Using ISO 13400 for IP diagnostics, Ethernet is widely used in today's automotive industry. Compared to the physical interface of standard Ethernet, this IP diagnostics allows for faster reprogramming. However, as automakers choose it as the ubiquitous in-vehicle network bus, the challenge still exists. The Advanced Driver Assistance System (ADAS), including the camera system, is one of the applications in the industry that is looking to maximize the benefits of Ethernet. Why should you consider an Ethernet-based connection and deprecate analog or LVDS methods? Especially in the case where the processing cost of the camera and the central unit is higher (Fig. 1). There are many key factors beyond this metric that ultimately provide lower cost and higher performance. Figure 1 Ethernet reduces the cost of the camera system One of the key factors is that support for low-cost unshielded twisted pair cables can significantly reduce cable costs. In addition, Active Ethernet (PoE) uses standards-based 100BASE-TX Ethernet, eliminating the need for additional cables. However, the true value of Ethernet is not limited to reducing the bill of materials. The ultimate goal of Ethernet is to provide a ubiquitous single in-vehicle network in a seamless, cross-domain communication – applying common data streams across the automotive spectrum, including chassis, powertrain, body, infotainment, and ADAS. And physical media (cables). Now, intra-domain and cross-domain information sharing can be supported on a single network without bridging, which can greatly reduce cost and complexity. In short, Ethernet is a network technology; whether it's for the automotive industry, consumers, businesses or the industry, this is the biggest value, and it's why it can reduce costs in any market. Car connectivity is the most significant challenge in in-car applications, so the ADAS camera design exemplifies the main challenges it faces: 1. Image quality is directly affected by the thermal noise generated by the camera. In the absence of the required space constraints, factors such as improved thermal power consumption and lower power are critical to achieving the desired performance. 2. Since electrical noise also degrades the image quality of the sensor, low noise must be achieved. Trying to use the low-cost unshielded cables you need will present another major challenge to meet automotive EMC emissions requirements. 3. The requirements for the quality and reliability of the automotive market must be adhered to. Cars are a demanding environment, with different considerations for passenger vehicles, commercial vehicles and industrial vehicles. 4. The need to deploy sensors throughout the vehicle is greater than ever, resulting in more and more space constraints for such applications. The strong demand for zero fatal accidents from various ADAS applications has pushed up such demand. For example, anti-collision, traffic lights, road signs and pedestrian identification. Solution: Ethernet-based ADAS Merrill has found automotive sensor specialist Silicon Micro Sensors (SMS) to design a “production-ready†solution for the most demanding automotive and industrial applications, featuring: megapixel (720p) high dynamics Range (HDR) camera, field of view from 55° to 190°, MJPEG video compression, Ethernet AVB and active Ethernet support, low cost unshielded twisted pair, up to IP68/IP6k9 standard, waterproof, scratch resistant, fog. The camera is suitable for passenger vehicles, commercial vehicles and industrial vehicles. Applications include panoramic view and rear view, side and rear view mirror replacement, traffic signs, blind spots, pedestrian detection and lane departure assistance. The solution clearly demonstrates that standard Ethernet meets the needs of ADAS cameras. The solution uses Quiet-WIRETM Ethernet and Auto-PoE technology and is one of a series of ADAS designs. (figure 2) A total of two options, the ApTIna AR0132AT or the OmniVision OV10635 image sensor, are available. Freescale's MPC5604 processor provides MJPEG compression based on incoming YUV digital image data and connects to the MARY KSZ8061 Quiet-WIRETM 100BASE-TX Ethernet PHY via a Media Independent Interface (MII). The Micrel DS1001 MEMS oscillator provides system timing and power management with an optimized automotive active Ethernet Auto-PoE. Ethernet directly faces challenges The Ethernet physical layer offers a range of benefits to meet the needs of ADAS camera systems. One of the great benefits of using a standards-based automotive Ethernet solution is the ability to provide an application-independent minimum standard bill of materials (BoM) (Figure 3). This enables economies of scale beyond any automotive-specific solution and creates a multi-vendor model that allows for a wider range of options