JP4219796B2 - Ignition device - Google Patents

Description

  The present invention relates to an ignition device for an occupant protection device mounted on a vehicle or the like.

  In recent years, occupant protection devices using supplemental restraint systems such as airbags and seat belt pretensioners are becoming popular in order to protect occupants in vehicles and the like. In such an occupant protection device, an auxiliary restraint device is disposed at a necessary place, and when an impact is applied to the vehicle, the sensor detects this and the auxiliary restraint device prevents the occupant from colliding with an object in the passenger compartment. Temporarily restrain and protect.

  Conventionally, since the number of auxiliary restraint devices arranged in the vehicle is small, the connection between the control device that controls the auxiliary restraint device and the ignition device that operates the auxiliary restraint device is, for example, a simple one-to-one connection ( Recently, the number of auxiliary restraint devices tends to increase because the auxiliary restraint devices are arranged at various locations in the vehicle. Between the control device and the control device and the ignition device of the auxiliary restraint device, It is required to reduce the number of connecting wires (harness) to be connected as much as possible. Therefore, the connection between the control device and the ignition device of the auxiliary restraint device is connected by a bus line capable of transmitting power and control signals, and the plurality of auxiliary restraint devices connected to the bus line are designated as the ignition device. A method of controlling by one control device using ignition control by communication has been proposed (for example, see Patent Document 1).

On the other hand, in order for the ignition device to be connected to the bus line and receive ignition control by communication from the control device, a communication circuit for communicating with the control device on the ignition device side and an explosive for operating the auxiliary restraint device are ignited. It is necessary to provide an ignition circuit that supplies electric power to the ignition element (see, for example, Patent Document 2).
In recent years, the communication circuit, ignition circuit, and ignition element are housed in a single IC mold, and this IC mold is built in an ignition device having the same external shape as the conventional one, thereby protecting existing passengers. Some proposals have been made to easily change the device to a bus connection specification.
Japanese Patent Laid-Open No. 10-154992 Japanese Patent No. 3294582

  However, in the conventional method in which the control device and the ignition device of the auxiliary restraint device are connected by a bus line, a plurality of auxiliary restraint devices can be efficiently controlled by one control device, but a plurality of auxiliary restraint devices can be controlled. Since the connection line for transmitting power or control signals to the apparatus is only a bus line, there is a problem that the transmission of power or control signals through the bus line must be highly reliable. In particular, when the ignition device includes a communication circuit and an ignition circuit as in the conventional ignition device, the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line. Therefore, there is a problem that the reliability of the bus line must be further improved.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ignition device that does not have an electrical influence on a bus line that supplies power and a control signal when an auxiliary restraint device is operated. And

In order to solve the above-described problem, the ignition device according to the invention of claim 1 is connected in parallel to a common power supply (for example, a bus line 3 in an embodiment described later), and a potential difference between the bus lines . 1 is an ignition device for an occupant protection device including a control circuit that activates an auxiliary restraint device by igniting explosives based on a control signal due to a change in pressure, each of which boosts power supplied from the bus line. A circuit (for example, a booster circuit 26 in an embodiment to be described later), an electric storage means for storing electric power boosted by the booster circuit (for example, a capacitor 28 in an embodiment to be described later), and an electric power connected to and stored in the electric storage means Is provided between the booster circuit and the power storage means, and the explosive is ignited. Implementation of the normal short-circuit conditions or low resistance state, to disconnect the electrical connection between the booster circuit and the ignition element by a cut-off state or a high resistance state when the ignition of at least the explosive (e.g. described later wherein the Ru with example protection circuit 27) and individually.

  In the ignition device having the above configuration, since the protection circuit in the short-circuit state or the low resistance state normally flows current from the booster circuit to the power storage means before the gunpowder is ignited, the ignition element is used as the gunpowder in the power storage means. Electric power that can be ignited is stored. On the other hand, when the gunpowder is ignited, the protection circuit is in a cut-off state or a high resistance value state, and the booster circuit and the power storage means are separated from each other. Even if the circuit on the ignition element side is damaged, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit.

The ignition device according to a second aspect of the present invention is connected in parallel to a common bus line for supplying power (for example, a bus line 3 in an embodiment to be described later) and receives a control signal due to a change in potential difference of the bus lines. An ignition device for an occupant protection device including a control circuit that activates an auxiliary restraint device by igniting explosives based on the booster circuit , each of which boosts the power supplied from the bus line, and the booster circuit Power storage means for storing the electric power boosted by the battery, an ignition element connected to the power storage means for igniting the explosive using the stored electric power, and a short circuit state or a low resistance at normal time before the explosive is ignited the value state, by a cut-off state or a high resistance state when the ignition of at least the explosive, a protection circuit for interrupting the electrical connection between the bus line and the booster circuit (e.g. Wherein the Ru a protection circuit 33) as the embodiment of that predicate separately.

  In the ignition device having the above configuration, since the protective circuit is in a short circuit state or a low resistance state in a normal state before the explosive is ignited, electric power that can ignite the explosive is stored in the ignition circuit. . On the other hand, when the gunpowder is ignited, the protection circuit is in a cut-off state or a high resistance value state, and the bus line and the ignition circuit are electrically separated from each other. Even if there is, it is possible to prevent an electrical influence from occurring on the bus line side to which the ignition device is connected.

  According to the ignition device of claim 1, during normal operation, a current flows between the booster circuit and the power storage means, and when the gunpowder is ignited, the protection circuit separates the connection between the booster circuit and the power storage means. Even if the circuit on the side of the ignition element ahead of the power storage means is damaged by the pressure or heat generated from the explosive, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit. Therefore, it is possible to realize an ignition device that further improves the reliability of the bus line in which the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line that supplies power and control signals. The effect is obtained.

According to the ignition device of the second aspect, since a current flows between the bus line and the ignition circuit in the normal state, and the bus line and the ignition circuit are electrically separated by the protection circuit when the explosive is ignited. Even if the ignition circuit is damaged by the pressure or heat generated from the explosive, it is possible to prevent an electrical influence from being generated on the bus line side to which the ignition device is connected.
Therefore, it is possible to realize an ignition device that further improves the reliability of the bus line in which the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line that supplies power and control signals. The effect is obtained.

