Path: csiph.com!feeder.erje.net!2.us.feeder.erje.net!news.glorb.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!spln!extra.newsguy.com!newsp.newsguy.com!drn From: Winfield Hill Newsgroups: sci.electronics.design Subject: Re: 5 to 10kV rated gate transformers Date: 2 Jun 2017 08:44:20 -0700 Organization: Rowland Institute Lines: 35 Message-ID: References: <592f1e94$0$8852$426a74cc@news.free.fr> <309fdaf8-1982-42da-95ef-792a528f3843@googlegroups.com> NNTP-Posting-Host: pce2cb3c8cdd41ba2f1414324e6111c467bfa3e93982fe0e0.newsdawg.com User-Agent: Direct Read News 5.60 X-Received-Bytes: 1808 X-Received-Body-CRC: 1500802983 Xref: csiph.com sci.electronics.design:462681 habib wrote... > Joerg wrote... >> >> I think Win meant regular transformers although >> he'll probably be open to PCB versions. > not on standard transfomer products but they > can do it on custom spec. I wrote earlier that I'm evaluating CM chokes. "I settled on a Panasonic ELF-21C023A. It has Lm = 1.7mH, Ll = 40uH and Rcoil = 0.08 ohms. An 100kHz H-bridge running from 24V, with 1N5819 Schottky bridge rectifier, makes a 24.5V output, into 5mA load, 23.6V at 25mA, according to SPICE, for +20,-4V SiC drive. The magnetizing current (discharge / charge the bulk cap) is 66mA p-p. [not bad] My next step, play with potting and a month-long 2x overvoltage test at 10kV." https://www.digikey.com/products/en?keywords=ELF-21C023A I'm preparing the potting fixture now. That will make this a custom transformer. :-) The Panasonic transformer looks well suited, with thick bobbin insulating plastic, and generous room for further insulation through potting. Only need to handle 2.5kV to the ferrite core. Another parameter, the coil-coil capacitance is under 2pF. Amazing, I had budgeted to 10pF. -- Thanks, - Win