# Equivalent turns ratio of parallel connected transformer windings

#### SiCEngineer

Joined May 22, 2019
444
I am designing a planar transformer and have a primary winding current requirement of 10A. The required trace width for the planar winding is too large for the winding window of the chosen core. I therefore think the best method is to use two parallel connected planar windings which each have about 5A of current when connected in parallel and interleaved.

Issue is in my simulation. Instead of having a single 4-turn winding, I instead connected two 8-turn windings in parallel. It was my assumption that to connect a transformer in parallel and get the same transformation ratio, the number of turns must be doubled. Similar to how it is halved if two are connected in series.

Is there something flawed in my thinking? Why is my transformer delivering almost half the voltage/current/power with 2x8 turns in parallel compared to a single 4x winding?

#### AlbertHall

Joined Jun 4, 2014
12,385
Probably because it should be 2 four turn windings in parallel.