MXPA00001015A - System and method for testing a circuit device for controlling an automobile passenger protection mechanism - Google Patents

Abstract

A circuit device for controlling an automobile passenger protection mechanism has a parallel circuit which is supplied by an energy source (5) delivering a test current (ILADE), said parallel circuit consisting of an energy storage capacitor (1), a series circuit consisting of a ignition element (2) and a controllable driver (3). When the energy storage capacitor (1) is discharged at least to a large extent and when the driver (3) is switched to a conductive state for testing purposes, a test voltage (UPRUF) which drops out in the series circuit (2, 3) is taken up and evaluated.

Description

ARRANGEMENT AND PROCEDURE FOR TESTING A SWITCHING DEVICE, WHICH IS PROVIDED FOR THE CONTROL OF A PASSENGER PROTECTION MEANS OF AN ENGINE VEHICLE Field of the Invention The invention relates to an arrangement and a method for testing a switching device that is provides for the control of a means of protecting passengers in a motor vehicle. BACKGROUND OF THE INVENTION A communication device for controlling a passenger protection means of a motor vehicle (684 163 Bl) is known in which a power supply capacitor parallel to a series connection of a first motor is arranged. controllable power stage, an ignition element of the passenger protection agent and another controllable power stage. The passenger protection means in the form of an airbag or a safety belt is only turned on, if both power stages are connected driving. For the verification of the operating capacity of a power stage, it is caused by a control switching each time one of the power stages is connected to the test objective, for which the other power stage simultaneously remains in force. blocking status. Each time a current sensor is coordinated to each power stage. The current obtained during the described test routine allows to obtain conclusions with respect to the operating capacity of the verified stage. Such series switching consisting of two controllable power stages and an ignition element require, in particular, the large number of controllable power stages in their implementation with the integrated switching circuit, and with this a complicated and expensive manufacturing. WO 93/17893 Al discloses a switching device for the control of a means of protecting passengers inside a vehicle, in which a power store is connected in parallel to a series connection of an ignition element and a single stage of controllable power. The passenger protection means in the form of an airbag or a belt is turned on, when the controllable power switch is connected driving. In this switching device the operating capacity of the power stage is not verifiable, since the energy storage capacitor in each control for the purpose of the test is discharged through the ignition element. An undesired start of the passenger protection means would be the consequence.

