As engineers develop increasingly complex solutions to meet the needs of comfort, safety, entertainment, powertrain, engine management, stability and control applications, the number of modern in-vehicle electronics will continue to grow steadily. In addition, with the increasing popularity of very sophisticated and sophisticated electronic products in automotive applications, even the most basic types of vehicles are equipped with electronic devices that have been available for a few years ago.
This article refers to the address: http://
In the past, the growth engine of automotive electronics was a safety- and non-safety-independent application. Usually, if electric lift windows or central locking are used, these products simply replace the existing mechanical systems. Recently, the scope of automotive electronics has expanded to support security-related applications such as engine optimization, active and passive security systems, and advanced infotainment systems including GPS.
Now, we are welcoming the third revolution in the development of automotive electronics. Automotive electronics no longer only supports critical functions, but also goes deep into the control of the car, providing important driver information, control engines, collision avoidance monitoring and collision avoidance, performing line-controlled braking and steering, or intelligent control of the interior environment. .
Speed ​​and cost are well known issues for general purpose embedded hardware electronic platforms. These platforms have basic or common hardware capabilities and are designed with application-oriented software to customize features for the same model range or for different vehicle models. System-on-a-chip (SoC) semiconductor devices integrate various functions into a single chip, reducing the number of components and footprint requirements, while ensuring long-term reliability, while successfully developing a universal embedded electronic platform It is important.
Electromagnetic compatibility
As the number of automotive electronics increases and the distribution of complex electronic modules throughout the vehicle increases, engineers face increasingly severe electromagnetic compatibility design challenges. The problems are mainly in three areas:
1. How to minimize electromagnetic susceptibility (EMS)? To protect electronic products from harmful electromagnetic radiation from other electronic systems such as mobile phones, GPS or infotainment systems.
2. How to protect electronic products from the harsh automotive environment? This includes disturbances caused by large transients in the supply voltage, heavy loads, or inductive loads such as lights and starters.
3. How to minimize the EME that may affect other automotive electronic circuits?
These issues will be even more challenging as system voltages, the number of in-vehicle electronic devices, and the frequency increase. In addition, many electronic modules will interface with inexpensive, less linear, and highly offset low-power sensors that operate in small-signal states, and the effects of electromagnetic interference on their operating conditions can be catastrophic.
Compliance and standards
The above problems indicate that automotive EMC compliance testing has become a major element of automotive design. Standardization of compliance testing has been carried out in car manufacturers, car supplier suppliers and different legislative bodies. However, the later the EMC problem is discovered, the more difficult it is to find the root cause of the EMC problem, the higher the cost of the solution, and the greater the limitations. Because of this, it is the basic design method to consider EMC issues from the whole process of IC design, PCB mass production, module implementation to vehicle design. To facilitate the implementation of this process, module-level pre-compliance testing and IC-level testing have been standardized.
Design EMC-compliant ICs and modules
The following are the EMC standards that IC design should follow:
EME standard IEC 61967: Measurement of radiated and conducted electromagnetic emissions in the 150 kHz to 1 GHz range.
EMS standard IEC 62132: Measurement of electromagnetic immunity (anti-electromagnetic interference) for the 150 kHz to 1 GHz range.
Transient standard ISO 7637: Measurement of conducted and coupled electrical interference caused by road vehicles.
How can system design engineers ensure that their SoCs and final modules meet the requirements of the above standards? The traditional SPICE model (an analog circuit simulator focusing on integrated circuit design) does not work here because the electromagnetic field is not compatible with the SPICE-based simulation environment. At the IC design level, electromagnetic fields can only be modeled by electric fields because the size of the chip and package is much smaller than the wavelength of the electromagnetic signal (the wavelength of the 1 GHz signal is 30 cm, which is much larger than the size of the IC). The key to note here is that radiated emissions and susceptibility are not major issues with ICs, and effective antennas on printed circuit boards and cables are the main cause of conductive emissions and susceptibility.
Design engineers have to adopt a number of techniques to ensure EMC compliance, followed by EME and EMS.
EM launch
EME (electromagnetic emission) is generated by high-frequency currents in an external loop like an antenna. Such high-frequency currents include:
-- Switching of core digital logic, such as DSP and clock drivers (synchronous logic generates a large number of current spikes containing many high frequency components);
- the action of the analog circuit;
-- the switch of the digital I/O pin;
-- High-power output drivers that deliver high current spikes to boards and harnesses;
To minimize the impact of these factors, design engineers should use low-power circuits where possible, including lower voltage, adaptive supply voltages, and architectures that spread the clock signal in the frequency domain. When some parts of the digital system are not working, turn them off to reduce the number of component switches on a single clock cycle. In addition, EME is also reduced by reducing the slope of the switching edges of the clock and drive signals and providing soft switching characteristics. Finally, design engineers should carefully design the layout of the external and chip. For example, a differential output signal using a twisted pair produces a lower EME and is less susceptible to EME. Proximity and effective power supply decoupling between VDD and VSS are also simple techniques for reducing EME.
