5V/24V DC-DC converter?

[BlueBeam]

Hi there!

Does anybody know of a commercially available (step up) 5V to 24V DC-DC converter? Where to find that? Until now my search for a vendor was not successful. In case that it does not exist, any ´simple´ idea how to build this function? The required power is around 30W!

Thanks in advance!

 

[Madcow]

If you don't require isolation a simple boost converter
will work. Alot of companies that supply power supply
chips have design tools to help. National Semiconductor
,Fairchild and Linear tech. for example. Many have simple switchers for easy designs (The fet and control are all in one chip). I dont know of any off the shelf solutions.
If your talking large volume then you may want to contact a custom power supply vendor. If just a few I would use
one of the simple switchers and use the online tools to design it.Some will even design the pcb for you.

 

[amorrison]

From a ME.

Consider changing the transformer of an existing multivibrator to get the desired voltages - already comes with case, power connectors etc.

If the "new" multivibrators are too optimized(unmodifable)consider obtaining a unit made 20 years ago which will have more discrete components that can be changed.

 

[walker1]

Have a look at:

http://henry.fbe.fh-darmstadt.de/smps_e/smps_e.asp#Ivw

(general SMPS)

and:

http://henry.fbe.fh-darmstadt.de/smps_e/aww_smps_e.html

(Boost converter)

It will give you an idea about things.

Home-brew switchmode is a little tricky, though. You have to be very carefull in chosing the core for the coil.

 

[BlueBeam]

Thanks for the help, guys!
The problem is, i am indeed looking for such a little 4pin, PCB-ready, "i have nothing to do" black box, 5V to 24V @ 30W output. Guess, i can shake it...
Walker, thx!, the links are quite useful and i´ve already startet some simulations. Problem here: either the "all-in-one" chips i found need additional 12V supply, or the controller/FET will only work up to ~18V in my simulations!? However, i could not spend much time yet for that, but i´ll keep on checking the vendors for suitable solutions + simulating selfmade circuits. Any further hint/advice is appreciated!

 

[felixc]

Have a look at the web site of Texas Instruments.

http://www.ti.com

They have a line of modules that covers quite a good range of DC-DC modules.

 

[sdmays]

One thing to keep in mind is: due to various losses (switching/switch losses, etc...) any typical boost regulator is generally only capable of 3 to 3.5 times gain. In other words, you might be limited to a maximum output voltage of 17.5V. You might consider using either a fly-back converter design or a forward converter design.

 

[lcsjk]

Look at Vicor's modules and search for the look-alikes. THey don't need much more than capacitor's to complete a DC/DC.

 

[nbucska]

Blue:

Why do you need 24V 30W ? Is this fix or mobile application?
( 12 V batt or 110V ac? )



<nbucska@pcperipherals.com>

 

[BlueBeam]

Hi all!
Thanks again for all the replies. However, it seems to need a little more explanation.
nbucska - we have an industrial device, which was originally designed for 24V DC power supply. This is provided by an AC/DC adapter for ´normal´ use. Now we´ve got customers with system-internal 5V power supply and need to adapt our device to this. Instead of a complete redesign of the electronics we would have liked to use simply a converter. And there´s the problem, the high voltage jump combined with the quite high power of 30W.
lcsjk - the Vicor modules look very nice, but i can only find converters starting at 12V input...??...maybe its me?
The IC´s of TI (and others) have also all a certain limit somewhere, somehow, which make them not suitable for our needs. Though i admit that i still have problems to make time for this research(actually, its not my main task).
Makes me even more grateful for all the help!!

 

[nbucska]

Blue:

You haven't answered but I assume it is not a mobile application, so it is powered by 110V ac.

Why not just buy a separate 110V AC to 24V DC supply and connect the two GND-s?

What does this mean:
"The IC´s of TI (and others) have also all a certain limit somewhere, somehow, which make them not suitable for our needs. Though i admit that i still have problems ....."

Why don't you just give me all of the data you have?

<nbucska@pcperipherals.com>