<p dir="ltr"><em>Co-authored by Andreas Hardock &nbsp;</em></p><h1 dir="ltr">Introduction</h1><p dir="ltr">Automotive connectivity, such as&nbsp;telematics and infotainment, as well as&nbsp;autonomous driving trends are pushing demand for higher data-transfer rates within the vehicle. To meet this need vehicles have a growing number of computer-based systems, applications, and connections as well as the cabling, network interfaces, and onboard computing power to support them. Automotive ethernet is now at a stage where it can reliably reduce these electronic costs and support increasing bandwidth requirements.</p><p dir="ltr">While automotive ethernet usage solves some problems it also brings to light the critical importance of Electrostatic Discharge (ESD) robustness to ensure the reliable high performance of automotive communication networks. As data rates in a communication network increase ESD robustness decreases.</p><p dir="ltr"><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe allowfullscreen="" class="fr-draggable" frameborder="0" src="https://www.youtube.com/embed/rIWff-hQP28?enablejsapi=1&origin=https://www.wevolver.com" style="width: 779px; height: 411px;" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span></p><p dir="ltr">In simple terms, ESD is the release of static electricity when two objects come into contact. It produces a high current in a very fast event. Much like the shock you can get from a door handle after walking on particular carpets. In an automotive setting, ESD events can result in sub-micron damage to the device that can lead to device failure. This article will examine how the risk of ESD can be mitigated with an optimized ESD protection concept.</p><h2 dir="ltr">The current state of in-vehicle networks</h2><p dir="ltr">The current makeup of today&rsquo;s in-vehicle networks is a culmination of past technologies including Local Interconnect Network (LIN) &nbsp;and Controller Area Network (CAN) as well as CAN-FD which is gaining more importance due to flexible data rates. &nbsp;This presents a challenge for the industry as it aims to both reduce the number of technologies while at the same time retaining the necessary legacy technologies to reduce cost and retain reliability.&nbsp;</p><p dir="ltr">All automotive subsystems were initially connected by dedicated cables. &nbsp;However, as automotive systems became more complex, and the number of automotive subsystems relying on electronics increased, so did the amount of cabling required for their interconnection. The concept of fieldbuses was introduced. A fieldbus is a serial bus allowing message exchange between nodes connected to the fieldbus. Using a fieldbus, several previously dedicated cables are replaced by a serial bus interconnecting the ECUs. This decreased both the weight and cost of the automotive system. More recently, in response to the ever-increasing network demands, in-vehicle networks now use zonal architecture which aims to form a network by which any Electric Control Unit (ECU) can talk to any other.&nbsp;</p><p dir="ltr">To do so, every ECU is connected to a domain or zone controller directly via a short CAN, LIN, or 10BASE-T1s interface. The domain or zone controllers are connected using a high-speed backbone network technology such as Automotive Ethernet (IEEE automotive Ethernet standards 100BASE-T1, 1000BASE-T1, and 1000BASE-RH) which provides flexibility and determinism (see Figure 1).</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 788px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNjAxODkwNTg5Njg2LTIwMjAtMDAxNyBORVhfMDY4X0ltYWdlcyBmb3IgWm9uYWwgQXJjaGl0ZWN0dXJlXzIuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ=="><span class="fr-inner" spellcheck="false">Figure 1.&nbsp;</span></span></span></p><h2 dir="ltr">Software for versatility</h2><p dir="ltr">Software is integral to making the zonal architecture system versatile. It allows for virtual CAN/LIN networks to be implemented, so that legacy ECUs can operate as though via a CAN-/LIN-only topology. Software also means that every ECU with a dynamic Internet Protocol (IP) address can be used in plug-and-play operations as well as support features such as over-the-air updates. Secure sub-networks can also be formed based on software to ensure compliance with safety standards in safety-critical applications and to protect sensitive data.</p><h1 dir="ltr">Automotive Ethernet</h1><p dir="ltr">Automotive Ethernet is a physical network that is used to connect components within a car using a wired network. In the past, it was previously reserved for limited to data heavy applications that CAN and FlexRay were unable to provide such as diagnostics, in-vehicle-infotainment (IVI) systems, and connecting remote sensors. However, the technology has now matured and is ready to meet the demand of fast-growing trends such as <a href="https://www.wevolver.com/article/putting.highperformance.computing.into.cars.automotive.discrete.semiconductors.for.autonomous.driving" target="_blank">autonomous vehicles</a>, providing the desired flexibility for zonal architecture configuration. It is also easy for engineers to implement with globally recognized standards specific to the automotive market.</p><h2 dir="ltr">Advancing specifications</h2><p>The Institute of Electrical and Electronic Engineers (IEEE) recognizes three automotive Ethernet standards; 100BASE-T1,1000BASE-T1 and 1000BASE-RH &nbsp;that can meet automotive emissions standards and reduce cabling weight and cost in automotive networking<sup>[1]</sup>. &nbsp; The standard was ushered in by the work of <a href="https://www.opensig.org/" target="_blank">the OPEN (One-Pair EtherNet) Alliance</a>, a special interest group formed by major automotive OEMs and tier-one suppliers who are collaborating to push the wide-scale adoption and standardization of Ethernet-based networks and their security and reliability. The alliance was early adopters of automotive Ethernet and have been key in defining automotive ethernet standards.&nbsp;</p><h1 dir="ltr">ESD robustness&nbsp;<iframe id="6422b69e2f9a8000088dee15" width="250" class="specs-iframe" height="420" src="https://wevolver.com/iframe/specs/nexperia-nevb21-usbc1ul-usb-type-c-esd-evaluation-board?iframe=true" frameborder="0" scrolling="true" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></h1><p dir="ltr">Automotive Ethernet Systems have to pass several environmental tests to be very robust in the field at any climate condition. One of these is the System-level ESD robustness which is a very crucial feature for any electronic system, even more so in an automotive environment where smaller ICs mean a loss of space for internal ESD protection. These <a href="https://www.wevolver.com/article/how.advanced.driverassistance.systems.adas.impact.automotive.semiconductors" target="_blank">smaller devices</a> are also vulnerable as even lower voltages can damage the thinner gate oxide. The danger posed by potential system failures caused by ESD is severe - particularly in autonomous driving technologies. Both discrete ESD protection devices as well as the system design play a role. Rigorous ESD protection can be avoided or heavily mitigated with an optimized ESD protection concept. ESD protection depends on several factors beyond the robustness of individual components, including the robustness of the weakest device in the system, the properties of the protection device, the properties of other elements in the signal path, and the parasitic effects arising from the board and mounting wires.</p><h2 dir="ltr">SEED simulation methodology for product development</h2><p dir="ltr">System-efficient ESD design (SEED) is a system-level approach to ESD simulation to develop protection components suitable for increasing demand. The concept of SEED is to consider all the parameters of ESD protection as outlined above into account in the form of an equivalent circuit or circuit-like simulation to predict system-level robustness. More detail on SEED can be found <a href="https://efficiencywins.nexperia.com/innovation/SEED-delivers-OPEN-Alliance-compliant-ESD-protection.html" target="_blank">here.