1. Meet Your Directors
   
2. APEC News
   
3. Welcome to PSMA
   
4. About our members
   
5. PSMA Annual Meeting at APEC 2025
   
6. PSMA Celebrates 40 Years
   
7. Student Mentorship at APEC 2025
   
8. Best Practices for Creating and Running an Industry Session
   
9. 3D-PEIM 2025
   
10. PwrSoC 2026
    
11. WiPDA 2026
    
12. 10th Annual Magnetics @ High Frequency Workshop at APEC 2025
    
13. Mythology in Power Magnetics
    
14. Challenges and Opportunities in Adopting Wide Band Gap Technologies like Gallium Nitride!
    
15. Raising the Bar for Energy Efficiency
    
16. Events of Interest - Mark Your Calendar
    

If you or anyone in your company is interested in getting on the distribution list for future issues of PSMA UPDATE, please send e-mail to: power@psma.com. Be sure to include your name and the name of your company.

Previous issues of update: Q3_2024 | Q4_2024 | Q1_2025

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PSMA UPDATE is published and distributed via e-mail quarterly by the Power Sources Manufacturers Association. Send editorial information and comments to:

Permission to reprint information and articles as published is granted: a courtesy line is appreciated.

Membership in PSMA is open to any organization or corporation involved in the power sources and supplies industry. For membership information, visit our website or contact us by fax, telephone or email.

If you or anyone in your company is interested in getting on the distribution list for future issues of PSMA UPDATE, please send e-mail to: power@psma.com. Be sure to include your name and the name of your company.

 

our members of the Board of Directors are elected at the PSMA Annual Meeting held every year, usually held during the APEC conference. Each Director serves a three-year term and is eligible to be reelected for one additional term.

In this issue we would like to introduce you to David Chen and Jaume Roig.
 

Mr. David Chen serves as Sr. Director of Applications Engineering for Power Integrations, which he joined in 2015. He leads a team of a hundred hardware and software development engineers in power electronics across three laboratories worldwide.

As an energy efficiency advocate from the power semiconductor industry, David loves the interplay between technologies and regulations to better the world. Contributing actively as an industry stakeholder in workgroups, David collaborates with standards bodies on energy efficiency, safety, and compliance, providing technical guidance on standards and regulations from the California Energy Commission, U.S. Department of Energy, Environmental Protection Agency (ENERGY STAR®), European Commission (Energy Label and Ecodesign), and China Quality Certification Center.

For six years, David has served as co-chair for the Power Sources Manufacturers Association (PSMA) Energy Management Committee and provides support for the PSMA Safety and Compliance Committee. In 2024, he also began his term as Vice President for the PSMA. He is a member of the International Energy Agency 4E Electronic Devices and Networks Annex and Power Electronic Conversion and Technology Annex, the IEC TC47/SC47E committee for semiconductor devices and TC59/MT9 committee for standby power measurement, and JEDEC's JC-70 Wide Bandgap Power Electronic Conversion Semiconductors Committee.

With over thirty years of experience in power system design and applications, David has held senior management positions at both publicly traded and privately held companies, including Volterra (acquired by Maxim), Akros Silicon, and Jade Sky Technologies, an LED driver start-up which he co-founded. David received both his B.S. degree in Electrical Engineering and M.S. degree in Mechanical Engineering from MIT and is the author of two patents.

Jaume Roig was born and raised in the picturesque Bay of Roses, renowned as one of the most beautiful bays in the world. Despite the allure of his hometown, Jaume ventured to the northern regions of Europe, where he dedicated his career to the research and development of semiconductor power devices.

Currently, Jaume is at the forefront of innovation at onsemi in Belgium, leading a program focused on heuristic simulations to explore device-system interactions in power electronic circuits. With over 25 years of experience, he has been instrumental in supporting and managing projects related to power ICs and discrete devices in both Silicon and Wide Bandgap (WBG) technologies. His prolific contributions to the field include authoring and co-authoring approximately 150 articles, as well as holding 31 issued and 12 pending US patents.

In addition to his professional achievements, Jaume actively participates in industry committees. He serves as the vice-chair of the JC-70 JEDEC committee and co-chair of the PSMA Semiconductor Committee. When it comes to hobbies, Jaume's two children play a significant role in deciding his leisure activities.

APEC 2025 Was a Huge Success with over 5,000 attendees. Third Highest-Attended East Coast Show. Plans Now Underway for San Antonio, March 22-26, 2026

PEC 2025 was a record year for the East Coast. Our expectations were exceeded with registrations of over 5,100. The last time APEC was held on the East Coast was in 2023 in Orlando and this year's conference in Atlanta surpassed that show with over 340 exhibitors. A big thank you to Aung Thet Tu, who stepped up with the passing of Tony O'Gorman APEC 2025 General Chair and the Organizing Committee for a job well done!

As always, the APEC exhibit hall was a vibrant and busy venue. A record high of 340 companies had booths at the show. And nearly 30 others were unable to exhibit at the sold-out venue.

Now it's on to APEC 2026, March 22-26 at the Henry B. Gonzalez Convention Center in San Antiono, TX. This is first time for APEC to return to San Antonio since 2018.

I recommend that you check the website in the weeks ahead (www.apec-conf.org) and watch for announcements about the calls for Technical Session and Industry Session submissions as well as proposals for the Professional Education Seminars.

Technical Sessions
Prospective authors will be asked to submit a digest explaining the problem that will be addressed by the paper, the major results, and how this is different from the closest existing literature. Papers presented at APEC must be original material and not have been previously presented or published. The principal criteria in selecting digests will be the usefulness of the work to the practicing power electronic professional. Reviewers value evidence of completed experimental work.

Professional Education Seminars
Professional Education Seminars at APEC 2026 will address the need for in-depth discussion of important and complex power electronics topics. Seminars are three-and-a-half hours (including breaks) in length, can range from broad to narrow in scope, and can vary from introductory to advanced in technical level. Topics are to address the practical issues of the specification, design, manufacture and marketing of power electronic components, products, and systems.

Industry Sessions
The Industry Sessions run in parallel with the technical sessions and have proven to be very popular. Submissions are due by late August. Speakers are invited to make a presentation only without submitting a formal paper. The target audience for these sessions differs from the engineers in typical technical sessions and may include system engineers/architects and business-oriented people such as purchasing agents, information technologists, regulatory agencies, and other people who support the power electronics industry.

Make your plans to be part of APEC 2026. Be sure you have this important event on your calendar and in your budget for next year. And do your part to make it an even better conference by volunteering to be on the peer-review panel in areas where you are qualified. See you in San Antonio.

Provided by Kathy Naraghi, APEC 2025 Publicity Co-Chair

Remtec Inc.
Brian Buyea
President
5 Campanelli Circle
Canton, MA 02021
Telephone: 7817629191
Fax: 781-762-9777
E-mail: bbuyea@remtec.com
Website: www.remtec.com

Remtec is a designer and manufacturer of thick film, direct bond copper
substrates and packaging products. Engineered specifically for electronics
applications involving high power, heavy circuit density, and rigorous
environmental conditions, our proprietary technology plates copper images
over thick film on ceramic substrates.

In addition to ceramic substrates, Remtec designs and fabricates a wide range
of metallized products utilizing our PCTF® technology, including chip
carriers, hermetic and non-hermetic ceramic SMT packages, and other specialty
components—all manufactured right here in our US-based facility.
Remtec is ISO 9001:2015 certified, RoHS and ITAR compliant.

Claros, Inc.
Brian Zahnstecher
Sr. Principal Energy Efficiency Architect
21515 Hawthorne Blvd.
Torrance, CA 90503
Telephone: 508-847-5747
E-mail: brianz@claros.tech
Website: www.claros.tech

Claros, Inc. is a technology company focused on power management solutions, particularly for the data center industry. They are innovating at the intersection of power and compute to optimize AI compute capacity, efficiency, and availability. Their solutions involve both hardware and software that improve energy delivery and consumption.From the chip to the meter, data center infrastructure must be redesigned to reduce energy loss while sustainably unleashing higher compute density on a global scale.Claros is developing novel approaches to data center power utilization.

MEAN WELL: A Global Leader in Standard Power Supplies with a Strong U.S. Presence

stablished in 1982, MEAN WELL is one of the few manufacturers globally dedicated to standard power supply products. Unlike many competitors who focus on custom OEM/ODM solutions, MEAN WELL distinguishes itself by generating nearly 99% of its global sales from off-the-shelf standard power products sold under its own brand name. According to a 2025 report by Micro Technology Consultant released in April 2025, MEAN WELL ranks as the world's fifth-largest manufacturer of DC output power supplies including OEM sales.

MEAN WELL's product portfolio encompasses over 10,000 standard off-the-shelf models, including enclosed type, DIN rail type, open frame and adaptor type AC/DC switching power supplies, LED drivers, DC/DC converters, DC/AC inverters, battery chargers, power accessories, and green energy products. These products are empowering manufacturing in the US and around the globe. They are widely used across various industries, such as industrial automation, energy storage, telecommunication, medical, LED lighting, and many more.

