JPH072050A - Expandable auxiliary restraint - Google Patents

Abstract

PURPOSE: To provide an improved inflatable auxiliary restraining tool system and method which does not hurt an electromechanical sensor. CONSTITUTION: An inflatable auxiliary restraining tool system consisting of a series circuit including a controlable current source 56, detonator 60 and electromechanical sensor 62 is provided. By providing the redundancy on the decision execution for deploying the restraining tool and the decision execution device with two different forms, the possibility of trouble of common mode generated by the unnecessary deployment of the restraining tool is eliminated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to an inflatable auxiliary restraint device and a method of deploying an inflatable auxiliary restraint.

[0002]

BACKGROUND OF THE INVENTION The subject matter of the present invention is related to pending Japanese Patent Application No. 261093/93.

In some current inflatable supplemental restraint systems, one or more electromechanical sensors detect a sudden deceleration of the vehicle and close electrical contacts to effect the required deployment of the inflatable supplementary restraint. Start. When the contacts are closed, current flows through the contacts and the auxiliary inflatable restraint deployment detonator. High levels of current flow through the sensor and detonator to ensure rapid deployment of the restraint. This high level of current often results in an arc of the sensor, which damages the electromechanical sensor and makes its reuse impossible.

In the event of battery interruption in the event that deployment of an inflatable supplemental restraint system is required, a storage capacitor is used as a temporary energy storage device to replenish the energy required to deploy the supplemental inflatable restraint system. To be Several large storage capacitors are typically provided. For example, the auxiliary inflatable restraint system
There is one storage capacitor for the controller and one storage capacitor for each detonator activated.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved inflatable auxiliary restraint device and a method of deploying such a device. According to one aspect of the invention, there is provided an inflatable auxiliary restraint device as claimed in claim 1. According to another feature of the invention, there is provided a method of deploying an auxiliary inflatable restraint device as claimed in claim 3. According to another characteristic of the invention, an inflatable auxiliary restraint device is provided as claimed in claim 4.

In certain embodiments, it is possible to provide an auxiliary inflatable restraint system with a reusable electromechanical actuator. It also provides improved energy management to an inflatable auxiliary restraint device that reduces the number of capacitors required and also reduces the size of the capacitors required by the system without causing system performance degradation. It is also possible to provide.
In a preferred embodiment, it is possible to control the auxiliary inflatable restraint system without arcing the electromechanical sensor.

[0007]

Preferably, the device is
Controlling the current through a deployable detonator by using a switchable current source controlled by a control line and activating the energy in a system storage capacitor by pulsing the controllable current source for a limited period of time. Used to eliminate eventual switching of current from the contacts of the electromechanical actuator to the switchable current source, the limited period of time being long enough to ensure deployment of the auxiliary inflatable restraint system. However, it has a finite duration that prevents unwanted discharge of the storage capacitor.

The device can advantageously prevent unwanted current discharge of the storage capacitor during deployment of the auxiliary inflatable restraint system. The device includes a microprocessor and one or more auxiliary inflatable restraint deployment circuits, all of which use one energy storage capacitor when the battery is disconnected.

In one embodiment, the apparatus provides a multi-deployment inflatable supplemental restraint system with graduated deployment of the inflatable supplementary restraint, such graduated deployment comprising a relatively small storage capacitor and (Or) Allows the use of a storage capacitor voltage and provides a more efficient use of the energy storage device.

In a preferred embodiment, the device comprises:
It includes a vehicle supply voltage source and an energy storage capacitor for producing a high voltage level at which the energy storage capacitor is constantly charged. The first diode is connected between the storage capacitor and the supply node and the second diode is connected between the voltage source of the vehicle and the supply node. The series circuit connected between the supply node and ground is
Includes a controllable current source in series with the detonator. A regulated voltage source is connected to the first node and provides a regulated voltage to the microprocessor controller. The microprocessor controller has a control output connected to the controllable current source and includes means for controlling the controllable current source to deploy the supplemental inflatable restraint system when needed, the supply of the vehicle In the case of a voltage source interruption, a storage capacitor can power the regulated voltage source, the microprocessor controller, the controllable current source and the detonator.

Preferably, the device includes a storage capacitor, a first controllable current source in series with a first detonator, and a second controllable current source in series with a second detonator. Including. A microprocessor controller responsive to sudden vehicle deceleration includes means for pulsing a first controllable current source to deploy a first inflatable auxiliary restraint, and the first current source is disconnected. Means for delaying the deployment of the second current source by a later predetermined period and means for pulsing the second controllable current source for deploying the second inflatable auxiliary restraint after said delay. .

