SparkFun Forums

[EliteGamer83]

I'm going to be making an external iPod battery using the 2000mAh Lithium Ion battery cell. The Lithium battery out outputs 3.7v The iPod charges at 5V 500-1000mA. Of course I'm shooting for 1 Amp if I can, it will take up an hour tops to re-charge/run the iPod. The 5V step-up I found at Sparkfun can only handle 300mA?

Is there any way to modify this step-up with higher rated parts that can handle 1 ampre? or even 500mA?

[leon_heller]

Look at the Nat Semi Simple Switchers.

[EliteGamer83]

Look at the Nat Semi Simple Switchers.

What about this?
http://www.sparkfun.com/commerce/produc ... cts_id=317
I stumbled across it as "related products" under the Nat LMZ14203. Do you think a heatsink will be required? I've never messed with a power "conversion" project like this before. I don't know how hot things will get.

Yeah people never usually help me, I'm new relatively to electronics and people don't ever want to explain things to me. Everyone has to start somewhere.

[60amp_relay]

You could always buy 3 of them and gang them together for up to 900mA output. Or take two batteries wired in serial for 3.7v + 3.7v = 7.4v and use a voltage regulator to get it back to 5v. A good voltage regulator can do 1000mA natively.

[EliteGamer83]

It says in the item description "Has an input range of 3V to 40V, output switch current of up to 1.5 amp. Step up, step down".

[leon_heller]

One of those should do what you want.

Switchers are very efficient and often don't need heat sinks. You will find on-line design software for all their devices on the Nat Semi web site.

[esklar81]

I'm going to be making an external iPod battery using the 2000mAh Lithium Ion battery cell. The Lithium battery out outputs 3.7v The iPod charges at 5V 500-1000mA. Of course I'm shooting for 1 Amp if I can, it will take up an hour tops to re-charge/run the iPod.

EliteGamer,
In doing this, you need to keep in mind:
1) the permissible discharge rate of your Li ion battery,
2) that a step-up converter increases voltage, but decreases power (The current being drawn from the battery will be the output current times the voltage ratio, divided by the efficiency.), and
3) the permissible minimum residual voltage in your battery.

Eric