JPH07165007A - Controller of occupant restrainst device - Google Patents

Abstract

PURPOSE:To prevent wrong operation of an occupant restraint device due to electric wave trouble at a low cost. CONSTITUTION:A first switching element FET 1 and a second switching element FET 2 formed on a single semiconductor substrate are provided in a driving means for the controller of an occupant restraint device provided with collision detecting means 11, 12, to output an operation command for the occupant restrains device after detecting vehicle collision, a starting means 14 to operate the occupant restraint device and the driving means to be started after energization from an electric power supply to the starting means 41 when the operation command is received from the collision detecting means 11, 12. While the first switching element FET 1 is connected in series to the starting means 41, the second switching element FET 2 is connected in parallel to a series circuit consisting of the first switching element FET 1 and the starting means 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant restraint system control device for restraining and protecting an occupant in the event of a collision.

[0002]

2. Description of the Related Art A control device for controlling the operation of an occupant restraint device such as an air bag or a seat belt is known (see, for example, New Model Car Manual (Y32-1) issued by Nissan Motor Co., Ltd. June 1991). . An outline of this type of occupant restraint system is shown in FIG. The control device of the occupant restraint system 60 is an acceleration sensor 11 that detects the acceleration of the vehicle, and a microcomputer that determines whether or not the occupant restraint system 60 needs to operate based on an acceleration signal output from the acceleration sensor 11. 12). In addition, the drive circuit of the occupant restraint system 60 uses the power source 30.
The switching element 20, the activation device (hereinafter, referred to as a squib) 41 of the occupant restraint device 60, and the safing sensor 50 are connected in series.

The safing sensor 50 is a switch that closes a vehicle by detecting a predetermined impact applied to the vehicle, and a sensor main body composed of a cylinder, a sensing ball in contact with the cylinder, an electric contact and a magnet together with a resin mixed with sand. It is housed in a metal case. Normally, the sensing ball is attracted to one end of the cylinder by a magnet. However, when a strong impact is applied to the vehicle, the sensing ball moves, contacts the electrical contact, and the contact closes.

When the microcomputer 12 determines the operation of the occupant restraint system 60 based on the acceleration signal detected by the acceleration sensor 11, the microcomputer 12 outputs an ON (conduction) command to the switching element 20 so that the switching element 20 is activated. Conduct. At this time, the safing sensor 50
When the vehicle detects a shock due to a collision and closes the circuit, a current flows from the power source 30 through the switching element 20, the squib 41, and the safing sensor 50, and the squib 41 operates the occupant restraint system 60.

The safing sensor 50 is a mechanical switch, such as the microcomputer 12 or the switching element 2.
Even if 0 receives a strong electromagnetic interference and malfunctions, the safing sensor 50 is not affected by such an electromagnetic interference, so no current flows in the drive circuit of the squib 41, and the occupant is restrained due to the electromagnetic interference. The device 60 does not malfunction.

[0006]

However, in the above-described conventional control device for an occupant restraint system, since the safing sensor is mechanically constructed, there is a problem that the cost is high.

It is an object of the present invention to provide a control device which prevents an occupant restraint device from malfunctioning due to radio interference by an inexpensive method.

[0008]

FIG. 1 showing a first embodiment.
The invention of claim 1 will be described with reference to FIG. 9 showing the second embodiment. Collision detecting means 11 and 12 for detecting a vehicle collision and outputting an operation command for the occupant restraint system, and an occupant restraint system. Starting means 41 for activating, and collision detection means 1
The present invention is applied to a control device for an occupant restraint system, which includes a drive means for energizing and activating the activation means 41 from the power source 30 when receiving the operation command from the power supply units 1 and 12, and the drive means is formed on a single semiconductor substrate. First switching element FET1
And the second switching element FET2 are provided to achieve the above object. The invention according to claim 2 will be described with reference to FIG. 1 showing the first embodiment. The control device for an occupant restraint system according to claim 2 is the first switching element FET.
1 is connected in series with the starting means 41, and the second switching element FET2 is connected to the first switching element F.
It is connected in parallel to the series circuit of the ET1 and the activation means 41. Claim 3 in association with FIG. 9 showing the second embodiment.
In the control device for an occupant restraint system according to a third aspect of the present invention, the activating means 41 activates the first switching element FET2.
Is connected in parallel with the second switching element F
The ET1 is connected in series with a parallel circuit of the first switching element FET2 and the starting means 41. Claim 4
In the control device for the occupant restraint system, the first and second switching elements are transistors. Claim 5
In the control device for the occupant restraint system, the first and second switching elements are FETs.

