The automotive industry is currently undergoing a huge transformation. New technical innovations are constantly finding their way into modern vehicles. This development is being propelled above all by legal requirements in the area of active safety and drive technology (emissions). Vehicle user’s new and heightened demands for infotainment, connectivity and comfort are another driving force. A variety of additional functions are having to be installed in virtually the same installation space. The order of the day is therefore: miniaturization. Find out more about this trend in the article below.
Reasons for the miniaturization trend
In order to meet new demands, not only are additional control units being integrated into vehicles, but additional functions are also being added to existing control units. In addition to the respective control units, corresponding actuator and sensor technology must also be taken into account and connected to the ECU via the on-board power system.
This development results in the challenge, both for OEMs and for vehicle electronics manufacturers, of implementing a wider range of functions with virtually the same installation space capacity. While the OEM is faced with the task of integrating more cables into the vehicle and positioning connectors, the control unit manufacturer is having to provide more contacts/connections on the electronic components without significantly increasing the installation space.
Integrating new vehicle functions with a virtually unchanged installation space can only be accomplished by adapting and optimizing the network topologies, and by miniaturizing on-board power system components and device connections (interfaces).
This trend towards miniaturization in the on-board power system may not be completely new, but in recent years, it has had an increasing impact on the area of data connectors.
From FAKRA to Mini Coax
The Mini Coax cable is one of the best known examples, and in the meantime, has become the most widely used system among OEMs. These coaxial cables have a similar constructive principle to FAKRA cables but differ considerably when it comes to size and technical properties.
In terms of maximum frequency and bit rates, Mini Coax systems represent a significant improvement compared to the traditional FAKRA system, and therefore are also perfect for meeting future requirements with regard to data transmission. However, the reason they were first used in cars was not due to the improved HF capacity but rather to the huge reduction in installation space that Mini Coax cables offer.
They also made it possible to increase the range of functions in the vehicle while at the same time significantly reducing the installation space requirement. By using one Quad Mini Coax cable instead of four single Fakra cables, a reduction of approx. 70% could be achieved. And what’s more, a weight reduction of approx. 75% can also be achieved– another advantage that often goes unmentioned.
Therefore, in the area of coaxial cables, the introduction of Mini Coax systems represented a decisive step in making this tried and tested technology future-proof for the next generations of vehicle.
Dimensions FAKRA SF and MATE-AX
More powerful: faster and higher data transmission achieved and frequencies up to 20 GHz are possible
Smaller: the main difference is that the Mini Coax cable is considerably more space-efficient (up to 70% reduction of installation space when comparing 4 x 1-pin FAKRA to 1 x 4-pin Mini Coax) than the FAKRA cable
Weight reduction: of approx. 75% when comparing 4 x 1-pin FAKRA to 1 x 4-pin Mini Coax
Additional automotive connectors
However, the trend towards miniaturization does not stop at coaxial cables, it applies to other vehicle (data) connectors too.
Twisted pair or twisted quad-based contacts cannot be indefinitely extended on the control unit or in the on-board power supply due to space issues. In addition to optimizing installation space requirements, the introduction of Automotive Ethernet and the use of in-vehicle networks are the main drivers for the many interfaces such as Mate Net; H-MTD /GEMnet and AMEC in the vehicle.
| Working Group | Transmission |  |
|---|---|---|
| IEEE 802.3bw OPEN All. TC2 |
100 Mbit / s electrical |
HSDe AMEC 100M UTP MATEnet UTP |
| IEEE 802.3bp OPEN All. TC9 |
1 Gbit / s electrical |
H-MTD STP MATEnet UTP MATEnet STP AMEC 1G UTP/STP |
| IEEE 802.3ch OPEN All. TC9ff |
2,5 Gbit / s 5 Gbit / s 10 Gbit / s electrical |
H-MTD STP GEMnet STP |
| IEEE 802.3 faster than 10 G |
25 Gbit / s 50 Gbit / s electrical |
H-MTD STP GEMnet STP |
| IEEE 802.3bv | 1 Gbit / s optical POF |
DIA |
| IEEE 802.3 10G optical |
10 Gbit / s optical GI |
 |
Automotive Ethernet Solutions
Through the introduction of central High Performance Computers (HPC) where the different data and power lines converge, the number of contact points on these control units is increased many times over. This leads to an increase in the number of multiple data cables such as 6-way or several 4-way connectors. However, in addition to the corresponding space requirement on the circuit board and for the interface to the vehicle’s on-board power supply, this development also generates an increase in the number of connection operations required during assembly. And yet, this trend has by no means reached its limits. Through the integration of further sensor technology and the introduction of redundant systems, which are required for autonomous driving, for example, the number of data contacts required in different power classes is also increasing.
A further miniaturization of the connection system with, at the same time, the same future-proof HF performance and a design that enables easy integration into multiple connectors, is therefore unavoidable.
Cooperation between connection system developers and assemblers
The push towards miniaturization not only poses considerable challenges for the developers of connection systems, but also for the assemblers. In order to ensure the high performance of the connection system, narrower tolerances both when producing connector components and when assembling components in connection with bulk stock must be observed. The result is a new product design in conjunction with an optimized manufacturing process. Therefore, close collaboration between assemblers and connector manufacturers is already essential during the early development stage.
MD is working together with several connector manufacturers to drive miniaturization forward. Through innovative product designs and the use of a new form of contact for the on-board power supply area, significantly higher data rates and at the same time a reduction in installation space of up to 30% compared to current connector systems can be achieved. These future connector systems can be integrated into hybrid or modular connector housing (such as on motor control device connectors). A reduction in installation space of up to 50% can be achieved while reducing the number of connection operations at the same time.
However, all of this is only possible by using new connection technologies and contacts which make the use of established joining technologies (required by the Automotive Industry Standard) virtually impossible. Within the context of development, different forms of contact are being examined, tested and optimized for their (large-scale) suitability for series production.
Summary and conlusions: Innovative product design and new production procedures as a prerequisite for miniaturization
The miniaturization of components has been a constant companion for many years in the development of a new vehicle on-board power supply or a new vehicle architecture. This trend has also been increasingly taking hold in recent years in the development of data connectors. The different Mini Coax systems have already been tried and tested by many OEMs in their applications. Although data connectors based on STP or UPT bulk stock take up less installation space than HSD connectors, for example, the trend towards further miniaturization can also be observed here. Higher HF demands, the increase in contacts on control devices and the integrability into multiple connectors make this step inevitable. However, to achieve this, new and innovative solutions need to be found both for product design and in the assembly process in order to enable the mobility of the future.
Tobias Fiedler
Tobias Fiedler is Director of Product & Project Management at MD. Together with his team spread across three continents, his mission is to define and implement the MD product portfolio so that it meets the requirements of future generations and satisfies market needs. Over 14 years’ experience in the automotive industry, including 12 years in the onboard network area have turned him into an expert in this field. In addition to technical exchanges with international development partners and customers, what excites him the most is the great diversity of his tasks which results from the continuous transformation of the automotive industry.