MEAN WELL USA: Serving North America with Excellence

To better serve the North American market, MEAN WELL USA was established in 1999 and is headquartered in Fremont, California. Our professionally trained teams provide local and prompt support to customers and partners across the continent. In addition to our headquarters, we have expanded our presence with two other offices: MEAN WELL Power Solutions in Kansas City, Missouri, and the New Jersey Service Center in Marlton, New Jersey.

MEAN WELL Power Solutions: Enhancing Value in the Heartland

Opened in 2023, MEAN WELL Power Solutions in Kansas City serves as a hub for providing enhanced value-added services, including custom integration, fast logistics, and localized engineering support. This strategic move reinforces our commitment to delivering innovative and efficient power solutions to our valued customers nationwide in the United States.

New Jersey Service Center: A Commitment to Innovation and Sustainability

Our New Jersey Service Center, strategically situated just 30 minutes from downtown Philadelphia and 90 minutes from New York City, operates within a 6,000 sq. ft. professional facility. More than just a sales office, the NJSC is a hub of innovation and expertise, featuring a state-of-the-art training facility for product demonstrations, technical seminars, and training sessions. Additionally, the NJSC is equipped with an engineering lab dedicated to product testing and troubleshooting. Aligned with MEAN WELL's dedication to sustainability, the NJSC facility is powered by a 40kW rooftop solar photovoltaic (PV) system, generating over 46,000 kWh of renewable electricity annually.

Engagement with PSMA: A Collaborative Future

MEAN WELL is proud to be an active member of the Power Sources Manufacturers Association (PSMA). We believe that collaboration and knowledge sharing within the industry are vital for driving innovation and meeting the evolving needs of our customers. We encourage all PSMA members to engage actively in committees and initiatives, as the collective effort contributes to the advancement of the power supply industry.

For more information about MEAN WELL and our comprehensive range of power solutions, please visit our website at www.meanwellusa.com.

Gene Sheridan, co-founder and CEO of Navitas

avitas is a leading innovator in wide bandgap power devices and specializes in gallium nitride (GaN) power ICs and silicon carbide (SiC) power devices that are at the leading edge of power delivery, efficiency and reliability.

The company was founded in 2014 as a GaN specialist, growing rapidly and acquiring one of the most innovative SiC specialists in 2022 - GeneSiC. The company is a leader in it's field and released a series of technology breakthroughs.

Technological advances
In GaN alone, it has been the first to announce a power IC prototype (2016), the first to reach mass production (2018), and the first ship 100 million ICs (2023). This year, Navitas became the first to release the first production 650V bi-directional GaN IC, enabling single-stage topologies.

In SiC, the company innovations include a unique ‘trench-assisted planar technology’, which offers world-leading efficiency performance over the temperature range, delivering high-speed, cool-running performance that ensures up to 25°C lower case temperatures and up to 3x longer life than alternative SiC products.

In terms of reliability, Navitas’s GaN technology comes with a 20-year warranty and has recently released it’s high-power GaNSafe™ with AEC-Q100/Q101 qualification. These ICs are the world’s most protected GaN power devices. 

As of April 2025, over 275 million GaN devices have shipped (running for more than 2.5 trillion field hours). During this time its cumulative field reliability has continued to improve - over 40% since 2022 – and today the cumulative field reliability stands at just 0.1 failure per million devices.  

And in terms of efficiency and power deliver, Navitas’s SiC and GaN devices are used across a wide range of industries including data centers, EVs, mobile and consumer, motor drives, plus smart grid and renewables. They deliver increased power delivery, increased efficiency, and smaller systems.

Performance advantages
Navitas’s GaN and SiC devices enable the size of on-board chargers to shrink in one EV design by 50% without affecting power delivery. Last year also saw Changan Auto turn to Navitas when creating the world’s first vehicle to use a GaN on-board charger (OBC). Changan Auto announced the GaN OBC will reduce both charging costs by more than 15% and increase the lifetime driving range of a vehicle by 10,000 km versus standard silicon OBC solutions.

Premium consumer electronics brands turn to Navitas to create thinner, sleeker TVs and monitors. While cell phone OEMs and charger manufacturers have incorporated technologies such as GaNSlim to create some of the world’s smallest and fastest-charging devices. 

And in data centers, Navitas continues to innovate, with its GaNSafe and Gen3 SiC devices used to improve power delivery and efficiency in CRPS and ORv3 standard-form-factor PSUs. In little more than a year, the company has quadrupled PSU power delivery – being the first to enable 3.2 kW, 4.5 kW, 8.5 kW and 12 kW PSUs. This is vital in enabling next-generation GPU architectures such as NVIDIA’s Blackwell and Rubin. 

Data center power delivery is essential with over 1,000 TWh consumed by the sector annually  – if data centers were a country, it would be the sixth biggest consuming nation in the world. Every 1 percentage point improvement in efficiency of these PSUS results in the reduction of 10 TWh of energy consumption.

The first CarbonNeutral® semiconductor company
Navitas creates power electronics solutions that improve efficiency and accelerate the transition to a sustainable, clean-energy economy. 

The move to ‘Electrify our World’ is a key mission with independent analysis by EarthShift Global suggesting each GaNFast power IC reduces emitted CO₂ by 4kg in versus legacy silicon chips.

In 2022, Navitas achieved a key milestone in this mission – becoming the world’s first semiconductor company to achieve CarbonNeutral Certified status.

Not only does our technology enable performance advantages of up to 20x faster switching, with high power densities that enable faster charging and smaller, lighter, lower cost systems, but we also deliver up to 40% energy savings versus competing technologies and against specification.

For more information visit www.navitassemi.com

Innovative Solutions for Power Electronics Supply Chain Challenges

s the power electronics industry continues to advance technologically, it also faces increasingly complex supply chain challenges. Whether in electric vehicles, renewable energy systems, medical equipment, or industrial automation, the stability of the supply chain is crucial for product development and manufacturing. However, issues such as global raw material shortages, logistics delays, and rising costs are putting significant pressure on the industry. Optimizing the supply chain and improving procurement and inventory management efficiency have become key areas of focus for companies today.

Strategies to Address Shortages and Supply Delays

Component shortages and supply delays are widespread challenges across the industry, potentially leading to delivery delays, increased costs, and even production disruptions. To mitigate these risks, companies need to adopt a multi-layered supply chain management strategy, which includes:

• Supply Chain Diversification: Expanding the supplier network to reduce dependence on single suppliers or regions and enhance supply chain stability.
• Advance Purchasing and Demand Forecasting: Leveraging data analysis and market trends to predict future demand, enabling early procurement of key components to reduce supply uncertainties.
• Strategic Partnerships: Establishing long-term relationships with reliable suppliers to ensure priority supply and reduce the impact of sudden shortages.

Optimizing BOM Management to Improve Procurement Efficiency

Efficient Bill of Materials (BOM) management can streamline the procurement process, reduce errors and delays, and improve overall operational efficiency. The following approaches can enhance BOM management:

• Standardized Components: Opt for universal or compatible components wherever possible to reduce dependence on specific suppliers and increase procurement flexibility.
• Real-Time Updates and Tracking: Utilize digital tools to monitor BOM changes, ensuring procurement decisions are based on the latest data and minimizing the risk of material shortages.
• Supplier Collaboration: Work closely with suppliers and share demand information to optimize production schedules and shorten delivery cycles.

Flexible Procurement Strategies to Adapt to Market Changes

With the ongoing growth in demand for electronic components, companies need more flexible procurement strategies to minimize supply chain risks. The following strategies can help companies increase procurement flexibility:

• Alternative Sourcing: Where compliance and quality standards allow, consider using alternative components to reduce dependence on specific suppliers or brands.
• Joint Procurement and Inventory Sharing: Collaborate with industry partners or third-party platforms to share inventory resources and enhance procurement efficiency.
• Smart Procurement Management: Use AI and data analytics to optimize procurement decisions and reduce human error.

Inventory Optimization: Reducing Costs and Enhancing Supply Chain Responsiveness

Inventory management is at the core of supply chain optimization. A well-designed inventory strategy can help companies lower costs while ensuring production continuity. The following methods can enhance inventory management:

• Smart Inventory Systems: Implement automated inventory management systems to optimize inventory levels, reducing overstocking or stockouts.
• Dynamic Inventory Strategies: Adjust inventory strategies based on market demand, such as implementing Just-In-Time (JIT) production or safety stock management.
• Logistics Optimization: Choose efficient logistics models to reduce transportation delays and improve overall supply chain responsiveness.

Industry Case Studies

WIN SOURCE has enhanced its market competitiveness by optimizing supply chain management. For example, some companies have leveraged global sourcing networks and intelligent inventory management strategies to increase supply chain resilience and reduce operational costs. Such practices offer valuable insights for companies looking to optimize their own supply chains.

