Does anyone have experience using any of the Buck regulator ICs available?

I'm interested in using something like the 1 amp' Micrel MIC4575 and the 3 amp' MIC4576 devices for distributing "cool" regulation along the length of a signboard matrix of 8x8 LED modules.

I'd also like to design and build a miniature plug-in 7805 replacement like the one Futz showed us recently for my assorted projects. I'm hoping I can build a few of them for much less then the $14-$18 price tag of the manufactured units.

My questions concern sourcing low esr capacitors and low profile power inductors.

Mike

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I have used the MC33167. It's cheap and can be configured as buck or buck/boost. I am using it for a 12 to 28 volt supply at 5 A with no problems. Do need heat sink. John

Edit: Had to get it from Mouser.

 

hi Mike,
I have used the LT1074CT and the LM2577ADJ switchers, with no problems.

Why are you asking.?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
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Hi Eric and jpanhalt,

My questions concern sourcing low esr capacitors and low profile power inductors. I'd like to make these as small as possible while still running 'cool' at 1 amp.

Mike

 

Gotcha.

Low ESR:
http://uk.farnell.com/jsp/search/bro...questid=234645

68uH:
http://uk.farnell.com/jsp/search/bro...questid=234723

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Based on my experience, the MC33167 should be barely warm at 1A. I get by without one at 3A and resistive load. It is warm, but not real hot. John

 

Hi John,

Did you use the TO-220 package with heat sink or mounted to PCB? Or, did you use D2PAK with certain number of square millimeter copper sink area?

Mike

 

Eric,

Thanks for info'. I'll look for some of those parts at Mouser here in the states.

Mike

 

I used the TO-220 case mounted vertically and a small, individual heatsink to conserve space. John

 

Ok, I think I'm all set guys.

I've found the four parts I need to build and test a through hole version of the 5 volt 1 amp' regulator for about $2.95 at Mouser (two low-ESR caps', Schottky diode, and 68 uh power inductor).

Thanks guys...

Mike

 

Also from mouser, 1.5A buck switcher from STM, L4962/A. Works pretty good, but ended up with giant low esr electrolytics and torroid inductor, and little under $10 in parts. Mind sharing your choices for caps and inductor? Thanks.

 

If I understand correctly the 200 KHz switching frequency allows us to use smaller inductors and capacitors but layout and connections becomes critically important. MIC4575 Data Sheet


I wanted capacitors which were physically the same size so I modified the values a bit. Capacitance values are a bit higher but the input voltage is reduced to a maximum of about 20 volts. I'm hoping this will be fine for the laptop power bricks I use on my projects, none of which are more then 16 volts output.

Here's what I think I'd like to order unless you folks have other suggestions/considerations;

Mike

 

hi Mike,
Whats the 'dc' resistance of the L1 68µH inductor.?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Hi Eric,

Data Sheet says 0.07 ohms.

 

That sounds OK, reason for asking is that some of the smaller inductors can have a highish resistance,
which you dont want in a swpsu.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/