The device includes an energy storage capacitor and a series circuit connected to the energy storage capacitor, the series circuit including a controllable regulated current source, a deployment detonator, and an electromechanical actuator. I'm out.

[0013]

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in one embodiment thereof. In FIG. 1, the illustrated device includes a storage capacitor 12 that is constantly charged to a predetermined voltage level, for example 36 volts, by a power source connected to line 10. A predetermined voltage level is set to allow the capacitor 12 to operate the inflatable auxiliary restraint device only for a short time after the power is shut off during the deployment operation.
Ensures sufficient energy storage at.

A series circuit including a controllable current source 14 and a detonator 18 is connected across the capacitor 12 and is thereby energized in the event of battery interruption. The controllable current source 14 is a line 1 connected to a control device (not shown).
6 in response to the control signal on line 16
It is possible to switch between a state in which no current is supplied to 8 and a state in which a biasing current adjusted to deploy the auxiliary inflatable restraint system is supplied to the detonator 18.

Controllable current source 14 is controlled by pulses 17 on line 16 of a predetermined duration. In response to the pulse of the predetermined duration, the current source 14 supplies current to the detonator 18 for a predetermined period of time, the current and the predetermined period of time energizing the detonator 18 as needed. And is sufficient to deploy the inflatable auxiliary restraint device. With the use of a controllable current source of predetermined pulse time and known characteristics, the amount of power used by the capacitor 12 during deployment can be predetermined and more efficiently managed and consumed. The elimination of the stored energy allows the capacitor 12 to be of a relatively small size.

Controllable current source 14 may be a transistor, a transmission gate, or, preferably, a controllable current source such as a regulated current source as shown in FIG. 10 and described in further detail below. The current source shown in FIG. 10 is controllable by several control lines connected to a controller or microprocessor and provides a constant current regulated from the energy stored in the storage capacitor, eg 2 amps.
The duration of the current supply is determined by the size of the energy storage capacitor and the initial voltage level. A suitable configuration is used at 22 and 36 volts, but the initial voltage level of the storage capacitor can be set to any level required by the system designer.

Referring now to FIG. 2, the embodiment of the control circuit shown is a 5 volt regulator 36, microprocessor 3
8. Includes one storage capacitor 24 as an energy storage source for current source 40 and detonator 42.

In the illustrated apparatus, the vehicle supply voltage is supplied from the vehicle power supply on line 20 which is connected through diode 30 to node 34 from which a 5 volt regulator 36 and controllable. Current source 40 receives power. Reference numeral 44 indicates that another load, such as a further deployment loop or diagnostic circuit, is attached to node 34. A regulated power supply 36 supplies regulated 5 volts to a microprocessor 38 which controls a current source 40 via line 39.

A voltage setup circuit 22 is connected between the ignition voltage source on line 20 and a storage capacitor 24, which is here indicated by its internal capacitance 26 and its equivalent series resistance (ESR) 28. The equivalent series resistance 28 is generated during cold operation and is 4,700 μF.
In the case of the aluminum electrolytic capacitor, the effective value is 1.5 to 2 ohms.

Normally, the output voltage of the voltage setup circuit 22 is greater than the ignition voltage supplied to the line 20, so that the regulated voltage source 36 and the current source 40 receive power via the diode 32. The diode 30 provides a redundant path for power in the event of a failure in the voltage setup circuit 22. The storage capacitor 24 powers the voltage regulator 36, the microprocessor 38, the current source 40 and the detonator 42 via the diode 32, if desired.

Referring now to FIG. 3a, the voltage across capacitor 24 at the deployment event at time t ₀ is shown, at which time the vehicle supply voltage is disconnected from the auxiliary inflatable restraint system. Between times t ₀ and t ₁ , microprocessor 38 is processing data for a sudden deceleration event,
On the other hand, its internal decision routine determines whether deployment of the auxiliary inflatable restraint system is required.

At time t ₁ when microprocessor 38 determines to energize current source 40, pulse 48 (FIG.
b) is applied to the control input of the current source 40 to cause the detonator 42
To drive. The pulses in the current source 40, whose length is known to be sufficient to energize the detonator 42, have a predetermined length between times t ₁ and t ₂ . For example, 2 ms
In the case of a detonator rated at a current of 2 amps between
It is desirable to provide a constant current of 2 amps for 2.5 ms. Therefore, the period between times t ₁ and t ₂ is 2.
5 ms.

