Forgot to mention that I have tried inductors from 100 - 270 uH range in various frequency combinations. I also simulate stuff, preferably using LTSpice (using TINA on most TI chips due to lack of spice-models).
The inductors were selected to be well above the peak-peak from simulations. Most chips can have the frequency configured easily by replacing a resistor and/or capacitor. My experiments have been in the 40-60 kHz range. On Thu, Nov 15, 2018 at 11:57 PM threeneurons <yumikoch...@gmail.com> wrote: > 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 neonixie-l+unsubscr...@googlegroups.com. > To post to this group, send email to neonixie-l@googlegroups.com. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/df6e07fc-cc45-4196-86d4-8c5fef998aaf%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/df6e07fc-cc45-4196-86d4-8c5fef998aaf%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- 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/CAEVk4t0yb3oeynnSPhccYGd12n4bzOK5vOs9XetgbEv03SsDvg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
