Board Assembly and Bringup 1

I’m in the process of bringing up the Power Transfer Controller (PTC). When I was 16, I might have loaded everything onto the board at once, then just fired it up. Today, I take a more incremental approach, loading the minimum number of components for the next test. The board is loaded with test points, so testing has been relatively easy so far.

some smt installed
Putting together the board is a very manual process for a hobbyist like me. As I solder parts on, I check them off on the Bill of Materials (BOM). Note the on-the-fly changes to the BOM, either because of parts availability, or design changes to address problems discovered.

I’m soldering by hand with a pair of irons, as I don’t have an SMT hot air tool. If you want to see how…

Come to think of it, my wife has an embossing hot air wand. I might try to use that to anneal the solder joints later. Maybe.

enough parts to actually convert energy
Here is the board with more parts in place. The inductor is just a temporary one. The actual toroid is the yellow thing in the background to the right. Supercapacitors have not been installed yet, nor most of the synchronous rectifiers.  The board as shown is already capable of converting energy.

To bring the board up on the bench, I’ve substituted a laptop power brick for the solar panel, and use incandescent lamps as dummy loads. Although not all parts are loaded,  the correct final devices are mounted – the sole exception being the main inductor.  The final part has 25 leads, and would be hard to remove if redesign was required.

In addition to my multimeter and scope, I use little test programs to stimulate and test sections of the board. Some of the data is gathered by the PTC’s own sensors, and printed to a log file.

So far, here are the things that are working. They correspond roughly to the assembly and bringup order:

  • voltage regulators
  • visibility flasher
  • processor
  • push-button input and indicator LEDs
  • sensors (characterization data below for my later use)
  • analog voltage limit comparator
  • basic power transfer
 Sensor  Zero Reading Base  Sensitivity  Native Reading
 Input Voltage  0 counts  102 mV/count  50 mV/V
 Input Current  106 counts  25 mA/count  200 mV/A
 Mid Current  103 counts  51 mA/count  100 mV/A
 Output Voltage  0 counts  81 mV/count  63 mV/V
 Output Current  103 counts  51 mA/count  100 mV/A
 Temperature  0 counts  0.51 ºC/count  10 mV/ºC
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