Sunday, June 1, 2014

Released design v0.3.0 - Learnings from Stand-alone Alt Reg + SMT conversion

Today I posted v0.3.0 of the controller and LCD remote to the blog (See links above, Schematic, PCB, BOM, CAD files..)  This has been a MAJOR update to the design, with highlights being:
  • Included leanings from Stand Alone Regulator, example:
    • Universal Field FET driver, no more need for stuffing options to support 12-48v, P or N fields.
    • Upgraded to INA226 and fixed divider resisters, no more need for stuffing options voltage sample
    • System pre-regulator now 12v, largely to support universal Field FET driver
  • Revised P-FET drivers to use a constant-current approach and thereby removing stuffing options (System voltage is still limited to 12v or 24v systems, even if Alternator / Field can go to 48v)
  • Increased a bit the robustness of CPU protection, ala adding 100 ohm resisters between clapping diodes and CPU to help protect CPU internal clamping diodes.
  • Moved most components to SMT.

This last change is perhaps the biggest, it will allow machine assembly of most all the low-power components on the board, plus a smaller PCB.   Not only will one no longer need to hand-solder the small SMT parts (esp the INA226's), but by leveraging lower costs in China, we can get the partially assembled PCB w/SMT components for about the same cost as the blank PCBs alone from the prior source.

Note:  Because the pre-regulator was modified (from 9v to 12v to support the FET driver) you MUST use a new LCD remote PCB with this new controller, or modify an existing one to use around a 12v pre-regulator.  The voltages on the CAT-5 interconnect need to be about the same on both ends for the P82B96's to function correctly....

I will be sending this design off for manufacturing Monday.  There is one set of boards not spoken for, if you want it drop me a line.  Else  I will start making a list, and perhaps do a next round if there are enough folks after this.

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