Conclusion

In today's complex market environment, power electronics companies must employ a variety of supply chain management strategies to address challenges such as shortages, delays, and rising costs. By optimizing procurement, inventory management, and supplier collaboration, companies can improve operational efficiency and enhance market competitiveness. Throughout this process, experienced supply chain partners can provide valuable support, helping the industry to grow steadily.

Reprinted from WIN SOURCE ELECTRONIC-NEWS
© 2025 Win Source Electronics. All rights reserved. This content is protected by copyright and may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Win Source Electronics.

Editors Note: We would like to feature your company in a future issue of the Update. Please contact the Association Office for information about how to submit an article for consideration.

ver 50 PSMA members and guests attended the PSMA Annual Meeting, held at the Omni Centennial Park in Atlanta, Georgia. The buffet breakfast before the start of the meeting provided attendees an opportunity for networking and reconnecting with colleagues. Chair Trifon Liakopoulos officially opened the meeting by welcoming all the attendees and asking each to briefly introduce themselves. Among those present were many of the recipients of the APEC Student Attendance Support provided for the thirteenth straight year by IAS, PELS and PSMA.

After the introductions Trifon asked for a moment of silence to remember Joe Horzepa and Arnold Alderman who had passed away since APEC 2024.

Next, the nominees for the open three-year terms to the PSMA Board of Directors were introduced. Votes were collected during the approval of the 2024 Annual Meeting minutes, and the winners were announced after a break midway through the meeting. Three board members were reelected to serve another term:

Ada Chen
Reenu Garg
Llewellyn Vaughan-Edmunds

In addition, Jaume Roig was elected to fill the seat vacated by Trifon Liakopoulos who had served two consecutive terms and was not eligible for reelection. Trifon will continue to serve as Chair of Board until the 2026 Annual Meeting.

Trifon then gave the Chair's Report highlighting the four key areas of focus:

1. Vision of the Organization
2. Strategic Marketing
3. Growth for Impact
4. Adding Value to Our Members.

Aung Thet Tu, APEC General Chair, gave a presentation on the state of APEC 2025. It is expected that APEC 2025 will continue the string of strong APEC performances since the pandemic ended. Attendance was up for an east-coast based APEC and revenues look to be higher than expected. Aung said he was looking forward to seeing everyone and having another strong APEC.

After Aung's report the first Joe Horzepa Lifetime Service Award was presented. The award was introduced at the Annual Meeting during APEC 2024 and is intended to recognize members who have contributed to PSMA in a significant way for at least 10 years. The award was created to honor longtime PSMA Executive Director Joe Horzepa. The first recipient of the award was Arnold Alderman, who passed away. His son Kendall was present to accept the award on behalf of his father and expressed how much PSMA had meant to Arnold.

Following the award presentation the committee chairs and/or their representatives gave a brief presentation on committee activities since APEC 2024. The PSMA Committee reports will be covered in an article in a future edition of PSMA update.

After the committee reports Tim McDonald presented the Financial Report featuring the six quarter forecast.

Tim started by saying we have not yet received the surplus for APEC 2024 which is expected to be around $150K distributed in June. The APEC organizing committee is expecting a surplus of $700K to be split among the three sponsors, PSMA will likely receive our $233 share in June of 2025.

Tim said revenue from membership is down thus far in 2025 by about 15-20%, he is forecasting a 15% reduction in membership dues for the next four quarters due to current economic conditions. Despite this expected reduction in membership dues PSMA remains on solid footing for funding some special projects going forward.

The invited speaker at this year's Annual Meeting was Johan Enslin, President of PELS. Johan spoke about the relationship between PSMA and PELS and identified areas where the two organiations can work together including co-sponsoring workshops and conferences and mentoring programs.

After Johan's presentation Chris Whaling presented on the marketing project that has been underway for the past 4-5 months or so. Chris indicated the Marketing Project had created a new mission statement for PSMA and had identified that PSMA gives a lot of value to the overall community but much of that value does not require PSMA membership. Following his presentation Chris led a discussion among those at the meeting to discuss how PSMA can direct itself going forward. It was understood this will be an ongoing discussion and that conclusions will not be reached during APEC.

Before adjourning, Chair Trifon Liakopoulos thanked all presenters and attendees for their participation and invited interested individuals to attend the March meeting of the PSMA Board of Directors, which immediately followed.

025 was a milestone year for both APEC and PSMA as both celebrated their 40th Anniversary. PSMA started the celebration off with the 10th annual Magnetics @ High Frequency Workshop held the Saturday before APEC. Over 120 attendees were present for a full day of presentations, demos and networking opportunities. More information on the workshop can be found elsewhere in this newsletter.

On Sunday, March 16th members of the PSMA Executive Committee and members of the Industry Education Committee had a lunch with members of the China Power Supply, an annual event that was reinstated last year following the pandemic. PSMA and CPSS discussed their membership models, how to grow the industry and ways the two organizations can work together.

Monday, March 17th started with the PSMA Annual Meeting (also covered elsewhere in this newsletter). A big highlight of the Annual Meeting was the awarding of the first Joe Horzepa Lifetime Service Award, presented to Kendall Alderman on behalf of his father Arnold. The Annual Meeting was also used to pass out PSMA-related badge ribbons for members to wear to celebrate PSMA's achievements over the years.

During the exhibition hall hours on March 17th PSMA announced the winner of the first Global Energy Efficiency Award, given to Pulsiv of the United Kingdom. This event is also covered in another article in this newsletter.

During exhibition hall hours PSMA offered free headshots to all attendees as part of the 40th Anniversary celebrations. This was a very popular event, and Eric Persson was kept busy. The headshots were taken in the PSMA mentoring room, another PSMA activity. This is the third year that PSMA organized mentoring for recipients of the APEC Student Attendance Support grants and the first year PSMA secured a room for the mentors and mentees to meet.

PSMA committees also ran a dozen Industry Sessions at APEC 2025 including the first three-committee sponsored Industry Session with participation from the Energy Harvesting, Energy Management and Energy Storage Committees. The Power Packaging and Manufacturing Committee presented an overview of their upcoming Power Technology Report on Embedded and Integrated Magnetics during their workshop. The Reliability Committee had a call to participate in the IPC 9592C Standards Committee being formed with IPC. We are looking forward to APEC 2026 in San Antonio and to 40 more years of PSMA and APEC leading the way in the power industry.

"Definitely [recommend this mentorship program to friends]! It's a great way to meet people, learn about the latest and greatest both in academia and industry, and get career guidance." Feedback from a student mentee.

SMA first created a mentorship program for APEC 2023. For APEC 2024 & 2025, we recruited IEEE IAS & IEEE PELS to support and expand the mentorship program. Consequently, 24 students signed up for the mentorship program along with 25 unique mentors who were matched to the mentees (with special thanks for the extra mentor who coordinated efforts in the headshots room next to the mentorship room at APEC 2025).

The mentorship program has six major objectives:

1. Take advantage of APEC
2. Explore career options & directions
3. Promote self & network (socially)
4. Meet subject matter experts
5. Introduce activities & events for PSMA, IAS & PELS
6. Have fun along the way

A key element to the program is to give mentees the opportunity to understand the true diversity of hardware, software and system integration career options open related to power electronics in areas such as renewable energy, med technology, environmental monitoring, industrial automation, smart mobility, data centres, Electric Vehicles and Internet of Things. It gives them the opportunity to talk first hand with people who have worked in a wide variety of roles and map out a suite of possible career paths both in industry and academia.

Each mentee receives a mentor and a mentorship workbook with three separate phases: Pre-APEC, APEC, and Post-APEC each containing multiple suggested activities.

To encourage mentees to try activities and attend events that they normally may be reluctant to try, they would receive points. The students had to take the initiative to accumulate the most points.

Congratulations to the winners for APEC 2025:

1st Place ($500): Soham Roy, University of Texas at Austin, USA
2nd Place ($300): Hoang Le, Lakehead University, Canada
3rd Place ($200 split over tie): Mehrnaz Madadi, North Carolina State University, USA & Shiqi Zhang, Yanshan University, China

Additionally, some mentees nominated their mentors for recognition:

• Thrax Cui & Kai Li – Mean Well USA
• Justin Henspeter – IBM

Thanks to these outstanding mentors and all other mentors who volunteered to guide our rising stars of engineers!

PSMA actively worked to improve the program for APEC 2025:

1) Updated the mentorship workbook by adding a "purpose" column, aiming to better motivate students by helping them understand the benefits of each activity.
2) Simplified the prizes to facilitate international distribution.
3) Actively recruited more international mentors, especially from Asia, to better match the student distribution and address social and cultural aspects in mentoring.
4) Created a Mentorship room as a dedicated and quiet location for mentors and mentees to meet in an unfamiliar destination. We posted several career options in the room to spark more discussion.