&nbsp;</a><a href="https://www.opensig.org/" target="_blank">OPEN Alliance</a> members use <a data-lf-fd-inspected-kn9eq4roawkarlvp="true" href="https://assets.nexperia.com/documents/white-paper/Nexperia_Whitepaper_ESD_Discharge_Current_Measurement_Using_SEED_1.pdf" target="_blank">SEED methodology</a> when developing silicon-based, OPEN Alliance-compliant ESD protection for 100 and 1000baseT1 Automotive Ethernet systems</p><h2 dir="ltr">Redesigning physical systems</h2><p dir="ltr">In previous Automotive Ethernet implementations, PHY (physical layer interface, referring to the transceiver) vendors were advised to put any required discrete ESD protection device between the CMC (common-mode choke) and the PHY.</p><p dir="ltr"><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNjAxODkxMTQ0OTQwLWVzZCBwcm90ZWN0aW9uLmpwZyIsICJlZGl0cyI6IHsicmVzaXplIjogeyJ3aWR0aCI6IDk1MCwgImZpdCI6ICJjb3ZlciJ9fX0=" style="width: 788px;"></p><p dir="ltr">Now, the ESD protection device is recommended to be placed immediately next to the connector, protecting not only the PHY but also the CMC and passives. In this position, external ESD protection is decoupled from internal protection of the PHY and protects also the DC block as well as other passive components. In the figure above there is a comparison shown between the OA approach with the ESD protection close to the connector (middle), a classic approach with the ESD protection close to the PHY (right), and without any ESD protections (left). The red color indicates a high current density. One can see that having the OA approach provides by far the lowest currents at the circuitry behind the ESD protection and especially the PHY. This means the best ESD robustness for the entire Ethernet system.&nbsp;</p><h1 dir="ltr">Nexperia ESD solutions</h1><p dir="ltr"><a href="https://www.nexperia.com/" target="_blank">Nexperia</a>, a leading semiconductor manufacturer and&nbsp;technical member&nbsp;of theOPEN Alliance, used the SEED methodology&nbsp;to replicate the ESD Discharge Current Measurement test when developing the industry&rsquo;s first silicon-based, ESD protection for 100/1000BAASE-T1 automotive Ethernet systems.&nbsp;Silicon-based ESD protection devices offer a significantly higher performance level of protection - up to 30 kV system level robustness &ndash; than competing technologies such as varistors.</p><p dir="ltr">Nexperia has a wide range of discrete components for ESD protection in targeted applications:</p><ul><li dir="ltr"><p dir="ltr">ESD protection for in-vehicle network lines in automotive environments</p></li><li dir="ltr"><p dir="ltr">OPEN Alliance 100BASE-T1 Ethernet and 1000BASE-T1 Ethernet</p></li><li dir="ltr"><p dir="ltr">PESD2CANFDx series for CAN-FD bus</p></li></ul><p dir="ltr">Key features and benefits of the first two OPEN Alliance Ethernet compliant ESD Protection devices:</p><h3 dir="ltr">PESD2ETH100-T For 100BASE-T1 Ethernet</h3><ul><ul><li dir="ltr"><p dir="ltr">Fully 100BASE-T1 OPEN Alliance compliant</p></li><li dir="ltr"><p dir="ltr">Low capacitance &lt;3pF</p></li><li dir="ltr"><p dir="ltr">ESD protection up to 30kV (IEC 61000-4-2, contact)</p></li><li dir="ltr"><p dir="ltr">1000 contact discharges with 30 kV (IEC 61000-4-2)</p></li><li dir="ltr"><p dir="ltr">High trigger voltage: Vt1 = 10V min.</p></li><li dir="ltr"><p dir="ltr">SOT23 package</p></li><li dir="ltr"><p dir="ltr">AEC-Q101 qualified/automotive grade</p></li></ul></ul><h3 dir="ltr">PESD2ETH1G-T For 100/1000BASE-T1 Ethernet</h3><ul><ul><li dir="ltr"><p dir="ltr">Fully 100/1000BASE-T1 OPEN Alliance compliant</p></li><li dir="ltr"><p dir="ltr">Low capacitance &lt;2pF</p></li><li dir="ltr"><p dir="ltr">ESD protection up to 30kV (IEC 61000-4-2, contact)</p></li><li dir="ltr"><p dir="ltr">1000 contact discharges with 15kV (IEC 61000-4-2)</p></li><li dir="ltr"><p dir="ltr">High trigger voltage: Vt1 = 100V min.</p></li><li dir="ltr"><p dir="ltr">SOT23 package</p></li><li dir="ltr"><p dir="ltr">AEC-Q101 qualified/automotive grade</p></li></ul></ul><p dir="ltr"><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNjAxODkyMjg0ODkwLWNvbXBvbmVudHMuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ==" style="width: 788px;"></p><p dir="ltr">Nexperia also has solutions for other relevant technologies within the network including: PESD2CANFDx for CAN-FD and PESxIVNx Series for LIN and CAN. More on these solutions can be found <a href="https://efficiencywins.nexperia.com/efficient-products/Automotive-ESD-Design-Engineers-Guide.html" rel="noopener noreferrer" target="_blank">here.</a></p><h2 dir="ltr">Essential elements for ESD design</h2><p dir="ltr">Nexperia&rsquo;s ESD products can help minimize the risk of ESD damage while their research, knowledge, and <a href="https://efficiencywins.nexperia.com/efficient-products/Automotive-ESD-Design-Engineers-Guide.html" rel="noopener noreferrer" target="_blank">design guides</a> support the engineering community in protecting applications and products against ESD issues. To help designers navigate ESD protection, Nexperia has developed a set of &lsquo;golden rules&rsquo; for ESD design.&nbsp;</p><ol><li dir="ltr"><p dir="ltr">Place the device as close to the input terminal or connector as possible.</p></li><li dir="ltr"><p dir="ltr">Provide a solid ground connection for the device</p></li><li dir="ltr"><p dir="ltr">Keep parallel signal paths to a minimum.&nbsp;</p></li><li dir="ltr"><p dir="ltr">Avoid running protected conductors in parallel with unprotected conductors.</p></li><li dir="ltr"><p dir="ltr">Minimize all Printed-Circuit-Board (PCB) conductive loops including power and ground loops.&nbsp;</p></li><li dir="ltr"><p dir="ltr">Minimize the length of the transient return path to ground.&nbsp;</p></li><li dir="ltr"><p dir="ltr">Avoid using shared transient return paths to a common ground point.&nbsp;</p></li><li dir="ltr"><p dir="ltr">Use ground planes whenever possible. For multilayer PCBs, use enough ground vias.</p></li></ol><h1 dir="ltr">Conclusion</h1><p dir="ltr">The increasing demands for higher bandwidth and low-latency communication in automotive are driven by the exciting increase in drive-assist technology, infotainment, connectivity, and autonomous driving. Automotive ethernet can reliably support these increasing bandwidth requirements but its adoption must be tied with optimized ESD protection concepts. The challenges of automotive communication can be met with new ESD protection concepts that deliver high system-level robustness, good signal integrity, and PCB design flexibility.&nbsp;</p><hr><h1 dir="ltr"><em>About the sponsor: Nexperia</em></h1><p dir="ltr"><em>Nexperia is the expert in high-volume production of discrete and MOSFET components and analog &amp; logic ICs that meet the stringent standards set by the Automotive industry. With an absolute focus on efficiency, Nexperia consistently produces the essential semiconductors required by every electronic design in the world: more than 90 billion annually. Products that are benchmarks in efficiency - in process, size, power, and performance - with industry-leading small packages that save valuable energy and space.</em></p><p dir="ltr"><em>With decades of experience, supplying to the world&rsquo;s biggest companies, Nexperia has over 11,000 employees across Asia, Europe, and the U.S., offering global support. The company has an extensive IP portfolio and is certified to IATF 16949, ISO 9001, ISO 14001, and OHSAS 18001.</em></p><p dir="ltr"><em><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNjAxOTY1MzEyMjU3LW5leHBlcmlhIGJhbm5lciBsb2dvLmpwZyIsICJlZGl0cyI6IHsicmVzaXplIjogeyJ3aWR0aCI6IDk1MCwgImZpdCI6ICJjb3ZlciJ9fX0=" style="width: 300px;"></em><br></p><p dir="ltr">&nbsp;</p><hr><h1 dir="ltr"><em>References</em></h1><ol><li dir="ltr"><p dir="ltr"><em>https://standards.ieee.org/standard/802_3bw-2015.html</em></p></li></ol><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p>

As data rates in automotive communication networks increase optimized ESD protection concepts become critical.

