I did some tests with the PA0367 and LT3757 using the datasheet schematic (350V/flyback), regulation was ok but the efficiency was poor, 78% at 5ma/170V with 5V input voltage
Am Mittwoch, 8. Mai 2019 02:18:49 UTC+2 schrieb Richard Arndt: > > I've made several PCB design attempts of a small USB 5v to 170v 1w power > supply for 1x IN-18 or Dalibor R|Z568M using the PA0367 Transformer > <https://media.digikey.com/pdf/Data%20Sheets/Pulse%20PDFs/PA0367A.pdf> and > LT3420 > <https://www.analog.com/media/en/technical-documentation/data-sheets/3420fb.pdf>. > > Initial design would run away into the 300+ volts unloaded with no sign of > regulation when loaded, even though it was set to 170. After some email > advice from Analog Devices looking over my PCB design, paying attention to > ground loops, using copper poors for current wires, and vias connecting > top/bottom ground planes, my third attempt regulated @170v to 1ma, but > required addition of snubber on secondary. It would fall out of regulation > quickly after 1ma. I got frustrated, had not ideas left, tossed it into > the scrap box... > > If anyone has ideas on how to resurrect this one, I'd work on it and share > the design. Maybe some of the other transformers would be a better > choice. I'd like a small SMD daughter board design costing maybe $10 to > incorporate into my OneNixie clocks. Of course I can buy them on EBay, but > that's no fun :-) I have been using HV supplies from VFDClock's > <https://vfdclock.jimdo.com/2017/08/03/hv5wekit/>for a few years. They > are quite good! > > Rich > > > > On Thursday, May 2, 2019 at 1:59:20 PM UTC-4, Paul Andrews wrote: >> >> One project I have on the back burner is a very small battery-powered >> nixie display. I thought that a variation of a power supply design that I >> had been using for everything else, would work fine. It turns out that the >> prototype of the power supply, which I had built a few years back, only >> worked because of a dry solder-joint somewhere on the mosfet (yes, I'm >> serious). The version I built specifically for this project quickly had >> everything overheating. When I went back and touched up the soldering on >> the prototype, it showed the same behavior. The culprit, BTW is pretty much >> down to the tiny 1:20 transformer. I have built variations of this design >> with bigger transformers that work very well. >> >> There are a lot of variations of power supply design that I could mess >> with - obviously I have already scoured the internet on this topic - but >> that is the trouble. This project will never get finished if I have to run >> through multiple prototypes trying to find one that is small enough and >> that works. So I was wondering if anyone could just say 'use this design'. >> >> The constraints are: >> >> 1. It has to fit on a circular PCB the same diameter as the tube or >> less (about 17mm). >> 2. It has to provide around 150V-160V regulated output, or maybe just >> 'limited' output. >> 3. It only has to provide 1.5mA to 2mA. >> 4. It has to use a LiPo as the power source, so it should work at >> voltages between around 3.5V and 4.5V. >> 5. It has to use parts I can get from digikey (so no sourcing >> transformers from old cameras that I can't find for example). >> >> Surface mount components are fine... >> > -- 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/759bc4f6-1f86-4122-b5be-9ab1ed1b1d42%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
