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USB battery + 12V DC charger

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akyranas

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Hello everyone

I could like to ask a question: I have an USB battery with 5V output. How I boost from 5V to 12V with a charger?
I have also have a DC to DC Boost Buck Converter from 5V to 12V, but it is not working!
With a transformer from 220AC-to-5V DC it is working: 5V input and 12V output. But with battery does not working...

Please help with this matter.

Thank you
Aris Kyranas
 

Easyrider83

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We may sugest, that your USB battery gives you 5V 1A power. After step-up converion we can expect for 300mA max and 200mA in real conditions. So, it should work, but don't expect high efficency because USB battery already has 3.2-4.2 -> 5V step up converter.
 

SunnySkyguy

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The real limitations of boost converters is not just the power relationships for VI in vs out but the requirements for impedance ratio being much lower than load than simply /N²
, where N is the voltage boost ratio.


this is because due to input load regulation requirements to keep USB charger within 10% , its source impedance must be 1/10 of expected transformed impedance levels . Or with 1% load regulation must be 1% =Rs/Rload


from testing your 5V source for load regulation using any reasonable load R measure drop in V for rise in current and this is your ESR. Then for Good regulation using 5% criteria and voltage gain of 12/5=2.4 your load impedance cannot be less than ESR(5v)*1/5%* 2.4²=ESR(5v) * 115

So what are your measurements?
 

akyranas

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Hello all

I have another experiment witch I believe it is a solution for DC-DC boost converter.
I have 2 5V USB batteries and I connect in series, so I have a 10V dc. The module in input is 10V and in the output is 12-13V, so I connect the load I prefer. The solution is not the best, but it works!

Thank you for your attention
Aris Kyranas
 

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