I have a few questions to use the boost convertor with sleep mode:
1) Table 6-4 in the datasheet (001-84933 Rev. *I) indicates "the chip must wake up periodically for boost active-mode refresh". How to define 'periodically'? Everytime the chip wakes up it uses power so I would like this to be as long a period as possible. Is this simply defined by how much you are willing to allow the VBOOST output to drop due to it being discharged by IBOOST in standby?
2) AN77900 section 3.6 indicates that when using with sleep mode on wakeup to refresh the boost convertor you need to set the boost mode to active and to restore the system clocks. Assuming that I only want to refresh the boost convertor on most wake-ups do I really need to restore the high-speed system clocks at all? Can I not simply put the boost convertor back into sleep mode and go directly to sleep again? Do I need to wait a time while the boost it is active? And if so what's the best way to reduce power during that process?
3) Instead of putting the convertor into sleep mode, if I disable the boost convertor via an API call does VBOOST get actively switched to VBAT (i.e. shorting out the external inductor)? If I re-enable the boost convertor after my RTC wake-up (assuming VBAT stays >1.8V) can I then switch it back on and bring my CPU voltages back up again without issue?
Would very much appreciate it if anyone knows any detail on this.