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

(overall structure)
FIG. 1 is a block diagram showing an outline of an ignition system in an occupant protection device including an ignition device and a bus line protection device according to a first embodiment of the present invention. In this embodiment, a case where the ignition device includes a bus line protection device will be described. The occupant protection device provided with the ignition device and the bus line protection device of the present embodiment is particularly useful when mounted on a vehicle such as an automobile. As an example, the occupant protection device is mounted on an automobile. The case will be described.
In FIG. 1, a control unit 1 is a control device that forms the center of an occupant protection device that protects an occupant from an impact applied to the vehicle, and includes a plurality of auxiliary restraint devices provided at appropriate positions of the vehicle to protect the occupant. The ignition devices 2a, 2b, 2c,... Of the auxiliary restraint device (not shown) provided on a one-to-one basis use, for example, an unbalanced bus line 3 in which one of two pairs of wires is grounded. Connected in parallel. The ignition devices 2a, 2b, 2c,... Are devices that operate the auxiliary restraint device using an igniting agent (a gunpowder that ignites the gas generating agent of the auxiliary restraining device). The ignition command signal (ignition command command) sent from the control unit 1 by designating the communication addresses of the ignition devices 2a, 2b, 2c,... The auxiliary restraint device is activated by ignition.

  Further, the control unit 1 is provided with a collision determination unit 11 realized by a CPU (Central Processing Unit). The collision determination unit 11 is provided in the front part of the vehicle and connected via a communication circuit 12. Based on the output signal of the front sensor 4 that detects the acceleration due to the deformation of the front part of the vehicle and the output signal of the G sensor 13 that is provided in the control unit 1 and detects the acceleration of the vehicle, the vehicle It is determined whether or not an impact requiring the operation of the occupant protection device is applied to the vehicle due to the collision.

  On the other hand, the control unit 1 is supplied with electric power to the ignition devices 2a, 2b, 2c... Via the bus line 3, and is designated with a communication address to indicate the ignition devices 2a, 2b, 2c. When the collision determination unit 11 determines that an impact that requires the operation of the occupant protection device is applied to the vehicle due to the collision of the vehicle with another object, the communication determination unit 11 performs communication. An ignition command signal (ignition command command) for operating an auxiliary restraint device (not shown) is sent to the ignition devices 2a, 2b, 2c,.

  The control unit 1 is connected to an in-vehicle battery 7 for storing electric power used in the vehicle via a fuse 5 and an ignition switch (IG / SW) 6 for preventing overcurrent. The electric power of the in-vehicle battery 7 input through the protection diode 15 that prevents backflow is supplied to a + 5V power source 16 that generates a power source of a CPU or the like that constitutes the collision determination unit 11, and the ignition devices 2a, 2b, and 2c. Are also supplied to the communication circuit 14 for supplying power to. Further, the control unit 1 stores a backup capacitor 17 that stores power and backs up the power source so as to operate for a certain period of time even when power supply from the in-vehicle battery 7 is stopped, and for charging the backup capacitor 17. Protection diodes 18a and 18b, a booster circuit 19 and the like are also provided.

(Bus line signal specifications)
Here, power supply and communication of control signals via the bus line 3 between the communication circuit 14 and the ignition devices 2a, 2b, 2c, ... will be described. FIG. 2 shows the specifications of signals transmitted and received between the communication circuit 14 and the ignition devices 2a, 2b, 2c... Via the bus line 3, the horizontal axis “time t”, and the vertical axis “voltage V”. It is the figure shown as. As shown in FIG. 2, the control unit 1 causes the bus line 3 to transmit and receive control signals by designating communication addresses between the control unit 1 and the ignition devices 2a, 2b, 2c,. The control unit 1 is controlled to alternately repeat the “power supply phase” for supplying power from the control unit 1 to the ignition devices 2a, 2b, 2c. Specifically, for example, in the “communication phase”, the potential difference between the two lines constituting the bus line 3 is 6 [V] and the data “High” (= 1). Similarly, the potential difference between the two lines is 3 [V] indicates data “Low” (= 0). Further, in the “power supply phase”, the electric power having a potential difference of 11 [V] between the two lines is transmitted from the control unit 1 to the ignition devices 2a, 2b, 2c. Is supplied to ...

(Details of ignition device and bus line protection device)
On the other hand, FIG. 3 is a block diagram showing details of the ignition device and the bus line protection device of the present embodiment, and shows the ignition device 2a including the bus line protection device in detail as an example. It is assumed that all other ignition devices 2b, 2c,... Connected to the bus line 3 have the same configuration as the ignition device 2a.
In FIG. 3, the ignition device 2 a is provided with a control circuit 21 that executes communication diagnosis by the bus line 3 and ignition control based on an instruction from the control unit 1, and from the bus line 3 through the reception buffer 22. In addition, a control signal (command) is input to the control circuit 21, and a response signal (response) to the control signal is output from the control circuit 21 to the bus line 3 via the transmission buffer 23. The power supplied from the bus line 3 is supplied to a + 5V power supply 24 that generates power for the control circuit 21 and the like, and the ignition device 2a ignites the igniting agent via the protective diode 25 to assist the auxiliary restraint device. Is also supplied to a booster circuit 26 that generates electric power necessary for operating the.

  A capacitor 28 is connected to the output of the booster circuit 26 via a protection circuit 27 that is a bus line protection device for protecting the bus line 3. Furthermore, one terminal of an ignition element 30 for igniting an igniter built in the ignition device 2a is connected to the capacitor 28 via a switching element 29, and the other terminal of the ignition element 30 is connected to the capacitor 28. Are grounded via the switching element 31. Note that both control terminals for controlling conduction (ON) and interruption (OFF) between the switching element 29 and the switching element 31 are connected to the control circuit 21.

  Thus, in the ignition system including the ignition device and the bus line protection device according to the present embodiment, when the control unit 1 supplies power to the bus line 3 and transmits a charge command, for example, the ignition element 30 of the ignition device 2a ignites. Since the electric power necessary for igniting the agent 54 and operating the auxiliary restraint device is stored in the capacitor 28, when the control unit 1 transmits an ignition execution signal (ignition execution command) to the ignition device 2a in this state, The control circuit 21 of the ignition device 2a makes the switching element 29 and the switching element 31 conductive (ON), energizes the electric power stored in the capacitor 28 to the ignition element 30, and explodes the igniting agent 54 built in the ignition device 2a. Thus, the auxiliary restraining device can be operated. Details of the operation of the protection circuit 27 will be described later.

