lpcware

external power for EA baseboard

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by sravet on Sat Jan 01 21:45:03 MST 2011
I'd like to power the EA baseboard, with mbed attached, with a LiPo battery.  A single cell 3.7 volts is too low to attach to VIN, since the onboard regulator has a dropout voltage of 1.2V.  Minimum VIN is therefore 4.5V as  noted in the baseboard schematic.  The schematic also says max VIN is 5.5V.

From looking at the SP1117 datasheet I think input voltage can be much higher than 5.5V, as long as you don't exceed the limit on internal power dissipation of the regulator.  I'll need to measure the total draw from the 3.3V supply for that, too bad there isn't a current measuring jumper for that.

Am I right in thinking that a 7.4V LiPo battery pack is fine to attach to VIN, subject to being careful about regulator power dissipation?

Also, has the baseboard regulator PCB design been characterized for thermal transfer as described in the SIP1117 datasheet?

thanks,
--steve

Outcomes