Hi all, I am currently working on powering a 24v DC load, with a 5v Battery. I'm thinking of using a voltage booster circuit to achieve this but can't seem to get at the right circuit diagram. Any kind ideas please?

 

www.national.com, simple switchers.

 

Thanks seniormember, for your prompt reply, that was great and snappy, but I couldn't source the 3478 IC locally since time factor is currently a challenge. I was only able to get 741, 555, 7824 ICs. Any clues on going around with these please?

 

Thanks seniormember, for your prompt reply, that was great and snappy, but I couldn't source the 3478 IC locally since time factor is currently a challenge. I was only able to get 741, 555, 7824 ICs. Any clues on going around with these please?

How much current does the 24V rail have to supply? That defines the part you need.

 

Its 1.5A sorry I forgot to include that initially

 

yeah.... 1.5A @ 24V ( 36 watts) with a 5V battery is not going to happen... what type of battery is it??

 

Nobody makes a 5V battery. Ni-MH cells are 5V only when their current is far lower than is needed here.
Maybe it is a 6V 14Ah lead acid battery that could drive a 6V to 24V voltage step-up circuit for 1 hour. Power transistors must have a current of anout 7.2A in the voltage stepup circuit. Maybe a custom-made transformer must be used or a very high current 120V to 30V transformer might work.

 

The best approach would be to use a push-pull (forward) switcher converter to boost up to 24V.

 

The battery actually came with a rechargeable LED touch-light unit and since it is quite cheap for a 30minute exhibition, I felt it could just serve the purpose. It actually dangles between 5V and 5.3V on an AVOmeter and I think could yield up to 6V on full charge. I really would love to try this on the '6V to 24V voltage step-up circuit'. Any further helps on the circuit diagram would perfectly save the day. Thanks a billion Guys!

 

Well, seems that you're just doing some wishful thinking.

You say your load requires 1.5A @ 24v. Figure ~80% efficiency for the converter (that could be improved with an increase in complexity) so you wind up with a 45 Watt input power requirement.

At 5v, that's 9 Amperes.

You've described your 5v power source as being cheap, and being able to power some LEDs for about 1/2 hour. I'd be willing to bet money that your 5v power source would not be able to output 9A @ 5v continuously for more than 10 seconds.

You're trying to get something for nothing; it doesn't work that way.

Even if you had an adequate 5v supply, building an efficient 45w 24v supply won't be particularly easy if you have not built one before. You'll need to have an oscilloscope available for troubleshooting, too.

You will likely be much better off to simply use a pair of 12v SLA batteries wired in series.

 

You will likely be much better off to simply use a pair of 12v SLA batteries wired in series.

Or get three more of the cheap 6V batteries he already has.