During the period between times t ₀ and t ₁ , the microprocessor 38 is driven by the power provided by the storage capacitor 24, as shown by the gradual decay in the voltage across the storage capacitor. Gradually releases the energy of. Time t at which the current source 40 is energized
_{At 1} , the large 2 amp current drawn by the current source 40 causes an instantaneous voltage drop across the effective ESR resistor 28, which in turn causes a capacitor voltage drop as shown.

Due to the increased current drawn from the energy storage capacitor 24 when the current source 40 is energized, the amount of energy stored in the capacitor 24 will increase at a faster rate than before time t ₁ or after time t _2. It decreases between t ₁ and t ₂ . At time t ₂ , the signal on line 39 shuts off current source 40. When the current source 40 shuts off, the decrease in load across the ESR 28 of the capacitor 24 results in an increase in voltage across the capacitor 24 as shown at time t ₂ .

The remaining energy storage of the capacitor 24 supplies the microprocessor 38, which causes the capacitor 24 to no longer be used by the microprocessor 3.
Record the deployment event until time t _{3 when} it does not have enough power to supply 8. Ideally, the times t _{0 to} t ₃ are at least 500 ms.

In FIG. 4, the circuit shown is a detonator 6 connected in series with an electromechanical sensor 62.
It includes a controllable current source 56 connected to zero. The entire series circuit is connected between the current source line 50 and ground. Energizing current is provided on line 50 from a vehicle power supply or storage capacitor 54 through diode 52. Controllable current source 56 is controlled via line 58 by a pulse of predetermined duration from a controller such as microprocessor controller 38 of FIG. The electromechanical sensor 62 may be any electromechanical sensor known to those skilled in the art that signals a sudden deceleration of the vehicle and consequently deploys the inflatable auxiliary restraint system.

The advantages of the circuit arrangement shown in FIG. 4 are doubled. First, two criteria are required to deploy the auxiliary inflatable restraint. The first criterion is the closing of the electromechanical sensor 62, which is time-proven and reliable in both its simplicity and accuracy. The second criterion is the decision by the system controller to pulse the line 58. The controller decision is responsive to a second acceleration sensor, such as a continuous range transducer type. These two criteria provide unique redundancy in the decision. The first decision is in the closed circuit of electromechanical sensor 62 and the second decision is to pulse line 58. The present system, by requiring redundant decisions, and by providing a system in which a single failure mode cannot result in deployment of an inflatable auxiliary restraint,
It can help prevent unwanted deployment of the system.

A second advantage of the device shown in FIG. 4 is the realization of an electromechanical sensor 62 which does not destroy the switch contacts of the sensor 62 by the arc during closing. In particular,
The system ensures that the electromechanical sensor 62 is closed before a pulse is applied to the controllable current source 56 on line 58 during sudden vehicle deceleration where it is desirable to deploy an auxiliary inflatable restraint system. Can be configured. In such a configuration, when electromechanical sensor 62 is closed, there is no current provided by controllable current source 56,
Therefore, there is no current to arc the switch electrode of sensor 62. After a very short delay, the system controller pulses the controllable current source 56 on line 58,
The current source responds by sending a current to the electromechanical sensor 62 which grounds through the sensor 62 to cause deployment of the auxiliary inflatable restraint system.

FIG. 5 shows a flow chart for the control routine. In step 64, the controller receives sensor input representative of the vehicle's acceleration condition. This sensor input is provided by an acceleration sensor in a manner well known to those skilled in the art. Known acceleration sensors include semiconductor, piezoresistive and capacitive devices that output a signal proportional to the acceleration of the vehicle, or, in a simpler case, an electromechanical device of the type used as sensor 62 in FIG. A two-state acceleration sensor such as

In response to the sensor input, the controller
At step 66, the input signal is discriminated in a manner well known to those skilled in the art to determine whether the inflatable supplemental restraint system should be deployed. If no deployment decision was made in step 68, the routine again returns to step 6.
Return to 4 and wait for new sensor input data. If a deployment decision is made, the routine proceeds to step 70, where there is a slight delay on the order of 100 microseconds to fully close electromechanical sensor 62 and / or optimize deployment time. to enable. In step 72, the control pulse causes the previously mentioned current sources 14, 40, 5
A controllable current source, such as 6, is deployed to deploy the auxiliary inflatable restraint system. The pulse output in step 72 has a predetermined duration that releases only a predetermined amount of stored energy from the energy storage capacitor.