SUMMARY OF THE INVENTION It is the task of the present invention to avoid the disadvantages of the known arrangements and especially to create an arrangement and a procedure for testing a switching device for the protection of passengers, which allows, despite a low number of construction parts, a satisfactory test of functioning. The part of the invention that refers to the arrangement of the task is solved by means of claim 1. The part that relates to the method of the invention is solved by the features of claim 10. Advantageous embodiments of the invention are characterized by The characteristics of the dependent claims of claim 1 and claim 10 Brief description of the figures The invention, its constructions and its advantages will be explained in detail in the form of exemplary embodiments with reference to the drawing. Where: Figure 1 shows a connection diagram of a first arrangement according to the invention; Figure 2 a connection diagram of another arrangement according to the invention; 3 shows a flow chart for the method for verifying the operating capacity of a power stage in an array according to Figure 1 or Figure 2. Detailed description of the invention Figure 1 shows a connection plane of 1 arrangement according to the invention. A Power source 5 in the form of a current source produces an Iladβ test current for a parallel switching circuit 1 as well as a series connection of an ignition element 2 and a controllable power stage 3. The terminals KL1 and KL2 characterize those connection points which are connected to the power source 5. In evaluator 4, it controls via control signal ST the driving stage 3 as well as grabs at the junction point V between the ignition element 2 and the control stage. 3 power of a Uprur test voltage, in this case refers to the mass potential (terminal K12). In addition, evaluator 4 can provide a fault signal f at its output. The predescribed parallel switching contains another parallel power supply capacitor 1 and the predescribed series connection 2, 3 having coordinated the series circuit, containing a resistor 6 and a controllable switch 7, which by means of another control signal STX of the evaluator is actionable. The basic thinking of the invention consists in that, in the discharged power supply capacitor 1, the closing capacity of the power or power stage 3 can be verified. With this the Ilad test current. provided by the power source 5, is measured such that the ignition element on receiving that Ilide test current still does not turn on. Thus presents the test current Ilade also no high level of the type that the energy storage capacitor 1 within a very short time could be charged to its ignition voltage Uc. It now conducts a control signal ST of the evaluator 4 to the passage of the power stage 3 from the capacitor to the discharger energy store approximately simultaneously from the blocking state to the driver, then the test current Ilade provided by the power source flows then 5 through the ignition element 2 and the power stage 3. The approximately Upru test voltage remains constant- where the Upruf test voltage is here at approximately the same mass potential, if it is understood as a potential difference between the junction point VC and the mass potential KL2 and with this the collector-emitter voltage of the power transistor 3, it is thus shown that the power stage 3 is allowed to switch from its blocking state to its conductive state and with this is good performance. The test voltage increases, however, to a value substantially greater than the mass or reference potential KL2, so that the controllable power stage 3 is not allowed to change from its blocking state to its conductive state, which is thus defective. A power of the power supply capacitor 1 by the test current Ilad. it is then responsible for the increase of the Uprut test voltage, especially if the test voltage Upruf exceeds a predetermined voltage value or an established increase, provides the control switching 4 a fault signal f as an indication for an incapable power stage 3. If the controllable power stage 3 is thus formed to be closed, then it is also possible, by measuring a voltage drop in the ignition element 2, to check the resistance state of the ignition pill and / or the test current Ii With this, the operating capacity of the power source 5 and of the ignition element 2 can be closed again. After this verification of the closing capacity of the power stage 3, it is verified, if the power stage 3, is can transform from its blocking state to its conductive state, a corresponding control signal ST is re-proportioned by the evaluator 4. If the power stage 3 is to open it and with this able to operate, then the test current Ilade provided by the power source 5 acts fully as power current for the energy storage capacitor 1 and powers it to an ignition voltage - Ux, from which an indication is recognized, it will light up. This also increases the potential at the junction point V. The evaluator 4 also checks the Uprut test voltage, either during charging of the power supply capacitor 1 or after a predetermined waiting time. charged the energy storage capacitor 1 to its ignition voltage Uz. If the power stage 3 is not allowed to open, then the test current Iladβ flows again on the ignition element 2 and the power stage 3: the test voltage Uprut corresponds approximately to the ground potential of the terminal KL2 and does not vary with time, but, if it is allowed to open, then the Upruf test voltage increases to a voltage value, which is essentially greater than the mass potential at terminal KL2. Thus the evaluator 4 recognizes that the test voltage Upru £ after the addition of the control signal ST to open the power stage 3 exceeds a minimum voltage increase, thus evaluating the power stage 3 as opening it. Alternatively, it is also possible to test the Uprut test voltage there after a minimum time after the application of the control signal ST to open the controllable switch 3, if it exceeds a minimum voltage value. If this is the case, then in this case the power stage 3 is open as well as capable of operation. However, if the Upru test signal does not reach the minimum voltage increase or the minimum voltage value, then a power stage 3 capable of operating in the direction is presented, that can not be changed from the closed state to the open state. , in this case the evaluator 4 produces a signal of f lla f. Simultaneously with the verification of the ability to open of the power stage 3, the operating capacity of the energy storage capacitor 1 and the current source 5 are tested together. The essential advantage of the arrangement according to the invention and the procedure of agreement with the invention consists in that despite the use of only a single power stage 3 controllable in an ignition circuit for a passenger protection means such as airbag, safety belt and others, the same power stage 3 can to be tested in regard to opening as to close without the ignition element 2 arranged in series with the power stage 3 being turned on. The number of construction elements used is minimal. For each individually controllable ignition element, only a single controllable power switch is