In high-current, multi-phase buck parallel applications such as AI servers and GPU power supplies, tiny resistance mismatches between phases are amplified by large operating currents, resulting in phase current imbalance. Inductors on certain phases will overheat prematurely as they carry excessive current.
SYNYON reminder: When evaluating inductor DC resistance, do not rely solely on the typical 25 °C (room temperature) values listed on the datasheet. Multi-phase parallel designs impose stringent requirements on lot-to-lot consistency of inductors.
Design and Selection Recommendations
Evaluate true DCR at elevated temperatures: The resistivity of copper rises significantly with temperature. During component selection, request SYNYON’s actual DCR data at the system’s maximum operating temperature, and use these values to calculate copper loss and overall temperature rise.
Tighten tolerance for reliable current sharing: Chasing an ultra-low room-temperature DCR alone often comes with looser tolerance, which creates risks for multi-phase parallel implementations. Leveraging advanced manufacturing processes and magnetic powder formulations, SYNYON maintains tightly controlled DCR tolerance (e.g., ±5% or even ±3%). We recommend customers specify resistance consistency as a key requirement in technical agreements. SYNYON can provide within-lot SPC (Statistical Process Control) data to robustly support the active current-sharing algorithm of the customer’s VRM controller.