This is still under investigation. The problem has now been narrowed down to be related to switching high loads when the input voltage is high. A solution has not yet been found. If you're curious about the progress, you can track my post on the TI forum here: http://e2e.ti.com/support/power_management/non-isolated_dcdc/f/196/t/390774
I'm pending on folks from SeeedStudio to provide some more measurements in order to be able to proceed. On Mon, Jan 26, 2015 at 2:39 PM, Paul McMahon <[email protected]> wrote: > Ytai, > have you come up with a solution to the problem, that might be rolled into > a new version of IOIO? > I might be building a board which integrates IOIO with some other stuff, > and wonder if you found some solutions to this issue, which don't restrict > Vin or cable length. > thanks > > > On Monday, October 21, 2013 at 8:30:27 PM UTC-4, Ytai wrote: >> >> If you're using 10V or less you can have the wires be as long as you >> want. If you're using *more* than 10V I'd be careful about wire lengths. >> I can give exact numbers, since they highly depend on the specific power >> supply that you're using: how fast it ramps up, how much current it can >> source during ramp-up, etc. >> >> In practice, I've been using 12V, 2A wall adapters for a long time with a >> 1-meter long wire with no problem. LiPo batteries (3S-4S over long wires >> may be more of a problem. >> On Oct 21, 2013 1:47 PM, "kolbe" <[email protected]> wrote: >> >>> Ytai, >>> >>> Could you enter into more detail if possible? >>> >>> Under 10V, OK... but any input on power cord lengths? Say with 9V how >>> long can the cord be without risking damage. >>> >>> Is there still a risk at lower voltages say 7.5V or 6V? >>> >>> Does this problem exist for modern switching supplies? >>> >>> The safest bet I guess is to just bypass the regulator and supply 5V to >>> the board. >>> >>> Maybe put this info as a sticky post. >>> >>> >>> On Monday, September 16, 2013 4:28:34 AM UTC+2, Ytai wrote: >>>> >>>> Hey folks, >>>> >>>> As some of you have noticed, we've had some recurring problems with the >>>> DC/DC regulator on the board getting fried during what appears to be normal >>>> usage. >>>> >>>> With some help from my friends in Shenzhen, we now believe we >>>> understand the root cause of this issue. It has to do with the combination >>>> of large bulk capacitance with low ESR on the power input of the board and >>>> inductance of wires coming from your power supply. The net effect is that >>>> when connecting power to the IOIO, the input voltage may briefly jump to >>>> about twice its nominal value, exceeding the input voltage rating on the >>>> voltage regulator (which is 20V). >>>> >>>> We are now working on a permanent fix, which is likely to require a >>>> board revision. >>>> In the meantime, you can protect your board by: >>>> >>>> - Try to use a lower voltage on the input, ideally 10V or less. >>>> - If that is not an option, use wires that are as short as possible >>>> between your supply and the IOIO. Also, if you have an option to "soft >>>> start" the power supply (ramping the voltage over the course of a >>>> millisecond or so), do so. >>>> >>>> Sorry about that. Will update when I have some news about a fix. >>>> >>>> Ytai >>>> >>>> -- >>> 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/groups/opt_out. >>> >> -- > 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.
