Future Copyleft devices

Adam Wang adam at sharism.cc
Fri May 28 05:01:43 EDT 2010


Hi Paul,

> Other think i want ask here to Adam how much current i can pull from the 3.3V pin that
> is labeled next to the GND  under  the battery compartment

I've not been tested precisely. According to p3 of [1] , p5 of [2] &
p33 empty info of [3]. An estimated last current can be

1, The 3.3V is out from U3, the max. consumption is 1.98W.
2, If I3v3(jz4720) is defined for consumption about all
VDDIO/VDDUSB/etc 3v3 to CPU, it still can not exactly be extracted in
[3] with its lack of info. But for a safe thinking, p12 of [3] said
150mW at 240MHz. So we can make an assumption that using 150mW with
45.5mA to all for 3V3 need not including 1.8V in CPU. (Surely this is
not correct!) Then go next iitem.
3,  The last consumption Po (defined in Watt for connecting external
needs ) can be estimately calculate:
    Po =  1.98Wmax - 0.8Wmax( which  is rough 0.759W for
SDRam/Nand/LCD/etc. ) - 0.15Wmax [I3v3(4720)]= 1.03W. This is pretty
safe for said in hypothetical assumption from 2.
4, So now the Po here have 0.312 Ampere in 3V3 at least.

For example this GPS Receiver 50-channel u-blox 5 engine,
http://www.sparkfun.com/commerce/product_info.php?products_id=9566
It has 150mA max in 3V3. Yes, this meets 0.3A of Po.
Anyone who have really been tested your BEN with external connections
using this 3V3 power, sharing experiences are welcome.

Of course from a conscientious and careful thoughts, I suggest you
using an external 3.3V power supply to drive your GPS module.
Meanwhile I am also asking Ingenic for more details.
Hope this helps.
Adam

[1] http://en.qi-hardware.com/w/images/9/9c/Lb60_schematic.pdf
[2] http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U2_3~EUP3406.pdf
[3] http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U1~Jz4720_ds.pdf




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