JPH07156747A - Occupant crash protection for vehicle - Google Patents

Abstract

PURPOSE:To reduce the number of parts of a diode, reduce thc cost, and enable the diagnosis of the failure of the diode for discharging to detect the failure at early stage. CONSTITUTION:When diodes 8, 14 for discharging generate the failure in the non-conducted (disconnected) condition, the voltage value on the cathode side of the diode 8 for discharging is dropped to the output voltage of a battery 1, and the diodes 8, 14 for discharging can execute the failure diagnosis by monitoring the drop by a microcomputer 26. When the failure in the conducted (short circuit) condition is generated, the starting of the charging voltage becomes earlier, and the failure diagnosis of the diodes 8, 14 for discharging can be made by monitoring the starting by the microcomputer 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag for protecting an occupant of a vehicle from a collision accident, and more particularly to a vehicle occupant protection device having a plurality of ignition detonators.

[0002]

2. Description of the Related Art A conventional vehicle occupant protection system will be described with reference to FIG. In FIG. 2, reference numeral 1 is a vehicle-mounted battery, and 2 is a DC / DC that boosts and outputs the output voltage of the battery 1.
The input terminal of the converter is connected to the battery 1 via the first backflow prevention diode 3. 4 is a second backflow prevention diode, the anode of which is the battery 1
And the cathode is connected to the cathode of a third backflow preventing diode 5 described later. The first
Also, an ignition switch (not shown) is inserted in a connection line between the anodes of the second backflow preventing diodes 3 and 4 and the battery 1. The anode of the third backflow preventing diode 5 is the DC / DC converter 2
Is connected to the output terminal of.

Reference numeral 6 is a first backup capacitor, which is connected to the cathodes of the second and third backflow preventing diodes 4 and 5 through an inrush current preventing resistor 7. 8, 9
Are first and second discharging diodes connected in parallel, the anodes of which are connected to the non-grounded side terminal of the backup capacitor 6, and the cathodes thereof are the inrush current preventing resistor 7 and the third reverse current preventing diode 5 It is connected to the connection point with.

Reference numeral 10 denotes a fourth backflow prevention diode, the anode of which is connected to the battery 1 and the cathode of which is connected to the cathode of a fifth backflow prevention diode 11 which will be described later. The anode of the fifth backflow prevention diode 11 is
It is connected to the output terminal of the DC / DC converter 2. Reference numeral 12 is a second backup capacitor, which is connected to the cathodes of the fourth and fifth backflow preventing diodes 10 and 11 via a rush current preventing resistor 13.

Reference numerals 14 and 15 denote third and fourth discharging diodes connected in parallel, the anodes of which are connected to the non-grounded side terminal of the backup capacitor 11, and the cathodes of which are the inrush current preventing resistor 13 and the third terminal. 5 is connected to a connection point with the backflow prevention diode 11. The second
The first circuit including the third and fourth reverse current preventing diodes 4, 5, the first backup capacitor 6, the first inrush current preventing resistor 7, the first and second discharging diodes 8, 9 includes the fourth and fifth reverse current preventing diodes. Diodes 10 and 11, a second backup capacitor 12, a second inrush current preventing resistor 13, and third and fourth discharging diodes 14 and 15 having the same function and connected in parallel. . A power supply circuit 16 is constituted by the first and second circuits, the battery 1, the first backflow prevention diode 3, and the DC / DC converter 2.

Reference numeral 17 denotes a first switch circuit, the input terminal of which is the output terminal of the first circuit, that is, the cathodes of the second and third backflow preventing diodes 4, 5 and the first and second discharging diodes 8, 9. Is connected to the first detonator 21 to limit the current supply amount. Reference numeral 18 denotes a second switch circuit having the same function as that of the first switch circuit 17, the input terminal of which is the output terminal of the second circuit, that is, the fourth and fifth backflow preventing diodes 10, 11 and the third and fourth It is connected to the cathodes of the discharging diodes 14 and 15 and limits the amount of current supplied to a second detonator 22 described later by a signal from a microcomputer 19 described later.