In FIG. 6, a multi-device inflatable auxiliary restraint system is shown. The illustrated apparatus includes a microprocessor 86, a regulated voltage source 84, controllable current sources 92, 9
6, including deployment detonators 98, 100, electromechanical actuator 104, and FET 110.

In general, the system shown is powered by a 36 volt supply voltage on line 76 via diode 82, which 36 volt supply voltage is connected to the vehicle supply voltage by a voltage step-up circuit (FIG. Given (not shown). When the supply voltage of the vehicle is cut off, the line 76 always turns on 3
A capacitor 78 charged to 6 volts is used as an energy store for the system and supplies power to node 81 via diode 82. A voltage regulator 84, connected to node 81, provides the regulated voltage to microprocessor 86, both under normal operating conditions and when the battery is shut off but stored energy is still stored in capacitor 78. , Supply power to the microprocessor 86.

Microprocessor 86 processes the sensor information and generally monitors the status of the auxiliary inflatable restraint system. Sensor monitoring and ignition decisions are implemented in a manner well known to those skilled in the art and are responsive to an acceleration sensor 88 of known type.

Lines 101, 105 and 109 are provided for system diagnostics. During system diagnostics, a small current is applied on lines 93, 95 and the voltage levels on lines 105, 109 are monitored to determine if a break has occurred anywhere in the electromechanical actuator circuit. Also, in a deployment event, lines 93, 95, 101, 105 and 109 are used by microprocessor 8 to record the deployment event.
Signal to 6.

The electromechanical actuator 104 closes during a sudden deceleration of the vehicle where it is desirable to deploy two supplemental inflatable restraints. Also, in response to sudden deceleration,
The microprocessor 86 connects the FET via the resistor 108.
FET 110 to output a signal on line 106 to 110 so that current flows from actuator 104 to ground.
Give a forward bias to. The microprocessor then controls the controllable current source 92, via lines 90, 94.
A current pulse of a predetermined duration is applied to energize 96 to energize initiators 98, 100, respectively.

In FIGS. 7 and 8, energy management of the storage capacitor for the system shown in FIG. 6 will be understood. In FIG. 7, graph 114 shows the voltage across the storage capacitor during a deployment condition in which the vehicle supply voltage is shut off and both driver and passenger detonators are energized simultaneously. During energization of the two detonators, the surge current flowing in the system is high due to the high current drawn across the ESR of the capacitor 78 between times t ₁ and t ₂ , as shown by portion 117 of the graph. A large voltage drop occurs at 78.

In order to maintain the required current for the current sources 92, 96, the capacitor 78 must be charged to a sufficiently high voltage and for the entire period from time t ₁ to time t _2. To ensure that each of the sources 92, 96 provides sufficient current to the detonators 98, 100 for a sufficient period of time, it must be of a sufficiently large size so that there is sufficient voltage across the capacitor 78. I have to. Line 115 represents the minimum allowable voltage across capacitor 78 during detonator deployment.

Referring now to FIG. 8, the gradual deployment of detonators 98, 100 occurring at times t ₁ and t ₃ results in more effective energy management of storage capacitor 78, lower capacitor charging voltage Vc 'and smaller size. Capacitor 78 is allowed.

The graph 116 shows the voltage across the capacitor 78 under development conditions after the supply voltage of the vehicle was cut off at time t ₀ . Line 122 represents the minimum voltage required to individually deploy the detonator on the driver side, line 1
24 represents the minimum voltage across the capacitors 78 which individually deploy the detonator on the passenger side. The minimum voltage levels 122, 124 are different because in many systems the total impedance on the driver and passenger sides is different, thus requiring different voltage levels to guarantee a current of 2 amps during deployment. However, if the driver side and passenger side circuits have the same impedance, then the lines 122, 12
4 will be on the same level.

