How can data and power be transmitted as efficiently as possible in the vehicle on-board network? 

Efficient data transmission is a prerequisite for on-board networks of the future, and multi-functional solutions should help to achieve this efficiently. Which connector systems make it possible to transmit power and data over the same physical layer? Which chipsets are available or being developed? These and further questions are answered below…

Power and data transmission – current systems

Three approaches currently exist for transmitting high-frequency data in vehicles while delivering power to actuators and sensors at the same time.

With Power over Coax, both the data signal and the positive supply voltage (e.g. +12 V) are transmitted via the coaxial cable’s inner conductor. The external conductor’s braid doubles as the ground (0 V) and the shield. The disadvantages of this method include the low current-carrying capacity (approx. 100-200 mA) of the inner conductor and the reduced shielding capacity of the outer conductor which simultaneously serves as the return conductor.

With Power over Dataline, the data and the supply voltage are transmitted via the data cables of the twisted pair cable. One wire serves as the plus pole (e.g. +12 V), and the other as the ground (0 V). With an STP (Shielded Twisted Pair), the external conductor can be considered a pure shield as the entire electrical current flows solely through the inner conductor. Here too, the current-carrying capacity is limited as the inner conductors have a small cross-section (type 0.13 – 0.14 mm²).

In some cases, data and power cables are routed separately. In addition to the coaxial or twisted pair connections, what are known as “MQS contacts” can be attached to the plug connectors for the power supply. One example is a 4-pole mini-coaxial connector with 2 MQS contacts. The advantage of this solution is that the data signal does not have to be combined with the power supply by means of expensive filters and then separated again on the other side. Higher currents can also be transmitted. However, the assembly effort is significantly greater as the different cable cross-sections require different crimping tools, which involves a considerable amount of extra work in production. Testing and validation work required for the different cables also increases significantly, as does the storage space required for the different types of cable.

These methods each have their advantages and disadvantages. While Power over Coax and Power over Dataline offer a compact and cost-effective solution for the simultaneous transmission of data and power, the separate routing of data and power supply cables involves more work, but offers greater power carrying capacity and flexibility. Choosing the most appropriate method depends, to a large extent, on the specific requirements and framework conditions of the respective application.

Which chipsets are capable of transmitting data and power efficiently?

In the area of vehicle electronics, several specialized chipsets exist, which have been developed for the efficient transmission of power and data. These chipsets support technologies such as Power over Coax (PoC), Power over Dataline (PoDL) and USB-based solutions.

Power over Coax (PoC)

This type of chipset contains a serializer and is used in camera systems, for example, for transmitting both data and power via a single coaxial cable. In this case, data rates are supported in the gigabit and multi-gig area.

Power over Dataline (PoDL)

These chipsets have been specially developed for transmitting data and power via automotive Ethernet cables, and use twisted data cables (UTP, STP). This ensures a high current-carrying capacity, and PoDL chipsets are therefore ideal for networked vehicle components.

USB-based solutions

A USB 3.2 hub controller supports high data transmission rates of up to 5 Gbit/s (USB 3.2 Gen1) or 10 Gbit/s (USB 3.2 Gen2) and at the same time enables the supply of power to USB devices with Power Delivery of up to 100 W (20V / 5A) – ideal for infotainment systems and other data-intensive applications in vehicles.

These advanced chipsets offer the necessary technology for efficiently transmitting both data and power via different types of cable such as C-KLIC in vehicles. Choosing the right chipset depends on the specific requirements and areas of application, but the availability of these solutions opens up new possibilities for designing modern on-board networks.

C-KLIC as a universal transmission solution

C-KLIC is a multi-functional connector system developed by MD ELEKTRONIK. It is technically based on a USB-C interface adapted to automotive applications, and combines a whole range of possibilities and advantages. C-KLIC breaks completely new ground. USB-C is a universal interface, which, together with USB 2.0 (480 Mbit/s) to USB 3.2 Gen2 (10 Gbit/s), also supports a range of alternative protocols. PCIe, HDMI and DisplayPort are certainly the best-known representatives here. However, C-KLIC also offers much more than “just” support for USB protocols. Through the typical automotive locking mechanism and all standard coding sockets which make it impossible to flip the cable when inserting, all 24 pins of the interface can be fully utilized. Thanks to the four freely available differential multi-gig high-speed data pairs (10 Gbit/s each), combined with high-speed data cables (480 Mbit/s) and power cables for up to 5 A at 20 V (max. 100 W), many alternative high-speed applications can also be implemented effortlessly.

Conceivable in this regard are, for example, multi-lane Ethernet applications or diverse customer-specific proprietary protocols with which the connected devices are also supplied with power. There are virtually no limits to the possibilities:

Simplified wiring:

With C-KLIC, different data and power cables can be integrated into a single connector system, reducing the wiring complexity.

Weight and space saving:

The reduction in the number of cables and connectors required reduces the overall weight of the vehicle – which is an advantage particularly for electric vehicles. At the same time, thanks to C-KLIC’s operational performance, less space is required on the control units.

Fewer tests:

As less individual components need to be tested, the amount of work involved in testing is reduced – saving time and costs.

Less costs:

Through the integration of more functions into one connector system, material and production costs can be reduced. In addition, less connection operations are required when assembling the complete vehicle. This simplifies the installation process and saves time and money.

Reduced error sources:

Less connections and connection operations also mean less potential error sources, which increases the system’s reliability.

More than a USB – one connector, one cable – 6 functions

C-KLIC combines functions which previously required up to 6 individual cables.

For example, the “all-in-one” maximum configuration (4x multi-gig data, 2x high-speed data and power), requires the following currently established technologies:

➜ 4x multi-gig – data (10 Gbit/s), e.g.: H-MTD*¹ or GEMnet *²    

➜ 2x high-speed data (480 Mbit/s), e.g.: HSD *²           

➜ Control signals + power, e.g.: HSD*¹ + MQS contacts 

The described characteristics offer huge benefits for use as a data cable in the vehicle:

➜ Connection and routing of just one cable instead of up to 6 different cables

• Saves time on the assembly board and during installation
• Saves costs (materials and time)
• Saves weight
• Minimizes error sources

➜ Huge space saving on the control unit (approx. 60% – 1 PCB connector instead of up to 6)

➜ Unhindered use of existing data and power cables for proprietary interfaces.

User interface application – less heat loss, less space requirement

When considering the characteristics of C-KLIC in the power supply area, further advantages of this interface become apparent. In the following application of a USB-C interface in the dashboard, Power Delivery technology is used and can provide a maximum charging capacity of 100 W (5A @ 20V). In addition, data can be transmitted at up to 480 Mbit/s (USB2.0). The specially developed cable enables a very low voltage drop (ground drop) over the entire length of the cable (80 mV /m).

Thanks to this setup, it is possible to remove the charging electronics, which generate a higher power loss (heat), from the customer interface and relocate them in a nearby control unit.

Control units generally manage temperatures very well and offer very good heat dissipation.

In turn, this results in two major advantages:

➜ Less space requirements for the user interface in the dashboard (saving of up to 60%)

➜ No heat generated at the user interface by decentralized charging electronics

*¹ H-MTD and HSD are products made by Rosenberger
*² GEMNet is a product developed by TE