High-end embedded systems designed for industrial applications can integrate only a specific selection of new processor technology. In fact, they are only fit for harsh everyday use if they are designed without fans.

This increases their reliability in harsh environments where they have to endure shocks or vibrations, and ensures they remain maintenance-free even after years of continuous operation.

Another plus is that fanless designs can be hermetically sealed against dust and humidity, something that is essential for virtually every industrial application.

Last, but not least, no fan also means no noise. This is ideal for devices that are used in close proximity to humans, for example; medical devices in an intensive care unit, in a professional recording studio or a testing and metrology lab.

So there are many reasons that favour fanless designs.

Cooling on small carrier board

Fanless systems are relatively easy to implement with processors that consume less than 10W. Currently, the limit of where fanless designs are still possible lies around 15 watts TDP. Many embedded  system developers work around this limit to get the most out of their fanless high-end applications such as industrial PCs with control and HMI in one system, image and video processing systems, professional audio and video equipment and digital signage.

Many systems will now require an internet connection for IoT and industry 4.0 applications. Both require additional data processing and communication capabilities – including encryption and virus protection. This can drive up the demand for computing power quite significantly.

Intel’s latest Core i7 / i5 / i3 processors come in a very wide range of powers from a few watts up to 91W. So i will look at what the 15W SoC versions of the processors have to offer, because only they allow the development of fully industrial grade, fanless high-end systems.

Benchmarks for this particular performance class are currently unavailable. However, it is safe to assume that the advancements made in the SoC segment of this processor generation are comparable to those achieved for desktop variants requiring active fans. Intel states that, compared to five year older platforms, the new Core processors provide up to 2.5 times more computing power, 30 times better 3D graphics performance and 3 times longer battery life. Compared to the 5th generation (codenamed Broadwell), there is an estimated increase of around 10% in the graphics and computing performance, and 11% in energy efficiency.

The higher performance comes from a 14nm manufacturing process and the revised Skylake microarchitecture. This includes an optimised fabric that connects CPU cores, graphics unit and last level cache (formerly L3 cache) via a ring bus architecture.

The ULV SoC versions that are relevant for 15W designs also include the system agent that integrates the display, storage and I/O controller. There is technology for faster switching between power states, leading to performance increases between 20% and 45% compared to Intel Core processors of the 5th generation. At the same time, the power consumption is lowered.

Intel has also reduced the SoC’s supply voltages and refined the power gating of the individual function blocks. This reduces power dissipation and it allows extended use of turbo boost, so that applications can cope better with peak loads.

The graphics unit, which has been optimized for Windows 10 and is integrated in the new 9th generation 15W SoCs as Intel graphics 500, now also provides greater performance. It supplies up to three independent 4k displays with 60Hz refresh rate via DisplayPort 1.2.

Also HDMI 1.4 is supported, and DirectX 12 ensures even faster 3D graphics under Windows 10. Furthermore, an additional video engine is integrated. This allows the encoding and decoding of HEVC, VP8, VP9 and VDENC video with minimal CPU load and low power consumption. For the first time, it is now possible to stream HD video efficiently in both directions, i.e. both upstream and downstream. With 24 execution units and OpenCL 2.0 support, the GT2 520 graphics of the ULV processors can also free the CPU from compute-intensive parallel tasks.

Another new feature is the support of DDR4 RAM. This brings a number of improvements: First, it provides a much higher bandwidth and works faster; secondly, at 1.2V it is also more energy efficient than current 1.35 V DDR3 RAMs.

In addition, thanks to a doubling of the memory density it is now possible to achieve 32Gbyte of working memory with two RAM slots. This is an enormous plus for many high-end embedded systems and probably the main reason for many system designers to upgrade to the new generation as soon as possible.

The 6th generation of Intel Core processors account for the high I/O requirements of many high-end IoT and embedded systems by providing more high-speed I/Os. The SoC versions with PCI Express Gen 3.0 offer almost double data rates.

The new processor generation also provides twice as many USB 3.0 interfaces (now 4) than their immediate predecessors. Thanks to the availability of a CSI MIPI-2 camera interface that for the first time integrates an Image Signal Processor (ISP), the images provided by the sensors can be processed in real time and extremely energy efficiently without CPU intervention.

The first three 15W embedded SoCs of the 6th generation Intel Core platform are the dual-core processors Intel Core i7-6600U, Intel Core i5-6300U and Intel Core i3-6100U with hyper-threading support.

For small form factor (SFF) boards, and if a customised set of interfaces is required, Computer-on-Modules (COM) are in my opinion the best choice.

The PICMG COM Express specification is designed specifically for the high-end segment. In designs where space is limited, the COM Express Compact form factor is used most often. It offers a compact footprint of just 95 x 95 mm and at the same time includes two double row SMD connectors with 440 pins for numerous high-speed interfaces.

In addition, COM Express is optimised for the high performance interfaces of standard PCs and meets the highest rugged demands thanks to the stable connection to the application-specific carrier board. In many cases, it is specifically the fanless high-end designs that rely on COM Express Compact, especially when the standard feature set of Mini-ITX motherboards do not meet the design requirements or space is limited in the application.

Do system design and processor fit together?

Individual system designs always present the embedded design engineer with some challenging questions: Is my system design really suitable for the chosen processor? Will I be able to operate the system long-term and without overheating, or will the application bring the system down when it comes to load peaks?

It is essential to ensure that the design does not overheat the processor, as this would shorten the service life or lead to extremely premature failures. Fortunately, there are now not one but two factors that make it easier for developers to balance hardware design, processor and application requirements and to develop applications that really reach the limits of the possible with a TDP of 15W.

The first factor is the configurable TDP of the processor (CTDP); the second factor is the availability of fanless cooling solutions that are a good fit for the computer module and processor. These two factors make it possible to optimize the design step by step to meet the requirements of a given hardware design and application.

The new 15W SoC processors are configurable from 7.5 to 15W. If the application is prone to overheating the system in certain scenarios, it is possible to minimise the hotspot at certain points by limiting the maximum heat output so that the system always remains within the permitted thermal range. Another option is to play with heat sink variants, provided different cooling concepts are offered for an identical footprint.

Since the PICMG COM Express specifications allow designers to limit the height of the heatspreader, it is possible to develop heat sink solutions with an identical footprint that offer different options. These can range from simple embedded heat sinks with fins to heat sinks with a housing connection or high-performance coolers with combined heat pipe and heatspreader technology

For fully enclosed designs that need to exploit the 15W to the maximum, system internal convection is recommended; another option is connecting the heat sink to the outer casing.
The availability of configurable TDP together with starter kits that offer flexible heat sink variants, will enable system developers to succeed more quickly than with trial & error attempts at system design and housing.

I believe, the new Intel Core processor generation will make thermal design a lot easier in the future. However, OEM developers will continue to face questions that require direct access to the expertise of module suppliers. It is a real advantage if the manufacturer has defined a transparent process that guarantees personal support, making it unnecessary to go from start to finish and explain issues again each time.

Christian Eder is marketing manager at Congatec