Hi Dan,
On 23/10/19 1:39 am, Dan Julio wrote:
> I tried to use the PocketBeagle with the battery and also found the
> extra current draw.  Ultimately I communicated with Octavo and got the
> following reply.  The OSD3358-SM SiP used on the pocketbeagle internally
> connects the LDO1 regulator to both the RTC clock input (VDDS_RTC) as
> well as the VDDS input.  The extra current is taken by the connection to
> the VDDS power input.  The answer from Octavo is copied below.
> 
> https://octavosystems.com/forums/topic/unexpected-current-consumption-with-pmic-sleep-mode-for-battery-charging/#post-6895
>  
>> Unfortunately, the connection between VDDS and LDO1 is internal within
>> the SiP and cannot be modified on the OSD335x and OSD335x-SM.  However,
>> we are in the process of characterizing the OSD335x C-SiP to see if it
>> can support the power use case where VDDS is not connected to LDO1.  We
>> should have that characterization finalized in early January.

Ahh right, so in other words, this is a quirk of the OSD3358 used in the
PocketBeagle that cannot be changed.  I was hoping there was some
register I could kick to fully power off the chip.  Ahh well.

Interesting that it powers the on-chip RTC, as this didn't seem to be
working when we connected a battery, hence we made a new revision of the
board with a I²C RTC (MCP7940N).

We'll put our heads together and see if we can come up with a suitable
switching arrangement that allows automatic disconnection of the
PocketBeagle from the battery when powered off without interfering with
the charging capabilities.

Thankfully it's not like the OSD3358 is drawing kilowatts from that
battery, so we have a few options. :-)
-- 
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
  ...it's backed up on a tape somewhere.

-- 
For more options, visit http://beagleboard.org/discuss
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