Fault detection method for safety voltage regulator in safety air bag system

Abstract

The invention relates to a fault detection method for a safety voltage regulator in a safety air bag system, an ignition control device of the safety air bag system comprises a current absorber, and the safety voltage regulator comprises a driver and a metal-oxide-semiconductor field effect transistor (MOSFET). The fault detection method comprises the following steps: a first voltage measurement step: supplying power to the MOSFET through a direct-current power supply of the airbag system so as to measure a first output voltage t of the MOSFET; a second voltage measurement step; then supplying power to the MOSFET through the current sink to measure a second output voltage thereof; a turn-on resistance value obtaining step: obtaining the turn-on resistance value of the MOSFET according to the first output voltage, the second output voltage and the output current of the current absorber; and a fault judgment step: if the obtained conduction resistance value is equal to or greater than a preset threshold value, judging that a fault occurs in the safety voltage regulator.

Description

[Technical field]

[0001] The invention relates to a fault detection method for a vehicle safety airbag system, and in particular to a fault detection method for a safety voltage regulator in the safety airbag system. [Background technology]

[0002] The "background technology" section is only used to help understand the content of the present invention. Therefore, the content disclosed in the "background technology" section may contain some common technologies that are not known to those skilled in the art. The content disclosed in the "background technology" section does not represent the content or the problems to be solved by one or more embodiments of the present invention, nor does it mean that it has been known or recognized by those skilled in the art before the application of the present invention.

[0003] The airbag system is a type of passive safety technology. It is a system used to protect the driver and passengers after a vehicle collision. It is usually composed of acceleration sensors, controllers, gas generators, and airbag components. When a collision occurs, the acceleration sensor captures the collision signal, and the airbag controller collects, analyzes, judges, and processes the captured collision signal. For collisions that may cause safety problems for the driver and passengers, the airbag controller will issue an ignition command in a timely manner to drive the gas generator to ignite, thereby detonating the airbag.

[0004] Figure 1 An airbag system 100 in the prior art is shown. The airbag system 100 includes a system DC power supply 102, an acceleration sensor 104, a controller 106, a safety voltage regulator 108, and a gas generator (airbag) 110, wherein the controller 106 includes a signal analysis device 1062 for collecting and analyzing collision signals from the acceleration sensor 104, and an ignition control device 1064 for outputting an ignition command to the gas generator 110 according to the analysis signal output by the signal analysis device 1062. The ignition control device 1064 includes a current absorber 1066 for detecting the safety voltage regulator 108.

[0005] The safety voltage regulator 108 is connected between the system DC power supply 102 and the controller 106, and is used to adjust the high voltage of the system DC power supply 102 to the low voltage required for ignition and has the switch function of shutting off the system power supply when an open circuit or short circuit fault occurs in the controller 106. The safety voltage regulator 108 is usually composed of a driver 1082 and a switch 1084, wherein the switch 1084 is usually a metal oxide semiconductor field effect transistor (MOSFET). If the on-resistance (RDS) in the MOSFET 1084 is too high (for example, 10 ohms to 100 ohms), it may cause the controller 106 to analyze and process the collision signal from the acceleration sensor 104 and determine that it is the real collision time. The current in the gas generator (airbag) 110 cannot reach the rated value, so that the safety airbag cannot be deployed, which violates the functional safety requirements of the safety airbag system.

[0006] Therefore, it is urgent to propose a method for detecting a working failure of a safety voltage regulator caused by an on-resistance (RDS) of a MOSFET in the safety voltage regulator being too high. [Summary of the invention]

[0007] In view of the above, an object of the present invention is to provide a fault detection method for a safety voltage regulator in an airbag system, which can not only improve the diagnostic coverage of the safety voltage regulator and meet the functional safety requirements of the airbag system, but also will not increase the additional cost of the airbag system.