This is just a summary of our mentorship efforts. Consider joining the PSMA Industry-Education Committee to help shape the mentorship program going forward.

Here is what one student mentee had to say about the APEC mentorship program: "Compared to other programs I've tried, this one gave more personal attention. In the past, some mentorships felt rushed or didn't offer regular contact, but APEC made sure we had real conversations and built a good relationship with our mentor."

Other positive results of the mentorship program:

1) Received specific feedback on how to improve
2) Some mentees already agreed to become mentors at a future APEC
3) Many mentees would recommend this program to friends
4) A number of mentors agreed to mentor again and would recommend this program
5) Several mentors agreed to continue the mentorship with their mentees

Interested in becoming a mentor for APEC 2026? Contact mentors@psma.com.

Most Importantly: Thank You for being a Mentor! Thanks again for giving our next generation of engineers a head start!

SMA Industry Sessions at APEC are most impactful when they deliver practical, real-world insights to an audience eager for application-driven content. This guide outlines proven tactics for building successful sessions that educate, engage, and grow both your audience and committee membership.

Attracting a Larger Audience

To attract a larger audience, keep sessions application-oriented.

The best approach is to invite power electronics customers (leading companies who buy or use power electronics) to speak as they know the application.

When you feature industry leaders, their competitors and potential suppliers will want to attend as well. Audience members will often contribute insightful questions and challenges.

This distinction can be tricky, as people often confuse technologies with applications. For example: Artificial intelligence (AI) is a technology, but not an application. People cannot buy AI specifically, but they can buy systems which use AI such as robots, gaming consoles or EVs. These systems or applications may even use the exact same Nvidia chip to implement AI, but the thermal, shock, EMI, testing, reliability, etc. requirements are different. Consequently, the attraction of speakers from Boston Dynamics (a key robotics leader), Sony Playstation, or Tesla is very different than a speaker from Nvidia, or Infineon, or Wurth; even though, all these companies are leaders in their own areas.

Support customer speakers in identifying non-proprietary topics, such as future power trends, design best practices, key tips, or common mistakes, etc.

Addressing Travel Constraints

If speaker travel is an issue, choose a local speaker, a speaker who normally attends APEC, or a speaker from an exhibiting company (who may also do booth duty). This is especially important for those customers who do not usually attend APEC (hopefully once they do attend APEC, they will consider attending APEC again). For example, utility companies traditionally have tight finances, and most do not attend APEC so finding a speaker from a utility company local to the APEC location will help.

Backup Speakers

Use a speaker from power electronics suppliers or committee members as backup when you cannot get power electronics customers to speak. If your committee invites seven speakers, but only gets a session with four speaking slots, the three "extra" speakers can backup the confirmed four. Consider offering the extra speakers to other industry sessions. If a speaker becomes available after all slots are filled—or was prepared but didn't present—consider inviting them to present at a Power Technology Roadmap (PTR) webinar or a committee-hosted educational webinar instead of waiting for the next APEC.

Committee Growth and Engagement

To grow the committee, invite industry session speakers or potential speakers to join.

Send a PSMA calendar invitation to previous speakers for the onsite APEC committee meeting or the next committee meeting. Encourage their involvement in planning the next APEC session.

During the industry session, clearly mention which committee organized it and invite attendees to join.

Early Speaker Recruitment

To get an early start, recruit speakers during the APEC exhibition. Visit booths and ask for speaker recommendations or contacts.

Additionally, ask your audience to suggest speakers and topics for the next APEC.

Consider recruiting speakers from a different conference which has the added benefit of evaluating their speaking skills ahead of time.

Avoiding Speaker Cancellations

To avoid last-minute cancellations, the Industry Session Chairs on the APEC organizing committee will proactively communicate the importance of speaker (and chair) responsibilities and commitments.

However, as the deadline for presentation submissions draws closer, speakers may want to drop out. Here's a sample email message to remind them of their responsibilities:

Subject: Reconsider Your Commitment to Speak at APEC

Dear [Speaker Name],

We are strongly encouraging you to reconsider dropping out of APEC as a rash decision may have larger consequences than intended. As a reminder, speaker no-shows can impact both individual and organizational participation in future APEC and IEEE events. A no-show after a commitment is treated as a possible systemic risk (i.e. your organization may not support its speaker commitments). You personally may be banned from all IEEE conference for a period of time. Please reach out if any conflicts have arisen—we're happy to work with you to find a solution.

Best regards,
[Your Name]

Managing Last-Minute Dropouts

Sometimes there is no way to avoid a last-minute empty slot. If a speaker cancels at the last minute, consider converting the speaking slot into a panel discussion with the remaining speakers. Session chairs or committee members can moderate. Share initial questions with the panelists beforehand to help them prepare, and encourage audience participation.

Speaker Order Strategy

If the session has a logical topic flow, let that guide speaker order. Otherwise, place the strongest speaker (or topic) at the end to keep the audience engaged.

Use the second strongest speaker to open the session and capture attention. Place the third and fourth strongest after and before the break respectively, if applicable.

Alternatively consider placing speakers who may need extra time either before the break or at the end of the session.
If adjusting the speaker order when the schedules is already published, take the opportunity to resolve any topical conflicts with the other industry & technical sessions running in parallel.

Chairing the Industry Session

At the speaker breakfast (or earlier) find out if any speakers cannot stay for the entire session. Announce if a speaker is only available for the break or immediately after his/her talk if he/she needs to leave early. If a speaker needs to leave right after his/her presentation, be sure to retrieve the wireless (or lapel) microphone immediately before the next speaker; otherwise, the speaker may end up talking over the next speaker's presentation!

Arrive early to the session to check the audio/visual (A/V) system (microphones on stage and in the audience, pointers, timers, etc.) especially if the session is scheduled on Tuesday morning (the first day of presentations). Have speakers ensure the correct version of their presentations are loaded. Know where to find the closest A/V support.

If the session is full (standing room only), encourage the audience to move towards the center seats so that those people who were standing can sit down.

For the Q& A parts, encourage the audience to state their name and affiliation before stating their question. This will discourage competitors from asking nasty questions or making snide comments.

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With special thanks to all the committees which not only put together these industry sessions for APEC, but also contributed to this article.

Do you have any other advice to offer? Consider sharing them so all of PSMA can benefit.

Ada Cheng
Jaume Roig Guitart
Renee Yawger

5th International Symposium on
3D Power Electronics Integration and Manufacturing (3D-PEIM)
Golden, CO, USA | July 8–10, 2025

3D-PEIM Will Offer In-Depth Power Electronics Lab Tours

his summer, the National Renewable Energy Laboratory (NREL) will open the doors of its state-of-the-art power electronics laboratories for attendees of the Fifth International Symposium on 3D Power Electronics Integration and Manufacturing (3D-PEIM).

Created and supported by the PSMA's Packaging & Manufacturing Committee and IEEEE EPS, 3D-PEIM will take place from July 8–10, 2025 in Golden, Colorado.

Over three days of technical programming, it will explore the latest advancements in 3D power electronics integration and manufacturing, with a strong focus on technologies to increase the density and performance of power solutions.

Nine technical sessions will focus on advanced artificial intelligence and machine learning for modeling, module and converter integration and manufacturing, thermal management, reliability, advanced materials, and passive components.

Laboratory Tours

New this year, guided tours of NREL's state-of-the-art laboratory facilities will be offered.

In NREL's power electronics laboratories, participants will be guided through the following facilities:

• Thermal Management and Thermomechanical Reliability of Power Electronics and Electric Machines Laboratory
• Thermal and Mechanical Characterization of Power Electronics and Electric Machines Laboratory
• Advanced Power Electronics Packaging Characterization and Prognostics Laboratory
• Electrical and Property Characterization of Power Electronics and Electric Machines Laboratory

Guided tours will also be offered of NREL's 182,000-square-foot Energy Systems Integration Center, the Solar Energy Research Facility, and the Science and Technology Facility. There, participants will be guided through facilities for the following research areas:

• High-Performance Computing and Analysis
• Materials Science, Energy and Grid Integration
• Advanced Research on Integrated Energy Systems (ARIES)
• Grid-Tied Power Electronics
• Hydrogen
• Solar Photovoltaics
• Transportation Electrification
• Commercial and Residential Buildings

Plenary Speakers

Dr. Harsha Nanjundaswamy, BorgWarner: Beyond 2030: Powering the E-Powertrain with High-Value and High-Efficiency Power Conversion Systems—A BorgWarner Perspective

Dr. Devan Iyer, IPC: Advanced Packaging to System Integration—Trends and Challenges

Dr. Subramanian Iyer, University of California Los Angeles: The Power Delivery and Energy Storage Challenge in Advanced Packaging.

Program at a Glance

Early-bird registration ends June 1, 2025.

