On Wednesday, July 22, 2015 at 1:55:55 AM UTC-6, dl4mea wrote: > > What about adding a 1k resistor from the VBat+ input to ground, just for > safety? > > That should not be necessary. The battery detection logic is complicated, but seems quite robust. Again from the datasheet:
9.3.13 Battery Detection and Recharge > Whenever the battery voltage falls below VRCH, IBAT(DET) is pulled from > the battery for a duration tDET to determine if the battery has been > removed. If the voltage on the BAT pin remains above VLOWV, it indicates > that the battery is still connected. If the charger is enabled (CH_EN = 1), > a new battery charging cycle begins. > If the BAT pin voltage falls below VLOWV in the battery detection test, it > indicates that the battery has been removed. The device then checks for > battery insertion: it turns on the charging path and sources IPRECHG out of > the BAT pin for duration tDET. If the voltage does not rise above VRCH, it > indicates that a battery has been inserted, and a new charge cycle can > begin. If, however, the voltage does rise above VRCH, it is possible that a > fully charged battery has been inserted. To check for this, IBAT(DET) is > pulled from the battery for tDET and if the voltage falls below VLOWV, no > battery is present. The battery detection cycle continues until the device > detects a battery or the charger is disabled. > When the battery is removed from the system the charger will also flag a > BATTEMP error indicating that the TS input is not connected to a thermistor. The one problem I see with the BBB design is that the test currents are applied to the BAT terminals and the battery voltage is measured on the BAT_SENSE terminal. Normally these would be connected at the battery, but they are not connected at all on the BBB. Perhaps connecting TP5 and TP6 with a jumper wire will help. Dennis Cote -- 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.