Enabling Robust Automotive Communication: Ethernet ESD Protection

<h2 data-element-id="headingsMap-4-0">Introduction</h2><p>Power MOSFETs play a key role in a range of common high power applications with a particularly essential position in the automotive industry due to their fast switching speed, easy advanced paralleling capability, low gate drive power, wide bandwidth, ruggedness, ease of application, and relative ease of repair.&nbsp;</p><p>One often an under-discussed aspect of power MOSFETs is their thermal performance.</p><p>Thermal system optimization is increasingly important in relation to electrical optimization as the power requirements in their applications increase. Additionally, a MOSFETs strong thermal performance is essential for reliability.</p><h2 data-element-id="headingsMap-5-0">Why is thermal important?</h2><p>In power-electronic systems, temperature is one of the critical parameters because many properties of power semiconductors are temperature-dependent. For example, the lifetime of semiconductor components is strongly affected by temperature fluctuations due to loading. Each change in temperature causes mechanical stress in the component which affects solder and bond connections. In this type of scenario, the emphasis is not on the maximum or minimum temperature that the device can withstand but the temperature cycling or switching between temperatures that is most critical to reliability and performance.<sup>[1]</sup></p><h2 data-element-id="headingsMap-6-0">Applications for high power MOSFETs</h2><p>Not all Power MOSFETs are suitable for the demanding power requirements of modern <a href="https://www.wevolver.com/article/2020.autonomous.vehicle.technology.report" rel="noopener noreferrer" target="_blank">automotive design</a> and cutting edge industrial applications. Only MOSFETs that can perform reliably under tough thermal conditions will be part of these developing industries.</p><p>The use of electronic control units (ECU’s) has increased in automotive applications as one method of reducing weight and increasing the efficiency of vehicles. A good example of this is in <a href="https://www.nexperia.com/products/mosfets/automotive-mosfets/family/ELECTRIC-POWER-STEERING/#/p=1,s=0,f=,c=,rpp=,fs=0,sc=,so=,es=" rel="noopener noreferrer" target="_blank">power steering</a> which has transitioned from conventional oil pressure control to DC motors that use electronic control or electric power steering ECU’s.&nbsp;</p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib fr-draggable" contenteditable="false" draggable="false" style="width: 766px;"><span class="fr-img-wrap"><p><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk5MjE3NDE5MTI0LWNvbXBsZWV0XzFfc3RlZXIucG5nIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ==" style="width: 788px;"><span class="fr-inner" contenteditable="true">Figure 1: Power steering now uses sophisticated ECU's.&nbsp;</span></p></span></span></div><p>Another application for power MOSFETs with strong thermal performance is in <a href="https://www.nexperia.com/applications/automotive/anti-locking-braking-systems.html" target="_blank">ABS braking systems</a>. Anti-locking braking systems help vehicles maintain contact with the road surface and prevent skidding in conditions such as icy or wet roads. When the driver applies braking the ABS responds many times every second, to changes in the rotational speed of each wheel. Reducing or increasing brake pressure as necessary to maintain control. A pump motor is used to re-pressurize the systems when the ABS system operates. MOSFETs in this application must be reliable and rugged enough to withstand both the high external temperature of the vehicle itself as well as manage the switching load while maintaining thermal efficiency.</p><p>These examples, as well as other automotive applications such as DC/DC conversion and reverse battery protection, have fed the demand for improved performance of power MOSFETs used in the switching device in ECUs.</p><p>Outside of the automotive industry power MOSFETs with exceptional thermal performance are required for battery-powered power tools, power supply equipment, and telecom infrastructure.</p><h2 data-element-id="headingsMap-7-0">Copper clip</h2><p>All MOSFET designers face the same challenges of trying to reduce the MOSFET resistance, it's switching capability and also it's Electromagnetic Compatibility (EMC) to result in a MOSFET with very low resistance and very good switching performance while not producing any radiated electromagnetic interference.</p><p>To meet the demand for high power with appropriate thermal properties MOSFET designers are rethinking traditional wirebond interconnects and moving towards copper clips for internal bonding. In clip-bonding technology, a solid copper bridge is attached to the die surface replacing multiple bonded wires.<sup>[2]</sup> Copper clip offers many advantages, which can offer significant improvements to MOSFET electrical and thermal properties, including increased maximum current capacity and excellent current diffusion, improved RDSon, low source inductance, and low thermal resistance (Rth).</p><h2 data-headingsmap-highlight="true" data-element-id="headingsMap-8-0">Introducing LFPAK MOSFETs</h2><p>In 2002, Nexperia teamed up with Hitachi to improve on the current power MOSFET solutions. From that cooperation came the <a href="https://youtu.be/IPvCtkeg35I?list=PL02JC46HY5hbLjEEk_d859Xv6iDicinsE" target="_blank">LFPAK family of power MOSFETs</a>. The LFPAK groups are a copper clip package that concretely addresses the limitations of previous MOSFET designs.</p><p>Let’s take a closer look at the physical design of the LFPAK. First, it has a very big source connection which provides a very low package resistance, it also has very short leads which help reduce the package resistance and inductance of the top clip. The new design has three source connections leads which greatly contribute to improving the current capability of the package. Previous DPAK designs were limited to 120 amps, but the smaller LFPAK is capable of as much as 300 amps.</p><p><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe width="1280" height="720" src="https://www.youtube.com/embed/-UkVlJq-9sA?enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-gtm-yt-inspected-31="true" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true" data-gtm-yt-inspected-34="true" id="597458571" title="LFPAK88: The automotive Power MOSFET driving power density to the next level"></iframe></span></p><h2 data-element-id="headingsMap-10-0">Current spreading</h2><p>In the LFPAK, the packaged resistance is improved by about 90 percent compared to the DPAK. From a current handling capability, it's not just about the maximum current the device can handle but about current spreading. With a typical internal wire-bonded package in a short circuit condition or a locked rotor condition, there will be a large inrush currents over short time periods so all the heat and current is crowding around the wire bonds resulting in very high current densities there and very little current density elsewhere in the device. This means local heating is created around the wire bonds and the full entitlement of the silicon is not gained in the application.</p><p>Compare this to the LFPAK - because it has the big source connection- the current spreads equally over the top surface of the device and get very good short-circuit handling capability is achieved compared to traditionally get with wire-bonded packages.