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I'll revisit the email list config parameters with respect to
attachments and total message size. <br>
<br>
I think the TI spec is saying your "control ground" paths go from
their various places to one point ("A") and the power ground paths
go from their places to another point ("B") and "A" and "B" are
connected at exactly one point. The figure for the parameter
measurement information on page 11 of the datasheet shows this
clearly.<br>
<br>
-Pete<br>
<br>
<div class="moz-cite-prefix">On 4/30/2014 7:38 PM, Charles
McClelland wrote:<br>
</div>
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<div><font face="Arial">To all, </font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">I have been looking at a way to improve
my battery life for my trail traffic counters. I am
currently using a linear power supply and with Sleep and
other power savings methods, I can easily get a week on
battery with 4 AA batteries (my board operates at 3.3V with
very low average current and I estimate a 150mA max).</font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">However, I want to do better: </font></div>
<div><font face="Arial"><span class="Apple-tab-span"
style="white-space: pre;"> </span>- For the SD Card
sensor - to go a week on just three AA cells</font></div>
<div><font face="Arial"><span class="Apple-tab-span"
style="white-space: pre;"> </span>- For the wireless
sensor - to go 6 months with a 6V lantern battery</font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">I started looking at Texas Instrument’s
buck-boost switching power supply chips and using their
WeBench tool, designed this circuit.</font></div>
</div>
<div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">What is better, TI sent me three of
these chips for free!</font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">My question is in how I am translating
their schematic into an EAGLE file I can ask OSHPark to make
for me. The schematic has both Control Ground and Power
Ground. And the design report says "Use a ecommon ground
node for power ground and a different one for control ground
to minimize the effects of ground noise. Connect these
ground nodes at any place close to one of the ground pins of
the IC.”</font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">I decided to use a Sparkfun solder
jumper which is normally closed to make the connection
between GND and pGND. But do any of you know a better way -
or could you take a look at my EAGLE files and tell me if I
did this right?</font></div>
<div><br>
</div>
<div><font face="Arial">Here are all the files on drop box - </font><a
moz-do-not-send="true"
href="https://www.dropbox.com/sh/9qdzturvffr66do/3QMS0SvYHP">https://www.dropbox.com/sh/9qdzturvffr66do/3QMS0SvYHP</a></div>
</div>
<div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">Thanks for the help. If this works,
happy to share the design for those who are looking to get
more life out of their batteries.</font></div>
<div><font face="Arial"><br>
</font></div>
<div><font face="Arial">Chip</font></div>
</div>
<br>
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