You are cordially invited to sign up for Partnership Tabletop Exhibit Opportunities!
Each Exhibit Partner may present products at the Symposium.
To learn more and sign up as an Exhibit Partner, visit
https://www.3d-peim.org/sponsors-exhibitors/

Technical Sponsors:

Media Sponsors:

PwrSoC 2025 – 9th International Workshop on Power Supply on Chip

• Dates: September 24–26, 2025
• Venue: Seoul National University, Seoul, Korea
• General Chair and Local Host: Professor Jaeha Kim (Seoul National University)

Overview

he International Workshop on Power Supply on Chip (PwrSoC) is the world's leading forum dedicated to the advancement of miniaturized and integrated power conversion and power management technologies. Held biennially, the workshop gathers experts from academia, industry, and the global supply chain to discuss current challenges and explore future opportunities in the field.

Host Institution: Seoul National University

Founded in 1946, Seoul National University (SNU) is Korea's premier academic institution, widely recognized for its excellence in education and research. With a student body of approximately 30,000, SNU has been instrumental in driving Korea's scientific, technological, and economic growth. The university serves as an ideal venue for this workshop, offering a vibrant academic environment and world-class facilities.

Technical Program

The technical program follows a single-track format to encourage active participation and discussion. Each session features presentations from leading researchers and engineers in power supply integration.

The program is overseen by Technical Program Chair Professor Hyun-Sik Kim (KAIST, Korea) and Vice Chair Dr. Rinkle Jain (Nvidia, USA), along with 22 internationally recognized experts. A complete and up-to-date technical schedule is available at: Programs - (pwrsocevents.com).

Poster Session

The poster session provides an excellent opportunity to share innovative research and foster direct interaction.

• Abstract Submission Deadline: July 18, 2025
• Best Poster Awards will be presented to three outstanding submissions.

For submission guidelines, please visit: Posters - (pwrsocevents.com).

Industry Visit: SK Hynix Fab Tour

As part of the program, participants will be offered a guided tour of SK Hynix's advanced semiconductor fabrication facility. This exclusive visit provides an inside look into one of the world's top memory manufacturers and its state-of-the-art processes and technologies.

Registration and Additional Information

Registration will open soon. We invite professionals, researchers, and students in the field of power electronics and system integration to participate in this high-impact international event.

To register or learn more, please visit: http://pwrsocevents.com/

Call for Papers and Tutorials Now Open for the 12th Annual
IEEE Workshop on Wide Bandgap Power Devices and Applications

he Twelfth Annual IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA 2025) will take place November 10–12, 2025, in Fayetteville, Arkansas. As one of the leading global forums for wide bandgap (WBG) power electronics, WiPDA brings together device scientists, circuit designers, systems engineers, and application experts to share the latest advances in materials, devices, packaging, and real-world implementations.

Sponsored by IEEE, PSMA, IEEE-PELS, and IEEE-EDS and supported by academia, industry, and national laboratories, WiPDA 2025 is a must-attend event for anyone working at the intersection of semiconductor innovation and high-efficiency power conversion.

Why Attend WiPDA?

Wide bandgap materials such as gallium nitride (GaN), silicon carbide (SiC), and emerging ultra-wide bandgap semiconductors are rapidly reshaping the landscape of power electronics. Their superior efficiency, thermal performance, and voltage handling capabilities are driving adoption in critical sectors such as renewable energy, electric transportation, data centers, aerospace, and grid infrastructure.

WiPDA 2025 provides a platform for thought leaders and innovators to discuss technical challenges, share breakthroughs, and forge collaborations that move the WBG industry forward.

This year's program will include:

• Technical Sessions covering device design and fabrication, converter architectures, packaging strategies, and system-level applications.
• Tutorials designed to provide in-depth knowledge on core and emerging topics.
• Keynote Presentations from top experts in industry and academia.
• Poster Sessions and an Industry Exposition for hands-on interaction and networking.
• Tours of the new National Multi-User Silicon Carbide Research and Fabrication Laboratory (MUSiC)—a cutting-edge facility advancing SiC research in the U.S.

Call for Papers and Tutorials

WiPDA 2025 is now accepting two-page abstracts for technical papers and one-page abstracts for tutorial proposals. The deadline for both is June 13, 2025.

All accepted and presented papers will be published in the IEEE Xplore Digital Library, giving authors global visibility and citation opportunities.

Technical paper topics include:

• Wide bandgap and ultra-wide bandgap materials growth
• Device structures, fabrication, and modeling
• High-efficiency and compact power converters
• Advanced packaging and gate drive circuits
• Applications in EVs, renewable energy, aerospace, industrial automation, and more
• System design philosophies and future roadmap discussions

Tutorial proposals should include:

• A half-page description of the proposed topic
• A brief biography of the presenter(s)

Final papers are due by August 22, 2025, and final tutorial presentations are due by August 9, 2025.

Be Part of the WBG Power Revolution

As wide bandgap devices continue to displace traditional silicon across performance-critical applications, WiPDA provides an essential space to explore these trends in depth. Whether you're a researcher developing the next generation of GaN or SiC technologies, a systems engineer designing converters for EVs or satellites, or an industry professional looking to stay at the forefront of power electronics—WiPDA 2025 is the place to be.

For submission guidelines, registration details, and the latest updates, visit: www.wipda.org

Sponsorship opportunities are also available for organizations looking to showcase their leadership in wide bandgap technology and connect directly with researchers, engineers, and decision-makers in this rapidly growing field.

For more information or to become a sponsor, contact Zhong Chen chenz@uark.edu

Mark your calendar. Prepare your abstract. And join us in Arkansas to help shape the future of power electronics.

Power Magnetics @ High Frequency
Saturday March 21 2026
Prior to APEC 2026
Henry B. Gonzales Convention Center
San Antonio, TX 78205

he PSMA Magnetics Committee and IEEE PELS is currently planning to conduct the eleventh Power Magnetics at High Frequency Workshop on Saturday, March 21, 2026, which is the day before and at the same venue as APEC 2026 in San Antonio, TX. The 2026 workshop will build on the ongoing dialogue established throughout the first ten workshops.

The purpose of this workshop is to explore recent improvements in magnetic materials, coil (winding) design, construction, and fabrication, as well as evaluation techniques, characterization methods, and modelling and simulation tools. This targets the advancements deemed necessary by the participants for power magnetics to meet the technical expectations and requirements of new market applications where higher operating frequencies and emerging topologies are driven by continuous advances in circuits topologies and semi-conductor devices.

The target audiences for the 2026 Power Magnetics @ High Frequency workshop include the designers of power magnetic components for use in electronic power converters responsible to implement the most technologically advanced power magnetic components that are necessary to achieve higher power densities, specific physical aspect ratios such as low profile, higher power efficiencies and improved thermal performance. The target audiences also include people involved in the supply chain for the power magnetics industry ranging from manufacturers of magnetic materials and magnetic structures, fabricators of magnetic components, providers of modelling and simulation software as well as manufacturers of test and characterization equipment.

The theme of the 2026 Power Magnetics @ High Frequency will be measurements and data processing trends to improve analytic models and simulation models towards developing better design tools, enabling magnetics optimization for existing and emerging applications. The workshop will address various aspects of measurement methods and creation of analytical models employing equations re-enforced with empirical data.

As with past workshops, the morning and afternoon sessions will open with keynote presentations that cover a broad range of related issues followed by lecture presentations on specific applications or technical issues. In addition to the brief Q&A period after each individual lecture presentation there will be a panel of the presenters at the end of the session who will address topics requiring more detail as deemed by the workshop attendees.

During lunch, breakfast, and the networking hour at the end of the workshop there will be an interactive session of tabletop technology demonstrations each addressing specific technical disciplines and capabilities consistent with the workshop agenda. Each technology demonstration station includes a brief ten-minute presentation. Interaction between the attendees and the presenters is highly encouraged during this portion of the agenda as a segue from the opening keynote presentation and the technical issues session.

If anyone would like to participate as a presenter for the technical demonstration session, please contact the organizing committee through PSMA via e-mail to power@psma.com with a description of your proposed technical topic. We are limited to ten technology demonstration sessions.

The specifics for the workshop structure and the presentations for the workshop are currently in progress and are not finalized. If anyone is interested in presenting on characterization of magnetic components and the development of analytical models or simulation models please contact the organizing committee through PSMA via e-mail to power@psma.com.

More details regarding the agenda for the workshop as well as registration for the workshop will become available on the PSMA website (www.psma.com/technical-forums/magnetics/workshop) over the coming months.

The 2025 Power Magnetics at High frequency Workshop was held on Saturday, March 15 in Atlanta, Georgia. The 2025 workshop marked the tenth annual workshop continuing the tradition of informative and synergistic dialogue between members of the magnetics design community that began in 2016 at Long Beach California.

