On 5/28/14, 5:06 AM, "Dr. Michael J. Chudobiak" <[email protected]> wrote:
>> I really donšt see how this can work. First, the supercaps are 2.5v so >>you > >No: > >http://www.digikey.com/product-detail/en/PHB-5R0V505-R/283-3520-ND/2770536 This is really two supercaps placed in series with a small resistor across each to balance the charge. This is not a good solution because the resistors discharge the supercaps with no load but for your application, it probably doesn't matter. > >> PMC wonšt like a short circuit, which the supercap is when it is fully >> discharged. I could go on, but this idea doesnšt make sense to me. > >Same is true of an uncharged battery. The charger circuit is >current-limited. (I pull it up with a diode drop + 10 Ohms to a +5V rail >also, for faster charging.) Batteries should never go to 0V or they will be damaged. Lithium Iron shouldn't be discharged below 2.7V. I'm not sure what happens to the battery charging circuit in the PMU, but my guess is that is will go to some sort of a lockout for safety reasons so I"m not sure if the switchers can run from this energy source. Have you asked anyone at TI if it is OK to use the PMU like this? Perhaps you should post a question on E2E. If you are charging at 440mA, it will take 50 Seconds to reach full charge. What happens when the power fails before that 50 Seconds? I would recommend that you monitor the supercap voltage and wait until it is fully charged before opening any files. It is an interesting concept, but I'm still skeptical if this can really work. Regards, John > > >- Mike > >-- >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.
