We have a bunch of perfectly good ethernet switches which have bad fans.
The problem is that the fans are 5 volt and the only power available in
the box is also 5 volts.

So far, the little 1&1/2 inch fans are not available anywhere that we can
find, but are an exact physical match for 12v CPU fans on older PCs, which
we have a ton of.

They take only a few mils to run.

Does anybody know of a dc to dc converter chip or a simple circuit that I
could mass produce to convert 5vdc to 12vdc? A voltage doubler maybe?

Thanks

DD

"DelphiDude" wrote in message
news
We have a bunch of perfectly good ethernet switches which have bad fans.
The problem is that the fans are 5 volt and the only power available in
the box is also 5 volts.

So far, the little 1&1/2 inch fans are not available anywhere that we can
find, but are an exact physical match for 12v CPU fans on older PCs, which
we have a ton of.

They take only a few mils to run.

Does anybody know of a dc to dc converter chip or a simple circuit that I
could mass produce to convert 5vdc to 12vdc? A voltage doubler maybe?

Thanks

DD

The LMC7660 should do the trick!

scada wrote:

"DelphiDude" wrote in message
news
We have a bunch of perfectly good ethernet switches which have bad fans.
The problem is that the fans are 5 volt and the only power available in
the box is also 5 volts.

So far, the little 1&1/2 inch fans are not available anywhere that we can
find, but are an exact physical match for 12v CPU fans on older PCs, which
we have a ton of.

They take only a few mils to run.

Does anybody know of a dc to dc converter chip or a simple circuit that I
could mass produce to convert 5vdc to 12vdc? A voltage doubler maybe?

Thanks

DD


The LMC7660 should do the trick!


the fans should need approx 100mA @ 12VDC. You have to check the fans!
a LMC7660 can not produce that much power. A 3-6Watt 5/12VDC switcher maybe.
rw
rw

the fans should need approx 100mA @ 12VDC. You have to check the fans!
a LMC7660 can not produce that much power. A 3-6Watt 5/12VDC switcher maybe.
rw

No. These are real small and thin fans and don't turn all that fast.
They were on some of the early 486's. Even stalled they only pull about
25 ma.

On

The LMC7660 should do the trick!

Thanks a bunch. So far, however, my usual suppliers don't carry them - Jamco,
BGMicro, etc. Still looking.

DD

On Wed, 13 Aug 2003 18:21:23 -0500, "DelphiDude"
wrote:

Check out www.digikey.com. They have some 17mm x 8mm Sunon 5V fans.
If you have a manuf. name and part number, you can probably find the
fans.

On

The LMC7660 should do the trick!

Thanks a bunch. So far, however, my usual suppliers don't carry them - Jamco,
BGMicro, etc. Still looking.

DD