The morning technical lecture session focused on physical implementations of magnetics designs for emerging applications and markets. The session consisted of presentations by Minjie Chen of Princeton, Ranajit Sai of Tyndall, Jens Kehl of Wurth Elektronik, Sebastian Bachman of Tridelta Weichferrite, and John McDonald of Atlas Magnetics.

The afternoon technical lecture session focused on trends in designing and modelling magnetics for emerging applications and markets. The session consisted of presentations by Charles Sullivan of Dartmouth, Mike Ranjram of Arizona State University, Lukas Mueller of Micrometals and Michael Freitag of Yageo.

Student poster presentations by Jacob Anderson, Nick Kirkby of ASU, Todd Marzec of UPITT, Rachel Yang of MIT and Yibo Wang of City University of Hong Kong were available during the breakfast and lunch sessions.

Technology demonstrations by Andres Arias, Risha Yu of Premier Magnetics, Alfonso Martinez and Mark Christini of Open Magnetics and Ansys respectively, Mike Arasim of Fair-Rite Products, Efrain Bernal of Wurth Elektronik, Reddy Andapally Bharadwaj of CBMM, Wilmar Martinez of KU Leuven, John McDonald of Atlas Magnetics, Lukas Mueller of Micrometals, Ryu Nagahama of Iwatsu, Akihiko Saito of Daido Steel, Jens Schweickhardt of PE Systems, JC Sun of Bs&T, Jun Wang of University of Bristol, Tom Wilson and Andrija Stupar of SIMPLIS Technologies and Kosuke Yuasa of Daido Steel were available during the breakfast and lunch sessions.

The high energy of the 2025 magnetics workshop has paved the way for the start of a second decade of workshops, beginning in 2026.

agnetic components appear to be so simple—just two parts, a core and some wire wrapped around it. How could that be very complicated? If you ask this question of yourself seriously enough, you begin your own descent into the abyss of magnetics design. As a "recovering magnetaholic," I have learned that magnetics really is simple, but the path to simplicity is fraught with misleading ideas. Some of these ideas are partially true, but misleading in the ways they are usually expressed; while others are not true at all, though they may be widespread. More importantly, some basic concepts that should be widely known are not. This article is a chat about some of them.

Magnetics Science Vs. Magnetics Optimization

A few years ago, I began design work on a battery converter for an off-grid inverter. The converter has low-input-resistance (low V, high I), from a 24-V battery and at 1 kW, by Watt's Law, takes in about 42 A. After some research, I concluded that the best power circuit is that of a boost push-pull (BPP), which is a common-active PWM-switch converter with a transformer, as shown in Fig. 1.

Fig.1. Boost push-pull (BPP) converter, the “optimal” choice for low-input-voltage, high-current conversion?

The converter has input inductor L and a center-tapped transformer, giving it essentially two primary windings and a 170-V secondary winding. The secondary voltage referred to the primary appears at the center-tap as Vs' = n⋅Vs where turns ratio n = Np/Ns = 1/5—a "step-up" transformer. Then Vs' = 34 V and is above the maximum specified input voltage Vg of 30 V.

The amount of power that the inductor must be capable of transferring decreases as Vs' decreases, which reduces the inductor voltage vL and flux change Δλ and thus its transfer power. However, unless Vs' > Vg, the transfer circuit quits boosting and the direction of power flow reverses. With changes in n, inductor power is greatly affected but not so much for transformer power because all power transferred between input and output ports must go through it.

The circuit poses questions about the design of the inductor and transformer and how to optimize them. These seemingly reasonable questions have not been given convincing answers. Textbooks do not give them because they do not address design optimization except in a somewhat facile sense. They concentrate primarily on the science of magnetics in its application to engineering. Engineering, however, is not only about science but is distinctively about design, optimization, and generally, about achieving goals that solve human physical problems.

Furthermore, at power-on and power-off and during load faults (output shorted), Vs' < Vg and inductor current ratchets upward, out of control. The basic push-pull boost circuit can have excessive current under these conditions because ratcheting is caused by driver loop delay; it takes a loop delay time to shut off the power switches, and during this time, inductor (or transformer magnetizing) current can increase more than it decreases in a switching cycle thereby causing the current ratcheting effect. Some way of avoiding it is required.

The solution that was found to be optimal (in the Volksinverter series of articles just completed [1]) was a Weinberg circuit, where the inductor is given a secondary winding that delivers current through a diode either to the output or back to the input port. Instead of operating with non-overlapping (CP or buck) push-pull switch drive, it has dual operation that can transition continuously to a CA or boost converter with overlapping switch conduction for Vs' > Vg. Thus, both input and output port ranges of voltages and currents must be considered in a converter design. Sometimes the exceptional yet critical states of a circuit are overlooked.

Maximum-Power Mythology

One of the semi-myths of magnetics design that I had carried in my notebook and mind for many years is the belief that maximum power is transferred through a transformer when the winding and core losses are equal, or average Pw = Pc. This is demonstrated by using the maximum power-transfer theorem (which is better called the maximum output power theorem), by letting winding loss be included in a series winding resistance with a shunt resistance for core loss, all referred to the secondary winding, as shown in Fig. 2.

Fig. 2. Interwinding power transfer model, referred to the secondary winding with a resistive load, secondary (load) current of Is and voltage of Vs. Rc is the secondary-referred core resistance representing core power loss, and Rw is the secondary-referred winding resistance of both windings combined.

Core-loss resistance Rc is across secondary-referred primary winding voltage Vp'. Because core loss varies directly with flux change, which is proportional to voltage, then the loss can be modeled in Rc. The dictum of maximum power transfer under the condition Pw = Pc is true only at zero power, or 100% efficiency. Otherwise, maximum power is transferred—that is, maximum efficiency occurs elsewhere. In the example given here, Pw < Pc at maximum efficiency, as seen in Fig. 3, though for typically much higher efficiency, Pw ≈ Pc.

In reference [4], the optimal power-loss ratio ψ of winding-to-core loss varies around one, depending on the extent of voltage drop across winding resistance and the winding-to-core resistance ratio β. For the general model (with individual primary and secondary winding resistances) referred to the primary side,  ψmax = β + 1 > 1, which makes Pw > Pc but not by much.

The primary winding is driven by a constant voltage source, referred to the secondary as Vp' with a secondary-winding terminal voltage of Vs. The secondary output power is

As Rw decreases, Ps increases along with Vs and Is. Pc is a function of Vp' and Pw is a function of both Vp' and Vs. Core power loss Pc and winding power loss Pw are

The total transformer power loss is

The primary-winding input power is

Power transfer as an output/input ratio is the same as efficiency,

Plots for the circuit are shown in Fig. 3 for constant Vp' = 10 V, Rc = 9 Ω, and Rw = 1 Ω. Power quantities are in watts and η is in percentage. Pc and Pw cross at 3.33 A while η peaks at 2.4 A with η = 51.9%. Where Pc = Pw, η &lt; ηmax by about 1.9%.

The cause of the error is that the maximum power-transfer theorem from introductory passive-circuits courses is based on a different circuit. The theorem is derived from a voltage source having a series resistance connected to a resistive load. The difference is that shunt core resistance Rc is not included in the theorem. If core loss is negligible for high-η design, it is approximately correct. However, to believe that it has been derived as exact is "mythological".

Fig. 3. Graph showing for the example given that maximum power is not transferred when core and winding losses are equal. Pt intersects Ps at two values of Is, neither of which is at peak efficiency, η. At one intersection, Pc = Pw.

There is also a subtle calculus error in the commonplace derivation of maximum η.[2] Hence, one longstanding interwinding power-transfer proposition found in much of the power-electronics literature is not really true. For high efficiency, it is approximately true which is why it has been possible to promulgate it all these years without undue suspicion. Yet if you suppose it is always true when analyzing your converter design over its full input-current range, you will find that the efficiency falls off rather abruptly at low current. Here the old dictum begins to fail noticeably.

Optimal Waveshape For A Core Material

Another underappreciated loose end is the relationship between circuit waveforms and optimal core material. Seemingly, there should be no direct relationship, but there is.[5] The question of how to select the right core material for a given magnetics design starts with the basic limitations on cores.

Frequencies much above audio eliminate 60-Hz transformer cores such as 3% Si steel. All of the low-frequency materials have excessive hysteresis loss for operation at power-converter switching frequencies. Operation at the highest possible frequency maximizes power-transfer density because power transfer in a converter is directly proportional to it. Frequency is also related to the more basic core limitation of power loss and maximum allowable core temperature.

The other basic core limitation is saturation, in which its magnetic properties diminish. Power loss limits a combination of the frequency and  = ΔB/2, the ripple amplitude of the core field density. Saturation limits static field intensity , and the two combined limit ripple factor γ. In field quantities,

where L = μ⋅A/l = field inductance, A = magnetic cross-sectional area, and l = magnetic path length.
The ripple factor of the winding current waveform is determined by core loss in the numerator and saturation in the denominator. Substitute the maximum allowable values for a given core material, and γopt for that particular material results. This γ is optimum because it allows maximum energy transfer through the core: maximum ΔB at maximum H for which

Ripple factor is a significant core material performance parameter which, to my knowledge, has not been made explicit in the development of power magnetics. Sanjaya Maniktala noted it in passing in his books,[3] but general awareness in the field has yet to take place.

