JP2002055114A - Occupant protector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a surely diagnosable with a small number of part items. SOLUTION: This occupant protector comprises a DC power source, a detonator, a switch circuit, an acceleration sensor, an acceleration switch and a microcomputer. A first resistor and a second resistor are connected to the positive potential side and negative potential side of the acceleration switch, respectively, and the positive potential-side terminal and negative potential-side terminal of the second resistor are connected to the first port and second port of the microcomputer, respectively. In general, the first port is set to an input port, and the second port to a low level output port. In diagnosis, the first port is set to the low level output port, and the second port to the input port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant protection device which deploys an airbag at the time of a collision accident to protect an occupant and has a diagnostic function.

[0002]

2. Description of the Related Art An occupant protection system of this kind will be described below with reference to FIG. The output voltage from the battery 1 is supplied to the DC / DC converter 3 via the ignition switch 2, and is charged in the backup capacitor 4 after being boosted. On the other hand, the acceleration signal from the first acceleration sensor 12 exceeds the reference value of the comparison circuit 13, a switch signal is supplied to the input port B of the microcomputer 11, and the acceleration signal from the second acceleration sensor 10 is It is supplied to the A / D input port A of the computer 11. When the microcomputer 11 determines that a serious collision has occurred based on the acceleration signals supplied to the input ports A and B, the microcomputer 11 outputs a high-level signal from the output ports C and D to the first and second switching electric fields. The first and second switching field effect transistors 5 and 7 are turned on to supply the ignition current from the backup capacitor 4 forming a DC power supply to the primer 6, and the air is supplied to the effect type transistors 5 and 7. Unfold the bag etc.

On the other hand, when a switch circuit is formed by using the first acceleration sensor 12 and the comparison circuit 13 to generate a switch signal, the circuit configuration of the acceleration switch becomes small.
Although it is possible to cope with the current world, there is a conventional idea that it is better to use a mechanical switch of a type different from that of the second acceleration sensor for this switch circuit. When the circuit is configured according to the conventional concept, the first resistor 14, the acceleration switch 15, and the second resistor 16 are connected in series as shown in the configuration of FIG. The first resistor 14 is connected to the potential side, the second resistor 16 is connected to the negative potential side, and the connection point between the acceleration switch 15 and the second resistor 16, in other words, the positive potential side terminal of the second resistor 16 is connected to the micro resistor. It is connected to a port (hereinafter, referred to as a second port F) F of the computer 11.

[0004]

However, in the configuration of the occupant protection device as described above, it is not possible to diagnose a poor soldering of the port F or the like, so that the acceleration switch 15 and the second resistor are not provided. 16 is connected to another port E of the microcomputer 11 (hereinafter, referred to as a first port). From the first port E, a diagnostic pulse, for example, “H” → “L” → “H” → Outputs “L”,
This is monitored at the second port F, and when the diagnostic pulse output from the first port E is monitored at the second port F,
It is determined to be normal, and if not monitored, it is determined to be abnormal.

Here, for example, when the second resistor 16 is disconnected, if the acceleration switch 15 is normally closed, the second resistor 16 is disconnected.
Only "H" is input to port F. If the port is normally open, the second port F becomes high impedance,
There is a problem that even if the acceleration switch 15 is turned on, it cannot be recognized.

[0006] The present invention has been made in view of such problems, and an object of the present invention is to provide an occupant protection device that can reliably diagnose.

[0007]

A first aspect of the present invention relates to an occupant protection system.
According to the invention, a DC power supply, a primer and a switch circuit are connected in series, a collision is determined based on a detection signal from an acceleration sensor and an acceleration switch, and a trigger signal is supplied to the switch circuit when it is determined that the collision is serious, An occupant protection device comprising a microcomputer for supplying an ignition current to the primer from the DC power supply, wherein a first resistor is connected to a positive potential side of the acceleration switch, a second resistor is connected to a negative potential side, and the second resistor is connected to the acceleration switch. Of the microcomputer is connected to a first port of the microcomputer, and a terminal of the negative potential is connected to a second port. Normally, the first port is used as an input port.
The second port is set to a low-level output port, and the first port is set to a low-level output port during diagnosis, and the second port is set to a low-level output port.
The port is set as an input port.

According to a second aspect of the present invention, a DC power supply, a squib, and a switch circuit are connected in series, and a collision is determined based on detection signals from an acceleration sensor and an acceleration switch. An occupant protection device comprising a microcomputer for supplying a signal and supplying an ignition current from the DC power supply to the primer, wherein the acceleration switch is of a normally open type, and a first and a second resistor are provided between terminals of the power supply. Connected in series, a connection point of the first and second resistors is grounded via the acceleration switch, and the connection point is connected to a first port and a second port of the microcomputer, and the first port is connected to the microcomputer. The second port is set as a low-level output / input port as an input port.