[0009]

Since the first switching element and the second switching element are formed on a single semiconductor substrate,
When a certain type of radio interference is received, the first and second switching elements are both in the ON or OFF state, which is the same operating state. By connecting the first switching element in series with the starting means and connecting the second switching element in parallel with the series circuit of the first switching element and the starting means, the first switching element and the first switching element and the first switching element When the two switching elements are both turned on, the current from the power source does not flow into the series circuit of the first switching element and the starting means, but flows through the second switching element connected in parallel to the series circuit. Since no current flows to the starting means, malfunction of the occupant restraint system due to radio interference is prevented. When both the first switching element and the second switching element are turned off due to radio interference, the current from the power source is blocked by the first switching element connected in series with the starting means.
The occupant restraint system does not operate because no current flows through the activation means.
Further, by connecting the first switching element in parallel with the starting means and connecting the second switching element in series with the parallel circuit of the first switching element and the starting means,
When both the first switching element and the second switching element are turned on by the radio wave disturbance, the current flowing from the power source through the first switching element is passed through the second switching element connected in parallel with the starting means. As a result, the current does not flow in the starting means, so that malfunction of the occupant restraint system due to radio interference is prevented. It should be noted that when both the first switching element and the second switching element are turned off due to radio interference, the current from the power supply is blocked by the first switching element, so that no current flows through the starting means, and the occupant restraint system. Does not work.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.

[0011]

【Example】

First Embodiment FIG. 1 is a circuit diagram showing the configuration of the first embodiment. In addition,
The same components as those of the conventional apparatus shown in FIG. 17 are designated by the same reference numerals, and the description will focus on the differences. FE
The T array 21 is, for example, as shown in FIG. 2, two FEs having drains (D1, D2) provided on a silicon substrate.
Power MOS-F with T (FET1, FET2) formed
ET, and its equivalent circuit is shown in FIG. The FET1 is connected in series with the squib 41, and the FET2 is connected in parallel with the series circuit of the FET1 and the squib 41. The drains D1 and D2 of the FET1 and FET2 are connected to the power supply 30. The source S1 of the FET1 is grounded via the squib 41, and the source S2 of the FET2 is directly grounded. F
The gate G1 of ET1 is connected to the output 1 of the microcomputer 12 and is pulled up to the power supply 30 by the resistor 22. The gate G2 of the FET2 is connected to the output 2 of the microcomputer 12. Although the power source 30 is a power source for igniting the squib 41, the acceleration sensor 11 and the microcomputer 12
May be used as the power source of the above, or these power sources may be provided separately.

The microcomputer 12 determines whether or not the occupant restraint system needs to be operated based on the acceleration signal detected by the acceleration sensor 11. When the operation is required, the output 1 to F
An ON signal for turning on ET1 is output, and an OFF signal for turning off FET2 is output from output 2. On the other hand, when it is not necessary to operate, the output 1 and the output 2 output OFF signals for turning off both FET1 and FET2.

Here, assuming that the microcomputer 12 itself malfunctions due to radio interference, it is conceivable that an abnormal signal other than the above-mentioned normal case is output to its outputs 1 and 2. Alternatively, an erroneous signal may be directly superimposed on the output 1 and output 2 signal lines due to radio interference. Output 1 and output 2 of the microcomputer 12
Considering all the normal and abnormal states, the states can be organized into four states as shown in FIG. In FIG. 4, state 1 and state 2 show the operating states of output 1, output 2, FET1, FET2 and squib 41 in a normal state. As described above, state 1 is a state when the operation of the occupant restraint system is unnecessary. State 2 is the state when the operation of the occupant restraint system is required. Further, the states 3 and 4 indicate abnormal states caused by the radio wave interference. Hereinafter, each of these states will be described in detail.