Reference numeral 19 denotes a microcomputer, which judges the magnitude of a collision accident based on an acceleration signal (generated at the time of collision) supplied to the terminal A, and the first and second switch circuits are supplied via an energization control circuit 20. Each of 17 and 18 is turned on for a predetermined time.

Reference numerals 21 and 22 denote first and second detonators, one ends of which are connected to the output terminals of the corresponding first and second switch circuits 17 and 18, respectively. The other ends of the first and second detonators 21, 22 are connected to one end of a mechanical acceleration switch 25 via the corresponding first and second diodes 23, 24. The acceleration switch 25 is controlled to be turned on and off between its input and output by a magnetic force of a magnet that is displaced by receiving acceleration, and its other end is grounded.

In the above configuration, when the microcomputer 19 determines that a serious accident has occurred based on the acceleration signal supplied to the terminal A, and the acceleration switch 25 is closed, the microcomputer 19 determines that the predetermined condition has occurred. By turning on the energization control circuit 20 for a period of time,
The first and second switch circuits 17 and 18 are turned on.

At this time, when the power supply circuit 16 is operating normally, the output current from the DC / DC converter 2 is the third reverse current preventing diode 5 and the first switch circuit 1.
7, first detonator 21, diode 23, acceleration switch 2
5 and the fifth backflow prevention diode 1
1, the second switch circuit 18, the second detonator 22, the diode 24, and the acceleration switch 25 also flow in this order.

When the battery 1 is destroyed due to a collision, for example, instead of supplying the output current from the DC / DC converter 2, the electric charges charged in the first and second backup capacitors 6 and 12 are charged. Flows in the order of the third backflow prevention diode 5, the first switch circuit 17, the first detonator 21, the diode 23, and the acceleration switch 25, and the fifth backflow prevention diode 11, the second switch circuit 18, and the second detonator 22. , The diode 24, and the acceleration switch 25 also flow in this order to activate the respective airbags.

[0012]

However, in such a vehicle occupant protection device, there is a problem that the cost is increased because the respective discharge diodes are designed with redundancy. It was That is, in the case where the redundancy is not provided, for example, when the discharging diode 8 is destroyed and becomes non-conductive, the discharge path cannot be secured, and when it becomes conductive, the backup capacitor is quickly caused by the inrush current at the initial stage. There was a problem of deterioration. The same applies to the other diode 14.

The present invention has been made by paying attention to such a problem, and the number of parts of the diode can be reduced to reduce the cost, and the failure diagnosis of the discharging diode can be made possible to detect the failure early. The purpose is to do so.

[0014]

A vehicle occupant protection system according to the present invention comprises a DC / DC converter for boosting and outputting a voltage from a battery, and a DC / DC converter connected in parallel to an output terminal of the DC / DC converter. Inrush current of the first series circuit, first and second series circuits including a plurality of inrush current prevention resistors and backup capacitors, first and second diodes having anodes connected in parallel to the output terminals of the battery, and inrush current of the first series circuit An anode is connected to a connection point between the prevention resistor and the backup capacitor, a cathode is connected to a cathode of the first diode, and the cathode forms a first output terminal, and a third diode of the second series circuit. The anode is connected to the connection point between the inrush current prevention resistor and the backup capacitor, and the cathode is connected to the cathode of the second diode. A fourth diode whose cathode forms a second output terminal, and first and second output terminals which are connected to respective output terminals formed by the cathodes of the third and fourth diodes through a switch circuit. A detonator and an acceleration signal associated with a collision are input to determine the magnitude of the collision, and a trigger signal is supplied to each of the switch circuits as needed, and a failure of the third and fourth diodes is diagnosed. And a microcomputer that outputs a failure notification signal.

