Introduction: Advanced USB Device Charger

Picture of Advanced USB Device Charger

With this tiny thing you can charge almost all devices that are charged via USB, like iPods or mobile phones, with only two AA-Cells!

Step 1: Having the Idea

Picture of Having the Idea

So why should i build this?
The reason is quite simple: I am bored of empty batteries (Ipod, mobile phone) while I'am on the go. And the solution with the linear regulator like the "7805" is in fact very simple, but very unefficient, because: firstly you need a supply that provides about 3 volts more than you need for usb and secondly in most cases the difference between input voltage and output voltage is lost in heat.

The solution for the problem comes from Linear Technology. The most important compenent of the cicuit presented in the next steps is the "LT1301". This is a small step up converter for to build switching mode power supplys with only a few external components.

Step 2: Parts You Need

What you need:

->The LT1301 and a ic socket (8DIP)

->2 electrolyte caps WITH! low ESR (6,3V 100uF)

->one inductor with a very LOW! DCR (around 0,03R) with 10uH should be able to handle switching
currents at about 1,5 Amperes.

->one schottky rectifier like "SB130" or "1N5817" (important if you can't get one of the two proposed
rectifiers:low forward voltage drop, fast switching capability and it should be able to handle
currents of 1 Ampere.)

-> A switch(on/off), an usb connector, a circuit board, a LED with resitor (limit led current to 2mA!, don't loose your mA by pumping them throu the LED) and don't forget the battery holder

Step 3: The Circuit in Detail

Picture of The Circuit in Detail

What is important when building?

The input capacitator should be as close as possible to pin 6 (Vin) of the LT1301!
Keep all cicuit traces short!
Directly tie Pin1(GND) Pin8 (PGND) and Pin3 (Shutdown) togheter and connect it to ground.
Avoid long soldering times for to prevent destruction of components by overheating...

For the detailed placement of the components on the circuit board you can use your own creativity...

Step 4: Finished!

Picture of Finished!

So now its done, but before connecting it to any usb device, be sure that it works properly! (the voltage should be 5 volts, the LED only should glow,etc...) When all is checked and you are sure that everything works you can (if you like it) start to put hot melt around it as kind of protection. In case you don't like hot melt you can put the device into a match box or everything you want...

on the left side of the picture you see an older version on the right you see the newer smaller, enhanced version

Some Technical data:
Input: 1,5 to 3 volts
Output: 5 Volts @ 200mA max. (really enough to charge an iPod mini or a mobile phone, trust me ;-) )
Watts and efficiency:
In: 0,95W at 2,5 V
Out: 0,875W at 5 V
loss: 0,075W
8 percent loss
92% efficiency


tkefalopoylos (author)2013-07-22

I think LT1302 will be good as it provides 600mA.I am trying to modify this project for use with this chip but i am not done yet, i will post if i achieve results.

whiskeysausage (author)2013-06-16

Does the phone monitor when to accept the charge? Or does the motherboard regulate the output?

When building this, would it be better to 'shoot for a higher' voltage and amperage, say, 5v and 2.5amps and simply let the phone regulate the incoming current?

Or does something on the motherboard adjust for current?

awharton3 (author)2013-05-27

Is there a substitute for the 1301 chip or somewhere it is available in Aus

pertamax11 (author)2012-12-20


can you show the perfboard configuration for me?
i want build this one.

ravi sibi (author)2012-12-06

sir, its so cool.... suppose if i want to improve the output current from 200ma to 300ma as well as 500ma, then what are all the modification should i done in the main circuit?? please respond because am doing a similar project with that ic....
also i want to know weather it is possible to make 300ma from this lt1301ic..

dcastor (author)2012-11-23

I agree 500mA would be helpful...

ZippoLag (author)2012-07-12

Great guide!

I'd like to use a similar set-up for powering other USB devices rather than just charging a phon and would need higher amperage (at least USB's standard 500mA), any toughts on how to modify your design to fit those needs?

Tom Kazansky (author)2012-03-10

Will it work for HTC Wildfire S?

Thanks for help.

imrankhan110 (author)2011-09-26

I really liked your stuff , I was searching for a subsitute to Minty Boost as it is expensive. But for me building your Circut is beyound my skills. As I am totally new to this world. I want to make these things on my own, I even tried to make a Solar USB charger but the Kit I got from a Hardware store was AC to DC, which I did not realise first. But every thing was done I connected the Solar cell and and My Samsung Champ phone It started to Charge but the fact is it was not charging In a Min. the screen dispalyed battery is full remove charger but the battery was still emppty. I am using a 6V 200 MAH. The circuit has 4 Diodes a capacitor 2 clay res. a 5v 7805 regulator.
Please help.

