I plan on making a power supply that has isolated outputs by charging capacitors in a sequence. The problem is, I want to have the lowest switching rate possible for 5-10% deviation from 15v. For a 2200uF capacitor, what frequency should I switch it at for a constant 5A draw? And how can I caclulate this>
Is there any way I can do some of that on a wire wrap board? PCBs are to expensive. I can connect all grounds only in one place, put caps everywhere, and I can isolate supplies. I can also surround the board with grounded sheet metal, if that will help, and the adc will be on a board all of its own. I may need help with the inductor/ capacitor values, especially at the input filters.
I am very experienced with digital circuitry, (7400 logic, not microcontrollers, cpld, fpga, etc.) I am in the U.S., but for some reason I thought it was digikey that cost a ton for shipping. I plan on making a portable storage oscilloscope, terminal, logic analyzer, waveform generator, and any other measurement tools/pong I can program into it.
Where can I find aAD9223ARZ for $15? Everywhere I looked sold it for $30 or more, or had extreme shipping costs. Also, will a wire wrapped board be sufficient and is there anything I need to consider as far as power supply noise, or input filtering?
Does anybody know of a 12-16 bit DIP ADC with two channels and a one megahertz sample rate or one channel and a two megahertz sample rate? I also need a parallel interface, or at least be able to get half of its data at a time.
Heathkid, you can just ask for a link if there is a specific item you previously saw that you want. I will post links for any other things I post here now as well.
I really like capacitor isolation, just make sure your turn-on times are shorter than your turn-off times, which they usually are not, and that will cause lots of shorts. I still think a relay is your best bet.
Now I see the problem, that picture helped a lot. You could use a relay to switch from series to parallel while charging, which would not consume battery power if done right. A 1:1 transformer would work, so would individually switching power and ground to capacitors at a very high frequency. I have had success with capacitor isolation, and it might be cheaper than transformers (I have no idea how much they cost, I never use them). a relay would probably be your best bet as far as cost, size, and convenience.
All that he needed was isolated supplies to power proper charging circuitry. I don't know anything about charging batteries, he just said he needed a constant current supply and that's what I gave him. Although I am still not sure why the chargers need to be isolated? would a picture be possible?
