Switchmode benchtop power supply

M

Mark Harriss

Guest
Anyone have recommendations for a benchtop switchmode power supply
curcuit?.

I'd like to build an adjustable unit with 0-24V minimum at 10 Amps
output. It's time I updated my old LM338 based unit with something
that has a bit more current and goes down to zero volts.
 
"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:F6OdnfNvD9b1CtbRnZ2dnUVZ8tKdnZ2d@westnet.com.au...
Anyone have recommendations for a benchtop switchmode power supply
curcuit?.

I'd like to build an adjustable unit with 0-24V minimum at 10 Amps
output. It's time I updated my old LM338 based unit with something
that has a bit more current and goes down to zero volts.
Click to expand...
Maybe the easiest way is to run a blocking oscillator style converter from
the low rails on a PC PSU box..

You can't draw much current from the 12V rails without properly loading the
5V & 3.3V outputs, so there's no alternative to adding some form of
converter.

Making it variable for anything like the range you want might be a bit
harder than a simple BO type converter - maybe someone could offer some
SEPIC designs.
 
On Sun, 25 Jul 2010 20:53:14 +0100, "ian field"
<gangprobing.alien@ntlworld.com> wrote:

"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:F6OdnfNvD9b1CtbRnZ2dnUVZ8tKdnZ2d@westnet.com.au...
Anyone have recommendations for a benchtop switchmode power supply
curcuit?.

I'd like to build an adjustable unit with 0-24V minimum at 10 Amps
output. It's time I updated my old LM338 based unit with something
that has a bit more current and goes down to zero volts.


Maybe the easiest way is to run a blocking oscillator style converter from
the low rails on a PC PSU box..

You can't draw much current from the 12V rails without properly loading the
5V & 3.3V outputs, so there's no alternative to adding some form of
converter.

Making it variable for anything like the range you want might be a bit
harder than a simple BO type converter - maybe someone could offer some
SEPIC designs.


Have a look at this article.
Click to expand...
http://www.qrp4u.de/docs/en/powersupply/

Ive built this , and it works fine, although I only needed 9V to 15 V.
Going down to 0 V and up to 24V @ 10A will be a hard ask for any SMPS
without some exotic transformers and switching Fets.
At very low output voltage but maximum current the transformer ripple
current becomes a major factor, and you must be sure that the
transformer core doesnt saturate, otherwise the switching fets will
blow.
 
Mauried wrote:
On Sun, 25 Jul 2010 20:53:14 +0100, "ian field"
gangprobing.alien@ntlworld.com> wrote:

"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:F6OdnfNvD9b1CtbRnZ2dnUVZ8tKdnZ2d@westnet.com.au...
Anyone have recommendations for a benchtop switchmode power supply
curcuit?.

I'd like to build an adjustable unit with 0-24V minimum at 10 Amps
output. It's time I updated my old LM338 based unit with something
that has a bit more current and goes down to zero volts.

Maybe the easiest way is to run a blocking oscillator style converter from
the low rails on a PC PSU box..

You can't draw much current from the 12V rails without properly loading the
5V & 3.3V outputs, so there's no alternative to adding some form of
converter.

Making it variable for anything like the range you want might be a bit
harder than a simple BO type converter - maybe someone could offer some
SEPIC designs.


Have a look at this article.
http://www.qrp4u.de/docs/en/powersupply/

Ive built this , and it works fine, although I only needed 9V to 15 V.
Going down to 0 V and up to 24V @ 10A will be a hard ask for any SMPS
without some exotic transformers and switching Fets.
At very low output voltage but maximum current the transformer ripple
current becomes a major factor, and you must be sure that the
transformer core doesnt saturate, otherwise the switching fets will
blow.
Click to expand...
Thanks for the link, It may be a better idea for me to have two units.
One for up to 5 volts at 20 A and the other up to say 30 volts at say 5A.
 
"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:npudnUbvAf1f99DRnZ2dnUVZ7tmdnZ2d@westnet.com.au...
Mauried wrote:
On Sun, 25 Jul 2010 20:53:14 +0100, "ian field"
gangprobing.alien@ntlworld.com> wrote:

"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:F6OdnfNvD9b1CtbRnZ2dnUVZ8tKdnZ2d@westnet.com.au...
Anyone have recommendations for a benchtop switchmode power supply
curcuit?.

I'd like to build an adjustable unit with 0-24V minimum at 10 Amps
output. It's time I updated my old LM338 based unit with something
that has a bit more current and goes down to zero volts.

Maybe the easiest way is to run a blocking oscillator style converter
from the low rails on a PC PSU box..

You can't draw much current from the 12V rails without properly loading
the 5V & 3.3V outputs, so there's no alternative to adding some form of
converter.

Making it variable for anything like the range you want might be a bit
harder than a simple BO type converter - maybe someone could offer some
SEPIC designs.

Have a look at this article.
http://www.qrp4u.de/docs/en/powersupply/

Ive built this , and it works fine, although I only needed 9V to 15 V.
Going down to 0 V and up to 24V @ 10A will be a hard ask for any SMPS
without some exotic transformers and switching Fets.
At very low output voltage but maximum current the transformer ripple
current becomes a major factor, and you must be sure that the
transformer core doesnt saturate, otherwise the switching fets will
blow.


Thanks for the link, It may be a better idea for me to have two units.
One for up to 5 volts at 20 A and the other up to say 30 volts at say 5A.
Click to expand...
That would certainly make the task a lot easier.
 
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