(Physical arrangement of ignition device and bus line protection device)
Next, the physical arrangement configuration of the ignition device and the bus line protection device of the present embodiment will be described with reference to the drawings. FIG. 4 is a longitudinal sectional view of the ignition device showing the physical arrangement of the ignition device including the bus line protection device of the present embodiment, and shows the ignition device 2a in detail as an example. It is assumed that all other ignition devices 2b, 2c,... Connected to the bus line 3 have the same physical arrangement as the ignition device 2a.

  Specifically, as shown in FIG. 4, the ignition device 2 a includes a pin 51 a that is a connection terminal provided for connection to the two-wire bus line 3 that is an external signal line, and a connection terminal. Above the header 52 having the pin 51b, the control circuit 21, the reception buffer 22, the transmission buffer 23, the + 5V power supply 24, the protection diode 25, the booster circuit 26, the protection circuit 27, the capacitor 28, the switching element 29, and the ignition are described above. An IC substrate 53A on which the element 30 and the switching element 31 are mounted is disposed, and an ignition agent 54 for igniting the gas generating agent of the auxiliary restraining device is disposed on the IC substrate 53A. In addition, the pin 51b and the header 52 shall be welded. Moreover, although it is separated in two places in the longitudinal sectional view shown in FIG. 4, the header 52 is actually arranged so as to surround the periphery of the pin 51a. Further, the space between the pin 51a and the header 52 is filled with an insulator such as glass in order to fix the pin 51a.

In addition, the ignition element 30 connected to the switching element 29 and the switching element 31 is provided between the IC board 53A and the ignition agent 54, and the IC board 53A is connected to the pin 51a and the header 52 to ignite. Electric power for ignition by the element 30 and a control signal for the control circuit 21 are configured to be supplied via a pin 51 a, a pin 51 b, and a header 52.
The igniter 54, the IC substrate 53A, the pin 51a, and the header 52 are covered with a cylindrical cap 56 whose upper portion is closed, and the igniter 54, the IC substrate 53A, the pin 51a, and the header covered with the cap 56 are further covered. 52 is integrated by covering the pins 51a and 51b with a resin mold 57 by molding. In the above description, the material of each part is an example, and various measures can be adopted, for example, the cap 56 can be made of metal.

(Protection circuit implementation example A)
On the other hand, the protection circuit 27 will be described in more detail with reference to FIG. 3. For example, as the implementation example A, the protection circuit 27 connects the booster circuit 26 and the capacitor 28 under the control of the control circuit 21. Alternatively, a switching element 27 a that can be separated is provided, and a control terminal that controls conduction (ON) and interruption (OFF) of the switching element 27 a is connected to the control circuit 21. That is, when the control circuit 21 turns on (ON) the switching element 27a of the protection circuit 27, the boosting circuit 26 boosts the ignition device 2a to ignite the ignition agent 54 and operate the auxiliary restraint device. The electric power can be stored in the capacitor 28 via the protection circuit 27. Further, when the control circuit 21 shuts off (OFF) the switching element 27a of the protection circuit 27, the connection between the booster circuit 26 and the capacitor 28 is separated and the capacitor 28, the switching element 29, the ignition element 30, The switching element 31 can be separated. If necessary, a low-resistance resistor may be connected in series with the switching element 27a.

(Ignition operation of ignition device including bus line protection device)
Next, with reference to the drawings, an ignition operation for the ignition device including the bus line protection device of this embodiment to operate the auxiliary restraint device will be described. FIG. 5 is a flowchart showing the ignition operation of the ignition device of the present embodiment.
In FIG. 5, simultaneously with the power activation, the control circuit 21 turns on the switching element 27a of the protection circuit 27 (step S1).

In the ignition devices 2a, 2b, 2c,... That have received delay time information that designates a delay time from the control unit 1, the control circuit 21 has an internal timer that counts the delay time for ignition. , The designated delay time is set (step S2).
Further, with the reception of the ignition presence / absence designation signal (ignition presence / absence designation command) from the control unit 1, in each ignition device, the control circuit 21 recognizes the presence / absence of ignition and sets it (step S3).

In each ignition device, when the reception of the ignition execution signal (ignition execution command) from the control unit 1 is recognized (step S4), the control circuit 21 first shuts off (OFF) the switching element 27a of the protection circuit 27. Then, the connection between the booster circuit 26 and the capacitor 28 is separated, and the capacitor 28, the switching element 29, the ignition element 30, and the switching element 31 are disconnected from the bus line 3 (step S5).
Next, the control circuit 21 makes the switching element 29 and the switching element 31 conductive (ON) after the designated delay time based on the set time of the timer that counts the delay time with respect to ignition, and connects the ignition element 30 to the capacitor 28. The stored electric power is energized, and an ignition process for operating the auxiliary restraint device by causing the built-in igniter 54 to explode is executed (step S6).

  As a result, at a normal time before the ignition agent 54 is ignited, the control circuit 21 sets the switching element 27a in a short-circuit state or a low resistance value state, and a current flows from the booster circuit 26 to the capacitor 28. As much power as 30 can ignite the igniter 54 is stored. On the other hand, when the ignition agent 54 is ignited, the control circuit 21 puts the switching element 27a into a cut-off state or a high resistance value state and separates the boost circuit 26 and the capacitor 28, so that the pressure generated from the ignited ignition agent 54 Even if the circuit on the side of the ignition element 30 ahead of the capacitor 28 is damaged by heat or heat, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit 26.

(Protection circuit implementation example B)
Next, another implementation example (= implementation example B) of the above-described protection circuit 27 will be described with reference to the drawings. FIG. 6 is a configuration diagram showing a form of an implementation example B of the protection circuit 27.
In FIG. 6, a thin film resistor 27b is a resistor having a low resistance value provided so as to connect between the booster circuit 26 and the capacitor 28, and is disconnected when a current of a predetermined value or more is passed instantaneously. A resistor that can be destroyed. In addition, a series circuit of a switching element 27c and a disconnection breaking capacitor 27d is connected in parallel to the thin film resistor 27b. In addition, power is supplied from the + 5V power source 24 to a connection point between the switching element 27c and the disconnection breaking capacitor 27d. The switching element 27c is a switching element that can be connected to or disconnected from the booster circuit 26 and the thin film resistor 27b and the disconnection breaking capacitor 27d under the control of the control circuit 21. A control terminal that controls conduction (ON) and interruption (OFF) of the switching element 27 c is connected to the control circuit 21.