Winding Area Allotment

Another loose end that relates to both converter circuit and transformer design is how much area should optimally be allotted to each winding. Usually, there is nothing mysterious about this; the primary and secondary windings should each be allotted equal area.

The rationale is simple. Power is being transferred from primary to secondary winding and except for the loss of a negligible amount of power as heat in the transfer, they are equal. Transformer thermal design is optimized by having no part of the transformer hotter than any other part. Although this is an ideal, it is approached by designing for equal power-loss density.

To achieve this for windings of near-equal power, their areas should also be made equal. In a sequential winding configuration, the primary is wound first for highest power transfer to the core, and it is thermally the farthest from ambient. For this kind of transformer design, the primary winding might be given somewhat larger area to reduce its power-loss density and hence its temperature.

However, the heat path of the primary is almost completely through the metal of the secondary winding. This heats the secondary with both its own loss and that of the primary winding, and argues for a lower power density and more area for it. Overall, allotting equal areas for primary and secondary windings is roughly optimal.

A thunderclap is now heard in this otherwise placid scenario when the boost push-pull (BPP) power-transfer circuit is considered. The complication is that it has (functionally) two identical primary windings and one secondary winding. The primary windings alternate in conduction cycles while the secondary conducts each cycle. The primary-side switch current waveforms have three levels, not the familiar two levels of square-waves.

The fractional allotment of total core window area Aw of a winding is kww: Awp = kwp⋅Aw; Aws = kws⋅Aw. Then the area ratio of primary to secondary windings, which in most transformers is optimally 1, is

(In the Volksinverter series of articles, the waveform equations are derived, but here they are given.) The primary and secondary currents are and , converter PWM duty-ratio = D, D' = 1 – D, n = transformer turns ratio of either primary winding to the secondary winding, Vs = secondary voltage amplitude, Vg = converter input voltage, and Vs' is the secondary voltage, referred to the primary winding and probed at the center-tap of the two primary windings. Some area math establishes the basic area relationships:

The Volksinverter-specified input voltage range is 20 V to 30 V. Over this range, the optimal Y changes, but as a transformer, n and Y and the other parameters are fixed in design. Our challenge is picking the best compromise optimum from the table of values.

Table. Winding area allotments for BPP.

The choice is to allot (0.6)⋅Aw to the primary windings, with (0.3)⋅Aw to each, and (0.4)⋅Aw to the secondary winding, as shown in Fig. 4

Fig. 4. Boost push-pull converter transformer primaries and secondary winding-area allotment. Primary windings have kwwp = 0.3 and secondary winding has kwws = 0.4.

Departure from Y = 1 is caused by the difference in primary and secondary waveforms; they are not the same in waveshape, and this affects the optimal Y. Usually in switching transfer circuits, the primary and secondary waveshapes are close to square-waves (with some slope from magnetizing-current ripple), but whenever a power-transfer circuit has different waveshapes across windings, the equal-area optimization might not be valid.

Optimal Core Shapes

Charles Sullivan at Dartmouth College and his student R. Jensen did a computer-simulation study of core shapes that minimize thermal resistance. A geometric optimization of core shape involves the winding window aspect ratio of width (the dimension along which winding turns proceed) to height, which affects the number of layers, is optimally between 1 and 2 for minimum Pw when dynamic resistance is taken into account.[5]

Commercial cores are in the range of 2 to 5 and typically around 3, including EE, ETD (4 to 5), EC, RM (2 to 3) and PQ (1.5 to 3) shapes, resulting in about a third greater loss. Although a large width/height aspect ratio reduces the number of winding layers and eddy-current resistance ratio FR, it also increases the winding length for a given window relative to the window area, thus increasing winding resistance and winding loss.

RM and PQ shapes are found in power inverters such as the Statpower 500 and its equivalent Samlex PS-24175A, but the core shapes this study found to be less thermally efficient, such as ETD and EFD, are also popular and not relegated to obsolescence. Perhaps that will change as these findings diffuse into the broader power-electronics design world and more research clarifies the power-loss picture as it relates to core shapes.

How To Avoid Mythology

Acquiring misleading ideas about magnetics can be avoided with a solid grounding in the fundamental principles that will be as true a century from now as they were a century ago (had they only been known). In surveying the literature, there are two textbooks and a research site that I found to be the most helpful, all from leading magnetics researchers and IEEE Fellows.

The most rigorous and complete book I found on basic magnetics is by Marian K. Kazimierczuk of Wright State U. titled High-Frequency Magnetic Components, Second Edition, Wiley, 2014. He has worked out all the equations relating to the fundaments of component analysis, and some for design.

The second book is thinner and has a different emphasis to it, by W. Gerard Hurley in Galway, Ireland, and Werner Wölfle, Transformers and Inductors for Power Electronics: Theory, Design and Applications. It has slightly less math density and covers some different topics than Kazimierczuk's book.

And finally, from Charles Sullivan's website in the Thayer School of Engineering at Dartmouth C. you can download his main research papers on magnetics.[7] Sullivan is primarily interested in how to minimize core and winding losses by reducing the eddy-current effects through wire strand twisting and braiding, and also in how core dimensions affect core loss. These three sources provide a foundation for proceeding to design optimization. More detail on that is in my book, Power Magnetics Design Optimization.[6] If you want a PDF copy (the paper version sustains a printing cost), contact me through the inquiry link[8] on the Innovatia website.

About The Author

Dennis Feucht has been involved in power electronics for 40 years, designing motor-drives and power converters. He has an instrument background from Tektronix, where he designed test and measurement equipment and did research in Tek Labs. He has lately been working on projects in theoretical magnetics and power converter research.

For more on magnetics design, see these How2Power Design Guide search results.

This article originally appeared in the April 2025 issue of the How2Power Today newsletter (https://www.how2power.com/newsletters)

he power electronics industry is once again at a pivotal inflection point. The advent of wide band gap (WBG) semiconductors, especially Gallium Nitride (GaN), is unlocking unprecedented performance gains—from higher efficiency and smaller form factors to reduced cooling requirements and lower system costs. Yet despite these compelling benefits, adoption across certain industry remains sketchy, shaped by both technical and organizational challenges.

Challenges of technological shifts
Having started my career in the late 1980s, I have witnessed and taken part in several major transitions in power technology. I have seen the move from linear to switching power conversion, the shift from bipolar transistors to MOSFETs, and more recently, the transformation from analogue to digital control. Now, we face the challenge and the opportunity of embracing WBG technologies such as GaN, but recalling from previous technology shifts, each change brought its own hurdles and there are always concerns about supply chains, reliability and customer's confidence and acceptance of something new.

GaN: A Leap Forward, not a Small Step
GaN offers a fundamentally different approach to power conversion. Its high electron mobility and breakdown strength allow devices to switch faster and handle higher voltages and frequencies than traditional silicon. This translates into higher system efficiency, more compact designs with improved thermal performance, and a greater operating frequency making magnetics smaller and boosting transient response. That sounds great but reaping these benefits is not as simple as replacing one device with another - if only it was!

Engineering the Transition: Technical and Cultural Barriers
Adopting GaN devices demands a new design mindset. Engineers must contend with much faster switching transitions, tighter layout constraints, and stricter EMI control. While these are solvable with the right tools and experience, they mark a departure from traditional silicon design practices. Beyond design challenges, the broader ecosystem is still developing. Availability of GaN-compatible drivers, robust packaging, and clear application guidelines continue to improve but remain perceive as obstacles, especially for risk-averse organizations. And perhaps most importantly, rightly or wrongly, for many end-users' reliability remains a key concern. Many industries served by power electronics—such as medical, transportation, and industrial automation (without mentioning space and defense)—demand extreme reliability and any new technology must prove itself over time, under stress, and in the field. The power electronics industry is committed to ensuring a seamless and reliable transition as it works to change perception by building a trust and reliable transition processes.

Building trust in reliable transition processes

Keeping the IPC9592 in consideration
All power supply manufacturers thoroughly develop their own processes to verify the quality of their products before commercialization. This is all part of company know-how and their trade secrets, but I would like to take a minute to remember an initiative that took place twenty years ago and highly contributed to reducing the communication gap between Telecoms OEMs and suppliers when considering power supplies.

In 2005, with the guidance of the Institute of Printed Circuits (IPC), a group of leading Telecom OEM and Power Electronics professionals collaborated to establish a set of shared requirements for power conversion devices. These efforts culminated in the formulation of "Requirements for Power Conversion Devices for the Computer and Telecommunications Industries" which by the end of 2008 materialized as the so-called standard IPC9592. The document included guidelines for Design for Reliability, Design and Qualification Testing, and Quality Process and Manufacturing Conformance Testing (figure 01). With consideration for additional parameters, in 2010 the IPC9592A was released, followed in November 2012 by the IPC9592B.