KITKAT69 (author)2010-03-19

ok I haven't try this but was usb connector is the only option for charging phones and other gadgets, what about some other phones that uses jacks and sockets to charge? i hope you get what I mean because not all phones charges from Usb coonections, there are phones that uses different sockets and connectors for it to charge, can you show me a configuration in your circuit if i wanted to use jack and socket for my NOKIA N73........... your project was cool...

kamathln (author)2009-09-18

Is there any way to charge one cellphone from another cellphone battery?

phephq (author)kamathln2010-02-14

 yes, just use alligator clips to attach the (+) and (-) from the source battery in place of the (+) and (-) from the  9v clip

phephq (author)2010-02-14

 why do the components need low ESR & DSR? what will higher levels do to the performance? 

06-0489 (author)2009-11-28

can 2 AA cells fully charge a celphone batery? many AA batteries are needed to fully charge a cellphone battery?=)

VV.Core. (author)06-04892010-01-03

Yes they can!
Look a standard cellphone battery has around 900 mAh at 3,6 volts. 2 standard AA cells or AA rechargeable batteries have aroound 2,4 to 3 volts at 2000 mAh. the charger has an loss of 10%... This will be enough for one and a half charge!

06-0489 (author)VV.Core.2010-01-04

 tnx.. :))

imakethings (author)2009-10-26

if u live in India go to to get this ic!

harishere (author)2009-07-23

Can we use any other IC, cause i cant find it.

arikyeo (author)2009-06-29

are u sure it works??? my multimeter only reads 2.17 volts

arikyeo (author)2009-06-29

are you sure it works??? from my multimeter, i only get 2.17 volts

oblivtion1 (author)2008-12-17

does this work with the iPod Touch?

arikyeo (author)oblivtion12009-06-26

no, u will have 2 connect the data+ and data- pin to two 150kohm resistors, and connect them to the 5vDC output.

dark sponge (author)oblivtion12008-12-19

If it charges from a USB port, it should work.

VV.Core. (author)2008-06-30

Hey! copying is simple but I do NOT copy, pfff... You can take a closer look on my Instructable and you'll see it's based on an other chip and an other circuit... I decided to publish this instructable because I wasn't able to buy/find the Maxim chip in my country. Maybe there are others who have the same problem? So why don't you agree that's better to have more options, I do not force you to use my instructable, if you like it fine, if not you are free to build a minty boost.

arikyeo (author)VV.Core.2009-06-20

this 1 is easier than the MintyBoost thks for writing ye 'ible! 're the best!

Artificial Intelligence (author)2008-06-08

This is really cool. I'm also tired of those 9V battery LM7808 regulator circuits. Too bad, the LT1301 aren't available in my country. (added to favorites)

OK, I will bite. What is wrong with the 9v, 7805 regulator circuits? They, too, will allow for over/under and with the 9v, would you not get a slightly longer life? For instance, my Sansa View would play off the 9v charger longer than 2AAA? The ONE advantage I see here is the under-volt pull-up that will suck the batteries dry. (I carry plenty of 9v rechargables for the 9v Charger when on a trip).

dark sponge (author)PhantomGamer2008-12-19

The problem with 7805 regulators is that they have a low effeciency. More power is lost to heat then with this method. And just because 9v batteries have higher voltages than AAs doesn't mean they will last longer. They have less mah (milliamp hours) than AAs. (more mah=longer run time)

arikyeo (author)dark sponge2009-06-05

then just get 6AA batteries and wire it to the 7805!!! obviously or if you think the size is too big, get 3xCR2 and a homemade battery holder!!! it works for me, and i can carry up the plane...

snowborden1 (author)2009-04-19

Does this work with a 160g ipod?

titlert (author)2008-12-19

Where could i buy the parts? I looked on and they werent there. Where did you get your stuff?

mikes80501 (author)titlert2009-03-29

Try Digikey for almost anything electronic. There are minimum amounts to order or they add a service charge. You'll want to order a bunch of things for best money efficiency.

phephq (author)2008-12-22

im looking at linear technology's product catalog. I see four LT1301 models.


are they all compatible or is there a certain one to get?


mikes80501 (author)phephq2009-03-29

I is Industrial temperature range. C is Commercial temperature range. Industrial is wider but you won't need it, it costs more and is harder to get.

