New Automotive Electronic System Component Solutions
In future automotive electronic systems, as the demand for safety, energy efficiency, environmental protection, comfort and entertainment increases, the related components and their Shipments of peripheral products will also continue to grow rapidly. Many of the design challenges in automotive electronics require solutions to be considered from the component level up. Around this topic, new sensors, protection devices, and high-voltage connectors are introduced for automotive power control, safety systems, communication and entertainment, and Applications such as charge and discharge systems.
The speed of technological upgrading of automotive electronics and other applications such as industrial control, medical compared is quite fast, there are many reasons for this. First of all, automotive electronics and people's daily lives are closely related, especially in Europe and the United States, these countries with a car to walk, the car as a necessity. It is almost the only option for most people to travel on a daily basis. And emerging markets such as China and India are seeing rapid growth in the car market, and according to recent reports, Shenzhen's car ownership has just been The number of cars exceeded 1.7 million, making it the mainland city with the highest car density. It can be seen that more and more families have the need to buy a car, thus promoting the wide application and development of car electronics technology.
According to a survey by isuppli, China's auto electronics sales will reach $16 billion in 2012, up from $16 billion in 2009. It grew to $20.6 billion. And the U.S. automotive electronics market will be $20.5 billion in 2012, when the number one spot will go to China.
Automobiles have multiple subsystems that are very complex. Each subsystem is dependent on a large amount of automotive electronics - although the amount of automotive electronics used varies by vehicle class. . For example, the mainstream automotive electronic systems in the Chinese market today are less complex and less intelligent. These systems mainly focus on steering, driver assistance, occupant passive protection, braking and control systems, and comfort and convenience.
As the market upgrades, the future of automotive electronics applications will also face changes, with energy systems, safety systems, collision avoidance, drive-by-wire, control systems, smart sensors and actuators, integrated vehicle electrical and electronic systems and thermal comfort systems all playing a more important role.
Here, we analyze what opportunities and challenges these emerging needs present for the components market.
Role of Components in Automotive Safety Systems
Safety is the first element to be considered in the design of automotive systems. New driving safety is dependent on a stable engine management system, and sensor components, one of the most heavily used devices in the car, are safe It is also used extensively in the system.
In terms of road safety, timely detection of engine temperature is a very important aspect. TDK's newest sensors weigh less than the weight of conventional metal structures and have a longer service life. The sensor's temperature measurement accuracy is guaranteed at 50%, yet its shock resistance and service life are significantly improved. The plastic housing on top of the sensor ensures excellent thermal conductivity, which optimizes response time and accuracy for the measurement of vehicle oil. Temperature and coolant temperature. In addition, fast response and wide range of adaptation are also features of this product.
During routine operations such as starting and stopping, the vehicle is subject to electrical interference and high frequency influences, creating interference. It is conducted through the wiring system and eventually coupled or radiated to the on-board electronics. Sources of interference include starting systems, AC motors, load switching, switching jitter, and "load throw" (i.e., when a DC motor is running). (cutting the power and the resulting voltage).
The most destructive of these surges is "load shedding", which occurs while the engine is running, and while the AC motor is feeding the battery. Disconnect the battery while charging. The magnitude of the transient voltage generated depends on the speed of the AC motor and the magnitude of the field excitation at the time of disconnection. This surge process can last for hundreds of milliseconds, generating voltages in excess of 100V, which can be potentially fatal to semiconductor circuits. Once the electronic circuitry is damaged, it can pose a significant safety hazard.
PPTC protection devices are resettable polymer positive temperature coefficient devices that have been used for overload on the DC output of power supplies. and short circuit protection. Tyco Electronics Rikan's PolySwitch products are capable of protecting power supplies, RXE input/output interfaces, as well as Protection from overheating, motor stalling, etc. is achieved.
In addition to PPTC devices, MOSFETs can also provide similar protection. However, in addition to high frequency performance, high input impedance, low drive power and excellent thermal stability, MOSFETs have the advantages of In addition, the power components can also be made more cost effective for the lowest possible system cost, resulting in better fail-safe systems. As a result, most designers turn to protective MOSFET power assemblies for this purpose.
