[Amps] 50V FET output transformer

Manfred Mornhinweg manfred at ludens.cl
Wed Jul 23 13:42:51 EDT 2014


> Has anyone built an output transformer for a 50V LDMOS FET (Freescale 
> device) that could lend some help with this?

I have some experience with such transformers. Not specifically with the 
Freescale devices, but that shouldn't matter. Also with 100V supplies.

> By my estimation a 16:1 constructed of (2) 4:1 Guanella?s should give a 
> satisfactory match to 50 ohms.

As long as they are for the correct impedances, yes. Building a Guanella 
transformer for 3.1:12.5 ohm isn't entirely trivial.

> The XFMR I've built currently only gives about 33% efficiency.

Tell me the details of its construction, and I should be able to suggest 
improvements. Most likely the leakage inductance is killing it.


Visit my hobby homepage!

More information about the Amps mailing list