There are a few issues with paralleling supplies that are not explicitly designed for that mode of operation.
Imagine you have two voltage sources in parallel. The smallest difference between the two would cause current to flow from the higher source to the lower source. Depending on the control loop parameters of the DC-DC converter, this could cause it to shut down in an overcurrent condition or oscillate. Even if paralleling the supplies together does not cause issues without a load, once a load is applied, the voltage sag between the two independently controlled DC-DC converters will also differ. So again we have conditions for oscillation or regulation problems. I would recommend using a single supply that meets the total system capacity, or keep the individual supplies isolated. If you want to try paralleling, there are a few schemes you can explore which might work better than direct paralleling. Here is se reading I found on the subject: https://powerctc.com/en/node/4577 On Fri, Aug 19, 2022, 6:28 PM Moses <[email protected]> wrote: > If the voltage from both supplies are about the same and the resistors on > the tubes are the same.. the brightness will be about the same. I don't see > how there would be a difference. > > Regards, > -Moses > > On Friday, August 19, 2022 at 3:12:00 PM UTC-7 [email protected] wrote: > >> Hello, >> >> As mentioned in one of my previous posts, I'm building a nixie clock with >> Dalibor's RZ568M tubes. >> >> The idea is to make the base as thin as possible and to achieve that I am >> using two power supplies, each with a transformer that is about 6mm tall. >> >> If I build a clock with 6 tubes and 2 colons, I can allocate 3 tubes + 1 >> colon to each power supply and the brightness is nicely balanced. >> >> If I build a clock with 4 tubes and 1 colon divider, then I am not sure >> if I should allocate 2 tubes + 1 colon to a power supply and 2 tubes only >> to the other power supply. If I do so, the brightness in the 2 tubes only >> will be different than in the 2 tubes connected to the colon. I could use >> PWM to adjust brightness but let's assume that I just do direct drive with >> no PWM. >> >> I thought, is it possible to put two HVPS in parallel as you'd do with >> the batteries to increase overall current for a higher load? I don't think >> that's possible with DC/DC boost converters as it messes up the voltage on >> the top resistor of the voltage divider/feedback loop. I can always try and >> experiment but wanted to hear any suggestions before frying two power >> supplies. >> >> I have built a larger power supply that can take all 6 Nixies etc but the >> transformer is much taller of course, so I am not using that one. >> >> I could add a third mini power supply just for the colon, but it seems >> overkill to have 3 power supplies! >> >> Any thoughts? >> >> Thanks, as always. >> Max >> > -- > 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 [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/28dc3079-a49a-4fdb-aa23-03ecaaf82037n%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/28dc3079-a49a-4fdb-aa23-03ecaaf82037n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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 [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CALcVLK%2Bffz4mxkPYoNyDgv7XkVNQJz80acydmBr3KNj43T%3DY2g%40mail.gmail.com.