(Ignition operation of ignition device including bus line protection device)
Next, the ignition operation of the ignition device when the protection circuit 27 is realized by the thin film resistor 27b (in the case of the implementation example B) will be described with reference to the drawings. FIG. 7 is a flowchart showing the ignition operation of the ignition device when the protection circuit 27 is realized by the thin film resistor 27b (in the case of the implementation example B).
In FIG. 7, since charging of the disconnection destruction capacitor 27d by the + 5V power supply 24 is started simultaneously with the power activation, the control circuit 21 shuts off (OFF) the switching element 27c of the protection circuit 27 (step S11).

In the ignition devices 2a, 2b, 2c,... That have received delay time information that designates a delay time from the control unit 1, the control circuit 21 has an internal timer that counts the delay time for ignition. The delay time is set to the designated delay time (step S12).
Further, with the reception of the ignition presence / absence designation signal (ignition presence / absence designation command) from the control unit 1, in each ignition device, the control circuit 21 recognizes the presence / absence of ignition and sets it (step S13).

In each ignition device, when the reception of the ignition execution signal (ignition execution command) from the control unit 1 is recognized (step S14), the control circuit 21 first turns on the switching element 27c of the protection circuit 27 (ON). By discharging the electric power charged in the disconnection breaking capacitor 27d, the thin film resistor 27b is broken by the discharge current. That is, by disconnection destruction of the thin film resistor 27b, the connection between the booster circuit 26 and the capacitor 28 is separated, and the capacitor 28, the switching element 29, the ignition element 30, and the switching element 31 are disconnected from the bus line 3 (step S15).
Next, the control circuit 21 makes the switching element 29 and the switching element 31 conductive (ON) after the designated delay time based on the set time of the timer that counts the delay time with respect to ignition, and connects the ignition element 30 to the capacitor 28. The stored electric power is energized, and an ignition process for operating the auxiliary restraint device by causing the built-in igniter 54 to explode is executed (step S16).

  As a result, at a normal time before the igniter 54 is ignited, the control circuit 21 sets the switching element 27c in a cut-off state or a high resistance value state, and current flows from the booster circuit 26 to the capacitor 28 via the thin film resistor 27b. The capacitor 28 stores enough electric power that the ignition element 30 can ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the control circuit 21 sets the switching element 27c in a short circuit state or a low resistance state, breaks the thin film resistor 27b with the electric power stored in the disconnection breaking capacitor 27d, and Since the capacitor 28 is separated from the capacitor 28, the pressure and heat generated from the ignited igniter 54 may damage the circuit on the side of the ignition element 30 ahead of the capacitor 28. It is possible to prevent the electrical influence from occurring.

(Protection circuit implementation example C)
Next, still another implementation example (= implementation example C) of the above-described protection circuit 27 will be described with reference to the drawings. FIG. 8 is a configuration diagram showing a form of an implementation example C of the protection circuit 27.
In FIG. 8, a conductor 27e is a thin plate-like conductor having a low resistance value provided so as to connect between the booster circuit 26 and the capacitor 28, and breaks the wire when a pressure exceeding a predetermined value is applied. It is a conductor that can The conductor 27e has a protrusion 50a at the center, and a protrusion 50a and two elastic bodies 51a on the rigid body 50 having elastic bodies 51a and 51b having the same height as the protrusion 50a at both ends. 51b so that it may be supported. In addition, an IC mold 52 that constitutes the control circuit 21, the reception buffer 22, the transmission buffer 23, and the like on the IC substrate 53A is disposed above the protrusion 50a and the two elastic bodies 51a and 51b with the conductor 27e interposed therebetween. Is arranged. It should be noted that a gap 52a of a size that allows the protrusion 50a to enter is provided at the center of the IC mold 52 corresponding to the protrusion 50a located at the center of the rigid body 50. The rigid body 50, the elastic bodies 51a and 51b, and the IC mold 52 are insulated from the conductor 27e.

In such a configuration, when the pressure generated from the igniter 54 when the ignition device is ignited is applied to the IC mold 52 from the Z direction shown in FIG. 8 and the IC mold 52 is pushed down toward the rigid body 50, the elastic body 51a, Due to the pressure deformation of 51 b, the protrusion 50 a of the rigid body 50 crushes the thin plate-like low-resistance conductor 27 e and enters the gap 52 a of the IC mold 52.
That is, when the thin plate-like low-resistance conductor 27 e is crushed, the connection between the booster circuit 26 and the capacitor 28 is separated, and the capacitor 28, the switching element 29, the ignition element 30, and the switching element 31 are separated from the bus line 3. In the implementation example C, it is not necessary to control the protection circuit 27 by the control circuit 21.

  As a result, during normal times before the igniter 54 is ignited, the conductor 27e flows current from the booster circuit 26 to the capacitor 28 as it is, so that the igniter 30 can ignite the igniter 54 in the capacitor 28. Is stored. On the other hand, when the igniter 54 is ignited, the conductor 27e sandwiched between the IC mold 52 and the rigid body 50 is crushed to separate the booster circuit 26 and the capacitor 28, so that the ignited igniter 54 is ignited. Even if the circuit on the side of the ignition element 30 ahead of the capacitor 28 is damaged by the pressure and heat generated from the capacitor 28, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit 26.

(Protection circuit implementation example D)
The protection circuit 27 is provided with a resistor having a low resistance value provided so as to connect between the booster circuit 26 and the capacitor 28 and melted when heat of a predetermined value or more is applied. Also good. In such a configuration, when the heat generated from the igniter 54 when the ignition device is ignited is applied to the resistor, the resistor is melted.
That is, when the resistor is melted, the connection between the booster circuit 26 and the capacitor 28 is separated, and the capacitor 28, the switching element 29, the ignition element 30, and the switching element 31 are disconnected from the bus line 3. In the implementation example D, it is not necessary to control the protection circuit 27 by the control circuit 21.

  As a result, at a normal time before the igniter 54 is ignited, the resistor passes the current from the booster circuit 26 to the capacitor 28 as it is, so that the capacitor 28 has an electric power sufficient for the ignition element 30 to ignite the igniter 54. Is stored. On the other hand, when the ignition agent 54 is ignited, the resistor is melted by the heat generated from the ignition agent 54 and the booster circuit 26 and the capacitor 28 are separated, so that the pressure generated from the ignition agent 54 is ignited. Even if the circuit on the side of the ignition element 30 ahead of the capacitor 28 is damaged by heat or heat, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit 26.