solis365 (author)phephq2009-03-16

look at the datasheets, they are very likely to be different packages. if you look on that site you linked, theres a column labeled "package," and you'll notice two types: SO and PDIP. The PDIP (Plastic Dual-Inline Package) is the kind of chip you'll want - with long leads that can fit into a breadboard and are much easier for the hobbyist to solder (through-hole soldering). The other package, SO, is a type of surface mount technology. It cannot fit in a breadboard, and is not a "through hole" component, i.e. you'll need to have a pcb with the right traces laid out and a surface mount soldering station (could be done with a regular iron if you're talented.) In short, get one of the PDIP packages. I looked at the datasheets for the CN8 vs. the IN8, they were identical. I would look a little deeper on the internet for the difference, but I'm short on time at the moment and I don't think its anything youll care about for this project. Maybe a different fabrication or revision or something. happy hunting

Moto13 (author)2009-03-29

Could a 1302 be interchanged w/ no mods? I realize it needs slightly higher V_IN_MIN, but want the higher 600mA output... the pins/pkg seem the same, and same family.. so can I just swap it in? Thanks

DualPhase (author)2009-02-20

Lets assume your device only needs 3v and you have 2 AA batteries. Would you even need a voltage regulation circuit like this? Or similarly you have a 5v battery. Isn't small voltage regulation built into the device anyway, enough to handle a few millivolts.

phephq (author)2009-01-06

I am having a great deal of difficulty finding the correct parts for this, could you reference me to the place or places that you got your parts or a place or places that I could get them? 'twould be super

TheInventor (author)2008-08-16

You just copied the minty boost instructable.

not necessarily, the LT1301 has been around longer than the minty if you notice the schematic provided above you should immediately notice the absence of the 0.1uF bypass tantalums used for high frequency filtering. In addition, the Mintyboost version 2 uses a 22uH ferrite core inductors for low EMI and low core loss and also allows the minty boost circuit to operate at a higher current (400 versus the 200 depicted here) Furthermore, the mintyboost has the pull-up/down capability to recharge gadgets that require current output from one of the central data pins. so no, this is NOT a copy of the mintyboost, but an imitation or perhaps a variance of the design. :)

polo99a9 (author)2008-09-26

great job, I think. I made a usb charging device in a much simpler way. I connected 4 AAA batteries in series, without any other electronics. it works great, and it is very simple. I charge my psp, my camera and my mp4 this way. why is yours so complicated? what is the advantage?

VV.Core. (author)polo99a92008-09-27

When you take 4 aa or aaa batteries you get and output voltage of 6 volts when they are full. (a bit to much for an usb devide!) the discharge graph of an alkaline batterie is linear so if you discharged them 50% the voltage will be about 50% of 1,5 volts lower = 0,75 volts, this is 3 volts for 4 batteries. 3 volts are not enough for an usb device to charge (you need at least a minimal voltage of 5 volts +- 0,3 volts) so you cannot really use the full capacity of your batteries. on the other hand nickel metal hydrid accus have a pretty constant discharge behaviour they deliver about most of the discharge time an voltage around 1,2 volts, this is usefull for photo cameras or portable devices with high power consumption. one of the key benefits of the LT 1301is that it has the ability to suck out near everything of the batteries or accus. the LT 1301 is a switching power supply, by switching the power on/off at a very high frequency it can produce 5 volts ouput at 2,4 volts input, by changing the config of the outer circuit you can even reach 12 volts! To resume the advantages: you only need two batteries, the batteries are really empty after use, it opperates at high efficiency (92%), you will not risk to damage your precious (psp) equipment because the output voltage will not exceed 5 volts. i hope you have understand why I prefer the more complicated mehtod... if you still have question you're welcome to ask.

polo99a9 (author)VV.Core.2008-09-28

OK...I will probably make one, and i will try to test the differences between the two models. thanks for a elaborate answer, i understand now.

Derin (author)2008-06-26

yay thank you

Derin (author)Derin2008-08-27

just what i needed

mutantxgene (author)2008-06-23

Please forgive my newbie question. I'm trying to make something like this based on these two instructables but use a solar cell and rechargeable batteries.

I have a 6v 100ma cell. How/could you wire the solar cell to this?


Sandisk1duo (author)mutantxgene2008-07-22

get one landscaping light, make sure iy's powered by TWO AAs then just attach this circuit to the batteries, and ta-da usb charger

ElectronicsPro (author)2008-07-07

They Wont let you bring that on an airplane!

VV.Core. (author)ElectronicsPro2008-07-08

That's right :-) I tested it by putting it near to an old midwave radio. You could hear the switch noise very clear... So it could probably interfere with the plane radio

joejoerowley (author)2008-06-13

Cool! Great Instructable! Thanks Joe

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