[0008] To achieve the above-mentioned object of the invention, the present invention provides a fault detection method for a safety voltage regulator in a safety airbag system, wherein the safety airbag system includes a system DC power supply, an acceleration sensor, a controller, a safety voltage regulator, a gas generator and an airbag assembly, the controller includes a signal analysis device and an ignition control device, the ignition control device includes a current sink, and the safety voltage regulator includes a driver and a metal oxide semiconductor field effect transistor MOSFET, and the fault detection method includes the following steps:

[0009] The first voltage measurement step: firstly, the system DC power supply is turned on to supply power to the MOSFET to measure the first output voltage V of the MOSFET 1st ;

[0010] The second voltage measurement step: continuously turning on the current sink to supply power to the MOSFET to measure the second output voltage V of the MOSFET 2nd ;

[0011] On-resistance value obtaining step: according to the first output voltage V 1st , the second output voltage V 2nd And the output current I of the current sinksink , obtain the on-resistance value R of the MOSFET:

[0012] R=(V 2nd -V 1st ) / I sink ;as well as

[0013] Comparison judgment step: compare the on-resistance value R with the preset threshold value R T If the on-resistance value R is equal to or greater than the preset threshold value R T , it is judged that a fault occurs in the safety voltage regulator. If the on-resistance value is less than the preset threshold R T , then it is judged that the safety voltage regulator is working normally.

[0014] According to the fault detection method of the safety voltage regulator in the airbag system of the present invention, it is possible to detect a working fault of the safety voltage regulator caused by an excessively high on-resistance value of the MOSFET in the safety voltage regulator, thereby improving the diagnostic coverage of the safety voltage regulator and meeting the functional safety requirements of the airbag system. Furthermore, since the existing current absorber in the ignition control device is used without adding any new devices, the additional cost of the airbag system will not be increased.

Brief Description of the Drawings

[0015] Figure 1 It is a structural block diagram of the airbag system in the prior art.

[0016] Figure 2 Flowchart of a fault detection method of a safety voltage regulator according to an exemplary embodiment of the present invention. [Specific implementation method]

[0017] The subject matter described herein will now be discussed with reference to specific embodiments. It should be understood that the discussion of these specific embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and is not a limitation of the scope of protection, applicability or examples set forth in the claims. The function and arrangement of the elements discussed can be changed without departing from the scope of protection of the present disclosure. Each example can omit, replace or add various processes or components as needed. In addition, the features described relative to some examples can also be combined in other examples.

[0018] As used herein, the term "including" and its variations represent open terms, meaning "including but not limited to". The term "based on" means "based at least in part on". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0019] like Figure 2 As shown, a fault detection method 200 of a safety voltage regulator according to an exemplary embodiment of the present invention is provided. The method 200 is applied to Figure 1 The airbag system 100 shown includes the following steps:

[0020] First voltage measurement step 202: First, turn on the system DC power supply 102 (in this embodiment, including a battery power supply and a capacitor power supply connected in parallel) to supply power to the MOSFET 1084 to measure the first output voltage V 1st ;

[0021] Second voltage measurement step 204: Continue to turn on the current sink 1066 to supply power to the MOSFET 1084 to measure the second output voltage V of the MOSFET 2nd ;

[0022] On-resistance value obtaining step 206: according to the first output voltage V 1st , the second output voltage V 2nd and the output current I of the current sink 1066 sink , based on the following formula, the on-resistance value R of MOSFET1084 in the safety regulator 108 is obtained;

[0023] R=(V 2nd -V 1st ) / I sink ;

[0024] Comparison step 208: Compare the on-resistance value R with the preset threshold value R T If the on-resistance value R is equal to or greater than the preset threshold value R T , it is determined that a fault occurs in the safety voltage regulator 108, if the on-resistance value R is less than the preset threshold value R T , it is determined that the safety voltage regulator 108 is working normally. T It can be preset according to the specific application scenario. In this embodiment, it is set to 3 ohms.