Further, a high-resistance resistor that does not affect the communication via the bus line 3 may be connected in parallel to the protection circuit 27 configured by the above-described implementation examples A to D. Thereby, it is possible to notify the control signal to the control circuit 21 capable of operating the ignition device provided in the activated auxiliary restraint device.
Furthermore, the above-described bus line 3 may be a balanced bus line in which, for example, two pairs of wires are not grounded.

  As described above, according to the ignition device and the bus line protection device of the present embodiment, the current is passed from the booster circuit 26 to the capacitor 28 by the protection circuit 27 at the normal time before the ignition agent 54 is ignited. The electric power that can be ignited by the ignition element 30 to the igniter 54 is stored in 28. On the other hand, since the booster circuit 26 and the capacitor 28 are separated by the protection circuit 27 when the ignition agent 54 is ignited, the ignition element 30 ahead of the capacitor 28 due to the pressure and heat generated from the ignition agent 54 ignited. Even if the circuit on the side is damaged, it is possible to prevent an electrical influence from being generated on the bus line side from the booster circuit 26.

  Accordingly, the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line 3 that supplies power and control signals, and the ignition device and the bus line protection further improve the reliability of the bus line 3. The effect that the apparatus can be realized is obtained.

Next, an ignition device and a bus line protection device according to a second embodiment of the present invention will be described.
(overall structure)
FIG. 9 is a block diagram showing an outline of an ignition system in an occupant protection device including an ignition device and a bus line protection device according to a second embodiment of the present invention. Also in this embodiment, the case where the ignition device includes a bus line protection device will be described.
The ignition device and bus line protection device of the present embodiment are different from the ignition device and bus line protection device described in the first embodiment in the circuit configuration (device configuration) of the ignition device including the bus line protection device. Is different. Accordingly, as shown in FIG. 9, the ignition system in the occupant protection device including the ignition device and the bus line protection device according to the present embodiment has the ignition devices 2a, 2b, 2c,... Described in the first embodiment. Is changed to a configuration provided with ignition devices 8a, 8b, 8c... Instead of the ignition devices 2a, 2b, 2c.

  Since the control unit 1 has the same configuration as the ignition system described in the first embodiment, the description thereof is omitted here. Further, the physical arrangement configuration of the ignition device and the bus line protection device is the same as the physical arrangement configuration of the ignition device and the bus line protection device described in the first embodiment, and the ignition device including the bus line protection device. The physical arrangement of 8a, 8b, 8c... Is omitted in the longitudinal sectional view of the ignition device 2a shown in FIG. Now, only the circuit configuration (device configuration) of the ignition device and the bus line protection device of this embodiment will be described. Also, the signal specifications of the bus lines are the same as the signal specifications of the bus lines described in the first embodiment, and thus description thereof is omitted here.

(Details of ignition device and bus line protection device)
FIG. 10 is a block diagram showing details of the ignition device and the bus line protection device of the present embodiment, and shows an ignition device 8a including the bus line protection device in detail as an example. It is assumed that all other ignition devices 8b, 8c,... Connected to the bus line 3 have the same configuration as the ignition device 8a.
In FIG. 10, the ignition device 8a is provided with a control circuit 21 that executes communication control by the bus line 3 and ignition control based on an instruction from the control unit 1, and the internal circuit of the ignition device 8a is a bus line. It is connected to the bus line 3 through a protection circuit 33 which is a protection device.
Specifically, a control signal (command) for the control circuit 21 is input from the bus line 3 via the protection circuit 33, input to the control circuit 21 through the reception buffer 22, and output from the control circuit 21 through the transmission buffer 23. A response signal (response) to the control signal is output to the bus line 3 via the protection circuit 33.
Similarly, the power supplied from the bus line 3 is supplied to the + 5V power source 24 that generates power for the control circuit 21 and the like via the protection circuit 33, and further, the ignition device 8 a is ignited via the protection diode 25. It is also supplied to a booster circuit 26 that generates electric power necessary to ignite the agent and operate the auxiliary restraint device.

  Further, a capacitor 28 is connected to the output of the booster circuit 26 via a protective diode 32, and the booster circuit 26 is required for the ignition device 8a to ignite the igniting agent and operate the auxiliary restraint device. The boosted power can be stored. Further, the output (cathode terminal) of the protection diode 32 is connected in series with a switching element 29, an ignition element 30 for igniting an igniting agent built in the ignition device 8 a, and a switching element 31 in parallel with the capacitor 28. The circuit is connected. Specifically, one terminal of the ignition element 30 is connected to the output of the protection diode 32 via the switching element 29, and the other terminal of the ignition element 30 is grounded via the switching element 31. ing. Note that both control terminals for controlling conduction (ON) and interruption (OFF) between the switching element 29 and the switching element 31 are connected to the control circuit 21.

  As a result, in the ignition system including the ignition device and the bus line protection device of this embodiment, the control unit 1 supplies power to the bus line 3 in the same manner as the ignition system described in the first embodiment, and the charge command , For example, the ignition element 30 of the ignition device 8a ignites the igniter 54 and the electric power necessary for operating the auxiliary restraint device is stored in the capacitor 28. In this state, the control unit 1 causes the ignition device 8a to When the ignition execution signal (ignition execution command) is transmitted to the control circuit 21, the control circuit 21 of the ignition device 8a turns on the switching element 29 and the switching element 31 to energize the ignition element 30 with the power stored in the capacitor 28. Then, the auxiliary restraint device can be operated by detonating the igniting agent 54 built in the ignition device 8a.

(Example of protection circuit implementation)
On the other hand, the protection circuit 33 will be described in more detail. The protection circuit 33 can be realized by any of the implementation examples A to D of the protection circuit 27 described in the first embodiment. Therefore, when the protection circuit 33 is realized by the above-described implementation example A, that is, the switching element 27a, the control circuit 21 sets the switching element 27a in a short-circuit state or a low resistance value state at a normal time before the ignition agent 54 is ignited. Since a current flows from the bus line 3 to the booster circuit 26, the capacitor 28 connected to the output of the booster circuit 26 stores enough electric power for the ignition element 30 to ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the control circuit 21 places the switching element 27a in a cut-off state or a high resistance state, and separates the bus line 3 from the booster circuit 26. Even if the circuit on the side of the ignition element 30 ahead of the booster circuit 26 is damaged by pressure or heat, it is possible to prevent an electrical influence from occurring on the bus line side.