In FIG. 8, the capacitor is initially at its normal voltage level V _C ′, eg 36, until the vehicle's voltage source is shut off by sudden vehicle deceleration at time t ₀ .
Charged to the volt. From time t ₀ to t ₁ , the microprocessor processes the sensor input to determine deployment of the auxiliary inflatable restraint system. From time t ₁ to t ₂ , a pulse is applied to current source 96 on line 94, which pulse provides a current of at least 2 amps to detonator 100 for a limited period between times t ₁ and t ₂ . At time t ₂ , the pulse on line 94 is terminated and after a short delay before time t ₃ , the pulse on line 90 is applied to current source 92, which provides 2 amps of current to passenger detonator 98. Deploy the passenger inflatable auxiliary restraint. The pulse on line 90 is applied from time t ₃ to time t ₄ and is terminated at time t ₄ to terminate the current through current source 92.
From time t _{4 the} voltage across capacitor 78 is level 126
Until the microprocessor 86 reaches the capacitor 7
The advantage gained by the stepwise deployment of the inflatable supplemental restraint system, which continues to function on the stored energy at 8 to record the signal level during the deployment event, is the relatively low required voltage across the energy storage capacitor. . When the two initiators are energized simultaneously, the current drawn from capacitor 78 is doubled. Similarly, the effect of ESR on capacitor 78 is increased resulting in a large voltage drop at time t ₁ in FIG. However, when the detonator is independently energized, the drawn current is limited to half the simultaneous energizing current, which limits the effect of ESR on the capacitor 78, and consequently the time in FIG. Limit the voltage drop that occurs at t ₁ and t ₃ . The smaller voltage drop that occurs during deployment reduces the required charging voltage across capacitor 78 just prior to deployment.

In FIG. 9, an embodiment of the flow chart used in the circuit of FIG. 6 is shown. Steps 128, 1
At 30 and 132, the microprocessor controller 86 receives sensor input from a sensor that monitors vehicle deceleration, discriminates the input signal (step 130), and determines whether to deploy the auxiliary inflatable restraint system (step 130). Step 132). The routine proceeds to step 134 where there is a slight delay to ensure the electromechanical sensor 104 is closed and to optimize the deployment time of the auxiliary inflatable restraint system. In step 136, a control pulse of limited duration is applied to the controllable current source 96 on line 94 to energize the driver-side detonator 100, which detonates the driver-side inflatable auxiliary restraint. Unfold the ingredients.

A very short delay is incorporated in step 138 to separate the driver-side detonator deployment in step 140 from the passenger-side detonator deployment. In step 140, a pulse of limited duration is provided on line 90 to controllable current source 92, which provides a current of 2 amps to passenger detonator 98 to energize detonator 98, and Deploy an inflatable auxiliary restraint on the passenger side. In this way, the energy of the capacitor 78 can be effectively managed and the power from the capacitor 78 can be developed for deployment in such a way that the output pulses are provided to the controllable current sources 92, 96 in a stepwise manner with a limited duration. The release can be predetermined.

In step 142, the microprocessor 86 continues to function with the stored energy in the capacitor 78 to reduce the signal level in the inflatable supplemental restraint system until the capacitor 78 does not have enough energy to power the microprocessor 86. Record.
An example pulse duration for the control pulse for the controllable current source is 2.5 milliseconds.

By staging the deployment in the system shown in FIG. 6, the current drawn from the capacitor 78 in one deployment time is, for example, 4.4 amps to 2.2 amps (including the safety difference). Approximation).
The drop in capacitor voltage during deployment, eg, the reference values 117, 118, 120 in FIGS. 7 and 8, is due to the ESR of the capacitor that occurs under high current draw conditions. The voltage required by capacitor 78 for simultaneous deployment as shown in FIG. 7 is equal to That is, V _req = V _as + V _dr + V _sat + V _esr, where V _as is the voltage drop across the electromechanical sensor, V _dr is the voltage drop across the driver side deployment circuit, and V _sat is the saturation voltage drop of the current source, And V _esr is the voltage drop due to the ESR of the capacitor. 0.075 ohm sensor impedance, 3.435 ohm driver side circuit impedance, 2 volt saturation voltage to current source, and 1.
Assuming an ESR of 5 ohms, the required voltage V _req is 1
It is 6.577 volts.

Voltage drop during energy storage time of (0.18 amps) / C, (4.46 amps * 0.002)
Second) / C simultaneous voltage drop during deployment, and 33.15.
It can be seen that the minimum capacitance for capacitor 78 is 11.399 μF, assuming an initial voltage of volts.

