Hello,
TLDR: Need to get 5v/4A DC from 48v DC without introducing problematic noise into the rest of the system.
Sorry if this is an obvious answer, I don't have any experience with DC-DC conversion.
I am planning to use an Eltek Flatpack2 48/2000 HE power supply in my next project. I'll use the can bus to set it to 48v DC output. This will power four tpa3255 class-D two channel amp modules.
As this power supply is overkill for just the amp modules I'd like to use the 48v DC to feed other bits of the system. Namely a miniDSP DDRC-88D (5v DC 2 amps) and several 5v Noctua case fans.
What are my options for converting the 48v DC to 5v DC for a maximum of 3-4 amps.
I'm most concerned with not polluting the DC rails with unwanted noise, not producing audible EM noise and with obtaining a clean 5v for the miniDSP, at least as clean as the cheap wall-wart that came with it!
Cheers
Dave
TLDR: Need to get 5v/4A DC from 48v DC without introducing problematic noise into the rest of the system.
Sorry if this is an obvious answer, I don't have any experience with DC-DC conversion.
I am planning to use an Eltek Flatpack2 48/2000 HE power supply in my next project. I'll use the can bus to set it to 48v DC output. This will power four tpa3255 class-D two channel amp modules.
As this power supply is overkill for just the amp modules I'd like to use the 48v DC to feed other bits of the system. Namely a miniDSP DDRC-88D (5v DC 2 amps) and several 5v Noctua case fans.
What are my options for converting the 48v DC to 5v DC for a maximum of 3-4 amps.
I'm most concerned with not polluting the DC rails with unwanted noise, not producing audible EM noise and with obtaining a clean 5v for the miniDSP, at least as clean as the cheap wall-wart that came with it!
Cheers
Dave
I would consider a buck convertor as use of a linear regulator means getting rid of about 160Watts of heat!
As long as you take some care with shielding and filtering you should be OK with a buck converter.
If the 48V supply is a linear one with a Toroidal transformer depending on the demand on it you may be able to wind another secondary and use that as the basis of another linear DC supply. You’ll need to use the correct gauge enamelled wire and make sure you’re within the VA rating of the transformer.
If the 48V supply is a linear one with a Toroidal transformer depending on the demand on it you may be able to wind another secondary and use that as the basis of another linear DC supply. You’ll need to use the correct gauge enamelled wire and make sure you’re within the VA rating of the transformer.
Thanks for the suggestions. You've convinced me that a buck converter is the right way to go!
The 48v is not linear, no.
I see lots of options on digikey etc for buck converters in the right range. Could you clue me in on isolated vs non-isolated. Also some are advertised as ultra low noise types, is that necessary?
How would you implement the shielding and filtering?
Thanks again.
The 48v is not linear, no.
I see lots of options on digikey etc for buck converters in the right range. Could you clue me in on isolated vs non-isolated. Also some are advertised as ultra low noise types, is that necessary?
How would you implement the shielding and filtering?
Thanks again.
The higher the switching frequency of a converter the less likely it is to generate significant audio noise and the easier it will be to filter the residual noise.
Here you need filtering on the input to the converter, note. Often the datasheet will quote a ripple current reflected to the input which gives some idea of the size of the problem.
Here you need filtering on the input to the converter, note. Often the datasheet will quote a ripple current reflected to the input which gives some idea of the size of the problem.
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