Voltge booster

[pby5cat]

anyone know of a circut that will boost 12vdc to 14vdc?

PS increased amps load is fine.

[Moto7451]

check out this thread (http://bbs.xlr8yourmac.com/ubb/Forum11/HTML/001162.html). It has some links to different parts which will do what you need & some discussion of how to use them. They tried going from 12 -> 25v but the idea is the same.

[four4875]

before readin the thread above.. im gonna say buck inverter.. its done with a switching circuit and inductors i believe.. ill see that thread and refresh myself tho.

[pby5cat]

i looked at the circut used in the thred and the lowest it will go is 15vdc, and that would be death, 14vdc is the max operating voltage.

unless i mis read the minimum output voltage

[BC|Wulf]

There a couple ways to boost your voltage. One would be by using a boost transformer, but as your voltage goes up, you available current goes down.

The other way would be to take a 12V and a 5V line from your power supply and hook them in series. This would give you 17V, which you could drop down by using a simple voltage dividing circuit. It consists of a coupel of resistors. The values of the resistors determined how much voltage you got out. I used this numerous times on project in college and they worked great and are easy to make. You could even put in a variable resistor in to give you control of the voltage you want.

I will see if I can find a link to a voltage dividor circuit. I have it in a book at home, so if I can not find it I will scan in the page.

[SolidxSnake]

There a couple ways to boost your voltage. One would be by using a boost transformer, but as your voltage goes up, you available current goes down.

The other way would be to take a 12V and a 5V line from your power supply and hook them in series. This would give you 17V, which you could drop down by using a simple voltage dividing circuit. It consists of a coupel of resistors. The values of the resistors determined how much voltage you got out. I used this numerous times on project in college and they worked great and are easy to make. You could even put in a variable resistor in to give you control of the voltage you want.

I will see if I can find a link to a voltage dividor circuit. I have it in a book at home, so if I can not find it I will scan in the page.


I think you mean 12v and -5v ;)

[techun]

i have no skills in electronics, but i dont see why it would be -5

[four4875]

going with the +12V and +5V lines, as available on a molex, gives you 7 volts. its basically the difference between the levels. with the -5V rail, you get a total of 17 volts. with -12 and 12 you get 24 Vs. but be careful, as going this route doesnt provide much current at all. you can google for "dc-dc inverter schematics" and see how the prospects look, may find something suitable, may have to do some modifications to a circuit to get the wanted results. will also give an idea of the complexity of the circuit and what you'll need to do.

[SolidxSnake]

i have no skills in electronics, but i dont see why it would be -5


Think about it as simple math.

a + sign means the positive lead of the object (LED, diode, fan etc.), and a - means the negative lead of the object.

normally, it goes like this:

12+(-0)=12v

now, lets see a 7-volt:

12+(-5)= 7v

Now, if you get it, lets see for 17-volt:

12+[-(-5)]= 17v

simple ;)

[four4875]

http://www.mcrent.com/workbench/dcdc1216/

that circuit looks most promising, and i believe the page gbives a brief description of how buck inverters work. im sure theres some resistance modifications you can do so it pulses slower and possibly change inductance and it should work for your needs, as long as the current isnt an issue.

[pby5cat]

I was looking through the circuit linked abouve and when to see about parts. Well it seems there are alot of diffarent types of inducters that satisfy the listed requirments looking at digi-key.com.

I also looked at the specs sheet on the voltage regulator chip and it has a bunch of formulas used to derive the type of inducter. it seemed Toroid inducters looked the best for my use, but which one? link (http://dkc3.digikey.com/PDF/T053/0900-0902.pdf)

[four4875]

well, need to figure what load you'll be running ,the inductance required by the circuit, and the size you want to go for. i would do ll the math the datasheet says and go from there, see what is closest to what you need for the current load you'll be at. im not sure how i would be graphed to show an in between rating on the load, whether its linear or a logarithmic, so im not of much help there.