EM susceptibility
Rectifier/pump, parasitic components, current, and power consumption are the four most important interference effects of EMS (Electromagnetic Susceptibility). High-frequency electromagnetic power is partially absorbed in the IC and, therefore, may cause interference. These disturbances include passing large high-frequency voltages into high-impedance nodes and passing large high-frequency currents into low-impedance nodes.
The main way to minimize the EMS effect is to align the circuit design and avoid rectification. This can be done with a differential circuit topology and layout design. Even for sensors that require small signals in the application, the ability to handle a large common-mode signal topology may help keep the system linear across a wide range of electromagnetic signals. Filtering can limit the frequency range into the sensitive device, which is another common technique, especially when on-chip filtering is possible. Adopting a high common-mode rejection ratio (CMRR) and a power-supply rejection ratio design (PSRR) will also protect the circuit from rectification and keep the internal node impedance low and all sensitive nodes on-chip. Finally, in order to avoid or control parasitic components and currents, it is important to use a protection device to clamp a portion that is greater than the required EMS rejection level. This technique helps to avoid rectifying interference and maintains the protection level and signal symmetry. It is also critical to keep the substrate currents to a minimum and to concentrate these currents in the controlled points.
The latest devices from AMI
Many design engineers are looking for mixed-signal semiconductor technology to provide SoC solutions for today's automotive applications. The latest high-voltage mixed-signal technology is particularly well-suited for designs that require higher voltage outputs, such as drive motors or excitation relays, to emulate analog signal conditioning. Complex digital processing combined.
As for high voltage and mixed-signal ASIC technology, AMI's I2T and I3T series are excellent examples. Designed to handle voltages up to 80V, the I3T80 based on 0.35μm CMOS technology integrates complex digital circuitry, embedded processors, memory, peripherals, high voltage functions and different interfaces in a single chip.
AMIS has developed a range of ASSPs for automotive applications using mixed-signal technology and many of the above-mentioned excellent EMC design methods, including the AMIS-41682 standard speed, AMIS-42665 and AMIS-30660 high-speed CAN transceivers. For 12V and 24V automotive and industrial applications requiring CAN communication rates up to 1Mbps, these devices provide an interface between the CAN controller and the physical bus and simplify design and component count. For example, the AMIS-30660 is fully compliant with the ISO 11898-2 standard and provides differential signaling capability to the CAN bus through the CAN controller's transmit and receive pins; this chip provides designers with a choice of 3.3V or 5V logic level interfaces. Ensure compatibility with existing applications and upcoming low voltage design requirements. By carefully matching the output signal, the common mode choke required to minimize EME can be omitted, while the wide common-mode voltage range (±35V) of the input input ensures high EMS performance.
The importance of electromagnetic compatibility design
As the number of electronic devices in modern automobiles increases, more and more good designs are required to ensure compliance with electromagnetic compatibility standards. At the same time, as integration increases, automotive design engineers need system-on-chip ASICs and ASSP solutions to replace multiple discrete components.
A communication cable is a type of cable that is used to transmit data, signals, or information between two or more devices or locations. It is typically made up of multiple wires or fibers that are enclosed in a protective sheath.
There are various types of communication cables, including:
1. Ethernet Cable: This is the most common type of communication cable used for wired internet connections. It is used to connect devices such as computers, routers, and switches.
2. Coaxial Cable: This cable is commonly used for cable television (CATV) and broadband internet connections. It consists of a central conductor surrounded by insulation, a metallic shield, and an outer protective sheath.
3. Fiber Optic Cable: This type of cable uses thin strands of glass or plastic fibers to transmit data through light signals. It is known for its high bandwidth and is commonly used for long-distance communication and high-speed internet connections.
4. USB Cable: Universal Serial Bus (USB) cables are used to connect devices such as computers, printers, and smartphones. They are designed to transmit both power and data signals.
5. HDMI Cable: High-Definition Multimedia Interface (HDMI) cables are used to transmit high-quality audio and video signals between devices such as televisions, DVD players, and gaming consoles.
Communication cables play a crucial role in various industries and applications, including telecommunications, networking, broadcasting, and home entertainment. They enable the transfer of data, voice, and video signals, facilitating efficient communication between devices and locations.
Data Communication Cable,Shielded Communication Wire,Communication and Data Cable,485 Communication Cable
Ruitian Cable CO.,LTD. , https://www.rtpowercable.com