V _BAT = 0, that is, when the power supply from the battery 10 is cut off, the process proceeds to step 204. In step 204, it is determined whether a collision detection signal has already been received from the satellite unit,
Step 206 is executed only when it is determined that the signal has been received. In step 206, power supply to the satellite unit is stopped. Thus, the power supply to the satellite unit that has already completed the role of collision detection is stopped, and the energy stored in the backup power supply is effectively used.

Next, a third embodiment will be described.
In the third embodiment, after the airbag corresponding to the satellite unit that has transmitted the collision detection signal is deployed, the power supply to the satellite unit is stopped. For example, after the deployment process of the right-side collision airbag is completed, the power supply to the right-side collision detection satellite unit is stopped.

FIG. 5 is a flowchart showing a processing procedure of the center ECU main routine according to the third embodiment. Steps 302, 304, and 306 in the figure are individually executed for each satellite unit, but for simplification of the description, processing for one satellite unit will be described.

First, in step 302, it is determined whether or not a collision detection signal has already been received from the satellite unit. Only when it is determined that a collision detection signal has been received, the process proceeds to step 304. In step 304, it is determined whether or not the deployment process of the airbag corresponding to the satellite unit has already been completed, and step 306 is executed only when it has been completed. In step 306, power supply to the satellite unit is stopped. Thus, also in this case, the power supply to the satellite unit that has completed its role is stopped, and as a result, the energy stored in the backup power supply is effectively used.

Finally, a fourth embodiment will be described.
In the fourth embodiment, after transmitting the collision detection signal, each satellite unit recognizes that it has completed its role, and transmits a power supply stop request signal to the center ECU 20. And the center ECU
In response to the power-supply stop request signal, the microcomputer 26 in the power supply 20 stops power supply to the satellite unit that has transmitted the power-supply stop request signal. also,
In this case as well, the power supply to the satellite unit that has completed its role is stopped, and as a result, the energy stored in the backup power supply is effectively used.

[0025]

As described above, according to the present invention,
In an airbag system that supplies power to a plurality of satellite units from a power supply device in a center ECU, the energy stored in a backup power supply in the power supply device is effectively used, and as a result, the airbag deployment guarantee time is extended.

That is, when the backup power supply capacity is the same as the conventional system, the airbag deployment guarantee time is extended. In addition, when the same airbag deployment guarantee time as the conventional system is used, the backup power supply capacity can be reduced, and as a result,
The size of the center ECU can be reduced. In addition, by stopping the power supply only for the satellite unit that has already detected the collision and has completed its operation, the time during which the functions of the other satellite units are maintained is prolonged, which is effective in the event of a secondary collision or the like. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a power supply device of an airbag system according to the present invention.

FIG. 2 is a layout diagram of each satellite unit in a vehicle.

FIG. 3 is a flowchart illustrating a processing procedure of a center ECU main routine according to the first embodiment.

FIG. 4 is a flowchart illustrating a processing procedure of a center ECU main routine according to a second embodiment.

FIG. 5 is a flowchart illustrating a processing procedure of a center ECU main routine according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Battery power supply 20 ... Center ECU 22A, 22B ... Backup capacitor 24 ... Satellite power supply circuit 26 ... Microcomputer 28 ... Ignition circuit 42,44,46,48 ... Squib 52,54,56,58 ... Satellite unit

Claims (5)

[Claims] 1. An airbag system comprising: a plurality of satellite units each including a collision sensor; and a center ECU that controls to deploy a corresponding airbag based on a collision detection signal from the plurality of satellite units. A power supply device mounted on the center ECU, a backup power supply charged by a battery power supply of a vehicle, a satellite power supply circuit for supplying power from the battery power supply and the backup power supply to the plurality of satellite units, A power supply control unit for controlling the satellite power supply circuit so that power supply to a satellite unit that does not require power is stopped. 2. The power supply control means controls the satellite power supply circuit so as to stop power supply to all of the plurality of satellite units when power supply from the battery power supply is cut off. The power supply of the airbag system according to claim 1. 3. The power supply control means stops power supply to only a satellite unit which has already transmitted a collision detection signal among the plurality of satellite units when supply of power from the battery power supply is cut off. The power supply device for an airbag system according to claim 1, wherein the power supply device controls the satellite power supply circuit. 4. The power supply control means controls the satellite power supply circuit so as to stop power supply to the satellite unit after deploying an airbag corresponding to the satellite unit which has transmitted the collision detection signal. The power supply device for an airbag system according to claim 1, wherein: 5. Each of the satellite units is configured to transmit an energization stop request signal after transmitting a collision detection signal, and the power supply control unit supplies power to the satellite unit that has transmitted the energization stop request signal. The power supply device for an airbag system according to claim 1, wherein the power supply device controls the satellite power supply circuit so as to stop.