Airbags play a key role in automotive assisted restraint systems (SRS). At present, the installation of airbags in passenger cars has become a standard. Everyone knows that airbags and seat belts can reduce the chances of the head and upper body of the car hitting the components inside the car when the car collides. They also reduce the risk of injury by distributing the impact force more evenly. But now, many people have realized that the auxiliary restraint system that can bring people safety can also endanger the safety of people in the car. Therefore, when developing a safety system, the various characteristics of the system must be fully considered to ensure that the required level of safety is achieved. In order to solve this problem, Infineon has developed a wide range of airbag trigger chips to help the system achieve automatic fault protection. This article refers to the address: http:// The automotive airbag system market in Asia is expected to continue to grow, mainly due to the growth of the Chinese market. In the next five years, the market will increase by 25%. In addition, South Korea's exports to Europe and the United States are equipped with more and more airbags, mainly because of the new safety regulations implemented in Europe and the United States. At present, South Korea's passenger cars have been equipped with 100% front airbags, and the increase in head airbags is expected to reach 44% by 2013. The current positive airbag installation rate in the Chinese market is only 62%, so we expect that the field will Welcome to grow rapidly. In addition, as China's vehicle exports continue to grow, safety issues are getting more and more attention, so we expect side and head airbags to continue to grow in the next four years. At present, with the implementation of new European and American regulations, the airbag system is expected to become more complete. Equipment manufacturers will face price pressures and need to address the challenges of balancing costs, innovation and reliability. Related research shows that the current front airbag with an average selling price of $105 is expected to reduce costs by 15% after four years. The industry believes that reliable application is the most important issue for automotive airbag systems, so this article will explore the poor implementation conditions. How to balance safety factors and system costs (eg, leaks and low pressures). In the past 30 years, the number of vehicles on the roads in Europe has increased by a factor of two, but the roads have only doubled. With the increasing traffic volume, Hyundai has presented an increasingly high level of safety and comfort for drivers and passengers. Electronic technology and other chemical and mechanical technologies play an important role in improving vehicle safety and comfort. GPS systems, auto mirrors, automatic lights, power seats, electronic jets and hundreds of other functions are now an integral part of the car. But in addition to comfort, users also want to buy cars with higher security for themselves and their families. Therefore, the security system is beginning to work. Currently, automobiles provide active and passive safety systems such as ABS, ESC, ASR, airbags, and pedestrian protection. In the future, the market is expected to continue to grow as the road is still far from 100% safe. The new security system uses separate components to provide the required functionality, but in recent years, all systems have been integrated. At present, most RCUs (Security Control Units) are composed of an MCU (Master Control Unit), a communication interface, a power supply, a sensor interface, and a blasting circuit. This article covers the blasting circuit portion of the RCU. The safety of the airbag system and the relevant safety features of the application IC are discussed below. Airbag safety The development of a safety system must take into account the various characteristics of the system to ensure that the required level of safety is achieved. From a system perspective, the airbag controller must have two safety features: 1. Triggering in an accident condition; 2. Preventing accidental triggering. Both of these characteristics must comply with the specific requirements of the relevant standard (ie IEC 61508) to ensure that the corresponding level of safety is achieved. The safety standards of the safety system propose the concept of 'automatic fail-safety'. When a safety system fails, it should be designed to ensure that the failure does not damage adjacent systems or cause injury to personnel. At first glance, one might think that the first feature is more important than the second feature. However, it is not. When the safety system detects an accident, if the trigger of the airbag cannot be completed due to some kind of failure, it will cause casualties. However, most owners still want to never need to trigger the airbag. On the other hand, after the RCU is installed in the car, from the car test period to the end of the use period, the airbag may be accidentally triggered at any time. If this happens, it can cause harm to the personnel involved (factory workers, car drivers or garage technicians). On the whole, it should be ensured that the correct triggering of the airbag is achieved in the event of an accident, and efforts must be made to prevent accidental triggering of the airbag. In order to enable everyone to better understand the airbag system and how to implement fault protection, it is necessary to introduce the implementation of the entire system (see Figure 2). Typically, the car satellite sensor interface acquires and analyzes the data sent by an external sensor (acceleration or pressure sensor). These sensors are distributed in the front end of the car, in the door or on the B-pillar depending on the function or type (front-end impact acceleration sensor, side-impact pressure sensor or side-impact acceleration sensor). In the event of a collision, the absolute acceleration or pressure experienced by the sensor is greatly increased, causing the main microcontroller to know that a collision has occurred. At this point, the main microcontroller must decide whether to trigger the airbag based on the sensor's data, the onboard sensor's data, the position of the seat, and other parameters. If it is decided to trigger the airbag, the main microcontroller will send an instruction to the blast interface. At the same time, the backup system (usually a spare 8-bit microcontroller) must also make decisions based on more basic data (ie, only onboard sensor data), allowing the designated hardware line to allow the blasting IC to trigger the airbag. Triggering is accomplished by passing current through a squib (usually between 1.2A and 1.75A). The squib is here a resistor with a resistance of only a few ohms, so to save energy you must control the current. If the current flows through the squib for a certain period of time (usually 0.5ms to 2ms), the airbag will complete the trigger. From generating sensor information, sending sensor information, analyzing all parameters, making decisions, transmitting decisions to the trigger IC, and finally ensuring that current passes through the squib only when needed, it must be reliable throughout this process Automatic fail-safe performance. The analysis of the last two steps of the process of triggering the airbag will be carried out below. Trigger IC security features Infineon's existing trigger ICs feature a variety of features that ensure fail-safe functionality. These include: 1. CrosSave 2. Leak detection 3. Start the software and hardware to trigger 4. Resistance measurement 5. Switch test 6. High Side Power Supply (HSS) Diagnostics 7. Onboard voltage measurement Among the above features, the former is designed to prevent accidental triggering, and the rest is used to ensure that the trigger is completed when needed. All of these features are discussed below. CrosSave In order to achieve fail-safe function in the event of a 'production failure' (defective wafer, ESD damage, etc.), the airbag system needs to be redundant or versatile. Each squib is equipped with two switches (see Figure 2). These two switches ensure that the current flows into the squib only under specified conditions. This feature can be achieved by using a single IC to integrate the high side (HS) and low side (LS) switches; using two identical ICs, but separating the high side switch from the low side switch through the PCB design (Cross-coupling); or two different chips can be integrated into one package (CrosSaveTM) using two different technologies. Ceramic Vape Pen,Full Ceramic Vape,Ceramic Oil Cartridge,Ceramic Refillable Vape ALD GROUP LIMITED , https://www.aldvapor.com