While the media focuses on the sections of the semiconductor industry that innovates around massive processing performance, you could be forgiven for thinking that smaller and faster is the industry’s only motivator. In fact they only form a small part of the bigger picture.
Once digital decisions have been made, they must be translated into motion or stored in the cloud, all of which requires the efficient use of power.
Industry 4.0, or Industrial IoT (IIoT), has provided much of the impetus to move from purely mechanical or electromechanical to more intelligent and refined connected electronic systems. However, this requires more equipment that draws electrical power. Should this be implemented without regard for electrical efficiency, part of its premise will be lost. Parallels can be drawn here with the computing industry mandating higher efficiencies for power supplies as the number of computers and servers in use rapidly grew.
Penetrating every market segment
As industrialised nations consider their carbon footprints, efficient consumption of the power used is a common binding theme. In an industrial context this encompasses a wide range of applications, such as power supplies and motor control systems, along with battery chargers due to the increasing use of autonomous guided vehicles (AGV). With this continued growth in installed electrical equipment it can be expected that further regulations will also emerge, or existing regulations tightened.
Then there are robots and, increasingly, collaborative robots (cobots) whose drive systems also need to be power-efficient, compact, and lightweight. And, as we encourage people and goods to move from private road transportation to greener alternatives, options such as rail also need to expand while additionally upgrading to more efficient control systems. Finally, energy delivered via high power transmission systems (HVDC) need to ensure that the power generated moves from source to point-of-use with as little loss as possible.
The same also applies to other markets: automotive is moving to 48V power electrical systems and drives; white goods must consume less energy while also being quieter.
Innovating beyond purely finer geometries
While digital systems, such as processors and artificial intelligence, benefit from ever finer lithography, silicon built with a high quantity of analogue components do not. Many passive components, such as capacitors and inductors, do not shrink, meaning that innovation needs to happen elsewhere. Power devices, such as IGBTs and MOSFETs, also fail to benefit from finer lithography. Instead, suppliers require an intimate understanding of the physical properties of the device’s structure, along with the interaction at the junctions of different materials, to deliver improvements.
Progress here has seen continuous improvement in reducing parasitic effects and other parameters, while increasing switching speed. Such improvements in static and dynamic losses deliver efficiency improvements and reduce heat dissipation in power supplies and control systems, such as servo drives. Packaging is another key area of innovation. Today’s package structures ensure that any dissipated heat can be removed easily, thanks to the elimination of conduction losses between the die and package, while simultaneously shrinking the package and maintaining reliability and supporting automated optical inspection quality regimes.
The control techniques employed have also advanced, allowing designers to address the impact these parasitic effects can have. This, coupled with increases in switching speeds in power converters, enables advancements to be attained that cannot be achieved from manufacturing process improvements and physics alone.
Perhaps the past decade’s most important development has been the large-scale introduction of wide bandgap (WBG) technology such as silicon carbide (SiC) and gallium nitride (GaN). These overcome many of the limitations of silicon, as determined by physics, and allow the use of innovative power solutions that can maximise performance. These are pushing applications involving power conversion into the domain of 99% efficiency or better.
Blending digital with analogue
While the IIoT focuses on data sharing and analysis, the signals entering such systems, and the actuators implementing the outputs, are still operating in the analogue domain. Digital processors, in the form of microcontrollers, are an essential part of the mix but it is not raw processing power alone that is required. Instead, highly integrated and sophisticated control mechanisms that, in some cases, operate almost autonomously, are more important than pure processing performance and need to be integrated alongside digital processors.
Toshiba offers a range of microcontrollers that integrate such control mechanisms, such as an integrated Vector Engine that handles the majority of the complexity behind field-oriented control making it simpler for such efficient motor control technology to be integrated by designers.
While semiconductor vendors have benefited from lithography shrinks and increases in wafer sizes, this does not mean that pricing for these devices should be defined purely on die area alone.
Semiconductors are an investment-intensive business, requiring enormous sums to establish new manufacturing processes, new packaging, and additional capacity in manufacturing facilities. As old technologies ‘go digital’, and existing applications become ever more integrated, the level of support and expertise expected from them is growing too. Today’s microcontroller-based systems may include motor control, digital power conversion, graphical user interface, network connectivity, and also security. Each of these would have been handled as individual disciplines in the past.
The move to WBG is not a drop-in replacement. Inherent understanding for gate drive, parasitic parameters, and long-term ageing are different compared to the silicon MOSFETs and IGBTs they are replacing. The approach to controlling the switching process and many other aspects also require careful consideration for a successful design that provides long-term reliability. WGB will also continue, for some time, to be more expensive than the silicon alternatives they replace. For semiconductor suppliers, this requires a capacity assessment: how will the demand on next-generation superjunction MOSFETs be impacted by the market adoption of SiC, and how should we best plan for this change?
Interactions with semiconductor vendors need to factor in the long-term total cost of ownership (TCO), and system-level and end-user benefits that result, rather than purely the cost of every single component on the board.
Conclusion
Without doubt, it is the efficient use of available power that is driving much of the demand seen in the semiconductor industry today. Regardless of whether something needs to reduce noise, minimise heat generation, or needs a smaller footprint or volume, it is the masterly handling of electrons that lies at the core of the issue. However, the semiconductor industry’s value here is much more than the products it supplies. Its application-level expertise, role as consultant, and deep market insights are as important as its ability to innovate at every level, from process, through package and die, to the resultant systems our customers develop.
Author details: Armin Derpmanns, Head of Semiconductor Marketing and Operations, Toshiba Electronics Europe
