View Full Version : Interesting article in circuit cellar

12-07-2012, 02:01 PM
The article on the uno power supply was a neat introduction into the thermal management issues associated with linear power supplies. Makes a good case for limiting the range of allowable input voltages for the UNO much further than is currently the case.

I suppose the 3.3v architecture of the Due and Teensy 3.0 could be helpful here - just specify a 5VDC power supply and hence limit the energy that has to be dissipated as heat from the regulator. Also illustrates the value of the oldie 7805 linear regulator in a TO-220 package with its (comparatively) massive heat sink and easy interfacing to standard heat sinks vs. the typical SOT223-3-based regulators found on most boards today.

That said, I could also see why the designers of the UNO wanted to specify a wide input range - it makes it easier to ensure that everything attached to the UNO has the same ground because all devices are attached to the same power supply. On the other hand, the article made a good point of showing how limited the thermal dissipation is for the small board area that the UNO has dedicated to it. The author went as far as epoxying a heat sink...