Yes, I like using the old MC34063. Its a relatively simple chip. But don't get stuck on the semiconductors. The coil is the main player. And real inductors behave a lot differently than ideal inductors. More so than capacitors and resistors, when comparing the ideal model with the real parts. For power applications, the inductance changes (to a lower value) as current increases. This happens well before the part goes into saturation, so any calculations made, are just a first stab. In reality, you may have to go 2 to 4 times higher, than calculated.
In practical matters I like using coils with E3 values (E3 meaning significant figures of 10, 22 & 47). With the MC34063, I can change base frequency with the timing cap. Smaller caps can be found, cheaply, in a wider range of values (E6 - 10, 15, 22, 33, 47, & 68). E12 or higher only with resistors (E12 - 10,12,15,18,22,27,33,39,47,56,68,82). You can get more power out of an SDR1806, but before going there you aren't get all the power out of the RLB9012. If you can't easily change frequency, then increase the inductor size. Buy some 220uH coils, though you should be able to get more power out of the 100uH part. I routinely get more than 30mA out, at nixie voltages. On Wednesday, November 14, 2018 at 12:24:36 AM UTC-8, Oyvind wrote: > > Hi, > > first: interesting & very useful webpage ! (recognized your nickname). > Appreciate people who share information like that. > > Increasing frequency will only result in maxing out duty cycles. Not sure > if I tested the RLB on >= 60kHz yet though, I'll > give it a go later. > > What frequency are you at, approximately ? > > Assuming you're using the MC34063, I'm not sure how the PWM scheme looks > on that one. Have you tried peeling off > the outer shrink tube on the inductor ? At first I didn't think there was > any significant heat, until I realized the shrink tube > was messing with me. > > Anyways, I found some nice off-the shelf transformers which looks very > promising in simulation, so I'm heading for > flyback. Slightly more expensive though, but not a concern for me. > > > - Oyvind > > >>> -- 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 post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/df6e07fc-cc45-4196-86d4-8c5fef998aaf%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
