Не все так однозначно. Правда это из G0, но думаю в L примерно
тоже. When VDD is present, it is possible to charge the external battery on VBAT through an
internal resistance.
The VBAT charging is done either through a 5 ㏀ resistor or through a 1.5 ㏀ resistor
depending on the VBRS bit value in the PWR_CR4 register.
The battery charging is enabled by setting VBE bit in the PWR_CR4 register. It is
automatically disabled in VBAT mode.
С другой стороны
During tRSTTEMPO (temporization at VDD startup) or after a PDR
has been detected, the power switch between VBAT and VDD
remains connected to VBAT.
During the startup phase, if VDD is established in less than
tRSTTEMPO (refer to the datasheet for the value of tRSTTEMPO)
and VDD > VBAT + 0.6 V, a current may be injected into VBAT
through an internal diode connected between VDD and the
power switch (VBAT).
If the power supply/battery connected to the VBAT pin cannot
support this current injection, it is recommended to connect
an external low-drop diode between this power supply and
the VBAT pin.
Andreas (18.05.2020 20:39, просмотров: 452) ответил fk0 на "An internal VBAT battery charging circuit is embedded and can be
activated when VDD is present."