DC-DC Converter Design

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Greg

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Jun 7, 2004
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I was asked by a film mixer (not sure of the exact title) to build him a pair of Neve-ish preamps. Since he's working on site, he said his input voltage will be between 11-16VDC. I'm going to need 24V and 48V for the preamp and phantom. I'll need some type of step-up DC-DC converter. Can someone help me out a little and point me in the right direction?

I looked at some "pre-made" DC-DC converters, but they didn't seem to be exactly what I'm looking for. Is there an IC out there that I could use to implement this?

I've never had to do this before so I'm swimming a bit...

Thanks.
 
[quote author="Greg"]I was asked by a film mixer (not sure of the exact title) to build him a pair of Neve-ish preamps. Since he's working on site, he said his input voltage will be between 11-16VDC. I'm going to need 24V and 48V for the preamp and phantom. I'll need some type of step-up DC-DC converter. Can someone help me out a little and point me in the right direction?

I looked at some "pre-made" DC-DC converters, but they didn't seem to be exactly what I'm looking for. Is there an IC out there that I could use to implement this?

I've never had to do this before so I'm swimming a bit...

Thanks.[/quote]
Most IC mfrs. making switching regulator chips offer cookbook application notes. While not trivial these are pretty well detailed. You want to keep critical high current paths around the switcher short to control noise. They will often show preferred layouts for critical components in the more comprehensive app notes.

Since the phantom supply is low current you could consider piggy backing a cap doubler/tripler on the primary switcher square wave to get above 48V and then use a simple pass element to realize clean 48V. I did this in a digital product with only one mic input, using a few smt .1uf caps and small signal diodes and it got the job done smaller and cheaper than a mains frequency doubler.

JR
 
Not that I have anything against building power supplies but you might want to look at this module:

Meanwell DKE15 Series - Model DKE15A-24

Input: 9-18VDC Ouput +- 24VDC at 300Ma.

Output is fully isolated so you could use a second one for +48VDC.

Jameco has them for $33 ea. Part# 213292PS
 
[quote author="burdij"]Not that I have anything against building power supplies but you might want to look at this module:

Meanwell DKE15 Series - Model DKE15A-24

Input: 9-18VDC Ouput +- 24VDC at 300Ma.

Output is fully isolated so you could use a second one for +48VDC.

Jameco has them for $33 ea. Part# 213292PS[/quote]

Amen... for a one off if you can buy rather than build, why re-invent the wheel.

JR
 
Thanks for the info. I'll check them out. The 300mA might not be enough, but I'll see.

This will completely be a one off... I'm not hell bent on building from scratch.
 
I just did a similar wattage closed loop boost supply for about $4.50, but thats 1K pricing and the output filter was a few less parts than you'd need. How many of these are you making, just two?
-Mike
 
I'm making one unit... inside will be a 2 channel 1272-ish preamp with a couple features i.e. LED metering, PPP, and a dual output so he can feed two different devices.
 
Yeah, it might not be cost effective for you to make just one, but if you want to learn a little more, check out either the TI TL5001 or the TI UC1843...
 
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