[0009]

Next, embodiments of the present invention will be described below. Embodiment 1 FIG. Embodiment 1 will be described below with reference to FIG. 1. The same components as those shown in FIG. 1 and those shown in FIG. 3 and FIG. The description thereof will be omitted, and different parts will be described below.

That is, in FIG. 1, the first resistor 1
4. In the series circuit composed of the normally closed acceleration switch 15 and the second resistor 16, the ground terminal of the second resistor 16 is connected to the port H of the microcomputer 11, and the connection between the acceleration switch 15 and the first resistor 14 is made. The point is connected to port G. In a normal state, the port H (second port) always holds “L”, and the port G (first port) is used as a monitor port to monitor the on / off state of the acceleration switch 15 and to monitor the acceleration signal from the acceleration sensor 10. The first and second switching field-effect transistors 5 and 7 are turned on as necessary, and an ignition current is supplied from the backup capacitor 4 to the primer 6.

During diagnosis, the port H is used as a monitor port, the port G is used as a diagnostic pulse output port, and a diagnostic pulse from this port G, for example, "H" → "L" → "H".
→ Output "L" and monitor this at port H. If the diagnostic pulse output from port G is monitored at port H, it is determined to be normal, otherwise it is determined to be abnormal. The port H corresponds to the diagnostic signal output port of the port E of the microcomputer 11 in FIG. 4, and the port G corresponds to the monitor port of the port F.

By making such a connection, disconnection between the port G and the port H, for example, poor soldering,
When the disconnection of the second resistor 16 occurs, the diagnostic pulse output from the port G cannot be monitored at the port H.

Embodiment 2 FIG. This embodiment will be described below with reference to FIG. 2. In FIG. 2, the same or equivalent components as those shown in FIG. Are omitted, and different parts will be described below.

That is, in FIG. 2, the difference from the one shown in FIG. 1 is that the acceleration switch 17 is of the normally open type, and the first and second resistors 14 and 16 are provided between the power supply line and the ground. The first and second resistors 1 are connected in series.
The connection points 4 and 16 are grounded via the acceleration switch 17, and the connection points are connected to the first port J and the second port K of the microcomputer 11, and the first port J is used as an input port. This means that the second port K is set as a low-level output / input port.

The microcomputer 11
In normal operation, if both the first port J and the second port K are "H", the acceleration switch 17 is determined to be normal, and if it is "L", it is determined to be faulty. In the microcomputer 11, the first port J is "L".
The diagnostic program is executed at a time other than when the second port K is at "L", and the acceleration switch 17 is diagnosed.

That is, the first port J is switched from the input port to the low-level output port, the second port K monitors "L", and then the first port J is switched from the low-level output port to the input port. At this time, if the second port K monitors "H", the port is determined to be normal, and if not monitored, the acceleration switch 17 or the port is determined to have a failure such as a disconnection.

[0017]

As described above, according to the present invention, it is possible to reduce the number of components in the peripheral circuit of the mechanical acceleration switch and to perform an accurate diagnosis.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram for explaining Embodiment 1 of the present invention.

FIG. 2 is a circuit block diagram for explaining Embodiment 2 of the present invention.

FIG. 3 is a circuit block diagram of a conventional occupant protection device.

FIG. 4 is a circuit block diagram of another conventional occupant protection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Ignition switch 3 DC / DC converter 4 Backup capacitor 5,7 Switching field-effect transistor 6 Detonator 8,10 Acceleration sensor 9 Comparison circuit 11 Microcomputer 14,16 Resistance 15,17 Acceleration switch

Claims (2)

[Claims] A DC power supply, a primer, and a switch circuit are connected in series, a collision is determined based on detection signals from an acceleration sensor and an acceleration switch, and when a serious collision is determined, a trigger signal is supplied to the switch circuit. An occupant protection device including a microcomputer for supplying an ignition current from the DC power supply to the primer, wherein the acceleration switch is a normally closed type, a first resistor is provided on a positive potential side of the acceleration switch, and a first resistor is provided on a negative potential side of the acceleration switch. A second resistor is connected, a terminal on the positive potential side of the second resistor is connected to a first port of the microcomputer, and a terminal on the negative potential side is connected to a second port. Normally, the first port is connected to an input port. In addition, the second port is set as a low-level output port,
An occupant protection device, wherein the first port is set to a low-level output port and the second port is set to an input port during diagnosis. 2. A DC power supply, a primer, and a switch circuit are connected in series, a collision is determined based on detection signals from an acceleration sensor and an acceleration switch, and when a serious collision is determined, a trigger signal is supplied to the switch circuit. An occupant protection device including a microcomputer that supplies an ignition current from the DC power supply to the primer, wherein the acceleration switch is a normally open type, and a first and a second resistor are connected in series between terminals of the power supply; A connection point between the first and second resistors is grounded via the acceleration switch, and the connection point is connected to a first port and a second port of the microcomputer, and the first port is used as an input port. An occupant protection device wherein the second port is set as a low-level output / input port.