  Further, when the protection circuit 33 is realized by the above-described realization example B, that is, the thin film resistor 27b, the switching element 27c, and the disconnection breaking capacitor 27d, the control circuit 21 is normally operated before the ignition agent 54 is ignited. Causes the switching element 27c to be in a cut-off state or a high resistance state, and a current flows from the bus line 3 to the booster circuit 26 via the thin film resistor 27b, so that the ignition element 30 is connected to the capacitor 28 connected to the output of the booster circuit 26. The electric power that can ignite the igniter 54 is stored. On the other hand, when the ignition agent 54 is ignited, the control circuit 21 sets the switching element 27c in a short-circuit state or a low resistance state, breaks the thin-film resistor 27b with the electric power stored in the disconnection breaking capacitor 27d, and Since it is separated from the booster circuit 26, even if the circuit on the ignition element 30 side before the booster circuit 26 is damaged by the pressure or heat generated from the ignited igniter 54, the bus line side is electrically connected. Can be prevented from occurring.

  Further, when the protection circuit 33 is realized by the above-described realization example C, that is, the conductor 27e arranged at the position shown in FIG. 8, the conductor 27e remains as it is at the normal time before the ignition agent 54 is ignited. Therefore, the capacitor 28 connected to the output of the booster circuit 26 stores enough electric power for the ignition element 30 to ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the conductor 27e sandwiched between the IC mold 52 and the rigid body 50 is crushed to separate the bus line 3 from the booster circuit 26. Even if the circuit on the side of the ignition element 30 ahead of the booster circuit 26 is damaged by the pressure and heat generated from the circuit 54, it is possible to prevent an electrical influence from occurring on the bus line side.

  Further, when the protection circuit 33 is realized by the above-described implementation example D, that is, a resistor that blows when heat of a predetermined value or more is applied, the resistor is directly removed from the bus line 3 at the normal time before the ignition agent 54 is ignited. Since current flows to the booster circuit 26, the capacitor 28 connected to the output of the booster circuit 26 stores enough power to allow the ignition element 30 to ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the resistor is melted by the heat generated from the ignition agent 54 and the bus line 3 and the booster circuit 26 are separated from each other. Even if the circuit on the side of the ignition element 30 ahead of the booster circuit 26 is damaged by pressure or heat, it is possible to prevent an electrical influence from occurring on the bus line side.

  In this embodiment, even when the protection circuit 33 is activated and the bus line 3 and the internal circuit of the ignition device 8a are separated, the control circuit 21 can continue the ignition control so that the + 5V power supply 24 can continue. Is provided with a function of backing up the power source for a time sufficient for the control circuit 21 to complete the ignition control for the ignition element 30.

  As described above, according to the ignition device and the bus line protection device of the present embodiment, current flows from the bus line 3 to the booster circuit 26 by the protection circuit 33 at the normal time before the ignition agent 54 is ignited. The capacitor 28 connected to the output of the booster circuit 26 stores enough electric power for the ignition element 30 to ignite the igniter 54. On the other hand, when the igniter 54 is ignited, the bus circuit 3 and the booster circuit 26 are separated by the protection circuit 33, so that the ignition and the heat generated from the ignited igniter 54 ignite before the booster circuit 26. Even if the circuit on the element 30 side is damaged, it is possible to prevent an electrical influence from occurring on the bus line side.

  Accordingly, the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line 3 that supplies power and control signals, and the ignition device and the bus line protection further improve the reliability of the bus line 3. The effect that the apparatus can be realized is obtained.

Next, an ignition device and a bus line protection device according to a third embodiment of the present invention will be described.
(overall structure)
FIG. 11: is a block diagram which shows the outline | summary of the ignition system in the passenger | crew protection device provided with the ignition device and bus line protection device of the 3rd Example of this invention. In the present embodiment, the case where the ignition device does not include the bus line protection device and the bus line protection device is independent from the ignition device will be described. The difference between the ignition device and bus line protection device of the present embodiment in the ignition device and bus line protection device described in the first and second embodiments is the circuit configuration inside the ignition device including the bus line protection device ( The device configuration is different, and the bus line protection device is always connected between the ignition device and the bus line 3 in a one-to-one correspondence with the ignition device.

  Therefore, as shown in FIG. 11, the configuration of the ignition system in the passenger protection device including the ignition device and the bus line protection device of the present embodiment is the configuration of the ignition system including the ignition device 2a described in the first embodiment. Are changed to a configuration having ignition devices 9a, 9b, 9c... Instead of the ignition devices 2a, 2b, 2c... And between the ignition devices 9a, 9b, 9c. In the meantime, the bus line protection devices 10a, 10b, 10c,... Having the protection circuits are always connected to the ignition devices 9a, 9b, 9c,. The ground potential of the bus line protection devices 10a, 10b, 10c,... Is the same as that of the bus line 3 and the ignition devices 9a, 9b, 9c,. Since the control unit 1 has the same configuration as the ignition system described in the first embodiment, the description thereof is omitted here. Also, the signal specifications of the bus lines are the same as the signal specifications of the bus lines described in the first embodiment, and thus description thereof is omitted here.

(Details of ignition device and bus line protection device)
FIG. 12 is a block diagram showing details of the ignition device and the bus line protection device of the present embodiment. As an example, the ignition device 9a and the bus line protection device connected between the bus line 3 and the ignition device 9a. 10a will be described in detail. All other ignition devices 9b, 9c,... Have the same configuration as the ignition device 9a. Further, the bus line protection devices 10b, 10c,... Connected in a one-to-one correspondence with the ignition devices 9b, 9c,... Between the bus line 3 and the ignition devices 9b, 9c,. It is assumed that the same configuration as the bus line protection device 10a is provided.

In FIG. 12, a bus line protection device 10a including a protection circuit 34 is connected between the bus line 3 and the ignition device 9a. Further, the ignition device 9 a is provided with a control circuit 21 that performs ignition control based on diagnosis of communication through the bus line 3 and an instruction from the control unit 1. Specifically, a control signal (command) for the control circuit 21 is input from the bus line 3 via the protection circuit 34, input to the control circuit 21 through the reception buffer 22, and output from the control circuit 21 through the transmission buffer 23. A response signal (response) to the control signal is output to the bus line 3 via the protection circuit 34.
Similarly, the power supplied from the bus line 3 is supplied to the + 5V power supply 24 that generates power for the control circuit 21 and the like via the protection circuit 34, and further, the ignition device 9 a is ignited via the protection diode 25. It is also supplied to a booster circuit 26 that generates electric power necessary to ignite the agent and operate the auxiliary restraint device.

