https://www.vicorpower.com/ POWER MODULES 13 www.power-mag.com Issue 4 2025 Power Electronics Europe must be accounted for in automotive applications. The requirements prevent undesired consequences resulting from electric current jumping through air gaps, better known as electrical arcing. The effects of arcing can destroy components in the vehicle, causing loss of functionality within the vehicle if severe damage is done. In vehicles with legacy 12V power systems, arcing was accounted for through modest, but very measured component rubrics, but with EVs and PHEVs beginning the transition to 48V architecture, all forms of powertrains are facing this challenge. Design requirements must adjust to ensure safety, increasing the distance between conductors to reduce the risk of arcing. Why is a 48V architecture more risky for creepage and clearance design? 48V architecture introduces new challenges for the design engineer because of the increased voltage. Voltage increase creates higher potential for arcing. According to the IPC-2221 Standards, transitioning from a 12V architecture to one based on 48V can require upwards of a 60% increase in creepage and clearance distancing. Adhering to proper creepage and clearance standard ensures safety In 2024, The National Highway Traffic Safety Administration (NHTSA) reported 6.3 million vehicle recalls impacted by electrical systems, accounting for 33% of all recalls, highlighting the significance of component-related safety concerns. Many of these concerns can emanate from electric arcing, causing severe power system problems for OEMs. With the implementation of an 800V battery pack in a 48V architecture, the risk of arcing increases. Traditionally, when addressing this requirement within a design, engineers allowed for adequate spacing between conductors throughout the PCB. Voltage range, material properties and intended application dictate how the standards are established. Thorough calculations are required to properly space conductive parts to ensure compliance with these safety standards. Higher voltages require further distancing. While discrete component solutions can fulfill these requirements, their off-the-shelf components often consume a large footprint, as akin to a silver box power supply. These larger components demand up to a 60% size increase within the PDN framework, posing design challenge for OEMs to accommodate greater spacing needs within the same footprint. This is nearly impossible to achieve without design tradeoffs or innovating the approach. Overmolded packaging virtually eliminates the problem of arcing and improves thermals Solving the challenge of high-voltage arcing while taking into consideration the size and space constraints is not something many discrete components can do well. What can help is a traditional packaging process called potting. Potting encapsulates components to protect them from external vulnerabilities. However, potting restricts heat dissipation, causing elevated component temperatures that accelerate material degradation, further contributing to component failures and reduced lifespan. A more efficient approach to eliminate air gaps that enable arcing is through a proprietary overmolding process. With Vicor innovative packaging, the overmolding process neutralizes the risk of arcing while allowing for better heat dissipation. It also reduces size, enabling a high-density power source. The molding compound creates a solid insulation within the product, reducing creepage and clearance distances. The complete seal not only prevents pollutants from entering and causing an arc, but also reduces the size, further allowing for more space within the vehicle’s chassis to store components. Solving space constraints with highdensity power modules The matrix of transitioning from a 12V to 48V power system coupled with 400/800V batteries causes increased complications for the design engineer, demanding extra caution in PCB system design standards for EV and PHEV applications. This evolution of automotive architecture creates challenges to the OEM that needs to add more spacing between components within that same footprint. From larger battery packs to various powertrain components, OEMs must look for efficient solutions in accommodating space limitations inside the vehicle’s framework. With EVs and PHEVs rapidly adopting a 48V architecture where high-voltage batteries are used, OEMs must step down the voltage as efficiently and safely as possible. Bridging these gaps requires greater component distancing. This is where many discrete module suppliers Figure 3: The Vicor ChiPTM package uses a proprietary overmolding (middle layer in gray) which completely encapsulates components. These modules are therefore free from risk of arcing, while delivering high efficiency and advanced heat dissipation to cool components more effectively.
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