and lower costs. The smallest PHY in the automotive industry is supplied by the MERRY KSZ8061 Quiet-WIRETM 100BASE-TX Ethernet transceiver measuring just 5mm x 5mm. It must be ensured that a minimum of power supply filtering is maintained, and that the line interface between the PHY transceiver and the magnetic components does not require additional passive components. This reduces signal cost and reduces board space on the printed circuit board while improving signal integrity. In recent years, qualified automotive Ethernet magnetic components have become popular, and standard Ethernet magnetic components can be used. Here, we use TDK's latest Ethernet magnetic components. The ALT4352 series is a solution that supports surface adhesion technology, winding with a winding machine and reduced size. The maximum height is only 2.9mm, which is very suitable. A camera module with limited space. Winding machines that wind magnetic components are not only less expensive, they are more accurate (relative to traditional manual windings), and offer more powerful and consistent performance. Use of active Ethernet 100BASE-TX magnetic components are equally important for achieving performance and delivering power. According to the "phantom power supply method" of IEEE 802.3af/at, the current installation of additional cables for powering remote sensors is no longer required, and power can be supplied only by the DC voltage supplied from the center tap of the magnetic element. This approach can be further optimized for use in automotive applications and offers all the benefits without any additional system cost. First, since the car wiring is fixed, it is no longer necessary to use a bridge rectifier. This is followed by a redundant active Ethernet controller configuration (significantly reducing costs). Since the powered device (PD) - in this case the camera is fixed and the power budget is known, there is no need to use a relatively expensive controller to coordinate the power requirements with the Power Supply Equipment (PSE). The camera power management solution can be implemented simply by providing a standard DC-DC regulator (Figure 4). The Meri MIC28511 60Vin 3A Synchronous Buck Regulator with Hyper Light LoadTM technology provides a step-down primary voltage that ensures high efficiency operation at low output power, such as standby. Figure 4 Standard DC-DC Regulator PoE While optimized and cost-effective, the standard automotive application Ethernet PoE offers the added benefit of a “phantom powered†approach. The camera (PD side) provides common mode noise rejection; the noise emitted by the PSE (ECU) or the noise extracted along the twisted pair cable is coupled as a common mode noise to the differential Ethernet signal for clearing. In addition, galvanic isolation between the camera (PD) and the ECU (PSE) ground prevents radiation ground loops due to potential differences; this has become commonplace. Interoperability can also be achieved by connecting to any other IEEE 802.3af/at PSE. In today's market, 100BASE-TX Ethernet provides the lowest power of PHY technology. Compared to gigabit-based technology solutions, power and cost are reduced by a factor of three. The IEEE 802.3az Energy Efficient Ethernet (EEE) KSZ8061 support provides another benefit to the camera, which can be converted to a low-power sleep mode when idle (for example, when video traffic is not being transmitted). This can reduce power consumption by more than 50%. The KSZ8061 Ethernet PHY also offers less than 1uA of industrial best-in-class ultra-low standby current, making it ideal for all battery applications. In addition, the KSZ8061 PHY provides a unique signal detection output jack that can be used to indicate the presence of an active link partner (Figure 5). The PHY standby mode can be automatically activated and awakened by the signal detection circuitry. In addition, the output jacks can be used to power down the processor and sensors and provide less than 1uA of remote standby and wake-up current to the camera module. This remote shutdown solution offers important benefits : Full interoperability (at the ECU) with any Ethernet provider link partner for reduced standby power consumption Alternative methods using special waveforms/sequences often require proprietary implementations that limit their practical application. In the consumer space, the vendor-driven Wake on LAN (WoL) approach is a good example. In fact, this method is rarely used in the field. From the standpoint of standby power consumption, implementing the detection circuit on the physical layer requires less signal processing and therefore less power consumption. In this alternative example, WoL still requires the PHY and part of the MAC layer to remain powered, resulting in approximately a thousand