[Gta04-owner] Short circuit on USB in B-mode -> gta04 off

Dr. H. Nikolaus Schaller hns at goldelico.com
Wed Aug 15 22:35:04 CEST 2012


Hi,

Am 15.08.2012 um 18:23 schrieb Andreas Kemnade:

> Hi,
> 
> I accidentially had a short circuit on the usb plug from +5V to the
> shield. That behaviour was not so expected. If the gta04 is
> in software-controlled linear charging mode, the gta04 turns off and
> does not turn on again. After some tries I removed the battery
> and put it in again and it booted again and everything seems fine.
> 
> What does happen here? Does the protection circuit in the battery

The shield is on GND, i.e. it is like partially unplugging and replugging
a charger. Maybe the TPS65950 did detect a voltage drop below a certain
voltage and accepted that as a command to stop charging and switch off the
device. But did not recognize the again rising voltage as a plug-in event
which usually powers on and boots the device.

It may also be that the kernel driver (you said software controlled charging)
is not prepared for this very special state but did not get time to write a log
file...

> power off the device or the twl4030 chip? Would I have an
> explosion here if there was a standard BL-6C battery in the device?
> Not that I plan to repeat that...

There is no reason to expect that by shorting the USB power input.

> Maybe if there is the GTA04 -> GTA05 mainboard upgrade in my post
> box ;-)

I will keep that for me :)

BR,
Nikolaus




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