necessary each time. The power source 5 is especially a current source, which produces a printed Iliable test current. Alternatively a voltage source can be used, which however must have relatively high internal resistance so as to be able to produce a test current Illd, printed almost independently of the load and with that especially limited. Charge for example the test current I? Ade with the power stage 3 open to the energy storage capacitor 1 with too great a time constant, it can for the charging of the energy storage capacitor 1, thus after the test of the capacitance of closing the power stage 3, the test current can also take a higher value. The ignition element 2 is coordinated to a passenger protection means in such a way that, in reaction to its ignition, for example gas is released, which inflates an air pocket or at least a part of that air bag. The controllable power stage is preferably a controllable power transistor, which is arranged for an ignition current from the energy storage capacitor 1, provided for igniting the ignition element 2. The evaluator 4 conducts not only evaluation routines but especially also control routines and is preferably a microprocessor, it can but also be constructed as an analogue switching or an evaluation and / or control facility. In their arrangement with respect to the energy source, controllable power stage 3 and ignition element 2 can also be placed interchangeable so that according to FIG. 1 the ignition element 2 is connected to the ground potential KL2. Similarly, the test voltage Upruf can not only be at the ground potential as the second terminal KL2 of the power source 5 but naturally also be in reference to the first terminal KL1. The evaluation of the Uruf test voltage corresponds to the minimum signs and thresholds. Before verification of the closing capacity of the power stage 3, it is preferably checked, if the energy storage capacitor 1 is at least so discharged, that its remaining charge can not lead to the ignition of the ignition element 2 when the power stage 3 is closed. For this, the capacitor voltage Uc is monitored, from the evaluator 4. If the capacitor voltage Uc is less than the minimum threshold then the capacitor of the power supply is almost discharged. After this verification, the procedure described above starts. If he; energy storage capacitor is not discharged to the minimum necessary extent, then it is possible, for example, before starting the described procedure, for a corresponding control signal STX to close the control switching 4, which closes to the control switch 7, to discharge through the resistor, before the next step the power stage 3 by the control signal ST from its closed state to its conductive state and in this way the test voltage U, pruff is measurable and workable. Preferably, after the controlled discharge of the energy storage capacitor 1 and before the operation check, the closing capacity of the power stage 3 is checked again for the charge state of the energy storage capacitor 1. For the evaluation of the ignition voltage Uc of the energy storage capacitor 1 or of the test voltage Upruf during the charging process with the open power stage 3, for example by evaluating the voltage increase or the voltage value at a measurement point or moment established, other conclusions about its capacity can be gained, with this the capacity C of the capacitor 1 is produced from the equation du / dt = Ilade / C, where du / dt is the voltage variation during the charging of the capacitor 1. After the test procedure according to the invention is completed, it leads a closing of the power stage 2 by the control switching 4 with a voltage of of the energy storage capacitor 1 at the ignition of the ignition element 2. for this purpose the evaluator 4 works, in particular by touch signals of the vehicle, taken by suitable sensors and then produces a corresponding ST control signal for triggering the control element. On 2, if a strong enough blow is felt for the firing or start of the passenger protection means. Figure 2 differs from Figure 1 essentially only because high ohmic value decoupling resistors 8 are connected to Terminal KL2 and Terminal KL1 or power source 5. These decoupling resistors 8 cause, that in a short circuit of one of the connection terminals of the ignition element 2 against one of the power potentials in each case the energy stored in the supply or storage capacitor 1 is not in one measure by means of the ignition element 2, which will reach for the ignition current sufficient for the ignition. The switching device can be placed in different ways, especially in the vehicle. Thus, for example, with the exception of the ignition element 2, the entire switching device can be placed together in a control device preferably placed in the center of the vehicle. The ignition element 2 is connected to the control device by means of ignition ducts. Alternatively, the entire switching device according to FIG. 2 can be placed in a space close to the passenger protection agent, where to the decoupling resistors 8 a conductor is connected to the power supply, which for example is connected directly to the edge network or to a central control device for the protection of people. In such a non-central arrangement, in particular, the communication device can also be transmitted in the form of data on the conductor connected to the coupling resistors 8. Such messages contain, for example, a start command for turning on the ignition element 2., commands of diagnosis or results of the diagnosis or initiation news, the data stream is decoupled and the control switching 4 is introduced, which deciphers the coded news and, if necessary, opens or closes the power stage 3. The connected conductor or conductors are it performs especially as a bus or conveyor, which is connected to the different switching devices or decoupling resistors 8 pre-described. the decoupling resistors 8, therefore, cause a short circuit in a switching device - for example, as a consequence of ignition of the ignition element - not to short circuit the entire bus and ignition of the rest of the device is not possible of switching. Figure 3 shows an exemplary embodiment of the method according to the invention. In step SI, the test routine according to the invention is introduced to verify the operating capacity of the power switch 3 of a switching arrangement according to Figure 1 or Figure 2. Here it is verified in step S2, whether the Energy storage capacitor 1 is sufficiently discharged. If the energy storage capacitor is sufficiently discharged, follow step S4, if it is not, it is almost completely discharged by means of step 3. In step 4, power stage 3 is first changed from the locked state to the conductive state. in step S41- before the UpruC test voltage is taken - step S42. In step S5 it is verified, if the test voltage Upru £ exceeds a minimum voltage value, if not, a fault signal "f" is generated in step S6, since the power stage obviously can not be connected driving, but if the Upru £ test voltage falls below the minimum voltage value, then step S7 is performed, 'wherein the power stage 3 is controlled in such a way, that step S71 must be opened.

