06/04/2007 TerraLUX MiniStar5 Model TLE-6EXB for 2 or 3 cell C & D MagLites, drop-in Technical Review. In process...<br />
<br />
<br />
Well, I got bad news as soon as I took it out of the package, it flashed for a moment, then failed to work.  Within a day of notifying Battery Junction, they sent a replacement.  This occured back on the 19th of May, and a replacement was shipped by May 21st!<br />
<br />
<br />
Meanwhile, while waiting for the replacment, I had to travel to a technical conference, and could not look into the failure mode.  The plan was to start a runtime, so it would be done and waiting when I returned home.<br />
<br />
Opening up the module, I first noticed, as typical for all my TerraLUX modules, the epoxy for adhearing the PR base had broken loose.  Additionally, the PR base also moved independent of the internal circuit board, which was odd, as the board in normally soldered onto the PR base. <br />
<br />
Upon unsoldering the board from the Seoul P4, it was clear what had happened to cause the module to cease functioning.  Due to poor process, skill of the assembler, and/or the difficulty of soldering to nickel, the PR base was not adequately heated, the solder flowed upon the metal of the PR base, and likely looked like it was soldered, but it was just sitting on a layer of flux.  Upon installation, since the internal board was not properly soldered, the "solder joint" popped loose from the PR base, breaking the negative, or minus contact to the input power, causing it to cease functioning.<br />
<br />
<br />
<img src="http://www.molalla.net/~leeper/TLE_6EXB_1.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.net/~leeper/TLE_6EXB_2.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.net/~leeper/tle_6EXB_3.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.net/~leeper/TLE_6EXB_4.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.net/~leeper/TLE_6EXB_5.jpg" border="0" alt="" /><br />
<br />
<br />
<br />
As can be seen above, the module utilizes a very low cost, non-synchronous boost switcher chip ZXSC400, in low volumes, the price is under 0.40 ea, yielding one of the lowest cost designs on the market- though, not all that efficient. It is the sister chip to the ZXSC300 that ArcMania uses in his SuperConverter 3, and has similar performance.  It is a throwback to the 2003 timeframe. <br />
<a href="http://www.zetex.com/3.0/pdf/ZXSC400.pdf">ZXSC400</a><br>
<br>
Also found on the board is a 40V 2A schottky, where roughly 10% of the efficiency goes out the door:<br>
<a href="http://www.zetex.com/3.0/pdf/ZHCS2000.pdf">ZHCS2000</a><br>
<br>
And the old infamous very low cost 0.10 to 0.20ea FMMT617 transistor from 2003 timeframe, which is used as the "switch" in this non-synchrous switcher:<br>
<a href="http://www.zetex.com/3.0/pdf/FMMT617.pdf">FMMT617</a><br>
<br>
Also there is the 0.56 ohm resistor, which, when coupled to the 0.3V threshold of the Vfb pin of the ZXSC400, yields very roughly 535.7 mA to the LED, not counting any trace resistances.  The choice of this resistor value should give another 9% losses to the circuit.  The other resistor is to set up the current theshold trip point, which flows thru the inductor.<br />
<br />
The circuit is essentially a very minor variation from one of Zetex's standard application notes for this chip:<br />
<a href="http://www.zetex.com/3.0/appnotes/design/dn79.pdf">Design Note 81</a><br>
<a href="http://www.zetex.com/3.0/appnotes/design/dn81.pdf">Design Note 67</a><br>
<a href="http://www.zetex.com/3.0/appnotes/design/dn67.pdf">Design Note 67</a><br>
<br />
<br />
Measurements:<br />
<br />
First off, we have the Effficiency vs. Input voltage.  Below about 2.2V (see chart below), the module flickers.  The second module flickers below 2.5V.  At about 2.1 to 2.8V (see chart below), the module audibly hisses like a snake.  At about 3.7 to 3.8V (see chart below), the module audibly squeels- the squeel changes frequency with input voltage. <br />
<br />
Since 2D cells under load drop to about 2.8 or less, and are pretty much discharged by 0.9V each (1.8V total), <b>the average efficiency of the TerraLUX PowerPush technology is about 40%.</b> <i>The situation is better in a 3D flashlight, where the efficiency averages 75%.</i>  For less than two dollars of circuitry and PCB, it isn't bad at all for a 3D flashlight efficiency, where for a 2D- well lets just say it sucks and leave it at that.  The module circuit and choice of circuitry implemented appears to be optimized for the absolute lowest possible cost- read as highest possible profit margin.<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_1.png" border="0" alt="" /><br />
<br />
<br />		
