Powering the Rgen usb chip bareback

Computer Audio Asylum

Music servers and other computer based digital audio technologies.

''DO NOT use internal reg to charge a lithium battery!

DO NOT under ANY circumstances use the internal 3.3V regulator to charge a lithium battery!!!!

These batteries have a very low impedance, hooking one up to the regulator in the REGEN will try and pull 50A or so out of it, which will current limit down to 1.2A or so. When it does this the voltage will be very low (there is a very low resistance path between the regulator and where the recommendation is to put the battery), which means almost the entire raw supply voltage will be converted to heat by the regulator. For a 7.5V input that is over 8 Watts. This will heat up the reg chip VERY fast, it will hit its thermal limit and drop the voltage even further. The reg chip is designed to live with this temperature for a short time, but it will fry if left in this state for long.

Even worse the whole board will quickly get into this temperature range and many of the other parts on the board are not designed to withstand this temperature, thy will fry within a few minutes of this condition.

So using the internal regulator as a charger for a lithium cell is almost guaranteed to well and truly fry the REGEN.

BTW the above scenario is NOT covered by the warrantee.

John S.

On using a 3.6V charger with the HUB and clock chips.

This will probably work, BUT it places very high stress on the transistors inside the chips, which will radically shorten their lifetime.

So instead of a lifetime measured in decades, you get a lifetime measured in months. It is that long because the chips are done in an older technology which can withstand this for a longer period. With the newer chips it would be weeks.

So yes it will probably work, but not for long.

John S. ''

Proposals made here on diy need to make electrical sense, and I have tried to point out potential issues of doing a bareback mod.

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Parts Connexion

Topic - Powering the Rgen usb chip bareback - fmak 21:45:58 11/30/15 (7)

I was thinking about that too.... - AbeCollins 14:18:34 12/01/15 (4)

RE: I was thinking about that too.... - jkeny 05:53:33 12/02/15 (3)

RE: I was thinking about that too.... - Ryelands 06:37:16 12/02/15 (2)

RE: I was thinking about that too.... - Jim Smith 06:52:26 12/02/15 (1)

RE: I was thinking about that too.... - jkeny 08:45:50 12/02/15 (0)

RE: Powering the Rgen usb chip bareback - SBGK 04:36:06 12/01/15 (1)

Correction: Regen usb chip bareback - fmak 05:29:21 12/01/15 (0)

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