Application of Semiconductor Components in In-vehicle Entertainment Systems
Infotainment equipment is also susceptible to damage from excessive voltage transients, both in the environment in which it operates and from surrounding equipment. Electrostatic discharge (ESD) pulses. ESD protection devices, metal oxide varistors (MOVs), and Zener diodes are often used to protect automotive electronics such as Antennas, backlight heaters, batteries, buttons, printed wires on circuit boards, CD/DVD players, data cable ports,... Hard disk drives as well as input/output ports and touch screens.
The need for overcurrent and overvoltage protection for portable devices charging in the car is high, and Tyco PolyZen devices meet that need. protection needs. When used in conjunction with a protection device similar to a Zener diode, this device provides synergistic protection and is capable of withstanding very high power The failure condition.
The high-speed input/output ports in the vehicle require the use of ESD protection devices with low capacitance to keep the signal quality from degrading as much as possible. The devices selected should be suitable for high speed data transmission lines and radio frequency data lines and be able to withstand numerous ESD voltage transients. PPTC circuit protection devices are just as widely used in in-car infotainment systems.
PPTC circuit protection devices are also widely used in in-car infotainment systems. It serves as a practical and cost-effective solution for overcurrent and or overheat protection. In the GPS, DVD or radio and car communication information system (telematics) in the circuit board, also often Use it to limit the current.
New energy vehicles lead the way in high-voltage connectors
The fast-growing electric and hybrid electric vehicle markets will lead to a large number of high-voltage connector applications for new, innovative, high-voltage, and high-voltage connector applications. impressive. Different vehicle manufacturers are experimenting with different ways to achieve the low or zero emissions target, which will further increase the demand for connectors. requirements of suppliers. These requirements have one thing in common, which is to continuously reduce costs and weight while meeting varying degrees of safety and physical protection requirements. and size. At the same time, manufacturers are not giving up on the high reliability and durability that modern consumers expect.
Among connector manufacturers, FCI has a strong presence in the electric and hybrid vehicle market. The new Power.S3 series is designed for the next generation of rechargeable battery-powered plug-in hybrids and electric vehicles The product.
The use of high-capacity lithium-ion batteries is a common denominator in the diversification of design options for electric and hybrid vehicles. The operating voltage of lithium-ion batteries ranges from 400 to 600V, which is at least 10 times higher than the standard 14V lead-acid battery for conventional vehicles. As a result, FCI Connectors has developed a full range of solutions for application-specific connectors and charging plugs.
These new connectors and charging plugs need to address a number of significant issues. Among them, the first and foremost is the safety issue, because the new connectors and charging plugs operating voltage range of 400 ~ 600V. Operating currents range from 50 to 300 A and beyond. Considering that the operator will inevitably come into contact with the engine compartment throughout the vehicle's life cycle, the need for a high standard of protection against electric shocks is Obviously. In addition, at such high power levels, electromagnetic interference is another important issue. Furthermore, electrical arcs are generated during connector insertion and removal, which can seriously damage electrical connections and electronics and can cause damage to the automotive industry. Combustion.
With the advent of high-capacity lithium-ion batteries, dangerous failure modes have been triggered in some cases. In addition, reducing the weight and cost of batteries remains a challenge: on the one hand, increasing the range and battery capacity of electric vehicles On the other hand, with the new generation of electric vehicles firmly positioned in the mass market, the economical They also play an extremely important role. The cost of the battery alone can run into the thousands of euros, so the pressure is on to reduce the cost of other features in the car.
To meet all these challenges, the new connectors and charging plugs of FCI Connectors' Power. The products are optimized for high power operation, cost competitiveness, durability, compactness, ergonomics and personnel safety. FCI Connectors, Inc. and REMA, a specialist manufacturer of plugs and sockets for electric forklift trucks. The first fruits of the partnership were single-phase 16/32A charging plugs and sockets, compliant with SAE J1772 and the IEC62192-1: International standard for "slow charge" electric/hybrid vehicle applications. These products are used to charge the lithium-ion battery of a car at a public charging station or at home, with a charging time of 4-8h.
The automotive field is still pioneering and it is not easy for engineers to ensure that the system works completely trouble-free. This kind of performance-specific simulation and analysis is crucial for designers of electric and hybrid vehicles. The companies involved in the design and manufacture of these new vehicles are in a fast-rising learning curve, and the need for product performance in real-world applications is not as important as it might seem. There is still much to learn.
Circuit protection scheme for vehicle-mounted network systems
In-vehicle network systems will play an increasingly important role. New passenger cars, trucks, buses and even motorcycles have become mobile networks, linking together numerous features and functions, such as Built-in controls, mobile media and wireless networks. Applications for infotainment systems, telematics, security control, etc., all require the use of several existing network standards, including LIN. CAN, FlexRay are the three most important standards.
