That's cool, I had considering using a switching supply on a previous project and the barrier was cost. I though perhaps the cost had changed since then.
PropController Ethernet - Construction question
- Thread starter Matt_Edwards
- Start date
That's cool, I had considering using a switching supply on a previous project and the barrier was cost. I though perhaps the cost had changed since then.
budude
Active member
True enough it would add some cost, but as I said before, most folks aren't going to have 10-12 PropControllers - more like 1 or 2 so the extra cost can be spread out over the total channel count. You would also be increasing the reliability of it as well since the parts would be running cooler and more efficiently.
Matt_Edwards
New member
Has anyone done any current measurements yet of the 5v and 3.3 regs?
How much current needs to be considered for J1, J2, J3, J4 and J5?
I support Brian's comment, making the regs run cooler has to be better for reliability.
How does ~$2 for a LM2576-005 and ~$4 for a 100uH 3A inductor, $1 for a 1000uF and 70c for a LM1117-3.3 compare to the overall cost of the finished board?
Adding $8 for a switching reg and a LDO reg or $14 for 2x switching regs is not unreasonable.
How much current needs to be considered for J1, J2, J3, J4 and J5?
I support Brian's comment, making the regs run cooler has to be better for reliability.
How does ~$2 for a LM2576-005 and ~$4 for a 100uH 3A inductor, $1 for a 1000uF and 70c for a LM1117-3.3 compare to the overall cost of the finished board?
Adding $8 for a switching reg and a LDO reg or $14 for 2x switching regs is not unreasonable.
chilloutdocdoc
New member
Considering these changes would be for a Rev 2 board... has anybody considered using a regulated 5V supply on the input, and anything that requires an AC zero crossing signal can have the required H1 chip onboard?
(Something similar to http://www.sparkfun.com/products/8269) This wouldn't be all that expensive considering you already need to spend about that much on a 6-9V ac supply anyway.
Josh
(Something similar to http://www.sparkfun.com/products/8269) This wouldn't be all that expensive considering you already need to spend about that much on a 6-9V ac supply anyway.
Josh
pmscientist
New member
It may be even less of a difference than that. Since the two regulators spec'd now run about $3 total, the total increase would only be about $5 per unit for a switching+LDO combination. Unless I'm double subtracting the existing regulators, which has been known to happen
This seems a good option for an on-board supply.Personally, this is an option I really like. I suspect many people working with RGB pixels probably would as well, as they'll have regulated DC power already available. Only a 3.3V regulator would be necessary, and since there would be virtually no AC current requirement, one could use a really cheap wall wart as the AC source for the ZC signal. For me, this would save a few bucks, as I don't have a 9-12VAC supply w/1A capacity, though I have 4 or 5 in the 250mA to 800mA range.
I'm fairly certain the main board is the best location for the ZC signal. While it certainly could be implemented at the daughter board level, it's simpler to implement it once, and then use it as many times as necessary. If you don't need it at all, the line is already tied high via R8 and the part can be omitted.
It appears that using a DC supply is doable now by dropping out the diodes and wiring regulated 5-12V power in directly. If a 5V source is used, pins 1 and 3 of the 5V regulator could be wired together in place of the regulator. The A/C would remain wired as designed, it just wouldn't have the same current requirements.
Are those correct assumptions? If so, I'll wire up one of mine this way and see how it goes.
As a dev platform, it seems like an on board supply is a good thing to have. Although it would be nice to have a place to solder on some terminals for an external DC supply. A jumper to bypass the 5V reg if it's not needed might be nice, tho soldering a wire there is just as good really. It seems like there's plenty of board space to add this without increasing the footprint.
chilloutdocdoc
New member
WooHoo! One less Transformer I need in my show!
chilloutdocdoc
New member
Question, what way does the DC get plugged in? Where gets + and where gets -? Rather ask then be stupid and blow up a controller
Matt_Edwards
New member
Well pull out D1 to D4, & place a wire link in D1 and D4, the "+" for C1 then indicates "+" for J12 too!
pmscientist
New member
Maybe this would be a set of refinements to revisit after the holidays are over and some experience has been gained. Certainly you've made it plenty flexible enough already to implement various power options without board modification.
Absolutely, I expect that the design will change over time and will be become a springboard for new designs....after all that is the point.