&nbsp;</p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib fr-draggable" contenteditable="false" draggable="false" style="width: 766px;"><span class="fr-img-wrap"><p><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk5MjE3NTEwNzEyLUxGUEFLNTZfUE9JTlRFUlMuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ==" style="width: 788px;"><span class="fr-inner" contenteditable="true">Figure 2: LFPAK&nbsp;</span></p></span></span></div><h2 data-element-id="headingsMap-11-0">Leaded advantages</h2><p>Nexperia is one of the suppliers that offer a copper clip leaded device. One of the key advantages of using a leaded device is the ability to use standard optical inspection equipment to examine the exposed leads. The solder joints are easily examined without needing expensive x-ray equipment and the top tabs solder joint is also easily inspected.</p><p>Another important aspect of the LFPAK design is that the exposed leads allow for wave soldering which can play a significant role in achieving reliability under stress. When a PC board goes through significant temperature cycles it will expand and contract and bend in response to the thermal conditions. In a scenario where a leadless package is fixed, with no flexibility in the lead, the repeated movements of the board can lead to the plastic at the join can crack posing a risk of contamination getting into the package or moisture ingress which can cause parametric shifts or even device failure.&nbsp;</p><p>In the instance of using the LFPAK or other leaded packages in the same demanding conditions, the leads act as a shock absorber for the movement. So as the PC board expands and contracts and bends, the leads expand and contract with it and absorb all of the flexing in the PC board. Trials of the LPAK have put the package through more than 2,000 temperature cycles and shown no degradation of the solder joint.</p><h2 data-element-id="headingsMap-12-0">Thermal performance</h2><p>One crucial area where the LFPAK differs from the DPAK family is its thermal performance. Smaller devices are preferred thanks to the space-saving they give, however, they also raise the valid concern about their thermal performance, and in applications where thermal performance is of primary importance, larger packages are generally chosen. However, the LFPAK family of MOSFETs demonstrates that high thermal performance is available in a small package.</p><p>A MOSFET in a fuel injection application in which thermal is a key element is a good example to examine this. In basic terms a fuel injection application is a MOSFET repetitively driving a solenoid load, switching it on and off. The timing and the clean turn on and turn off is of paramount importance. Because a solenoid is an inductive load, the turning off of the inductive load means the MOSFET is operating in avalanche mode. Avalanche mode refers to a considerable amount of current going through the MOSFET, hence why the thermal performance is key.</p><h2 data-element-id="headingsMap-13-0">Thermal Simulation</h2><p><a href="https://youtu.be/ASC4zvJKSFE" target="_blank">RC thermal simulation</a> of MOSFETs is an important tool for early design validation, allowing engineers to quickly check the device is suitable for the power and temperatures associated with the application. Currently, circuit simulators - which use mathematical models to replicate the behavior of an actual electronic device or circuit - are standard tools in the development and optimization of electronic systems. However, simulation has until now been limited to electronic functions because, in the simulation models available today, temperature dependence is generally limited to changing the static global temperature. Nexperia offers designers easy to use tools to better understand the <a href="http://assets.nexperia.cn/documents/application-note/AN11261.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">thermal requirements</a> and limits of their designs by providing the Foster RC Thermal models for all Power MOSFETs.</p><h2 data-element-id="headingsMap-14-0">The LFPAK family</h2><p>There are six products in the LFPAK portfolio. The LFPAK88 replaces the larger wire-bonded power packages such as D²PAK and D²PAK-7. It has an 8 x 8 mm footprint, - a physical footprint reduction of 60%, with a 64% lower profile.</p><p>The LFPAK88 copper-clip and solder die construction results in low electrical &amp; thermal resistance, good current spreading, and heat dispersal. The maximum rating of 425 A and low RDS (on) of 0.7 mΩ in small package size, presents a power density of 48 times when compared to D²PAK devices.</p><p>Finally, the LFPAK88 offers unique low-stress gull-wing leads which create a rugged and thermally robust package and delivers reliability levels more than two times better than is required by the automotive standard AEC-Q101.</p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib fr-draggable" contenteditable="false" draggable="false" style="width: 766px;"><span class="fr-img-wrap"><p><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk5MjE2ODkxMTM2LVJTMTE4Nl9MRlBBSzg4X2NvbWJpbmVkLnBuZyIsICJlZGl0cyI6IHsicmVzaXplIjogeyJ3aWR0aCI6IDk1MCwgImZpdCI6ICJjb3ZlciJ9fX0=" style="width: 788px;"><span class="fr-inner" contenteditable="true">Figure 3: LFPAK88.</span></p></span></span></div><h2 data-element-id="headingsMap-15-0">Conclusion</h2><p>Power MOSFETs for automotive and industrial innovation need to offer a growing range of features including soft-start, live insertion, short-circuit resilience, avalanche ruggedness, and careful thermal management. Attention will be increasingly given to various thermal simulation models as the power density demands of these applications rises. MOSFET packages that can provide performance, reliability, and proven AEC-Q101 quality will play a key role in pushing innovation.</p><hr><h2 data-element-id="headingsMap-16-0"><em>About the sponsor: Nexperia</em></h2><p><em>Semiconductor manufacturer Nexperia is tackling the demand for strong thermally performing MOSFETs for the automotive industry. They are developing products that take advantage of copper clip technology to produce packages with very low resistance and solid switching performance while not producing any radiated electromagnetic interference.</em></p><p><em>The Nexperia LFPAK products such as the LFPAK88 are ready for use in the automotive industry and perform to AEC-Q101 standard qualification standards.&nbsp;</em></p><p><em><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk5MjE2NzY0MDA2LVVudGl0bGVkLTMuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ==" style="width: 100px;"></em><br></p><hr><h2 data-element-id="headingsMap-17-0">References</h2><p>1. Thermal Modeling of Power-electronic Systems [Internet]. Munich: Fraunhofer; 2000. Available from: https://www.iisb.fraunhofer.de/content/dam/iisb2014/en/Documents/Research-Areas/Energy_Electronics/publications_patents_downloads/Publications/Therm_Modelling_2000_IISB.pdf&nbsp;</p><p>2. Copper Clip Package for high performance MOSFETs and its optimization [Internet]. Singapore: United Test and Assembly Center Ltd; 2016. Available from:https://www.utacgroup.com/wp-content/uploads/2019/09/Copper-Clip-Package-for-high-performance-MOSFETs.pdf</p>

Thermal system optimization is increasingly important as the power requirements of MOSFET applications increase.