Circuit protection measures for LIN topology
The LIN bus topology is typically used to connect switches, sensors and actuators to an on-board network. In the event of a short circuit in the line due to a positive voltage of less than 26.5V or ground, the network shall return to normal operation. The ESD surge resistance on the physical layer according to IEC61000-4-2 must meet the minimum discharge voltage level ± 2kV. however. levels up to ±8kV may be present on the ECU connector.
The diagram below is a synergistic circuit protection diagram showing how a resettable PolySwitch device set at the power input protects the ECU and LIN node connectors from damage from overcurrent conditions at the power input, and how a MLV (Multilayer Voltage Varistor) provides the high current handling and energy absorption over-voltage protection required for in-vehicle network applications.
Overcurrent protection is needed to limit overcurrent in the event of a fault or overload condition. It is also necessary to limit voltage spikes or stable overvoltage conditions through circuit protection devices.
Circuit protection measures for CAN topology
CAN bus transceivers can allow bus supply voltages up to +/-80V DC. However, load-shedding surges can produce higher transients than those specified in the ISO-7637-2 standard (86.5V maximum). May damage the transceiver. Transceiver operating currents also vary depending on the supplier.
The following diagram shows how to apply a resettable PolySwitch device and MOV (metal oxide varistor) at the power input to avoid damage due to inrush currents and voltage anomalies at the center of the on-board power supply system.
Circuit protection measures in FlexRay topology
The FlexRay protocol is designed for in-line applications such as in-line braking and in-line steering. The wire networking method supports synchronous and asynchronous data transfer at a rate of approx. 10 Mb/s, with time triggering and event trigger behavior, redundancy and fault tolerance.
The architecture supports a "bundle" of 2 to 64 nodes and relies on two types of processors - ECU and " Activity Star". FlexRay communication takes place between ECUs via a common bus or a star connection. The bus input must be protected from shorts between the bus line and the system supply voltage or ground potential.
The scheme shown below utilizes a PolySwitch device for overcurrent protection.
Protection scheme for on-board lighting circuits
Automotive lighting systems require peak inrush currents of up to 55A. One of the ideal solutions for controlling automotive lighting is to combine a high-side front FET driver with a power FET.
A front-side FET driver is used to control four different loads in the system. This combination allows for better control of resistive loads through the temperature coefficient. Normally, the load is connected on the low voltage side, while the power FET is configured on the high voltage side to supply the load. Each channel can be controlled by a parallel input signal from the microcontroller or by a serial programming register. In a parallel configuration, a general purpose I/O or timer based output is used to control the load current.
The gate drive output is typically a constant current source and draws an output to control the charging and discharging characteristics of the FET gate capacitor. The FET switch can be switched up or down in series with an external resistor. An external resistor in series with the output limits the number of ups and downs of the FET switching transition. This effect allows the conversion rate to be controlled while also helping to reduce the electromagnetic interference that can increase the Rapid current changes during the switching limit. These outputs are internally controlled below a maximum output voltage of 17V to protect the external FET gate from source breakdown. damage. A combination of front FET drivers and power FETs can be configured compared to an integrated solution. to prevent dynamic and static failures in the application.
Fault detection and control solutions for vehicle lighting circuits
Fault detection is critical in all systems. Each fault with short-circuit loads and overcurrent phenomena in the "on" state and open-circuit loads in the "off" state can be independently detected. Fault detection of the channels will enable the system to react correctly. This detection also isolates the faulty channel so that it does not affect other normal channels, especially in cases involving thermal When there is a phase interaction problem, the FET will automatically retry and "turn on" the FET with a low duty cycle when an overcurrent condition is detected.
When an overcurrent condition is detected, the device will automatically retry and "turn on" the FET with a low duty cycle by "turning off" the device or activating it. The FET can be protected by setting the options for the FET. This allows the system to continuously check that the fault has been corrected without destroying the FET.
Monitoring open-circuit load faults in the "OFF" state provides the system with load integrity information. By monitoring the supply voltage of the external power FET while the switch is fully "off", it is possible to monitor the load integrity of each FET. One channel open-circuit load fault detection.
Likewise, to prevent false fault reports during switching, an anti-spike filter is activated during power switching to shield faults
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