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davenn
Moderator
and what is the load ?
current drawn is determined by the load resistance
5V x 12A = 60W
You will probably need a Switch-mode Power supply.
There are more details needed.
1.What is the noise level allowed on the 5V.
2.P.S regulation parameters (i.e. how stable is the 5v).
3.How is the heat from the P.S be dissipated
Will one of these do?
Edit:
They are about 30cm height,though that seller doesn't advertise it.
Need to contact him about that.
There are more details needed.
1.What is the noise level allowed on the 5V.
2.P.S regulation parameters (i.e. how stable is the 5v).
3.How is the heat from the P.S be dissipated
Will one of these do?
Edit:
They are about 30cm height,though that seller doesn't advertise it.
Need to contact him about that.
Last edited:
Sorry guys I'm not trying to be insulting by being secretive. I'm working on a new idea.
Dorke, I did see those and similar units while researching. They might be a good option. My worry is voltage drop / ripple / bad power generally. Part of the load is a microcontroller that is adversely affected by bad power.
What does everyone think about using a higher voltage switch-mode PS (say 12v) and several L78S05 in parallel? Does that make sense?
Or would I be better off filtering that 5v psu, say with some substantial caps/whateve else is needed.
Dorke, I did see those and similar units while researching. They might be a good option. My worry is voltage drop / ripple / bad power generally. Part of the load is a microcontroller that is adversely affected by bad power.
What does everyone think about using a higher voltage switch-mode PS (say 12v) and several L78S05 in parallel? Does that make sense?
Or would I be better off filtering that 5v psu, say with some substantial caps/whateve else is needed.
Last edited:
I'm looking at the Mean Well LPV-100-5.
Seems like a decent quality unit and will fit with some space to spare.
Datasheet: http://www.meanwell.com/mw_search/lpv-100/LPV-100-SPEC.PDF
Seems like a decent quality unit and will fit with some space to spare.
Datasheet: http://www.meanwell.com/mw_search/lpv-100/LPV-100-SPEC.PDF
great
a solution
I think it is a bad solution...
VOLTAGE TOLERANCE ±8% , i.e. nearly useless in my book
davenn
Moderator
I think it is a bad solution...
VOLTAGE TOLERANCE ±8% , i.e. nearly useless in my book
well I never said it was a good solution hahaha
OK. So maybe it's not figured out yet then. I'm certainly still open to suggestions.
Dorke: the board has its own 3.3 regulator, so 4.6v (5v @ 92%) is still sufficient there. Ripple & noise is what I'm most concerned about here.
I understand a substantial cap (bigger the better, yeah?) will filter out a lot of the ripple, but I'm less clear on how how to reduce noise.
Dorke: the board has its own 3.3 regulator, so 4.6v (5v @ 92%) is still sufficient there. Ripple & noise is what I'm most concerned about here.
I understand a substantial cap (bigger the better, yeah?) will filter out a lot of the ripple, but I'm less clear on how how to reduce noise.
OK I didn't know that. I understood ripple and noise to be two different things. I though ripple was repeating pulses from the power supply (like when rectifying AC to DC) as part of the waveform, and that noise was like random spikes here and there caused by the way switch mode PSU's work.
I understood why rectified AC produces ripples, but I didn't understand that noise is the same thing, this is just stuff I've read and am regurgitating.
Anyway....now that I know its the same thing, do you have any capacitor type/sizing recommendations? Am I wrong in thinking bigger is better in this case?
I understood why rectified AC produces ripples, but I didn't understand that noise is the same thing, this is just stuff I've read and am regurgitating.
Anyway....now that I know its the same thing, do you have any capacitor type/sizing recommendations? Am I wrong in thinking bigger is better in this case?
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Well you see,
You do need to totally specify the requirements of the P.S ,
otherwise the solution you will get to will be far from optimal in terms of cost/space/efficiency/reliability/performance etc.
So Lets start from the beginning,shall we?
.
1. What is it "driving"?
(as you now say,
the voltage is converted to 3.3V by a regulator,which one?,
any other like this?).
2. What is the min and max voltage swing allowed?
3. What is the current you need(min and max?
4 .What is the space you have for it (LxWxH).
5. What is the noise and ripple levels allowed?
6. Any safety regulations requirements?
7. Heat dissipation issues?
