If your source is 25V, you should really consider a switching regulator. If you go to the Digikey web site and search for “7805 replacement”, you will find a switcher
with the same pin out as a 7805 regulator. From: [email protected] [mailto:[email protected]] On Behalf Of Rizalino Antonio de Guzman Sent: Friday, February 19, 2016 8:16 PM To: [email protected] Subject: Re: [beagleboard] Custom Power Supply given that my source voltage is 25V, i assumed that i should scale up this resistor. ill give that a try next time. Thank you Rizalino de Guzman On Feb 19, 2016, at 6:06 PM, Bill Pretty <[email protected]> wrote: Looking at your schematic, I believe that 1K is too large a value. It should be about 240 ohms and R2 should be scaled accordingly. It could be that the LM317 is taking too long to stabilize. You will notice that the application circuit provided by the data sheet uses a 240 ohm resistor. From: [email protected] [mailto:[email protected]] On Behalf Of Rizalino de Guzman Sent: Friday, February 19, 2016 7:06 PM To: BeagleBoard Subject: [beagleboard] Custom Power Supply Hello, I am currently trying to build a power supply based on an LM317 to provide different voltage outputs, powered by a single voltage source. One of the loads is a Beaglebone Black. I'm curious as to why my beaglebone black does not turn on even when my p/s output is a steady 5V (give or take. my simulations show 4.6V while my actual circuit produces around 5.3V). I'm attaching a schematic of my LM317 power supply. When I hook up the beaglebone on a DC power supply, it turns on. Any help would be appreciated. Thanks! -- 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/d/optout. -- 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/d/optout. -- 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/d/optout. -- 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/d/optout.
