View Full Version : What topology is this and how does the driver work?

08-01-2019, 05:18 AM
I've been trying to repair and reverse engineer a welding inverter and came across some interesting circuitry.
It uses the UC3845 control chip and a low-high side driver L6386. Since the UC has a single ended output connected to both inputs of the driver chip, it makes me think that it's a two-switch forward/flyback topology. But it would be interesting to see how they can drive both transistors, especially the high side one, without a gate transformer.
I managed to find a schematic from another welder which is similar to what I found in mine, it is attached below.

08-01-2019, 05:50 AM
please check this http://valvolodin.narod.ru/schems/repgysmi183.pdf

08-01-2019, 06:32 AM
cek also this appnote https://www.st.com/content/ccc/resource/technical/document/application_note/5c/00/05/fd/e5/65/46/97/CD00004008.pdf/files/CD00004008.pdf/jcr:content/translations/en.CD00004008.pdf70067007