On 5 maj 2014, at 19:27, John Rehwinkel <jreh...@mac.com> wrote: >> I finished my HV PSU design and decided to share it as open-source hardware, >> for anyone to use >> freely:http://jan.rychter.com/high-voltage-power-supply-for-nixie-tube-projects > > That's a nice bit of work, thank you for sharing it! I'll just offer one > tip: when supporting multiple package > variants and not wanting your schematic to look wonky, make a custom Eagle > part that has a footprint > with the package variants, and use that. A side advantage is that you don't > have to try to overlap parts > to get the arrangement you want, avoiding design rule check errors.
Yes, that's definitely the better approach. But I'm wary of investing too much time into Eagle, as I think it is on its way out (looking forward to switching to KiCad), so I don't want to spend too much time tweaking libraries. >> The supply generates up to 220V from a 12V input. In addition to that, it >> also provides 2*Vout (so, up to 440V, for dekatrons), and two outputs for >> powering digital logic: 5V and 3.3V. The primary HV boost circuit reaches >> 88% efficiency when going from 12V to 185V at 55mA, with a 3% output ripple. > > Those are some useful parameters. That would also make a nice tube/CRT > supply. The 5V output could be > adjusted to 6.3V for heaters, and the doubler could be extended to a tripler > (or more) for CRTs that want more voltage. The regulation, efficiency, and > available current would all be less, but CRTs don't need much current. And this is why making a design public makes sense -- I would never have known! > I really appreciate details like mounting holes! Yes, I'm tired of devices that don't have them, and as a result are only useful as a bench toy. I don't know how people mount the other PSUs I've seen -- cast them in resin? Make rails? Use clips? > [...] > I'd be intereseted if you care to share more details on loop stability or the > parasitic ringing on the switching node and > how to tame it with a snubber. I'd love to, but unfortunately there isn't much to share. The loop stability calculations were done using SwitcherPro. It did require some tweaking, as it wasn't really meant to design a supply like that. I managed to get a decent margin, but I can't be certain of the actual behavior, because: * the output cap plays a role, but isn't easily controllable, especially its ESR, * the design is intended to be used with various inductors and caps. And since I don't have access to a network analyzer, I can't really verify the calculations. All I can see is that I get no oscillations or unstable behavior, and that load transient behavior is nice and clean, in the circuits I've built. As to the snubber, I just went with TI recommendations again -- I don't think I can properly design a snubber with my 100MHz scope. TI has good literature on the topic: http://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=slup100 http://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=slva255 The test points placed on the board should be enough for someone to connect a network analyzer, so perhaps some day this will happen :-) --J. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CB663D74-6DD5-48E9-B4AA-BD7B3E35154E%40gmail.com. For more options, visit https://groups.google.com/d/optout.