FIG. 5 is a circuit diagram showing the operation of the first embodiment in the case of the state 1 shown in FIG. In the figure below,
To make the explanation easier to understand, FET1 and FET2 are represented by switches in an open state or a closed state. When the control device is normal and the microcomputer 12 determines that the occupant restraint device is not required to be operated, both the output 1 and the output 2 of the microcomputer 12 output the OFF signal. As a result, F
Both ET1 and FET2 are turned off, the current from the power supply 30 is blocked by FET1 and does not flow to the squib 41, and the occupant restraint system does not operate.

FIG. 6 is a circuit diagram showing the operation of the first embodiment in the case of the state 2 shown in FIG. When the control device is normal and the microcomputer 12 determines that the operation of the occupant restraint device is necessary, the output 1 of the microcomputer 12 outputs an ON signal and the output 2 outputs an OFF signal. As a result, the FET1 is turned on, the FET2 is turned off, the current from the power source 30 flows through the squib 41, and the occupant restraint device operates. A method of determining whether or not the occupant restraint system is operated by the microcomputer 12 is disclosed in, for example, Japanese Patent Laid-Open No. 63-50.
As disclosed in Japanese Patent No. 3531, a method of determining the operation when the integrated value of the acceleration signal exceeds a predetermined value may be used, or another method may be used. Further, the determination unit for determining whether or not the occupant restraint device is required to operate may be configured by hardware instead of the microcomputer.

FIG. 7 is a circuit diagram showing the operation of the first embodiment in the case of the state 3 shown in FIG. When some abnormality occurs due to radio interference and both the output 1 and the output 2 are turned on, both the FET1 and the FET2 are turned on. At this time, a current tries to flow from the power source 30 to the squib 41 via the FET1, but since the power source 30 is grounded by the FET2, all the current from the power source 30 flows to the ground and flows to the squib 41 via the FET1. No current flows and therefore the occupant restraint system does not operate.

As described above, since the FET1 and FET2 which form the FET array 21 have a monolithic structure provided on a single silicon substrate, when the FET array 21 itself receives some kind of radio interference, , FET
Both 1 and FET2 are in the same operating state, either ON or OFF. FET1 and FET2
When both are turned on, the operation is the same as in the case of state 3 described above, and the occupant restraint device does not operate. Further, when both FET1 and FET2 are turned off, the operation is the same as in the case of state 1 described above, and in this case also the occupant restraint device does not operate.

FIG. 8 is a circuit diagram showing the operation of the first embodiment in the case of the state 4 shown in FIG. When the output 1 is in the OFF state and the output 2 is in the ON state due to some abnormality due to the radio interference, the FET 1 is turned off and the FET 2 is turned on. At this time, since the FET1 is off, the power source 30
Current does not flow from the squib 41 to the ground through the FET 2 from the power supply 30. Therefore, the occupant restraint system does not operate.

-Second Embodiment- FIG. 9 is a circuit diagram showing the configuration of the second embodiment. In addition,
Devices similar to those shown in FIGS. 1 and 17 are designated by the same reference numerals, and differences will be mainly described. The FET array 23 is a power MOS-FET in which two FETs (FET1 and FET2) are formed on a silicon substrate as shown in FIG. 10, for example, and FIG. 11 shows an equivalent circuit thereof. The source S1 of the FET1 and the drain D2 of the FET2 are in service. The FET2 is connected in parallel with the squib 41, and the FET1 is connected in series with the parallel circuit of the FET2 and the squib 41. The drain D1 of the FET1 is connected to the power supply 30. The source S1 of the FET1 is grounded via the squib 41, and the source S2 of the FET2 is directly grounded. The gate G1 of the FET1 is connected to the output 1 of the microcomputer 12 and is pulled up to the power supply 30 by the resistor 22. The gate G2 of the FET2 is connected to the output 2 of the microcomputer 12. Although the power source 30 is a power source for igniting the squib 41, it may be used as a power source for the acceleration sensor 11 and the microcomputer 12 or may be separately provided.

The microcomputer 12 determines whether or not the occupant restraint system needs to be operated based on the acceleration signal detected by the acceleration sensor 11, and when the operation is required, the output 1 to F
An ON signal for turning on ET1 is output, and an OFF signal for turning off FET2 is output from output 2. On the other hand, when it is not necessary to operate, the output 1 outputs the OFF signal for turning off the FET 1, and the output 2 outputs the ON signal for turning on the FET 2.

