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

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 !!

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danyelo (author) 3 years ago
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?
danyelo (author)  danyelo3 years ago
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:

iceng3 years ago
Classic inductors huh,

Here you go with a pic of the smallest inductor Ive seen :-)
danyelo (author) 3 years ago
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...
danyelo (author) 3 years ago
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.
Will TI ship to you? I posted the link below but they give free samples. You will have to sign up for an account.
The schematic is detailed here
iceng3 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.
MrRedBeard3 years ago
Here's one with free samples from TI. or

danyelo (author) 3 years ago
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.
This article will go a long way to helping you design your own boost converter.