Figure 01 – The four main sections of the IPC-9592 (Source: PRBX)

Several power supplies companies are using in part or all of the IPC9592B standard but as many new technologies and market conditions have taken place over the last decade or more; e.g., Digital Control Technics, Wide Band Gap (WBG) semiconductors, and Cyber-resilience, naturally users now consider that the standard might need to be updated. Working groups such as the Power Sources Manufacturers Association (PSMA) Reliability Committee have initiated activities to restart this process which as at its origin will involve many experts from multiple disciplines.

It is difficult to predict when the next revision will be released but until then and in complement to the IPC9592B, power supplies manufacturers developing products for demanding applications are working in close collaboration with semiconductor manufacturers, and they are also conducting their own WBG component evaluations as specified by the JEDEC standard.

JEDEC and JC-70
With a long history starting in 1924 by the establishment of the Radio Manufacturers Association, by combining one council for both tubes and semiconductors, in 1958 the organization was renamed the Joint Electron Device Engineering Council (JEDEC). JEDEC has been the reference in the semiconductors industry and with the development of new technologies, in 2017 the JC-70 committee for Wide Bandgap Power Electronic Conversion Semiconductors was formed, along with two subcommittees: Gallium Nitride (GaN) and Silicon Carbide (SiC). In 2019 the JC-70 published its first document: JEP173: Dynamic On-Resistance Test Method Guidelines for GaN HEMT Based Power Conversion Devices. Since then, the JC-70 has published several documents such as the JEP198: Guideline for Reverse Bias Reliability Evaluation Procedures for Gallium Nitride Power Conversion Devices, which is used as a reference when qualifying GaN semiconductors.

JEDEC standards for WBG are for sure important for semiconductors manufacturers but also for power supplies manufacturers as part of their new products development process and understanding of the reliability mechanisms related to that technology.

Demanding applications such as ruggedized industrial or space are extremely concerned by how power supplies manufacturers are qualifying new components and are requiring them to perform individual tests at component level based on the JEDEC standard, which requires a close collaboration with semiconductor manufacturers of a certain level of expertise in that area.

Building Confidence: EPC's Reliability Validation
As we have presented, adopting a new technology is very challenging and despite GaN transistors having been used in power amplifiers for a long time, the implementation of that technology to power electronics raises a lot of concern, requiring specific effort by the semiconductor manufacturers to demonstrate not only the benefits, but also to prove the long-term reliability of that technology.

Figure 02 – EPC2045 GaN RDS(on) shift versus input voltage and temperature, extracted from EPC GaN reliability and lifetime projection: Phase 17. (Source: With courtesy of Efficient Power Conversion (EPC))

In that respect, it's worth mentioning Efficient Power Conversion (EPC) which developed GaN semiconductors in a very innovative packaging when GaN power semiconductors were considered by many as a concept.

From its inception in 2007, to overcome skepticism EPC has conducted extensive reliability studies to validate device performance. The EPC's test programs included high-voltage bias stress, temperature cycling, power cycling, and accelerated life testing. These studies showed that GaN devices, when properly designed and integrated, can not only meet but exceed the reliability benchmarks established by silicon, which have been presented at conferences such as the Applied Power Electronics Conference (APEC).

Figure 03 – EPC2212 lifetime calculation and verification, extracted from EPC GaN reliability and lifetime projection: Phase 17. (Source: With courtesy of Efficient Power Conversion (EPC))

Experimental results are interesting but equally important, EPC has published its findings openly, helping to create a foundation of trust and understanding of GaN technology. From Phase One released in 2019 to Phase Seventeen released in 2025, the test data shows that failure mechanisms in GaN are well understood and manageable, and that degradation is predictable over time, both being essential traits for designers to strongly consider when ensuring mission-critical operation (Figure 02, 03).

Figure 04 – 1000 hours High Temperature Reverse Bias reliability (HTRB), Ambient temperature 150°C and 650VDds (Source: PRBX/COSEL).

This type of third-party validation is crucial to driving broader acceptance. It bridges the gap between theoretical advantages and real-world deployment, particularly for engineers responsible for long-life systems.

COSEL: Applying GaN to Deliver Compact, Efficient Solutions
Established in Japan since 1969, the power supply manufacturer COSEL has been through the long chain of technology evolution and has been one of the pioneers in adopting switching power conversion and launching a range of commercial, Switch Mode Power Supplies, products in 1977. As we all know Japanese manufacturers have been the reference in developing quality best practices and so it's no surprise that when a new technology such as GaN emerged that they considered reliability first, before any technical benefit.

When qualifying GaN semiconductors for a new generation of power supplies, Cosel performed several tests such as High Temperature Reverse Bias reliability (HTRB). The High HTRB test is one of the most common reliability tests for power devices. Because HTRB tests stress the die, they can lead to junction leakage. There can also be parametric changes resulting from the release of ionic impurities onto the die surface, from either the package or the die itself. During an HTRB test the device samples are stressed, usually to 80 or 100% of repetitive peak reverse voltage (VRRM), at an ambient temperature close to their maximum rated junction temperature (TJMAX) over an extended period, usually 1,000 hours. (Figure 04). Then once the GaN power transistor has qualified and integrated into the power-stage of the power supply, a 1000 hours aging test has been performed to verify thermal stability. (Figure 05).

Figure 05 – 1000 hours aging test to verify the temperature stability (Source: PRBX/COSEL).

Figure 06 – COSEL TE series powered with GaN transistors and short-loop integrated transformers (Source: PRBX/COSEL).

The result is a new generation of power supplies that set benchmarks for performance, density, and reliability. In their latest research, COSEL demonstrated that by carefully co-designing the magnetic, control, and switching stages, power systems can achieve breakthrough levels of power density while maintaining stringent EMI and thermal targets (Figure 06).

Inspiring the Next Generation
What excites me most is the enthusiasm and innovation being driven by the next generation of engineers. Today's young designers are learning about GaN, SiC, and digital control as core elements of their engineering education. They're entering the field not with hesitation, but with a spirit of exploration.

They see power electronics not as a static discipline, but as a platform for invention where materials, control theory, packaging, and systems thinking all converge. And their openness to new technologies will be the catalyst for tomorrow's breakthroughs.

Even now, the industry is looking beyond GaN to diamond-based semiconductors which offer extraordinary thermal and electrical properties. While diamond devices remain in early research stages, their potential to redefine high-voltage, high-frequency conversion is enormous. This is not science fiction; this is where power electronics is headed.

Conclusion: The Opportunity Ahead
The adoption of GaN and other WBG technologies is more than a shift in materials, it's a shift in mindset. It requires embracing faster switching, smarter control, and tighter integration. It challenges power designers to break old habits and develop new skills. And it opens the door to efficiencies and capabilities that were previously out of reach.

Thanks to companies like EPC and COSEL, we are beginning to see the tangible impact of GaN in the real-world for demanding applications. Their work validates the technology, reduces the learning curve, and gives power designers the tools they need to succeed.

As someone who has seen several waves of innovation in this field, I believe we are at the beginning of one of the most exciting chapters yet. The technologies are here, the data is encouraging, and the new generation of engineers are ready to take the lead.

The future of power electronics is not just brighter, it's smaller, cooler, faster, and far more efficient. From GaN to diamond, the possibilities are limitless.

Provided by Patrick Le Fèvre Chief Marketing and Communications Officer, Powerbox

SMA awarded its first Global Energy Efficiency Award at APEC 2025 in Atlanta, GA to Pulsiv for its 65W USB-C design. Congratulations to Pulsiv for adopting leading technology (such as GaN switches and AI optimized custom magnetics) for its energy efficient design! PSMA recognizes Pulsiv for energy efficiency excellence and hopes that this will inspire others to innovate. For more details on the finalists, see the previous newsletter article here: https://www.psma.com/HTML/newsletter/Q4_2024/page4.html. To see the award presentation, go here: https://vimeo.com/1068157216/8e93e00870?ts=0&share=copy.

Nominations are now open for the 2nd Global Energy Efficiency Award at APEC 2026 in San Antonio, TX until September 2, 2025. PSMA members should take the lead to nominate any of its customers that have interesting energy efficient systems, although the award is open to nominations from anyone. For more details and to enter nominations, go here: https://www.psma.com/technical-forums/energy-management/energy-efficiency-award. Together we can raise the bar on energy efficiency! Furthermore, each member can nominate more than one.

The biggest criterion is the global impact of energy efficiency which translates to energy savings. This means that both large high power industrial systems which constantly run all day, every day, or small (but pervasive) low power systems are candidates for this energy efficiency award.

Questions? Email power@psma.com.

David Chen
Ada Cheng

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