Next-generation MOSFET technology Meets Demand for Strong Thermal Performance in Automotive Applications.

<h2 dir="ltr" data-element-id="headingsMap-4-0">Introduction</h2><p dir="ltr">Once a luxury used primarily by early adopters, electric vehicles (EVs) are becoming increasingly commonplace due to rising awareness about carbon emissions and their impact on climate change, supportive government policies, volatile oil prices, and growing cultural acceptance of green energy use. Global EV stock is projected to reach 243 million by 2030 - over 30 times higher than today’s level <sup>[<a href="https://www.iea.org/reports/global-ev-outlook-2020" target="_blank">1</a>]</sup>. Most major car manufacturers are planning either a complete shift or a transition to EVs <sup>[<a href="https://www.nature.com/articles/d41586-018-07585-6?source=post_page-----e0f2661bf61----------------------" target="_blank">2</a>]</sup>.</p><p dir="ltr">As demand for electric vehicles increases, so does demand for improved performance, including decreased cost and charge time, increased range and battery life, and improved safety. The cost of EV batteries continues to fall and EV battery technology is advancing rapidly in the form of increasing capacity and energy density <sup>[<a href="https://www.iea.org/reports/global-ev-outlook-2020" target="_blank">1</a>,<a href="https://www.nature.com/articles/d41586-018-07585-6?source=post_page-----e0f2661bf61----------------------" target="_blank">&nbsp;2</a>]</sup>. However, increases in energy density are accompanied by a growing challenge - safety. In particular, lithium ion batteries - the power source of choice for EVs thanks in part to their high energy density - are susceptible to overheating, and even explosion, and safety incidents have been widely reported <sup>[<a href="https://www.mdpi.com/2076-3417/9/12/2483/htm" target="_blank">3</a>,<a href="https://link.springer.com/article/10.1007/s10694-019-00944-3" target="_blank">&nbsp;4</a>]</sup>. As EV batteries become more powerful and complex, ever more sophisticated battery management systems are needed to ensure the safe, reliable, and cost-efficient operation of electric vehicles.</p><h2 dir="ltr" data-element-id="headingsMap-5-0">What is a battery management system?&nbsp;</h2><p dir="ltr">Battery management systems (BMS) are electronic control circuits that closely and accurately monitor and regulate the charging and discharging of rechargeable batteries, serving as the “brains” of an EV battery system. The BMS maintains batteries within their safe operating area and ensures optimal use of the residual energy in batteries, thereby maximizing their safety, reliability, durability, and performance.</p><h3 dir="ltr" data-element-id="headingsMap-6-0">Functions of battery management systems</h3><p dir="ltr">Battery management systems are central to the safe and efficient operation of electric vehicles and perform a broad array of functions, including:</p><p dir="ltr"><strong>Battery monitoring&nbsp;</strong></p><p dir="ltr">The BMS monitors the state of an EV battery system through a variety of direct and indirect measures. Current, voltage, and surface temperatures of battery cells are directly measured using sensors. These are in turn used to estimate the battery pack State of Charge (SOC), which indicates the charge level of the battery; the State of Health (SOH), which represents the remaining capacity of the battery pack and indicates when it should be replaced; the internal temperature of battery cells; and other parameters. Accurate voltage monitoring is of particular importance, since voltage deviations due to overcharging, over-discharging, or high power pulses can lead to significantly reduced battery life and safety issues.</p><p dir="ltr"><strong>Battery protection&nbsp;</strong></p><p dir="ltr">The BMS is also equipped to prevent operations outside the safe operating area of and damage to the battery system, for example due to overcharging, over-discharging, or high temperatures. The action of the BMS can be physical (such as emergency shut down of the battery) or informational (by triggering an alarm or otherwise reporting trouble to the driver).</p><p dir="ltr">For example, the BMS controls the charger to protect the battery from overheating as well as ensure optimal charge of the battery, thereby prolonging its life and improving capacity utilization. The BMS is also responsible for thermal management of the battery. Battery temperature has a significant impact on battery life and performance, and the BMS controls the pump, fans, coolant (where relevant), and heater to maintain the temperature of the battery pack within its optimum operating range.&nbsp;</p><p dir="ltr"><strong>Battery optimization&nbsp;</strong></p><p dir="ltr">The BMS also optimizes battery performance via a process called cell balancing. Within an EV battery pack, no two cells are identical, due to manufacturing differences as well as variation in their on-vehicle environment. Weaker cells charge and discharge faster than other cells. Because charging and discharging stop as soon as any cell hits programmed upper and lower capacity limits, the weaker cells cause energy within the other cells to go unused while discharging and limit the capacity of the battery pack while charging. This also results in an increase in the number of battery charge and discharge cycles, which shortens the lifetime of the battery.</p><p dir="ltr">Cell balancing helps resolve these issues and ensure optimum performance of the battery by equalizing the individual cells’ state of charge. Two types of cell balancing can be used – passive and active. In passive balancing a bleed resistor is used to dissipate energy from cells with excess charge until all cells have a similar state of charge. While this approach is lower cost, it is also less efficient since excess energy is lost as heat. Active cell balancing is a more complex technique that redistributes charge between cells during the charge and discharge cycles. While it is more efficient, since energy is transferred to where it is needed instead of being lost as heat, it also requires additional components at higher cost. Either method extends battery life and improves safety by preventing damage to battery cells due to overcharging or over-discharging.</p><p dir="ltr">High precision cell voltage and temperature measurements and robust communication links between cells and to battery controllers can further contribute to optimizing battery performance. By collecting better measurements and communicating them faster, the BMS can be more responsive to battery conditions and enable more efficient use of the battery.</p><h2 dir="ltr" data-element-id="headingsMap-7-0">Communication</h2><p dir="ltr">The BMS also facilitates communication of information to the driver, for example by triggering an alarm or reporting the state of charge, as well as to other on-board equipment, for example to request changes in vehicle operation in response to monitored battery pack conditions.</p><h3 dir="ltr" data-element-id="headingsMap-8-0">Design of battery management systems</h3><p dir="ltr">Electric vehicles are powered by hundreds or even thousands of individual battery cells. These cells are connected in modules in series and parallel and placed inside a steel casing to form the battery pack. Battery packs are typically very large, occupying the entire floor area of an EV, and are connected to the BMS and thermal management system. The BMS transmits information from the battery pack to the controller, which converts the DC voltage produced by the battery pack and drives the motor, and the rotational energy from the motor is transferred to the wheels by the transmission system (Figure 1).</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 788px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk3MjQzMjU3MTc1LUlMTFVTVFJBVElPTiAyMi0xLTAxICgxKS5qcGciLCAiZWRpdHMiOiB7InJlc2l6ZSI6IHsid2lkdGgiOiA5NTAsICJmaXQiOiAiY292ZXIifX19"><span class="fr-inner" spellcheck="false">Figure 1: Schematic showing layout of BMS, battery pack, controller, transmission, etc. within a car</span></span></span></p><p dir="ltr">&nbsp;The BMS itself is a combination of hardware and software (Figure 2). Hardware includes sensing microchips, transceivers, power management microchips, and microcontrollers. The sensors measure battery voltage, current, and surface temperature to monitor the condition of individual cells. Transceivers relay information between components. Power management microchips allow the connection and isolation of the battery pack between the charger and load. Microcontrollers receive information from sensors and plug it into algorithms which model internal battery states, such as internal temperature, SOC, and SOH. Once these internal states have been defined, the microcontroller can make decisions, such as optimizing the charging and discharging of the battery or triggering alarm or safety modules.