Assuming that the microcomputer 12 itself malfunctions due to radio interference, it is conceivable that an abnormal signal other than the above-mentioned normal case may be output to its outputs 1 and 2. Alternatively, an erroneous signal may be directly superimposed on the output 1 and output 2 signal lines due to radio interference. Output 1 and output 2 of the microcomputer 12
Considering all the normal and abnormal states, the states can be organized into four states as shown in FIG. In FIG. 12, state 1 and state 2 show the operating states of output 1, output 2, FET1, FET2, and squib 41 in the normal state, and as described above, state 1
Is the state when the operation of the occupant restraint system is unnecessary, and state 2
Is the state when the operation of the occupant restraint system is required. Also,
State 3 and state 4 indicate abnormal states caused by radio wave interference. Hereinafter, each of these states will be described in detail.

FIG. 13 shows the second state 1 shown in FIG.
3 is a circuit diagram showing the operation of the embodiment of FIG. In the following figures, FET1 and FET2 are represented by switches in an open circuit state or a closed circuit state for easy understanding. When the control device is normal and the microcomputer 12 determines that the occupant restraint device does not need to be operated, the output 1 of the microcomputer 12 outputs an OFF signal and the output 2 outputs an ON signal. As a result, the FET1 is turned off and the FET2 is turned on, the current from the power source 30 is blocked by the FET1 and does not flow to the squib 41, and the occupant restraint device does not operate.

FIG. 14 shows the second state 2 shown in FIG.
3 is a circuit diagram showing the operation of the embodiment of FIG. When the control device is normal and the microcomputer 12 determines that the operation of the occupant restraint device is necessary, the output from the microcomputer 12 is turned on.
A signal is output, and an OFF signal is output from the output 2. As a result, the FET1 is turned on, the FET2 is turned off, the current from the power source 30 flows through the squib 41, and the occupant restraint device operates. A method of determining whether or not the operation of the occupant restraint system in the microcomputer 12 is necessary is described in, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 503531, a method of determining the operation when the integrated value of the acceleration signal exceeds a predetermined value may be used, or another method may be used. Further, the determination unit for determining whether or not the occupant restraint device is required to operate may be configured by hardware instead of the microcomputer.

FIG. 15 shows the second state 3 shown in FIG.
3 is a circuit diagram showing the operation of the embodiment of FIG. When some abnormality occurs due to radio interference and both the output 1 and the output 2 are turned on, both the FET1 and the FET2 are turned on. At this time, a current tries to flow from the power source 30 to the squib 41 via the FET 1, but the FET 2 connected in parallel with the squib 41 is grounded, so the power source 3
All current from 0 will flow to ground and no current will flow to the squib 41 and therefore the occupant restraint system will not operate.

FIG. 16 shows the second state 4 shown in FIG.
3 is a circuit diagram showing the operation of the embodiment of FIG. When some abnormality occurs due to radio wave interference and both the outputs 1 and 2 of the microcomputer 12 are turned off, both FET1 and FET2 are turned off. At this time, since the FET 1 is off, no current flows from the power supply 30 to the squib 41, and therefore the occupant restraint device does not operate.

As described above, since the FET1 and FET2 constituting the FET array 23 have a monolithic structure provided on a single silicon substrate, when the FET array 23 itself receives some kind of radio interference, , FET
Both 1 and FET2 are in the same operating state, either ON or OFF. FET1 and FET2
When both are turned on, the operation is the same as in the case of state 3 described above, and the occupant restraint device does not operate. When both FET1 and FET2 are turned off, the operation is the same as in the case of state 4 described above, and in this case also, the occupant restraint system does not operate.

In each of the embodiments described above, two FETs formed on a single silicon substrate were used as the first and second switching elements, but two transistors on a single silicon substrate. May be formed and these may be used as a switching element. Further, the number of switching elements is not limited to the above-mentioned embodiments.

In the structure of the above embodiment, the acceleration sensor 11 and the microcomputer 12 serve as a collision detecting means, the squib 41 serves as a starting means, the FET arrays 21 and 23 serve as a driving means, and the FET1 and FET2 serve as a first and a second. Each of the switching means is configured.

[0029]

As described above, according to the present invention, since the first switching element and the second switching element are formed on the single semiconductor substrate as the driving means, the occupant restraint system can be manufactured by an inexpensive method. It can prevent malfunction. When the radio wave is disturbed, both the first and second switching elements are in the ON or OFF state, which is the same operating state. By connecting the first switching element in series with the starting means and connecting the second switching element in parallel with the series circuit of the first switching element and the starting means, the first switching element and the second When both of the switching elements are turned on, the current from the power source does not flow into the series circuit of the first switching element and the starting means, but flows through the second switching element connected in parallel to the series circuit, Since no current flows to the starting means, malfunction of the occupant restraint system due to radio wave interference is prevented. When the first switching element and the second switching element are both turned off due to radio interference, the current from the power supply is blocked by the first switching element connected in series with the starting means, so No current flows and the occupant restraint system does not work. Further, the first switching element is connected in parallel with the starting means, and the second switching element is connected in series with the parallel circuit of the first switching element and the starting means, so that the first switching element is prevented due to radio interference.
When both the switching element and the second switching element are turned on, the current flowing from the power source through the first switching element flows through the second switching element connected in parallel with the starting means, and the starting is performed. Since no current flows through the means, malfunction of the occupant restraint system due to radio interference is prevented. It should be noted that when both the first switching element and the second switching element are turned off due to radio interference, the current from the power supply is blocked by the first switching element, so that no current flows through the starting means, and the occupant restraint system. Does not work.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment.

FIG. 2 is a structural diagram of the FET array of the first embodiment.

FIG. 3 is an equivalent circuit diagram of the FET array according to the first embodiment.

FIG. 4 is a diagram showing an output state of the microcomputer of the first embodiment.

5 is a circuit diagram showing an operation of the first embodiment in the case of the state 1 shown in FIG.

6 is a circuit diagram showing the operation of the first embodiment in the case of state 2 shown in FIG.

7 is a circuit diagram showing the operation of the first embodiment in the case of the state 3 shown in FIG.

8 is a circuit diagram showing the operation of the first embodiment in the case of state 4 shown in FIG.

FIG. 9 is a circuit diagram showing a configuration of a second embodiment.

FIG. 10 is a structural diagram of a FET array according to a second embodiment.

FIG. 11 is an equivalent circuit diagram of the FET array of the second embodiment.

FIG. 12 is a diagram showing an output state of the microcomputer of the second embodiment.

13 is a circuit diagram showing an operation of the second embodiment in the case of the state 1 shown in FIG.

14 is a circuit diagram showing the operation of the second embodiment in the case of the state 2 shown in FIG.

15 is a circuit diagram showing the operation of the second embodiment in the case of the state 3 shown in FIG.

16 is a circuit diagram showing the operation of the second embodiment in the case of state 4 shown in FIG.

FIG. 17 is a circuit diagram showing a configuration of a control device for a conventional occupant restraint system.

[Explanation of symbols]

 11 Accelerometer 12 Microcomputer 21, 23 FET array 22 Resistor 41 Squib

Claims (5)

[Claims] 1. A collision detecting means for detecting a collision of a vehicle and outputting an operation command for an occupant restraint system, a starting means for operating the occupant restraint system, and a power source for receiving an operation command from the collision detecting means. A control device for an occupant restraint system, comprising: a drive means for energizing and activating the activation means, wherein the drive means includes a first switching element and a second switching element formed on a single semiconductor substrate. An occupant restraint system control device. 2. The control device for an occupant restraint system according to claim 1, wherein the first switching element is connected in series with the starting means, and the second switching element is connected to the first switching element. And a control device for an occupant restraint system, which is connected in parallel to a series circuit of the starting means. 3. The control device for an occupant restraint system according to claim 1, wherein the first switching element is connected in parallel with the starting means, and the second switching element is connected to the first switching element. And a control device for an occupant restraint system, which is connected in series to a parallel circuit of the starting means. 4. The control device for an occupant restraint system according to claim 1, wherein the first and second switching elements are transistors. . 5. The control device for an occupant restraint system according to claim 1, wherein the first and second switching elements are FETs. .