Next we have the Input Voltage vs. Watts Out.  You can clearly see the module has zero regulation <i>(TerraLUX PowerPush Regulation <b><- whatever</b>)</i>, and constantly changes very considerably as the input voltage changes.  Above 3.8V, the module is basically in direct drive (zero regulation), and burns up 20% to 30% of the power.<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_2.png" border="0" alt="" /><br />
<br />
<br />
Finally, we have the Power In, vs. Power Out.  This is how the efficiency is determined, for the first chart.  The TerraLUX drop-in module has some odd and interesting behavior, and yes, I went back and re-measured the module, with the same results.  The two modules I have behave similar to each other, but have different "features" at various voltages, and where the flicker, hiss, and squeel stop and start.
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_3.png" border="0" alt="" /><br />
<br />
<br />		
Here are some Oscilloscope captures of the output, measured across the LED:<br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_10.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_11.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_12.jpg" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_13.png" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_14.png" border="0" alt="" /><br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_15.png" border="0" alt="" /><br />
<br />
<br />		
Here is an Oscilloscope capture of the input voltage, measured @ 3.25V:<br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/tle_6EXB_16.jpg" border="0" alt="" /><br />
<br />
<br />
Below is the Lux @ 1 meter vs. hours in dark blue, and temperature of the TerraLUX "heatsink" vs. hours.  The module is not regulated, and in a MagLite 2D host it runs cooler and puts out less light as compared to the 3D host. In a 2D host, the "heatsink" stays 2.5 degrees F below the boiling point of water, unlike the 4D to 6D module I reviewed previously.  Over the first hour and a half, you can see the Lux drop as the module heats up, and then the Lux and Temperature continue to drop after that.  By the most popular version of runtime used, where runtime is determined as the point at which the light reaches 50% output, the runtime would be considered to be 6 hours. <br />
<br />
The tint shifted considerably to a very cold white (bluish white) by an hour and a half. The test was ran without the front window of the MagLite which would drop the Lux further due to losses of the front bezel window, and also the heat would be contained more, causing higher temperatures in actual use- which would drop the Lux readings also.  Tests were performed with a recently purchased MagLite LED host flashlight, and fresh new Duracell batteries with an expiration date of 2014.<br />		
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_20.png" border="0" alt="" /><br />
<br />
<br />
<b> 3D cell testing:</b><br />
<br />
<br />		
Well, on 3D cells, this module did some rather serious shifting to blue, not just to baby blue.  As you can see, the module ran above the temperature of boiling water for most of the runtime, which is likely not good for the LED's longevity.  The temperature peaked at 260.7 degrees Fahrenheit (127.1 degrees C). For the first four hours, the module was in the direct drive "resistor" mode, and then you can see where the boost circuit kicked in (see spikes ~ 4 hours), and again caused a rise in the heatsink temperature.  Due to the extreme temperatures, the Seoul P4 which is used in the module, has a very temperature sensitive phosphor, and you can see how the light output quickly drops to about 50% output.  Keep in mind, even though the Seoul P4 utilizes the CREE EZ1000 die inside of it, they use their own phosphors, which make it different than a CREE XR-E, as well as Seoul epoxies their die down, unlike LumiLEDs, OSRAM, and CREE.  I do have some concerns over the reliability of the LED over time in this application, due to the low cost epoxy attachment method Seoul uses- which is similar to what you'd find in low cost 5mm LEDs.<br />
<br />
For details on the Seoul P4 LED used in this module, see this page here:<br />

<a href="http://www.molalla.net/~leeper/seoulmy.htm" target="_blank">http://www.molalla.net/~leeper/seoulmy.htm</a><br />
<br />
<br />
Finally, we have the 3D host TLE-6EXB runtime graph:<br />
<br />
<br />
<img src="http://www.molalla.com/~leeper/TLE_6EXB_30.png" border="0" alt="" /><br />
<br />
<br />
<br />
<br />

<a href="http://www.molalla.net/~leeper/led.htm">Main site</a><br>
Mirror:<br>
<a href="http://jarhead.hobby-site.com/~jarhead/led.htm">Main site mirror</a><br>

<br>
<br>
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-2114182-1";
urchinTracker();
</script>