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(oops, used the wrong "reply" and this just went to Martin the first
time.<br>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">Subject:
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<td>Re: [TriEmbed] Power Supply Testing - Am I over or under
thinking this?</td>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">Date: </th>
<td>Tue, 24 Jun 2014 22:26:13 -0400</td>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">From: </th>
<td>Pete Soper <a class="moz-txt-link-rfc2396E" href="mailto:pete@soper.us"><pete@soper.us></a></td>
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<td>Martin Brooke <a class="moz-txt-link-rfc2396E" href="mailto:martin.brooke@duke.edu"><martin.brooke@duke.edu></a></td>
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The tests I'll be doing with one of these is measuring the
temperature rise for a given current output using an IR
thermometer. We think the thermal pad soldered pretty well, and
Chip designed in a via connection of the pad to a relatively large
ground plane on the bottom side. Per <a moz-do-not-send="true"
href="http://datasheet.octopart.com/TPS63031DSKT-Texas-Instruments-datasheet-10283974.pdf">datasheet
figure 5</a> it appears the challenge will come with low input
voltage (i.e. like with an almost flat lithium cell) and high
current output. I don't expect to see .8A output sustained in this
case (I expect the thermal protection to cut in quickly). That is,
I'll be surprised if the setup can get by without a great deal of
airflow and/or extra heat sink area to reach its current limit in
boost mode while still a mile away from the spec lower limit for
input voltage.<br>
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-Pete<br>
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<div class="moz-cite-prefix">On 06/24/2014 01:46 PM, Martin Brooke
wrote:<br>
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cite="mid:CALjzumpruzL9SjmUYAecwdOduEveJjaN5svY7WKC2NeKY0Bt7Q@mail.gmail.com"
type="cite">
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The data sheet Figure 12 says that at 100mA load current you
will be around 90% +-5% efficient for Battery 5.5V to 2.6 V
after 2.6V you are on your own! For 250mA the efficiency
will be a bit worse particularly at the lower voltages. </div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif;font-size:small"><br>
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<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif;font-size:small">The
voltage will stay at 3.3 V very precisely over that range
but will have a small ripple that will not change.</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif;font-size:small"><br>
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<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif;font-size:small">I
think it will do what you want if used correctly.</div>
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<pre wrap="">_______________________________________________
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