Hello Gandhar,
I don't really understand table 4-14 in the datasheet.
Minimum main battery high threshold VMBHI (2V5) is lower than minimum main battery low threshold VMBLO (2V55).
My backup voltage is 1V9, supplied by an external LDO (TPS71519) to the BKBAT-pin of the TPS65930, directly supplied from one rechargeable LiIon-cell.
When the voltage of the LiIon-cell drops below minimum input voltage (2V7 @ VPLLA3R.IN for the VRRTC, switching the device off), the clamping circuit should take effect.
Unfortunally the RTC sometimes looses its time, altought BKBAT is always supplied with 1V9, buffered with470nF.
When switching the device off, all other supply voltages for the TPS65930 (except 1V9 @ BKBAT) are cut off.
Do you have any suggestion to avoid the RTC loosing it's time sporadically?
Maybe the TPS65930 thinks there is no power connected at all. (batteries not present, VBNPR)
Regards, Thomas