times more standby power. Quiet-WIRETM technology uses the KSZ8061 Ethernet PHY, which reduces EMI line emissions and meets automotive OEM standards compared to unshielded twisted pair. Low cost cables such as CAN or FlexRay can be deployed. Cables can also be made by hand, and each connector is equipped with a length of up to 5cm, eliminating the need for a non-stranded portion of the jacket, providing the lowest cost. Active Ethernet common mode noise rejection and isolated camera grounding reduce electrical noise and optimize camera sensor image quality. It also includes thermal noise reduction due to the KSZ8061 low-power 100BASE-TX technology. Reducing heat dissipation not only improves sensor performance, but also achieves higher stability and fuel efficiency. The Quiet-WIRETM technology used in the camera solution not only reduces emissions, but also provides superior immunity to interference due to its excellent current injection performance. In the entire frequency range of 1MHz to 400MHz, when a 200mA noise current injection occurs, the PHY transceiver does not show any errors at all, which exceeds the OEM limit. Even with Quiet-WIRE radiation filtering enabled, the enhanced PHY transceiver design in the KSZ8061 provides an error-free cable range of up to 130 meters. Such performance is very beneficial for industrial and commercial vehicles because the interference immunity and cable range are typically longer than the maximum car wiring length of 15 meters. To meet the needs of safety-critical ADAS applications such as rear-view cameras, the KSZ8061 is capable of powering up and linking within 20ms without processor intervention. In addition, the KSZ8061's unique Transceiver Signal Quality Indicator (SQI) continuously monitors harness quality in real time. The camera clock timing is provided by the Micrel DSC1001 MEMS 25MHz oscillator. MEMS technology's superior frequency-temperature stability provides up to 20 times the pre-fault averaging time and 500 times more impact resistance than crystal oscillators, making it ideal for this type of application (Figure 6). All equipment used in the camera design is compliant or fully compliant with the automotive AEC-Q100 standard. Figure 6 Comparison of output frequency temperature stability between DSC1001 MEMS and quartz crystal to sum up Governments’ legislation has been working to improve road safety, which has led to an increase in the vehicle's ADAS. The National Highway Traffic Safety Administration (NHTSA) recently stipulated that starting on May 1, 2018, all new vehicles will need to meet new rear-view standards to prevent 210 deaths and 15,000 people per year. The average status of the injury. Europe is also planning to implement similar initiatives to achieve the great mission of zero road accidents. The challenges of ADAS, especially the challenges of camera sensors, are extremely demanding. It must combine power dissipation, electrical noise, and assembly into extremely limited spaces while meeting stringent vehicle safety, quality, and reliability requirements. It has been proven that standard Ethernet not only overcomes these challenges, but even brings additional benefits. From the perspective of testing these benefits, standard Ethernet clearly not only meets the needs of ADAS, but also addresses cost challenges. To achieve successful deployment in the marketplace, all solutions must be both business and technical. This is a key element in helping Ethernet successfully span multiple markets: it delivers network performance at the lowest total cost of ownership. You can purchase the camera module mentioned in the article from Silicon Micro Sensors, which is part of a demonstration kit that includes four camera modules that can be connected via an Ethernet switch for display on a computer or laptop. At the same time, you can purchase video analyzer advanced development and analysis framework software. In addition to identifying objects, the software can control, stream, display, record and playback up to 4 cameras. Author Mike Jones (Director of Local Area Network Solution Marketing, Merrill Lynch): Mike Jones has been in the semiconductor industry for 25 years and has extensive experience in high-tech design. He is responsible for the marketing of Merrill's LAN solutions for automotive and industrial products. Mr. Jones holds a first class honours degree in Electrical Systems Engineering from Aston University in Birmingham, England. In addition, he has authored numerous technical magazine articles and published them in several technical and industrial publications around the world. Hybrid Solar Inverter,Hybrid Grid Inverter,Solar System Inverter,Three Phase Inverter JIANGSU BEST ENERGY CO.,LTD , https://www.bestsolar-group.com
figure 2 
Figure 3 Standard Ethernet BoM 