</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 788px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk3MjQzMjk1MzYxLUlMTFVTVFJBVElPTiAyMS0wMSAoMSkuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ=="><span class="fr-inner" spellcheck="false">&nbsp;Figure 2: Schematic showing layout and components of a simplified BMS</span></span></span></p><p dir="ltr">Battery management systems can be implemented using a variety of architectures. The choice of architecture has a significant impact on the cost, development time, flexibility, and reliability of a BMS. Architectures can be broadly classified as centralized and decentralized (Figure 3). In centralized architectures, a single controller monitors, balances, and controls all battery cells and is connected to them through a large number of wires. This approach is relatively inexpensive but also challenging to expand. In decentralized architectures, which include distributed, master-slave, and modular architectures, the BMS functionality is not concentrated on a single circuit board. These approaches entail fewer wires and are more flexible, but also more expensive.</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 788px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk3MjQzNDkzODAwLUlMTFVTVFJBVElPTiAyMi0wMSAoMSkuanBnIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ=="><span class="fr-inner" spellcheck="false">&nbsp;Figure 3: Diagram comparing generic centralized BMS architecture to decentralized/distributed BMS architecture</span></span></span></p><p dir="ltr">Generally speaking, decentralized architectures are advantageous because they offer superior measurement precision, because shorter wires are less susceptible to noise; more reliable connections, because shorter wires are less prone to disconnection due to mechanical shocks and vibrations; scalability; and more robust communication between components.&nbsp;</p><p dir="ltr">Achieving reliable, high performance communication is a key challenge faced by BMS designers. Besides opting for decentralized architectures, designers can improve communication between components (and therefore achieve more accurate, real-time measurements and control) by using microchips which consolidate a variety of functions and controllers with built-in diagnostic functions. Minimizing the number of components, as well as the size of the components which are used, offer the added benefit of giving designers more flexibility and allowing for optimal placement of components within the vehicle.</p><p dir="ltr">Another challenge BMS can help designers tackle is security. Because EVs (including smart vehicles and autonomous vehicles) connect to the internet, these vehicles run the risk of cyberattacks. BMS security controllers can prevent unauthorized modification of the battery system, protecting the safety of the system as well as privacy and intellectual property.</p><h2 dir="ltr" data-element-id="headingsMap-9-0">What’s next for battery management systems?</h2><p dir="ltr">Demand for improved performance and societal changes are driving new developments in battery management systems. One trend which promises major improvements to the performance and cost of EVs is the advent of wireless BMS. In a typical BMS, components are connected by a large amount of wiring - up to several kilometers long - which adds weight to the EV and makes it less efficient. This wiring is also costly and prone to mechanical failure. Furthermore, the wiring can make it so complex and time consuming to replace an individual battery cell that it makes more sense to simply replace the entire pack. By eliminating the need for wiring and associated components, a wireless BMS helps decrease the weight and size of the BMS, thereby improving vehicle efficiency, extending driving range, and helping make vehicles easier and cheaper to produce and maintain. At the same time, wireless BMS could offer even more accurate and useful information about the condition of the battery cells.</p><p dir="ltr">Another development is the increasing expectation that BMS components meet the most stringent safety standards. The safety of automotive components is assessed according to the ISO26262 standard, defined by the International Organization for Standardization (<a href="https://www.iso.org/standard/68383.html" target="_blank">5</a>). During the development of hardware and software components, all potential hazardous scenarios are evaluated for a particular component and classified based on the levels of severity, probability of occurrence, and driver controllability. The component is then assigned an Automotive Safety Integrity Level (ASIL), which indicates the level of safety required by the component to function normally without posing any threats to the vehicle. ISO 26262 defines four ASIL levels - A, B, C, and D - where ASIL D refers to the highest level of safety required. Vehicle manufacturers increasingly demand that BMS components are ASIL D compliant. At the same time vehicle designs are becoming increasingly complex, meaning that BMS suppliers need to be more rigorous than ever to meet safety requirements and ensure that EVs can operate safely.</p><p dir="ltr">Finally, a rapidly evolving and urgently needed development for EVs is fast charging, especially for buses and shared mobility vehicles which need to operate continuously (<a href="https://www.annualreviews.org/doi/full/10.1146/annurev-control-053018-023643" target="_blank">6</a>). With the established AC charging, it can take several hours to fully charge an EV, whereas fast charging enables this within about 20 minutes. Batteries undergoing fast charging require more sophisticated battery management and much more accurate estimations of conditions inside battery cells to prevent overcharging and overheating.</p><h2 dir="ltr" data-element-id="headingsMap-10-0">Conclusion</h2><p dir="ltr">As electric vehicles become increasingly ubiquitous, so will demand for EVs to offer performance and cost which is comparable to that of traditional vehicles. By improving the safety and reliability of EVs, increasing the efficiency and range of EVs, and prolonging EV battery lifetimes, battery management systems will play a pivotal role in achieving comparable, affordable performance, thereby enabling society to reap the benefits of EVs on a large scale.</p><hr><h2 dir="ltr" data-element-id="headingsMap-11-0"><em>About the sponsor: Infineon Technologies<br></em></h2><p dir="ltr"><em>Infineon Technologies provides semiconductor products for use in a wide range of applications.&nbsp;</em><em>Infineon Technologies is dedicated to developing integrated circuits and design resources for battery management systems that contribute to more efficient, longer-lasting, and reliable battery-powered applications. To learn more click&nbsp;</em><a href="https://www.infineon.com/" rel="noopener noreferrer" target="_blank"><em>here.</em></a></p><p dir="ltr"><em><img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk3MjU2MTk0MzQyLUluZmluZW9uLWxvZ28tMDYucG5nIiwgImVkaXRzIjogeyJyZXNpemUiOiB7IndpZHRoIjogOTUwLCAiZml0IjogImNvdmVyIn19fQ==" style="width: 300px;"></em><br></p><hr><h2 dir="ltr" data-element-id="headingsMap-12-0">References</h2><ol><li dir="ltr"><p dir="ltr">Global EV Outlook 2020 – Analysis - IEA [Internet]. IEA. 2020. Available from: https://www.iea.org/reports/global-ev-outlook-2020</p></li><li dir="ltr"><p dir="ltr">Figueres, C. Nature. [Online]. Available from: https://www.nature.com/articles/d41586-018-07585-6&nbsp;</p></li><li dir="ltr"><p dir="ltr">Ouyang D, Chen M, Huang Q, Weng J, Wang Z, Wang J. A Review on the Thermal Hazards of the Lithium-Ion Battery and the Corresponding Countermeasures. Applied Sciences. 2019;9(12):2483. &nbsp;</p></li><li dir="ltr"><p dir="ltr">A Review of Battery Fires in Electric Vehicles [Internet]. Springer. 2020. Available from: http://A Review of Battery Fires in Electric Vehicles &nbsp;</p></li><li dir="ltr"><p dir="ltr">ISO 26262-1:2018 [Internet]. ISO. 2020. Available from: https://www.iso.org/standard/68383.html &nbsp;</p></li><li dir="ltr"><p dir="ltr">Xinfan L. Modeling and Estimation for Advanced Battery Management [Internet]. Annual Reviews. 2020. Available from: https://www.annualreviews.org/doi/full/10.1146/annurev-control-053018-023643 &nbsp;</p></li></ol><p><br></p><p><br></p>

As EV batteries become more powerful and complex, ever more sophisticated battery management systems are needed to ensure the safe, reliable, and cost-efficient operation of electric vehicles.

