How to run a 4 volt LED from a 2.4 volt source?

zmoz

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I want to run an LED that is rated at 3.6-4 volts using 2 Nicad AA's. (2.4 volts) Is there any way I can do that?
 

INRETECH

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You will need a inverter "step-up" circuit, there have been several posted here on CPF

There are several companies that make chips just to do this purpose, you will need to add a inductor, recovery-diode and a cap

The problem is the eff, most of them are less than 60% eff; which means you waste 40% of the energy of the batteries in the conversion, its much more eff to go more batteries and higher voltage
 

tonyb

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Do a search on Micro-Puck on this site I think it does what your looking for if I'm not mistaken.
 

UK Owl

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By stating 2.4 volt supply i assume you will be using NiCd or NiMh cells so eficiency of 60% will not be a problem.
I suggest you try a Max756 or Max757, you will need to add an inductor, Schotky diode, and a capacitor (with the 757 two resistors) this will will be cheaper than the puck and will work for most white/blue LED's, but if you wish to run a Luxeon Star then the Micro-Puck could be the better option. Try downloading data sheets for Max756 & 757 and see if that is what you want. (note: they are both available in either discrete or SMT sizes)
 

jeff1500

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Jul 9, 2001
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Click the link below for some ideas. Efficiencies range from 50% to 90% depending on the circuit.
 

Entropy

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Re: How to run a 4 volt LED from a 2.4 volt source

dat2zip's BadBoy/MadMax converters will work well for this and are rather high efficiency circuits. (Note: These are designed for high-current use, mainly the Luxeons)
 
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