[0025] In a variation of this exemplary embodiment (not shown), the system DC power supply 102 includes a battery power supply and a capacitor power supply, and before the first voltage measurement step, it also includes: a pre-processing verification step: turning on the battery power supply and the capacitor power supply respectively, and verifying whether the output voltage of the battery power supply is within the normal voltage range, and whether the output voltage of the capacitor power supply is less than 20V. When the output voltage of the battery power supply is within the normal voltage range, in the first voltage measurement step, the MOSFET is powered by the battery power supply to measure the first output voltage V 1st When the output voltage of the battery power source is not within the normal voltage range, in the first voltage measurement step, the capacitor power source is used to supply power to the MOSFET to measure the first output voltage V 1st .

[0026] According to the fault detection method of the safety voltage regulator in the airbag system of the present invention, it is possible to detect the working failure of the safety voltage regulator caused by the excessively high on-resistance value (e.g., 10-100 ohms) of the MOSFET in the safety voltage regulator, thereby improving the diagnostic coverage of the safety voltage regulator and meeting the functional safety requirements of the airbag system. Moreover, since the existing current absorber in the ignition control device is used without adding any new period, the additional cost of the airbag system will not be increased.

[0027] The specific embodiments described above in conjunction with the accompanying drawings describe exemplary embodiments of the present invention, but do not represent all embodiments that can be implemented or fall within the scope of protection of the claims. The term "exemplary" used throughout this specification means "used as an example, instance, or illustration" and does not mean "preferable" or "having advantages" over other embodiments. For the purpose of providing an understanding of the described technology, the specific embodiments include specific details. However, these technologies can be implemented without these specific details.

[0028] The description of the above disclosure of the present invention is provided to enable any person of ordinary skill in the art to implement or use the present invention. It is obvious to those of ordinary skill in the art that various modifications to the above disclosure of the present invention are made, and the general principles defined herein may also be applied to other variations without departing from the scope of protection of the above disclosure of the present invention. Therefore, the disclosure of the present invention is not limited to the examples and designs described herein, but is consistent with the widest range of principles and novel features consistent with the above disclosure of the present invention.

Claims

1. A method for detecting a fault of a safety voltage regulator in a safety airbag system, wherein the safety airbag system comprises a system DC power supply, an acceleration sensor, a controller, a safety voltage regulator, a gas generator and an airbag assembly, the controller comprises a signal analysis device and an ignition control device, the ignition control device comprises a current sink, and the safety voltage regulator comprises a driver and a metal oxide semiconductor field effect transistor MOSFET, the fault detection method comprises the following steps: The first voltage measurement step: firstly, the system DC power supply is turned on to supply power to the MOSFET to measure the first output voltage V of the MOSFET 1st ; The second voltage measurement step: continuously turning on the current sink to supply power to the MOSFET to measure the second output voltage V of the MOSFET 2nd ; On-resistance value obtaining step: according to the first output voltage V 1st , the second output voltage V 2nd And the output current I of the current sink sink , obtain the on-resistance value R of the MOSFET: R=(V 2nd -V 1st ) / I sink ;as well as Comparison judgment step: compare the on-resistance value R with the preset threshold value R T If the on-resistance value R is equal to or greater than the preset threshold value R T , it is judged that a fault occurs in the safety voltage regulator. If the on-resistance value is less than the preset threshold R T , then it is judged that the safety voltage regulator is working normally.

2. The fault detection method according to claim 1, wherein: The system DC power supply includes a battery power supply and a capacitor power supply, and before the first voltage measurement step, also includes: Pre-processing verification step: respectively turning on the battery power supply and the capacitor power supply, and verifying whether the output voltage of the battery power supply is within a normal voltage range, and whether the output voltage of the capacitor power supply is less than 20V.

3. The fault detection method according to claim 2, wherein: When the output voltage of the battery power source is within a normal voltage range, in the first voltage measurement step, the MOSFET is powered by the battery power source to measure a first output voltage V of the MOSFET. 1st .

4. The fault detection method according to claim 2, wherein: When the output voltage of the battery power source is not within the normal voltage range, in the first voltage measurement step, the capacitor power source is used to supply power to the MOSFET to measure the first output voltage V of the MOSFET. 1st .

5. The fault detection method according to claim 1, wherein: The preset threshold is 3 ohms.

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