However, for the stepwise expansion, V _req = V _as + V _dr + V _sat + V _esr However, a current of only 2.2 amps flows to the sensor and the expansion circuit, and 2.26 across the ESR. It turns out that amperes are valid and V _req is equal to 13.112 volts. Assuming a driver-side voltage drop during deployment of (2.26 amps * 0.002 sec) / C and all else being the same as the previous example, the minimum capacitance for capacitor 78 is 9,209 μF. It turns out that Since the impedance of the passenger side expansion circuit is smaller than the impedance of the driver's expansion circuit, the passenger side circuit will only require a smaller capacitor 78. However, the circuit with the highest impedance determines that the actual minimum capacitance is used. Thus, in this example, a reduction of approximately 20% in the minimum required capacitance for the capacitor 78 can be obtained.

As can be seen, the gradual deployment results in a reduced capacitor size for the energy storage capacitor. If needed, the capacitor size is a trade-off with the initial charging voltage,
That is, the higher the initial charge voltage, the smaller the required capacitor size.

In FIG. 10, the configuration of the controlled current source is shown. Line 209 is connected to a current source, for example, line 34 and output line 310 of FIG.
Power is supplied by connecting to a detonator such as. The controlled current source works as follows.

The enable line 328, the input A line 330, and the input B line 332 control the logic gates 312 to 326, and the IC current sources 268, 278, 282, 28 by the following method.
4 is turned on selectively, the circuit 2A, 150mA, 10
Control mA and 2 mA current sources. Current sources 268, 2
78, 282, 284 are transistors 248, 26
6, 286, 302 serving as a current sink and its emitter as shown in Darlin.
gton) -transistor pair (258, 260), (2
74, 276), (292, 294) and (304,
306). Current sources 268, 278, 2
Turning off 82 and 284 shuts off power by turning off their Darlington transistor pair.

The resistors 256, 264, 280 and 296 in series act as a current sensing resistor for the current source. Resistor 256 provides transistors 258, 2 for line 310.
Controls the 2 amp output of 60. Resistors 256,264
The series combination of
Controls 150 mA output of 4,276. Resistor 256,
The series combination of 264 and 280 controls the 10 mA output of transistors 292, 294 to line 310, and the series combination of resistors 256, 264, 280 and 296 sets the transistors 304, 30 to line 310.
6 2mA output. The Darlington transistors are current sources 252, 254, 270, 2 as shown.
Biased through 72, 288, 290, 298, 300.

A circuit including amplifiers 222, 232 biased by voltage bias sources 220, 234 controls transistors 224, 230 to set up a bias voltage across resistor 218. The resistors 226 and 228 are
Adjusted to set the bias voltage, resistor 226
Are temperature sensitive because they create temperature stability for the circuit.

In summary, a resistor 256 equal to the bias voltage across resistor 218, which is also an adjustable resistor,
By maintaining a voltage drop across 264, 280, 296 (sense resistor), a regulated current is provided on line 310. Amplifier 236 controls transistor 246 in response to an error between the bias voltage across resistor 218 and the voltage across the resistor string of sense resistors.

Transistor 246 is operatively associated with current source 244 to provide control transistors 248, 26.
6, 286, 302 are controlled. Detection resistors 256 and 26
When the current across 4, 280, 296 is higher than necessary,
The resulting increased voltage across the sense resistor is
The output of 36 is increased to partially turn off transistor 246. Transistor 246 also partially turns on control transistors 248, 266, 286, 302, which results in the Darlington transistor pair (258, 2).
60), (274,276), (292,294),
Affects the adjustment of the current output of (304, 306).

This circuit operates as follows. Line 328
When is low, only 2mA of current output from transistors 304 and 306 is enabled. When line 328 is high and lines 330 and 332 are low, only 10 mA output of Darlington transistors 292 and 294 is enabled. Darlington transistor 27 for line 310 when line 328 is high, line 330 is low and line 332 is high.
Only 4,150 mA output of 150 mA is enabled. When line 328 is high, line 330 is high and line 332 is low, only 2.11 mA output of Darlington transistors 258, 260 to line 310 is enabled. Three lines 328,330,33
When all two are high, all current sources are turned off.

The current mirror 208 includes a transistor 24.
8 and 266 supply current to the current source 2
Biased by 16. Line 202 is normally high during normal operation of the circuit and is biased by current source 210 and transistors 212, 214. However, operational amplifier 204, whose inverting input is biased by voltage bias 206, responds to the output voltage level on line 310,
This is the bias set by the voltage bias 206.
When rising above the level, it indicates that the circuit is saturated and unable to provide a regulated current output. In such a condition, transistor 203 is forward biased and line 202 is used to indicate the saturation of the circuit.
Let go low.