  Further, a capacitor 28 is connected to the output of the booster circuit 26 via a protective diode 32, and the booster circuit 26 is necessary for the ignition device 9a to ignite the igniting agent and operate the auxiliary restraint device. The boosted power can be stored. Further, the output (cathode terminal) of the protection diode 32 is connected in series with a switching element 29, an ignition element 30 for igniting an igniting agent built in the ignition device 9 a, and a switching element 31 in parallel with the capacitor 28. The circuit is connected. Specifically, one terminal of the ignition element 30 is connected to the output of the protection diode 32 via the switching element 29, and the other terminal of the ignition element 30 is grounded via the switching element 31. ing. Note that both control terminals for controlling conduction (ON) and interruption (OFF) between the switching element 29 and the switching element 31 are connected to the control circuit 21.

  As a result, in the ignition system including the ignition device and the bus line protection device according to this embodiment, the control unit 1 supplies power to the bus line 3 in the same manner as the ignition systems described in the first and second embodiments. When the charging command is transmitted, for example, the ignition element 30 of the ignition device 9a ignites the igniter 54 and the electric power necessary for operating the auxiliary restraint device is stored in the capacitor 28. In this state, the control unit 1 When an ignition execution signal (ignition execution command) is transmitted to the ignition device 9a, the control circuit 21 of the ignition device 9a turns on the switching element 29 and the switching element 31, and the capacitor 28 stores the ignition element 30. The auxiliary restraint device can be operated by energizing the electric power and causing the ignition agent 54 built in the ignition device 9a to explode. Details of the operation of the protection circuit 34 will be described later.

(Physical arrangement of ignition device and bus line protection device)
Next, the physical arrangement configuration of the ignition device and the bus line protection device of the present embodiment will be described with reference to the drawings. FIG. 13 is a longitudinal sectional view of the ignition device and the protection circuit showing the physical arrangement configuration of the ignition device and the bus line protection device of the present embodiment. As an example, the ignition device 9a and the bus line protection device 10a are shown. Show in detail. The other ignition devices 9b, 9c... And the bus line protection devices 10b, 10c... Connected to the bus line 3 all have the same physical arrangement as the ignition devices 9a and the bus line protection device 10a. It shall be.

  Specifically, as shown in FIG. 13, the ignition device 9 a is a connection terminal and a pin 51 a that is a connection terminal provided for connection to a two-wire bus line 3 that is an external signal line. Above the header 52 having the pin 51b, the control circuit 21, the reception buffer 22, the transmission buffer 23, the + 5V power supply 24, the protection diode 25, the booster circuit 26, the protection diode 32, the capacitor 28, the switching element 29, and the ignition are described above. An IC substrate 53B on which the element 30 and the switching element 31 are mounted is disposed, and an ignition agent 54 for igniting the gas generating agent of the auxiliary restraint device is disposed on the IC substrate 53B. In addition, the pin 51b and the header 52 shall be welded. Further, in the longitudinal sectional view shown in FIG. 13, the header 52 is actually arranged so as to surround the periphery of the pin 51a, although it is separated at two places. Further, the space between the pin 51a and the header 52 is filled with an insulator such as glass in order to fix the pin 51a.

Further, the ignition element 30 connected to the switching element 29 and the switching element 31 is provided between the IC board 53B and the ignition agent 54, and the IC board 53B is connected to the pin 51a and the header 52 to ignite. Electric power for ignition by the element 30 and a control signal for the control circuit 21 are configured to be supplied via a pin 51 a, a pin 51 b, and a header 52.
The igniter 54, the IC substrate 53B, the pin 51a, and the header 52 are covered with a cylindrical cap 56 whose upper portion is closed, and the igniter 54, the IC substrate 53B, the pin 51a, and the header covered with the cap 56 are further covered. 52 is integrated by covering the pins 51a and 51b with a resin mold 57 by molding. In the above description, the material of each part is an example, and various measures can be adopted, for example, the cap 56 can be made of metal.

  On the other hand, for the bus line protection device 10 a, the protection circuit 34 is mounted on the board 62 connected to the bus line 3 and supplied with power and a control signal from the bus line 3, and the protection circuit 34 is mounted on the board 62. Connection terminals 61a and 61b for connecting to the pins 51a and 51b are provided, and the whole is molded and covered with a resin mold 63, so that it is inserted into the pins 51a and 51b as shown in FIG. The bus line protection device 10a is configured. The bus line protection devices 10a, 10b, 10c,... Are not limited to between the pins (for example, between the pins 51a and 51b in the case of the ignition device 9a), but the bus line 3 and the ignition devices 9a, 9b, 9c,.・ You can connect anywhere on the connection path.

(Example of protection circuit implementation)
On the other hand, the protection circuit 34 will be described in more detail. The protection circuit 34 can be realized by either the implementation example A or the implementation example B of the protection circuit 27 described in the first embodiment. However, since the protection circuit 34 is independent of the ignition devices 9a, 9b, 9c... As the bus line protection devices 10a, 10b, 10c..., As shown in FIG. Of the ignition execution signals (ignition execution commands) to the ignition elements 9a, 9b, 9c,..., And receives the ignition execution signals (ignition execution commands). In the case of the implementation example B, it is necessary to provide a control circuit 35 for controlling conduction (ON) or interruption (OFF) of the switching element 27c.

  Therefore, when the protection circuit 34 is realized by the above-described implementation example A, that is, the switching element 27a and the control circuit 35 that controls the switching element 27a, the control circuit 35 is switched at a normal time before the ignition agent 54 is ignited. The element 27a is brought into a short-circuited state or a low resistance value state, and a current flows from the bus line 3 to the booster circuit 26 of the ignition elements 9a, 9b, 9c..., So that the capacitor 28 connected to the output of the booster circuit 26 ignites. Electric power that can ignite the igniter 54 by the element 30 is stored. On the other hand, when the ignition agent 54 is ignited, the control circuit 35 puts the switching element 27a into a cut-off state or a high resistance state and separates between the bus line 3 and the ignition elements 9a, 9b, 9c. Even if the circuits of the ignition elements 9a, 9b, 9c,... Are damaged by the pressure and heat generated from the ignition agent 54, it is possible to prevent an electrical influence from being generated on the bus line side. .