Stop this waiting for a predetermined time T, before the test voltage Upruf? it is compared with another threshold value, which in the case is equal to the minimum threshold value of step S5. If the test voltage exceeds that threshold value, then the SIO step continues with the normal operation of the switching device for the control of a pass protection means. In another case in step S9, an optical or acoustic "f" fault signal is generated again, since the power stage obviously can not be transferred from the conductive state to the non-conductive state. Verification or over proof according to Figure 3 can be carried out during normal operation of the switching device - thus with the vehicle on, where then at step ca S3 will be necessary to discharge the energy storage capacitor. If the proposed procedure is carried out by operating the control device, so when starting or starting the vehicle, then the energy storage capacitor will usually be discharged.

Claims (11)

1. NOVELTY PE THE INVENTION Having described the invention as above, property is claimed as contained in the following: CLAIMS 1.- Arrangement to test a switching device, which is provided for the control of a means of protecting passengers in a vehicle of motor, characterized in that - the switching device has an energy-storage capacitor, which is arranged parallel to a series switching of an ignition element, and a controllable power stage - the parallel switching is provided with a test current which produces an energy source, and - with an energy storage capacitor at least widely discharged and with a power stage connected in a conductive way, a test voltage that decreases in the series switching by an evaluator is taken and evaluated.
2. 2. Arrangement according to claim 1, characterized in that the test voltage is taken between the point of attachment of the ignition element and the power stage and a terminal of the power source.
3. 3. - Arrangement according to one of the preceding claims, characterized by the tester is tested by means of a voltage drop in the energy storage capacitor, if the energy storage capacitor at least is almost completely discharged, and in which then first the power stage is connected by conducting through the evaluator for the purpose of the test, if it has been determined, that the energy storage capacitor is at least widely discharged.
4. 4. - Arrangement according to one of the preceding claims, characterized in that the test current provided by the power source is less than a starting current necessary to ignite the ignition element.
5. 5. - Arrangement according to one of the preceding claims, characterized in that depending on the evaluation of the test voltage a fault signal is generated by the evaluator.
6. 6. Arrangement according to one of the preceding claims, characterized in that the power stage is switched after its conductive connection for the purposes of the test in a blocking manner and thus the test voltage is taken and evaluated from the evaluator.
7. 7. Arrangement according to claim 6, characterized in that the test voltage after a given period of the blocking switching of the power stage is taken and evaluated.
8. 8. - Arrangement according to one of claims 6 or 7, characterized in that depending on the evaluation of the test voltage obtained after the block switching of the power stage a fault signal is generated.
9. 9. - Arrangement according to one of the preceding claims, characterized in that at least one decoupling resistance is arranged in series to the parallel circuit.
10. 10. Process for testing or testing a switching device, characterized in that it is provided for controlling a means of protecting passengers in a motor vehicle, wherein the switching device has a parallel switching device of a storage capacitor. energy and a series switching of an ignition element and a controllable power stage, where the parallel switching is powered by a test current that produces an energy source-where it has been connected conductively to the energy storage capacitor when less widely discharged the power stage, where after the conductive connection of the power stage is taken is evaluated a test voltage that falls in series switching.
11. 11. - Method according to claim 10, characterized in that the power stage after its conductive connection is connected blocking, and then the test voltage is taken and evaluated.