I just ordered a couple samples of the MAX628 from Maxim. The 628 and TSC428 are both in current production, but the 628 was available in a DIP package as a sample, hence my choice. Since my PIC coding skills are novice at best, I'm planning on trying a 555 oscillator to drive the 628. Since the the chip is inverting / non-inverting at its outputs, I'll try tying the input pins together. I want to series connect 6 IV22 filaments and see how this chip will do at driving them. The rest of the clock will be TTL based with driver transistors to supply about 24 volts to the segments and grids.
Joe, N6DGY On Dec 18 2011, 6:46 pm, John Rehwinkel <[email protected]> wrote: > > I am interested in building a IV-11 clock from scratch, and have Maxim > > 1771s, inductors around 1000 uH, and IRFD220s on hand but am open to > > ordering whatever parts I need. I'm most interested in solutions for > > generating the grid voltage, but ideally am looking for a nice circuit for > > both grid and filament. > > An approach other than an inductor based one is a driver and a voltage > multiplier. This was one of the example uses for the LM9022 (click on the > data sheet link for more details): > > http://www.national.com/opf/LM/LM9022.html#Overview > > Alas, the LM9022 is obsolete, but our own Konstantin has found a possible > replacement in the MAX628, now known as the TSC428, a chip designed for FET > gate drive, but basically two power amplifiers in an 8-pin DIP. You need an > external clock (unlike the LM9022), but pretty much any oscillator circuit > will do, a 555, a couple of transistors, or a logic chip rigged as an > oscillator. It could also be driven with a microcontroller pin, but that's > not the approach you're interested in. > > This lashup appeals to me - it gives real AC filament drive and grid/anode > supply with one chip, doesn't require magnetics, or high speed diodes > (1N914s will work fine) and is fairly insensitive to layout - you can > construct it on a solderless breadboard and it will work. > > Alternatively, you could lash up a cheap and common (you can get one at Radio > Shack if you're in the states) LM386 as a power oscillator (circuit is in the > data sheet) and use that and a voltage multiplier for the anode/grid supply. > It's less help with the filament supply, but a single 8-pin DIP is an > appealing solution. > > - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