The pivotal role of battery management systems on the performance of electric vehicles

<h1 dir="ltr"><strong>What is GaN Technology?</strong></h1><p dir="ltr">Gallium Nitride (GaN) is a material with high heat capacity and thermal conductivity used in the production of semiconductor power devices such as GaN FET (field-effect transistor).&nbsp;</p><p dir="ltr">GaN semiconductors are poised to replace silicon as the semiconductor of choice for high voltage power devices as they can operate at higher frequencies, with increased efficiency and higher power density - providing the basis to create smaller, more efficient, and more robust power devices.&nbsp;</p><p dir="ltr">These attributes are largely thanks to GaN’s wide band gap. <a href="https://en.wikipedia.org/wiki/Band_gap#In_semiconductor_physics" target="_blank">Band gap</a> is an energy range between a semiconductor’s valence band and conduction band where electron states are forbidden. A wide band gap allows devices to operate at much higher voltages, frequencies, and temperatures than conventional semiconductors. GaN has a band gap of 3.2 eV, in comparison, silicon has a bandgap of just 1.1 eV.</p><p dir="ltr">GaN is successfully applied in RF (Radio Frequency) components, and light-emitting diodes (LEDs). The blue light in your old BluRay player is created using a GaN-based violet laser diode. It’s also present in solar cells for photovoltaic systems and is an essential component of energy-efficient LED globes. GaN is used in radiation-hardened transistors for satellites and is quickly replacing silicon in this area due to its small physical die size. GaN microwave<a href="https://www.sciencedirect.com/science/article/abs/pii/S0026271418304815" target="_blank">&nbsp;transistors</a> will be onboard <a href="https://earth.esa.int/web/guest/missions/esa-future-missions/biomass" target="_blank">The Earth Explorer Biomass</a> satellite set to launch 2021 which will provide global maps of the amount of carbon stored in the world's forests. GaN is also showing up in consumer power devices such as lightning-fast mobile and laptop <a href="https://www.gizmochina.com/2020/04/09/huawei-65w-gan-charger-launched/" target="_blank">chargers</a>.</p><p dir="ltr">The automotive industry is the next challenge for GaN to tackle. Although proven to outperform reliable silicon, the question remains if GaN can deliver the quality, reliability, and scalability in manufacturing required by the demanding automotive market.&nbsp;</p><h1 dir="ltr"><strong>But Wait, What’s Wrong With Silicon?</strong></h1><p dir="ltr">It is widely accepted that silicon is reaching its physical limit. While continuing to be a highly reliable semiconductor material in many applications, silicon is limited when it comes to high-frequency switching and power density. Some incremental improvements in silicon increase some parameters but these improvements generally result in a loss in other parameters. This means new silicon uses will become more application-specific where these losses have less of an impact. Even with incremental gains, it is clear, there is a near-future limit on power density and frequency available from silicon.&nbsp;</p><p dir="ltr">The limitations of silicon in high-frequency and high power applications were seen early by the industry and investigations into other materials have been progressing in the background for decades. One of the <a href="https://www.arrow.com/en/research-and-events/articles/silicon-carbide-and-gallium-nitride-compared" target="_blank">leading contenders&nbsp;</a>is GaN - outperforming silicon for higher voltage applications in most comparisons even when it's in early maturity stages.&nbsp;</p><p><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe allowfullscreen="" class="fr-draggable" src="https://www.youtube.com/embed/PP6DrOzxX-Q" style="width: 801px; height: 447px;" frameborder="0"></iframe></span><br></p><p dir="ltr">GaN’s significantly wider bandgap means current can travel faster through GaN semiconductors, ensuring greater efficiency and fewer switching losses when they are used in hard switching applications. They also lose less power when devices are charged and discharged thanks to having less capacitance than silicon metal-oxide semiconductor field-effect transistors (MOSFETs). Finally, they also take up much less space on circuit boards pushing open the opportunity for smaller and smaller appliances.&nbsp;</p><p dir="ltr">Silicon most likely will continue to remain king in lower power and lower frequency devices as well as processing applications but with the electrification of rapidly advancing industries such as automotive, space, and the military more robust alternatives such as Gallium Nitride are required.</p><h1 dir="ltr"><strong>GaN: the good, the bad, and the better&nbsp;</strong></h1><p dir="ltr">GaN was first explored in the 1990s but its maturation has been slow due to some key challenges. Developing a reliable and consistent manufacturing process for GaN has been difficult in comparison to the reliability of silicon.</p><p dir="ltr">Gallium Nitride contains a massive number of crystal defects over a small area compared to silicon which contains as low as 100 defects per square centimeter. Only very recently have researchers been able to manufacture GaN effectively with fewer than one billion defects/cm. This problem has been largely overcome but the cost to produce the same amount of GaN wafers compared to silicon is still notably higher.&nbsp;</p><p dir="ltr">A successful strategy for GaN development while maintaining the large-production ability of silicon is GaN-on-Si. Thick GaN epitaxial layers are grown on large silicon substrates in standard 150 mm (6 inch) fabs. GaN-on-Si offers true scalability with manufacturing confidence.&nbsp;</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 300px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1593420372806-shutterstock_687161686+%28100px%29.jpg"><span class="fr-inner">A silicon wafer<br></span></span></span></p><h1 dir="ltr"><strong>GaN in the Automotive Industry</strong></h1><p dir="ltr">The automotive industry is quickly electrifying with a global number of electric passenger cars passing 5 million in 2018, an increase of 63% from the previous year. Positive forecasts suggest electric vehicle (EV) sales will reach <a href="https://www.iea.org/reports/global-ev-outlook-2019" target="_blank">44 million vehicles&nbsp;</a>per year by 2030.</p><p dir="ltr">For this growth to continue, electric cars are being pushed to be both more efficient and lower cost.&nbsp;</p><p dir="ltr">Despite headway being made towards more efficient, lighter, and smaller batteries - this core feature of EVs remains the number one obstacle to overcome before the introduction of the next generation of cheaper and more efficient vehicles.&nbsp;</p><p dir="ltr">While battery development grinds away, innovation is driving major powertrain improvements. Efficiency increases in each component of an EV powertrain can have a significant impact on the overall efficiency of the vehicle through a reduction in weight and overall smaller physical size allowing for alternative design layouts.