High power LLC converters often end up with an awkward magnetic problem. The transformer handles the energy transfer, but the resonant inductor sits somewhere else on the board, taking up space and quietly complicating the layout. At a few kilowatts this becomes difficult to ignore. Power density is already tight, thermal margins are narrow, and every magnetic component seems to claim more board area than expected. The PTLA / PTLC Series from YAGEO approaches this constraint from inside the transformer itself rather than adding another part around it.
Turning Leakage Inductance Into A Design Tool
Leakage inductance in a transformer is normally something engineers try to suppress. In LLC converters it behaves differently. The resonant tank actually depends on inductance in the system, which means the leakage field inside a transformer can become useful rather than problematic.
The PTLA / PTLC Series intentionally shapes its magnetic structure so that approximately 6.4 µH of controlled leakage inductance appears on the primary side. Instead of fighting that behavior, the design makes the inductance available to the resonant circuit itself. That means the resonant tank no longer requires a separate external inductor.
Once that inductor disappears from the schematic, the surrounding design changes slightly. One less magnetic component reduces the overall magnetic count, lowers cost, and frees PCB space that normally ends up occupied by bulky inductors. Engineers pushing dense power stages will recognize the value immediately when the layout phase begins.
A 3.6 kW Transformer In A Compact Magnetic Package
The PTLA / PTLC Series is aimed at converters operating in the multi kilowatt range, delivering up to 3.6 kW while maintaining a compact magnetic footprint. The transformer measures roughly 53 × 52 × 43 mm, which is small for a component carrying this level of power.
Open circuit inductance is specified around 42.4 µH, while the intentionally controlled 6.4 µH leakage inductance becomes part of the resonant network. Isolation is rated at 4.2 kVrms with basic insulation, and the structure maintains approximately 5 mm of creepage and clearance distance. Those numbers matter because high voltage isolation often dictates the physical geometry of magnetics in power supplies.
In practice, transformers operating at these power levels often dominate the mechanical layout of the converter. When part of the resonant network is absorbed into the transformer itself, the surrounding magnetic ecosystem becomes slightly simpler.
Automated Winding And Automotive-Oriented Reliability
Magnetic components have always depended heavily on winding consistency. Small variations in spacing or placement can change leakage behavior, which in turn affects converter performance. The PTLA / PTLC Series uses fully automated winding processes to improve repeatability across production units.
The design is aligned with IATF requirements and compatible with AEC Q200 qualification expectations. That places the transformer family within reach of automotive and transportation applications where component reliability requirements are considerably stricter than typical industrial electronics. Material compliance follows modern manufacturing expectations as well, with support for RoHS, REACH, and halogen free requirements.
Where High Power LLC Designs Are Heading
Power architectures across several industries are moving toward higher density conversion stages. Electric vehicle charging, AI computing infrastructure, large data servers, telecom power systems, and intermediate bus converters all continue pushing power levels upward while available board space shrinks.
The PTLA / PTLC Series reflects this shift by treating the transformer as part of the resonant structure rather than a standalone magnetic element. Integrating the resonant inductance directly into the transformer changes how the LLC stage is built and simplifies the surrounding component set. That sort of integration usually becomes most noticeable during layout and validation. When the board is already crowded and the thermal budget is tight, removing even a single magnetic component can make the difference between a clean design and a long debugging session.
Learn more and read the original announcement at www.yageo.com
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