On Apr 4, 6:35 pm, jason greskoviak <[email protected]> wrote: | This is based off of a 34063a boost converter with feedback.
Which configuration of the MC4063 ? This chip is used in three common ways. for HV (over 40V) supplies: http://cid-f9db37b8211ce831.office.live.com/self.aspx/Snippets/MC34063.gif Hopefully, you're not using the MK.I incarnation. The MK1.5 & MK.II versions add an active pull-down, which the MK.I does not have. Its important for these fly-back circuits to turn the FET off quickly. That means dumping the charge (Qi) from the FETs gate in short order. With the MK.I, that's only a 330 ohm resistor. A passive pull-down method. The active pull-down of both MK1.5 & MK.II versions dump that gate charge thru a transistor, which is substantially faster than the passive method. I've sold quite a few power supplies, on eBay, using a series of supplies based on the MK1.5 version. Even with Taylor's offerings right there next to them. A couple of fixed 180V versions, I sold mostly on price. I got a bunch of parts cheap thru surplus channels. In particular, a 220uh coil that All Electronics use to carry. I bought over 500 of them, for ~ 20 cents each. They where real gems. I could squeeze 45mA out of them (@180V, 12V in) with efficiency ~80%. All Electronics sold out of those coils over a year ago, and the only coils that spec similarly, cost considerably more. The power FETs I also got on special. I'm very proud of that last supply, since it came pretty close to Taylor's units (though still inferior), but using basically junk parts. I sold hundreds of these. My last supply variant skirted direct competition, by being a dual supply, It output both 180V and 540V, so you could run both nixies and a dekatron at the same time. I just listed a new version, of the dual supply that is adjustable, and uses a beefier coil. V1: 115V-225V, & V2: 230V-450V. Plus I brought out the raw pulse, off of the coil, if you want to multiply the voltage even more, or make a negative voltage. The last dual supply sold quite well (used a different coil). -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