The blocked reverse bias causes the amplifier 238 to
And device 240. When the current source is reverse biased, line 310 rises above the voltage on line 209. This condition results in a high output from amplifier 238, which triggers bias shutoff circuit 240, which is a standard circuit readily constructed by those skilled in the art to shut down the operation of the IC.

Device 242 is a standard heat sensitive circuit that controls the thermal shut down of the IC. The device 242 includes a temperature sensitive VVE transistor connected to a voltage comparator that outputs a high signal when the temperature of the circuit rises above 150 ° C. Such circuits are standard and well known to those skilled in the art. The high signal from device 242 sets flip-flop 250, whose output, which is inverted by inverter 262, shuts off current source 268 and inhibits the output of 2 amp current source transistors 258, 260. Flip-flop 250 cannot be reset until line 328 goes low and then high again. Provided is an auxiliary inflatable restraint system designed such that the detonator is energized 2 milliseconds after a current of 2 amps. The thermal cutoff must be set so that it does not occur for at least 4 to 7 milliseconds of operation of the 2 amp current source.

In normal operation, a 2 mA current source is energized to set up a bias on the auxiliary inflatable restraint system for system diagnostic purposes. 150m
A current source tests the impedance of the detonator, so 5% of 1 Hz for 4 pulses on each firing cycle
Energized by a duty cycle square wave. Figure 10
The circuit of can be readily configured by those skilled in the art to be controlled by a microprocessor or other type of controller, according to the above description.

US Patent Application No. 0 from which this application claims priority
The disclosure in No. 33,230, and the abstract accompanying this application are incorporated herein by reference.

[Brief description of drawings]

FIG. 1 is a circuit diagram illustrating an example of a portion of an auxiliary inflatable restraint device.

FIG. 2 is a circuit diagram showing an example of an auxiliary restraint device.

FIG. 3a is a graph showing the voltage across a storage capacitor of the system of FIG. 2 in a deployment event where the vehicle supply voltage is cut off. b is a graph showing controlled pulses for controlling the current source of the system of FIG.

FIG. 4 is a circuit diagram showing a second embodiment of a part of the auxiliary restraint device.

5 is a flow chart used by the auxiliary inflatable restraint system of FIG.

FIG. 6 is a circuit diagram illustrating one embodiment of a deployment system for multiple inflatable auxiliary restraints.

7 is a graph showing energy management of a storage capacitor during deployment of the multiple inflatable supplemental restraint of FIG.

8 is a graph showing energy management of a storage capacitor during deployment of the multiple inflatable supplemental restraint of FIG.

9 is a flow chart used by the controller of the multiple inflatable auxiliary restraint device of FIG.

FIG. 10 is a circuit diagram showing an embodiment of a controllable current source.

[Explanation of symbols]

 14 controllable current source 18 detonator 22 voltage setup circuit 28 equivalent series resistance (ESR) 36 voltage regulator 38 microprocessor 40 current source 42 detonator 56 controllable current source 60 detonator 62 electromechanical sensor 84 voltage regulator 86 Microprocessor 88 Acceleration sensor 92 Controllable current source 96 Controllable current source 98 Deployment detonator 100 Deployment detonator 104 Electromechanical actuator 204 Operational amplifier 208 Current mirror

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kevin Dale Kincard Lara Garden Court 1401 Kokomo, Indiana, USA 1401 (72) Inventor Mark Wendell Goes Indiana 46902 Kokomo, USA South 400 East 722

Claims (4)

[Claims] 1. An expansion characterized in that it comprises a series circuit including a controllable current source (56) for an inflatable auxiliary restraint device, a detonator (60) and an electromechanical sensor (62). Possible auxiliary restraint device. 2. A control means (63) for controlling the controllable current source to cause a current to flow in a series circuit after the closing of the contacts of the electromechanical sensor.
The inflatable auxiliary restraint device described. 3. While the developing current is not present in the current loop,
The electromechanical actuator connected in the current loop to the detonator is closed to provide a delay prior to providing a current to the controllable current source that flows through the detonator and the electromechanical sensor to energize the detonator. A method, comprising the step of deploying a secondary expandable restraint device that occurs. 4. An inflatable device comprising in series a detonator (60) and a regulated current source (56) including means for providing a regulated current rather than self-destruction in response to a control signal. Auxiliary restraint device.