Looking for simple and reliable voltage doubler 12->24v

Hello as the topic says i'm looking for a simple design for a 12 to 24 volt convereter. I have been looking around and realize that there are charge pumps, transfomer methods and inductor methods to use. When it comes down to it i need up to .5 amps at the 24 volts and it needs to be reliable and not sensitive to mechanical vibrations (to be mounted on something similar to a gocart and run off of the 12 volt system) The smaller the package the better no more than two cubic inches or so. This will be used to drive two air solenoid valves for shifting and clutching. Any recomendations are welcome. I know there are many maxim chips that are very much suitable for the application but for some reason i feel somewhat hesitant to go the route of a single IC. thanks in advance

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Reply to
rkremser
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Hello as the topic says i'm looking for a simple design for a 12 to 24 volt convereter. I have been looking around and realize that there are charge pumps, transfomer methods and inductor methods to use. When it comes down to it i need up to .5 amps at the 24 volts and it needs to be reliable and not sensitive to mechanical vibrations (to be mounted on something similar to a gocart and run off of the 12 volt system) The smaller the package the better no more than two cubic inches or so. This will be used to drive two air solenoid valves for shifting and clutching. Any recomendations are welcome. I know there are many maxim chips that are very much suitable for the application but for some reason i feel somewhat hesitant to go the route of a single IC. thanks in advance

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Reply to
rkremser

Then you need to use a transformer - preferably with push pull drive.

Reply to
Homer J Simpson

As your air solenoids presumably wouldn't require a regualted 24V, you may find this off-the-shelf unit meets your requirements (unless you have compelling reasons to build your own).

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Reply to
budgie

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Like you know something about it?  "Charge pump" _requires_ a DC
output,  so post a schematic instead of just flapping your jaws,
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Reply to
John Fields

I have some 24v hydraulic valves that work just fine at 12v -- so just for grins -- try tripping the solenoid on 12v -- its just an electromagnet and may pull suffciently to operate on the lower voltage

Reply to
John Barrett

Use the Maxim solutions. THey are the best possible solution. Sure, you could 'roll your own' with discrete components, but that's the hard way, will be less reliable, and probably be *much* larger in the end.

Reply to
PeterD

I assume you work for Maxim.

The OP can get a DC-DC convert from almost anyone else for the job. Look in Digikey.

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kensmith@rahul.net   forging knowledge
Reply to
Ken Smith

Sure rolling your own may be more work, but I doubt that it will be any larger and is ,in fact, likely to be smaller. I have done a number of PS designs and they mostly were smaller than off the shelf designs, also cheaper. But the work is not trivial, even with a design example. In automotive apps (not sure how similar go-carts are to autos in this regard) you need a lot of input protection way beyond anything you see in other environments. Unless a module is designed for that it is likely to fail at a high rate. This applies to both bought modules and self designed ones.

Reply to
rickman

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2.7 cubic inches:

http://vicorwebapps.vicorpower.com/upc/FirstGenDCDCInit
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Reply to
John Fields

huh? a charge pump needs push-pull but no transformer. and a boost converter needs only a single ended drive on the inductor

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Bye.
   Jasen
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Reply to
jasen

for 12 W?

Reply to
Homer J Simpson

sure.

Bye. Jasen

Reply to
jasen

You can use a diode to replace the the other transistor. You actually don't need a transformer, just a coil. The coil is between the battery voltage and the load with the diode in series after the coil. The transistor pulls the coil-diode connection to ground long enough to put enough current into the coil, then it releases. While the transistor is turned on, the diode is reverse biased. When the transistor opens up the coil field collapses and the voltage on it reverses boosting the output voltage. With this wiring the coil voltage adds to the battery voltage. A controller modulates the pulse width of the transistor drive in order to maintain a set output voltage.

These circuits are not hard to understand, but they are closed loop feedback controllers and attention must be paid to all the details. So it would be easier to use one off the shelf or to change the solenoids to work on a 12 volt drive.

Reply to
rickman

The solenoid valves I have seen have 2 parts: the valve body and the coil. You select the coil according to the voltage source you have available. Is getting a coil of the proper voltage not an option?

Reply to
JeffM

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