What Engineers Need to Know About Implementing Enhanced eCall Automotive Designs
[Copy link]
Engineers are constantly striving to find the simplest solutions to complex system design challenges, and eCall design in automotive applications is no exception. In this article, we will review how system designers approach automotive application design and how new eCall solutions can optimize the entire platform. We will also share some RF design expertise and integrated solutions to help address some of the demanding product challenges in eCall applications.
What is eCall?
eCall is a European vehicle emergency call system that provides rapid assistance in traffic accidents. Its goal is to save lives, reduce injuries and minimize property damage. Here's how it works: When an accident occurs, it automatically activates the emergency call or eCall through the vehicle's sensors. The system then automatically calls the European emergency service 112 call center. A telephone line is connected to the emergency center, which sends details of the exact location of the accident via the GPS. The emergency dispatch center then sends appropriate assistance to that location.
Since 2018, all cars and trucks sold in the European Union must be equipped with the eCall system. The basic idea is to shorten emergency response times and reduce accidents such as casualties. According to Thales Group, the system can reduce response times by 40% in urban areas and 50% in suburban areas. It can also reduce the number of deaths in accidents by 4% or more and the number of serious injuries by 6%.
From a reliability perspective, the eCall system must be resilient because when an accident occurs, the battery's power line may be cut and the electronic devices may be disconnected or damaged. Therefore, a backup power source such as a small battery is required so that the eCall system can operate effectively under harsh environmental conditions.
Traditional emergency call methods
Traditional eCall systems have multiple switches to provide RF paths to multiple antennas. These switches require matching and power circuits to operate, which means the design can be time-consuming, the form factor can be large, and the RF loss is high. In addition, for multi-antenna layouts, it can be complex to configure the switch array while achieving design flexibility.
Here are some of the challenges faced by traditional design approaches:
FR4-PC board materials require careful matching, which increases insertion loss and degrades performance.
Additional matching and power circuitry will increase the system's thermal temperature, thus limiting the overall system performance.
When configuring switch arrays for different antenna configurations, design flexibility is limited.
Compared with non-Dual SIM Dual Active (DSDA), DSDA is limited by the traditional eCall design in achieving a common layout for higher-end designs.
Figure 1 shows a traditional eCall design using discrete switches. There are multiple RF paths, which means that system engineers must carefully match each path to optimize the design. Figure 1 also shows the complexity of such a system because each signal requires multiple digital GPIO controls (GPIO - General Purpose Input/Output) for each path. This traditional design requires careful PC board design of the power splitter or the addition of an external power splitter to meet the requirements of proper layout and lower RF loss.
Figure 1: Example of a traditional eCall switch architecture
Meeting challenges through integration
Complexity can be easily addressed by implementing simple integration on some of the RF paths. While this approach clearly reduces some complexity, path loss, and matching challenges, it does not significantly improve your design. As shown in Figure 2, integrating some switches does help reduce matching, so instead of using many GPIO controls, fewer MIPI (Mobile Industry Processor Interface) controls can be used instead, and the number of switches can be reduced. This approach can also save cost, although the cost savings achieved are very small compared to a fully integrated approach.
Figure 2: Examples of eCall switch architectures with certain levels of integration.
As shown in Figures 3 and 4, a fully integrated approach can provide additional improvements beyond the integration shown in Figure 2. Figure 3 uses a DSDA switch option architecture to reduce front-end matching and RF losses, and uses an RFFE MIPI control to integrate all dividers in one package, reducing bill of materials and design time.
Figure 3: Example of a fully integrated eCall switch architecture – using the pin-compatible optional DSDA (QPC1252Q).
Figure 4: Example of a fully integrated eCall switch architecture – using a non-DSDA (QPC1251Q) routing switch.
The design shown in Figure 4 is similar to Figure 3, but without the integrated DSDA switch option architecture. However, it still requires a small amount of RF front-end matching in order to realize all the benefits shown in Figure 3.
Qorvo Expands Automotive eCall Solutions Portfolio to Improve Emergency Communications
Qorvo's high-performance broadband antenna switches for eCall help ensure connectivity to life-saving services after an accident. With these switches, the vehicle's primary cellular signal can automatically relay (or hot-swap) to an undamaged car antenna to summon help.
Qorvo's automotive portfolio has been expanded with the QPC1220Q high-linearity, wideband double-pole, four-throw (DP4T) antenna switch, which operates within the full range of AEC-Q100 Grade 2 automotive qualification requirements. With up to +34dBm hot-switching capability, it is ideal for all telematics control unit (TCU) eCall and antenna switching configurations. It also reduces insertion loss by up to 1dB, maximizing the effective power delivered to the external eCall antenna array, enabling better cellular and 5G connectivity even in areas with limited coverage.
The compact design saves up to 35% of board space, whereas traditional designs require four or more discrete switches, associated matching and months of engineering resources. This simplifies and speeds up board design for multimode, multiband systems.
...We will continue to work with our customers to meet their complex design needs and help them build high-quality vehicles.
Using the fully integrated QPC1251Q and QPC1252Q in an eCall solution further simplifies the design by replacing five separate switches with a single chip. This design approach can be used in both 4G and 5G chipsets, eliminating the need for multiple switches and reducing overall system power consumption while allowing automakers to connect both the primary and secondary antennas. The benefits of using these two highly integrated components in either DSDA or non-DSDA solutions include:
Flexible single component solution
Design simple solutions to support complex eCall antenna routing
No need for multiple switches or RF matching on the TCU module
Enables flexible on/off control
Provides excellent insertion loss and isolation performance
High linearity and low power consumption
Broadband solutions for 5G applications (up to 6GHz)
Integrated crossovers eliminate the need for external PC boards or discrete crossovers
Fully AEC-100 Grade 2 qualified solution
Our cars are becoming increasingly complex from an electronics perspective, essentially becoming a new type of mobile device. As RF connectivity infrastructure becomes more ubiquitous, our cars will become safer and more connected to each other and to our existing wireless ecosystem. The integration of antenna electronics will help accelerate this mobile connectivity. Semiconductor companies like Qorvo are working hard with automakers and standards bodies to provide highly integrated solutions to help automotive system engineers meet the needs of next-generation designs. With our integrated eCall switch system solution, we will continue to work with our customers to meet their complex design needs and help them build high-quality vehicles.
| 
提升卡
变色卡
千斤顶