The Hidden Engineering Problem: Leakage Current
Leakage current is probably the most misunderstood topic in power adapter design.
Every switching power supply has some amount of capacitive coupling between the primary and secondary side.
That’s unavoidable.
The question is:
How much of that current reaches the output—and potentially the patient?
In consumer electronics, a slight tingling sensation may be annoying.
In medical devices, even microamp-level leakage can matter.
That creates a difficult engineering tradeoff:
• Larger Y capacitors → better EMI performance
• Smaller Y capacitors → lower leakage current
Medical adapter engineers constantly balance:
✔ EMC compliance
✔ Conducted emissions
✔ Radiated emissions
✔ Patient leakage limits
Sometimes transformer winding structures are redesigned multiple times just to reduce leakage by a few microamps.
That’s why genuine medical power supply development takes significantly longer than standard ICT adapters.
Posted May 12, 2026, 2:53 PM UTC