There are some interesting and unbelievably cheap converters on eBay (i.e. $1.56 + $1 shipping!):
However, in order to force a clean shutdown you'll need to detect loss of input power (voltage comparator circuit on a breadboard cape?), generate an interrupt to the CPU, and have a software driver force a shutdown. The shutdown process might take more time than your supercaps will supply. Might be easier to use a cheap UPS, or keep a few backup SD cards. These converters are small, so you could put one of these on a breadboard cape with your supercaps and a voltage comparator, feed input power to the cape, and power the BBB from the cape, ignoring the 5V connector on the BBB. This converter will accept inputs from 3V-35V. You need to set the output voltage with a trimpot. *http://www.ebay.com/itm/3-35-12V-to-1-2-30V-5V-Auto-DC-Boost-Buck-Converter-Solar-Charge-Regulator-/111071880612?_trksid=p2054897.l4275*<http://www.ebay.com/itm/3-35-12V-to-1-2-30V-5V-Auto-DC-Boost-Buck-Converter-Solar-Charge-Regulator-/111071880612?_trksid=p2054897.l4275> This one produces 5V output and will work with input voltage 0.9V - 5V. *http://www.ebay.com/itm/NEW-DC-DC-Booster-Module-0-9V-5V-5V-600MA-USB-Step-Up-Module-/330986274973?pt=LH_DefaultDomain_0&hash=item4d1051c09d*<http://www.ebay.com/itm/NEW-DC-DC-Booster-Module-0-9V-5V-5V-600MA-USB-Step-Up-Module-/330986274973?pt=LH_DefaultDomain_0&hash=item4d1051c09d> Or this one if you don't want a USB connector for output: *http://www.ebay.com/itm/NEW-DC-DC-Converter-Step-Up-Module-1-5V-5V-500mA-/231018191521?pt=LH_DefaultDomain_0&hash=item35c9c1daa1*<http://www.ebay.com/itm/NEW-DC-DC-Converter-Step-Up-Module-1-5V-5V-500mA-/231018191521?pt=LH_DefaultDomain_0&hash=item35c9c1daa1> -Kevin On Wednesday, January 1, 2014 12:11:53 PM UTC-8, [email protected] wrote: > Hi > Happy New Year > > I would like my BBB to be shot down correctly via shut down or halt > command if power into BBB is interrupted ( and by doing that avoid > corruption of my SD card). > So, I have two supercapacitors - 10F 2.7v connected in series, what I am > looking for is a dc/dc converter ( stepUp) to keep output at 5V even when > voltage from capacitors is slowly dropping. I need about 6 sec for system > to shut down correctly from the moment of power shortage . So up to 500 mA > stepUp voltage regulator. Any idea which one to use?? Anybody worked on > this kind of design?? > Thanks in advance > Robert > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
