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Subject: Re: Questions about LiIon charger circuit and power drain

Re: Questions about LiIon charger circuit and power drain

From: Linus Nielsen Feltzing <>
Date: Tue, 17 Aug 2004 19:41:17 +0200

Christi Alice Scarborough wrote:

> 1) The charger circuit has a PROG pin, which can be used to indicate
> charging progress in the constant voltage stage of LiOn charging. Is
> this wired up on the JB in such a way that V(PROG) is available to Rockbox?

Yes. It is connected to A/D channel 7 (ADC_EXT_POWER). See powermgmt.c
for a (limited) use of it.

> 2) What is the value of R(PROG) in the Jukebox? If I can find this out,
> then I can work out what current is being applied in the constant
> current stage of charging.

It depends on the power source, USB or external DC. I have my notes at
home, I'll check it out when I get home.

> 3) (Personal curiosity) If the circuit shuts down automatically, how
> come my JB remains hot when plugged into the mains?

It never stops charging, AFAIK, it keeps on charging with a very low


Received on 2004-08-17

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