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Can anyone help me with an schematic for dc-dc boost converter,from 3.5-3,7V to 5V to charge a phone? Answered

Hello everyone !! I need a schematic for boost converter but with basics components,i need to find them in my country and not very much to cost. I need it for charge my phone from another cell battery with 3,7V. Like an portable charger. Please help !!


Thank you so so much. But i have one question as a nobbie:
in this chematic i cant find 2SA616, can i use something else? an equivalent? http://i40.tinypic.com/i4qu03.gif

But in this 2 schematic, this one and the first schematic from the header comment what is the maximum mA.

These are 1 watt 500 ma transistors that will work.

SS9012 – SS9013

2N9012 – 2N9013

2N5086 – 2N5088

2N5087 – 2N5089

You can get the data sheets here:




4 years ago

Classic inductors huh,

Here you go with a pic of the smallest inductor Ive seen :-)


thank you everyone but is not what i need. a classic one with inductors? i want to learn from it too. i`m a beginner and a student !! so...

I`m from romania. I want to make a boost converter from 3,7V to 5V to charge my iphone. i dont have much money so i need i cheap schematic if you know.

The schematic is detailed here https://www.sparkfun.com/products/10255


4 years ago

Here is probably the most cost effective circuit I know.
Except a joule-thief.

And you could have more money
if you stayed away from girls.


i had seen that, but i cant find MAX756, can you give me an equivalent for him?

It would help if you put your actual country in your profile.