[0015]

According to the vehicle occupant protection system of the present invention, when the discharging diodes 8 and 14 have a failure in the non-conducting (disconnection) state, the voltage value on the cathode side of the discharging diode 8 is equal to that of the battery 1. Since the output voltage drops to the output voltage, the microcomputer 26 monitors the output voltage to diagnose the failure of the discharging diodes 8 and 14.
In addition, when a failure in the conduction (short) state occurs,
Since the charging voltage rises faster, the microcomputer 26 monitors the rising of the charging voltage, so that the failure diagnosis of the discharging diodes 8 and 14 can be performed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIG.
Although the configuration will be described based on FIG. 1, the same configuration as that described in FIG. 2 or equivalent components will be denoted by the same reference numerals and the description thereof will be omitted, and only different configurations will be described.

That is, in FIG. 1, the third and fifth backflow preventing diodes 5 and 11 in FIG. 2 are omitted,
Along with this, points X and Y of the cathode-side power supply lines of the discharging diodes 8 and 14 are connected to the microcomputer 26 for failure diagnosis.

That is, this microcomputer 26
2 has a failure diagnosis function added to the function of the microcomputer 19 in FIG. In other words,
The failure diagnosis function of the microcomputer 26 is a connection line between the cathodes of the discharge diodes 8 and 16 and the input terminals of the first and second switch circuits 17 and 18 connected to the discharge diodes 8 and 14, respectively. X above
It is monitored whether or not the voltage value at each of the points Y and Y coincides with the output voltage of the DC / DC converter 2 in a steady state, and if the output voltage of the battery 1 drops, the discharging diode is used. It is judged that 8 and 14 are in a non-conducting state and have failed, and a failure notification signal indicating that fact is output from the Z terminal.

Further, when the ignition switch is turned on and the rising state of the voltage at each of the points X and Y immediately after the start of charging the backup capacitors 6 and 12 is earlier than a predetermined value, it is for discharging. It is determined that the diodes 8 and 14 are in a conductive state and has failed, and a failure notification signal indicating that fact is output from the Z terminal. This is because when the discharge diodes 8 and 14 become conductive, the second inrush current preventing resistors 7 and 13 are not used.
This is because the backup capacitors 6 and 12 are directly charged from the battery 1 via the fourth backflow preventing diodes 4 and 10 in many portions.

[0020]

As described above, according to the present invention, the number of parts of the diode can be reduced, the cost can be reduced, and the failure diagnosis of the discharging diode can be made possible to detect the failure early. Is demonstrated.

[Brief description of drawings]

FIG. 1 is a circuit explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional circuit.

[Explanation of symbols]

 2 DC / DC converter 3, 4, 10 Reverse current prevention diode 6, 12 Backup capacitor 7, 13 Inrush current prevention resistor 8, 14 Discharge diode 17, 18 Switch circuit (current limiting circuit) 20 Energization control circuit 21, 22 Detonator 25 Acceleration switch 26 Microcomputer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Shibata, 1910 Nisshincho, Omiya City, Saitama Prefecture Kansei Co., Ltd.

Claims (1)

[Claims] 1. A DC / DC converter (2) for boosting and outputting a voltage from a battery (1), and a plurality of inrush current preventing resistors (7) connected in parallel to an output terminal of the DC / DC converter. , 13) and backup capacitors (6, 12) and first and second series circuits, and first and second diodes (4), (10) each having an anode connected in parallel to the output terminal of the battery (1). ), An anode is connected to a connection point between the inrush current preventing resistor (7) and the backup capacitor (6) of the first series circuit, and a cathode is connected to a cathode of the first diode (4). An anode is connected to a connection point between a third diode (8) whose cathode forms a first output terminal, a resistor (13) for preventing inrush current of the second series circuit, and a backup capacitor (12). A fourth diode (14) whose cathode is connected to the cathode of the second diode (10) to form a second output terminal, and each of the third and fourth diodes (8), (14) First and second connected to each of the output terminals formed by the cathodes of the switch via switch circuits (17), (18)
The detonators (21) and (22) and the acceleration signal associated with the collision are input to determine the magnitude of the collision, and a trigger signal is supplied to each of the switch circuits (17) and (18) as necessary. And a microcomputer (26) for diagnosing the failure of the third and fourth diodes (8), (14) and outputting a failure notification signal. .