&nbsp;</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 300px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1593419898584-Nexperia-GaN-FET+02.jpg"><span class="fr-inner">GaN FETs<br></span></span></span></p><h2 dir="ltr"><strong>GaN Powertrain Components</strong></h2><p dir="ltr">GaN delivers on smaller, more efficient, and lower-cost power systems thanks to its ability to offer lower switching loss, faster-switching speeds, increased power density, and improved thermal budgets. The power density and efficiency of <a href="https://assets.nexperia.com/documents/brochure/nexperia_brochure_gan_202006.pdf" target="_blank">GaN</a> will have the biggest impact in three areas of electric vehicle and hybrid vehicle design.&nbsp;</p><ul><li dir="ltr"><p dir="ltr"><strong>Onboard Charger</strong></p>An on-board charger (OBC) in an EV or hybrid electric vehicle (HEV) is used to charge the traction battery. The On-Board charger system converts the AC power from the grid to a DC input which charges the battery. Using GaN semiconductors can result in OBC’s that are <a href="https://www.prnewswire.com/il/news-releases/visics-smallest-6-7kw-on-board-charger-reference-design-300814720.html" target="_blank">lighter and smaller</a> than their current physical size. This decrease in size and weight indirectly provides the vehicle with a longer driving range via an overall decrease in vehicle weight.<br>Improved OBC efficiency will also reduce car charging times. Currently, a full charge at a 50 kW charging station takes about 50 minutes and gives a driving range of about 200 Km (125 miles). Fine for commuters, but a huge deterrent for people looking to make longer trips. The goal for the industry is to reach 35 kW charging stations that would drop the charging time down to less than ten minutes, the perfect restroom or coffee break time - and a comparable time to what we now experience stopping for petrol for a combustion engine vehicle.</li><li dir="ltr"><p dir="ltr"><strong>DC-DC Converter</strong></p>DC-DC converter bridges the high-voltage battery pack with the vehicle’s low voltage auxiliary circuits. The use of GaN semiconductors in DC-DC converters result in devices that are highly efficient, reducing loss and wasted power to heat, and featuring best in class power density. This one <a href="https://ieeexplore.ieee.org/abstract/document/7855159/similar#similar" target="_blank">efficient design change</a> contributes significantly to the overall weight decrease of the car resulting in better range.&nbsp;</li><li dir="ltr"><p dir="ltr"><strong>Traction Inverter</strong></p>Within an electric vehicle’s drivetrain, the traction inverter converts DC current from the battery to AC current used by the motor to power the vehicle’s propulsion system. The most common three-phase <a href="https://www.electricmotorengineering.com/an-electric-motor-works-car/" target="_blank">AC motors</a> used in today’s EVs run at voltages up to 1,000 V and switching frequencies up to 20 kHz. This configuration bumps close to the current operational limits of the silicon-based MOSFETs and insulated-gate bipolar transistors (IGBTs) currently used in traction inverters.&nbsp;</li></ul><p dir="ltr">GaN technology pushes past these limits. A highly efficient traction inverter with GaN components provides longer range, fewer charging cycles, and extended battery life with similar battery costs. Operating at 30 kHz it provides the opportunity to use smaller, more efficient, and powerful electric motors and consequently smaller, cheaper, and lighter batteries to achieve the same driving range. These improvements would help enable manufacturers to get closer to price parity with internal combustion engine vehicles and thus extending the market reach of Evs&nbsp;</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 300px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1593420503427-02.png"><span class="fr-inner">A 50kW GaN traction inverter on a test bank<br></span></span></span></p><h1 dir="ltr"><strong>Conclusion</strong></h1><p dir="ltr">GaN semiconductor power devices will usher in a new era of electric vehicle powertrain components that will deliver more efficient vehicles. Innovative collaborations between semiconductor manufacturers and automotive companies will drive innovation and speed up the technology adoption. The full potential of GaN semiconductor power components is likely to be fully realized within the next decade, paving the way to a greener and more efficient future.&nbsp;</p><hr><h1 dir="ltr"><em><strong><em>About the sponsor: Nexperia&nbsp;</em></strong></em></h1><h2 dir="ltr"><em><strong>Power GaN FET solutions</strong></em></h2><p dir="ltr"><em>Semiconductor manufacturer Nexperia is tackling the manufacturing issues of GaN by developing processes that utilize existing Si-based technology and infrastructure ready for large volume mass production. While the technology is still in early maturity stages it has proven its robustness for commercial application and the best is yet to come. Nexperia Power GaN products such as the GAN063-650WSA are primed for use in the automotive industry and already perform to AEC-Q101 standard qualification standards.&nbsp;</em></p><p dir="ltr"><em>Research and development show promising results for GaN’s success in EV traction inverters. To close the gap between the lab and an applied tested product, Nexperia, has <a href="https://www.nexperia.com/about/news-events/press-releases/nexperia-partners-with-ricardo-to-develop-gan-based-ev-inverter-design.html" target="_blank">teamed up</a> with Ricardo, an automotive engineering consulting company, to put its GaN devices into a 50 kW EV traction inverter for extensive testing. The collaboration is rigorously testing the GaN components to look for any possible weaknesses or failure points in an applied EV setting.&nbsp;</em></p><p dir="ltr"><em>The project also works to demonstrate to the wider automotive industry the huge potential of GaN. The results of the project, which we expect to see later in 2020 and early 2021 will be of interest to a lot of automotive designers and provide real value to the industry as a whole. &nbsp;</em></p><p dir="ltr"><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe allowfullscreen="" class="fr-draggable" src="https://www.youtube.com/embed/QAxY43x4jLg" style="width: 788px; height: 447px;" frameborder="0"></iframe></span></p><hr><h1 dir="ltr"><em><strong>Curious about GaN and its applications in the automotive industry?&nbsp;</strong></em></h1><p><em>2-3 July 2020, Nexperia is hosting an&nbsp;</em><a href="https://www.nexperia.com/nexperia-power-live-event.html" rel="noopener noreferrer" target="_blank"><em>online event called 'Power Live'&nbsp;</em></a><em>to share knowledge about their work on power semiconductors. One of the event's 4 tracks is completely dedicated to GaN, and the 'automotive' and 'packages' tracks also cover GaN.&nbsp;</em></p><p><em>Engineers of Nexperia and their partner Ricardo will share share their insights: From tackling common application issues with GaN FETs to a deep dive into the development of their GaN based traction inverter.<br></em></p><p dir="ltr"><em>You can read more and register for Nexperia’s Power Live Event <a href="https://www.nexperia.com/nexperia-live-power-event-registration.html" rel="noopener noreferrer" target="_blank"><em>here</em></a>.</em></p>

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