Safe way to power 5V MP3 speaker box from 5/6 dry cells without damaging memory card

I have a speaker box which plays audio from mp3 files from flash memory card and runs on 5 V dc ,
came with a cellphone type rechargable battery which requires charging through external USB port
problem is battery doesn't last more than 30 min
I wld like to supply DC power using 5/6 dry cells each of 1.5 V
what kind of Circuit/IC is needed in between dry cells and the speaker box?
I tried it directly before but memory card got damaged
Any explanation and solution?

pls do not mention components commercially available in US

Hi Aniket,

Well, memory card runs only at 2.7V-3.6V. it is quite sensitive when it comes about voltage range. The USB port runs on 5V, USB reader and other related devices has its built-in voltage translator in order to ensure that the output voltage ranges 2.7V-3.6V.

If you want to power up your speaker box with USB cable or cable with adapter. You should create a circuit that could provide you 2.7V-3.6V like voltage divider circuit using resistor or voltage regulators or simply diode in parallel assuming that you know how to manipulate those things.

God Bless.

Best,
Neil

The first order of business is to determine the total current draw of the device. Once you have this information, you can then calculate how long a particular set of batteries will last, and then look at either a simple LDO, or even employ a buck/boost to get the last bit of charge from the batteries. Also review the battery chemistries, some will drain off slowly and the voltage reduced, others keep the voltage up until they drop off the cliff. I wont tell you which ones, its a good exercise to understand to apply the correct solution to your problem