  Further, when the protection circuit 34 is realized by the above-described implementation example B, that is, the thin film resistor 27b, the switching element 27c, the disconnection breaking capacitor 27d, and the control circuit 35 that controls the switching element 27c, the ignition agent 54 is In a normal state before ignition, the control circuit 35 sets the switching element 27c in a cut-off state or a high resistance value state, and the boosting circuit 26 for the ignition elements 9a, 9b, 9c... From the bus line 3 through the thin film resistor 27b. Therefore, the capacitor 28 connected to the output of the booster circuit 26 stores enough electric power for the ignition element 30 to ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the control circuit 35 sets the switching element 27c in a short circuit state or a low resistance value state, breaks the thin film resistor 27b with the electric power stored in the disconnection breaking capacitor 27d, and Since the ignition elements 9a, 9b, 9c,... Are separated from each other, the circuit of the ignition elements 9a, 9b, 9c,. However, it is possible to prevent an electrical influence from occurring on the bus line side.

  Also in this embodiment, even when the protection circuit 34 is activated and the bus line 3 and the internal circuit of the ignition device 9a are separated, the control circuit 21 can continue the execution of the ignition control so that the + 5V power supply 24 can be continued. Is provided with a function of backing up the power source for a time sufficient for the control circuit 21 to complete the ignition control for the ignition element 30.

  As described above, according to the ignition device and the bus line protection device of the present embodiment, at the normal time before the igniter 54 is ignited, the protection circuit 34 causes the ignition elements 9a, 9b, 9c,. Since the current flows to the booster circuit 26, the capacitor 28 connected to the output of the booster circuit 26 stores enough power to allow the ignition element 30 to ignite the igniter 54. On the other hand, when the ignition agent 54 is ignited, the bus circuit 3 and the ignition elements 9a, 9b, 9c,... Are separated by the protection circuit 34, so that if the pressure or heat generated from the ignition agent 54 is ignited. Even if the circuits of the ignition elements 9a, 9b, 9c,... Are damaged, it is possible to prevent an electrical influence from occurring on the bus line side.

  Accordingly, as in the first and second embodiments, the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line 3 that supplies power and control signals. An effect is obtained that an ignition device and a bus line protection device that further improve the reliability can be realized.

  In the first, second, and third embodiments described above, the ignition device provided in the activated auxiliary restraint device does not electrically affect the bus line 3 that supplies power and control signals. When the ignition agent 54 is ignited, the protection circuit is configured to separate the bus line 3 from the ignition device or the internal circuit of the ignition device. For example, the protection circuit is realized by the above-described implementation examples A and B. In such a case, a failure in the internal circuit of the ignition device is detected, and based on the result, the switching element 27a in the implementation example A and the switching element 27c in the implementation example B are turned on (ON) or cut off (OFF). ) May be separated from the bus line 3 and the ignition device or the internal circuit of the ignition device. The switching elements 27a, 27c, 29, and 30 may be any elements that can be electrically controlled (ON) or blocked (OFF), such as FETs and transistors.

It is a block diagram which shows the outline | summary of the ignition system in the passenger | crew protection device provided with the ignition device and bus line protection device of 1st Example of this invention. It is the figure which showed the specification of the signal transmitted / received via a bus line in the Example. It is a block diagram which shows the detail of the ignition device and bus line protection apparatus of the Example. It is a longitudinal direction sectional view of an ignition device showing physical arrangement composition of an ignition device including a bus line protection device of the example. It is a flowchart which shows the ignition operation | movement of the ignition device of the Example. It is a block diagram which shows the form of the implementation example B of the ignition device and bus line protection apparatus of the Example of the Example. 6 is a flowchart showing an ignition operation of the ignition device when the protection circuit is realized by a thin film resistor in the ignition device and the bus line protection device of the embodiment. It is a block diagram which shows the form of the implementation example C of the ignition device and bus line protection apparatus of the Example of the Example. It is a block diagram which shows the outline | summary of the ignition system in the passenger | crew protection device provided with the ignition device and bus line protection device of 2nd Example of this invention. It is a block diagram which shows the detail of the ignition device and bus line protection apparatus of the Example. It is a block diagram which shows the outline | summary of the ignition system in the passenger | crew protection device provided with the ignition device and bus line protection device of the 3rd Example of this invention. It is a block diagram which shows the detail of the ignition device and bus line protection apparatus of the Example. It is a longitudinal direction sectional view of an ignition device and a bus line protection device showing a physical arrangement configuration of the ignition device and the bus line protection device of the same embodiment.

Explanation of symbols

3 Bus line 26 Booster circuit 27, 33 Protection circuit 28 Capacitor (electric storage means, ignition circuit)
30 Ignition element (ignition element, ignition circuit)
29, 31 Switching element (ignition circuit)
9a, 9b, 9c ignition device

Claims (2)

An occupant protection device comprising a control circuit that is connected in parallel to a common bus line that supplies electric power and that activates an auxiliary restraint device by igniting explosives based on a control signal resulting from a change in potential difference of the bus lines The ignition device of
Each is
A booster circuit for boosting power supplied from the bus line;
Power storage means for storing the electric power boosted by the booster circuit;
An ignition element connected to the power storage means for igniting the explosive using the stored power;
Together provided between said storage means and said booster circuit, during normal before the explosive is ignited in a short-circuit state or a low resistance state, it enters a cutoff state or a high resistance state when the ignition of at least the explosive ignition device characterized by Ru comprising separately a protection circuit for cutting the electrical connection between the booster circuit and the ignition element by. An occupant protection device comprising a control circuit that is connected in parallel to a common bus line that supplies electric power and that activates an auxiliary restraint device by igniting explosives based on a control signal resulting from a change in potential difference of the bus lines The ignition device of
Each is
A booster circuit for boosting power supplied from the bus line;
Power storage means for storing the electric power boosted by the booster circuit;
An ignition element connected to the power storage means for igniting the explosive using the stored power;
In normal short circuit condition or a low resistance state when before the explosive is ignited, by a cut-off state or a high resistance state when the ignition of at least the explosive, the electrical connection between the bus line and the booster circuit ignition device characterized by Ru and a protection circuit for interrupting separately.

Images