Supply modification the Low Voltage board

eBrnd edited this page Jul 17, 2012 · 3 revisions
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Modification the Power Socket Low Voltage board to 3.3V supply voltage

For power saving purpose the supply voltage inside the power socket is 2.5V. In case of interconnection to external components via mounted header ST1 probably a higher supply voltage 3.3V is needed. This can be done easily by replacing the components IC3, R22 and R24, see this image:

Where to find the components to modify
  • Remove and replace IC3 with LP2985AIM5-3.3 by National Semiconductor.

  • Remove and replace R22, R24 with resistor 82Ω/0603/1% (or 560Ω/0603, read the note).

Note: I 82Ω resistors are too small. The current through the LEDs would be 20mA (according to some online tool). The 3.3V regulator runs much hotter than the 2.5V version, and I think the increased LED current could be a reason for this. I tried 560Ω resistors and the board works fine.