Electronics > Beginners

Howto make 10.4V out of 4xAA batteries?

<< < (3/3)

Buriedcode:
There are plenty of boost converters specifically for driving LED strings - the only real difference is the feedback voltage is lower so one uses a current sense resistor effectively making it a constant current boost. (normally 1.2-1.25V, but often CC boosts have a 0.3-0.6V feedback threshold).

Example: https://www.mouser.com/ds/2/115/ZXLD1615-93645.pdf

However, the reason I suggested a charge pump was the lower EMI.   Even with shielded inductors, careful layout, switchers still tend to radiate more interference than charge pumps.  A simple (high frequency) boost converter would probably be the most efficient, but you will have to test it with your metal detector - just because it has a high switching frequency doesn't mean it won't interfere.  In fact you could probably just buy a cheap boost "module" from amazon/ebay set it to your desired voltage, and see if it interferes.  If it doesn't, then you could probably get away with almost any boost converter.  If it does, then you have to be more picky.

You don't have to have a constant current converter.  Whilst efficiency will take a hit, using a 12V supply and a series resistor won't be that inefficient, especially considering you're going to run the LED's at 2mA - often switchers will have a quiescent current of 2mA+ so it won't get to 80%+ anyway.

So I say, if you can source some cheaper modules to test they might be everything you need, or at least highlight any issues.
https://www.ebay.co.uk/itm/5V-USB-Input-to-12V-Output-DC-DC-Step-Up-Boost-Power-Supply-Converter-Module-G/132613091764?hash=item1ee05b31b4:m:mUxjpGHBQMGT4hfCCCUQolQ

(note, I have never used these, they could be noisy trash for all I know, just an example!).

OE2WHP:
I found a cheap module at amazon based on a MT3608 ( https://www.olimex.com/Products/Breadboarding/BB-PWR-3608/resources/MT3608.pdf ).
I'll give it a try.

Thanks for all the good advice!

Microcheap:
There are a number off boost converters module available on ebay and aliexpress, as OE2WHP pointed.

I was looking at this same subject recently and found some Dave's videos that might be of interest:

https://youtu.be/-V_p1GBH4pk

https://youtu.be/qGp82xhybs4

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod