A TVS diode is probably a better choice. Zeners cannot handle a lot of current. The problem with TVS is that they have a big voltage gap between when they're fully off to fully on. Am LDO is not a good idea if you have any non trivial load connected to the 5V rail (such as an Android trying to charge itself). It will get extremely hot. Interestingly, when LDOs fail they tend to short the input to the output... On Jun 11, 2014 10:45 PM, "Gustav Sohtell" <[email protected]> wrote:
> Thank you! I'll try that. > > I have about two meters of 24V wire from power source, but I have a 7812 > regulator on the circuit board with the IOIO. Perhaps I should add some > capacitors to even out small ripples or even a 15V zener diode over the VIN. > > Thanks! > > > On Thu, Jun 12, 2014 at 6:20 AM, Ytai Ben-Tsvi <[email protected]> wrote: > >> Yes, you can bypass the 5V VREG with an external one. Before you do that, >> make sure there is no short between 5V and ground caused by the fried VREG. >> If there is, desolder the switcher. Make sure your external supply can >> source at least 1A. Your 3.3V VREG is probably OK. >> To my knowledge, the possible ways to fry the switchers are reverse >> voltage or over-voltage (even very short spikes). The latter may be caused >> by using Vin > 10V over long wires (high inductance). >> >> >> On Wed, Jun 11, 2014 at 9:03 AM, Gustav Sohtell <[email protected]> >> wrote: >> >>> Hi! >>> >>> The same thing has happened to me to two of my IOIOs. They still work >>> when connected to my mac but neither 5V nor 3.3V rail has any voltage when >>> power is connected to VIN. >>> >>> I have two questions: >>> >>> Can I fix them by adding external 5 and 3.3V regulators so that they >>> will still work in host mode? (and check for heat) >>> I tried adding 5V and then connecting to an android tablet but that did >>> not seem to work. >>> >>> Does anyone have any guesses of how I might have broken them? In both >>> cases I'm guessing that I was connecting/disconnecting a USB cable to an >>> Android tablet. Could I have had a grounding error or something? >>> >>> Best regards, >>> Gustav >>> >>> Den lördagen den 5:e april 2014 kl. 16:33:14 UTC+2 skrev Lagz Moncs: >>> >>>> Okay I will try that, thanks. >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "ioio-users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/ioio-users. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "ioio-users" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/ioio-users/RqHb02KU5G4/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/ioio-users. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "ioio-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/ioio-users. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "ioio-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/ioio-users. For more options, visit https://groups.google.com/d/optout.
