This is essentially a Q & A tutorial set - as provided for in SE rulez.

I am trying to build a Power Bank* on my own.
Can anyone assist me in designing a circuit or suggest ones which may form a good starting point.

I have tried searching for the circuit online. I have found circuits which use SMD components. For reasons which seem good to me [tm] I'd rather obtain information on solutions that do not use SMD devices, if possible.

*The name "Power Bank" or "PowerBank" is common parlance amongst those of about Gen-X on - so much so that they may not realise that it may confuse those with Gen-Q brains or before. So,
The technical name for a "Powerbank" is a boost converter.
A PB is usually a BC designed to operate from a single LiIon (Lithium Ion) cell and to produce 5V output intended to charge a cellphone or similar via a 5V "USB" connection. The target device usually uses a LiIon cell as well so it's essentially part of a LiIon to LiIon charging circuit.

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    \$\begingroup\$ How is even possible that a 68k account asks for something like that? \$\endgroup\$ – Vladimir Cravero Jun 14 '14 at 10:08
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    \$\begingroup\$ @VladimirCravero - when you see the finished question AND answer you MAY understand :-). I think it's called Gen-Q / arrogance/ cussedness/ driving the beginner away. I do not understand it, but this is part of my what-can-one-man-do stand against it. Whatever . /// :-) \$\endgroup\$ – Russell McMahon Jun 14 '14 at 10:29
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    \$\begingroup\$ @VladimirCravero - OK. All done. See if that now makes sense :-). And perhaps see This question which I was in the process of answerimng when it was closed. \$\endgroup\$ – Russell McMahon Jun 14 '14 at 10:33
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    \$\begingroup\$ @Russell all USB power banks I've seen include a charger as well. You should either include a Li-Ion charger in your answer as well or change the question to how to get 5V from a Li-Ion battery. \$\endgroup\$ – PeterJ Jun 14 '14 at 10:55
  • \$\begingroup\$ @RussellMcMahon I didn't even think about the "auto" Q&A format, sorry about that... My bad \$\endgroup\$ – Vladimir Cravero Jun 14 '14 at 11:12

Most Powerbank circuits use ICs and most are surface mount. Learning to solder the larger sizes of SMD ICs is not too hard and well worthwhile.

By looking through circuits that are described as boost converters and which are suitable of using a LiIon cell for input and having a 5V output you should find a number to choose from. Ask further once you have found some possible candidates if you need more advice.

2 transistor self oscillating converter:

Here is a suggested 3V to 5V boost converter circuit. This is not a marvellous circuit compared to IC based ones.

enter image description here


Here is a powerbank kitset for a device known as a MintyBoost - This is usuallyt used as a 2 to 3V input circuit but should work with a LiIon cell input. The circuit is available and you can build it yourself from parts obtained elsewhere if you wish. This version uses an SMD IC but I think earlier versions had a DIP IC option.

NCP3065 / MC34063 boost converters:

Boost converters available in DIP packages are the NCP3065 and MC34063. Both are old design ICs and not as efficient as more modern ICs but still useful and they have a low external parts count and are easy to use.

NCP3065 data sheet

MC34063 data sheet

Figure 6 in the MC340-63 data sheet shows a boost converter which would form the basis for experimenting with.

Example circuit below. The values that have been struck out in red were specific to a particular voltage in and out. See data sheet for details on values for eg LiIon in & 5V out.

enter image description here

  • \$\begingroup\$ I feel MintyBoost completely answers that question. \$\endgroup\$ – Kamil Jun 14 '14 at 13:20

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