GD32W51x User Manual
132
5.3.
Function overview
Figure 4-3. Power supply overview
provides details on the internal configuration of the PMU
and the relevant power domains.
Figure 4-3. Power supply overview
PMU
CTL
FWDGT
IRC32K
LDO
LXTAL
RTC
WKUPF
IRC16M
HXTAL
PLLs
POR/PDR
BPOR
ADC
Backup Domain
NRST
PA2
PA15
PB2
PA12
V
DD
Domain
WKUPx
WKUPR
V
DD
V
BAT
Power Switch
3.3V
V
BAK
AHB IPs
1.2V Domain
APB IPs
SLEEPING
SLEEPDEEP
1.2V
LVD: Low Voltage Detector
LDO: Voltage Regulator
POR: Power On Reset
PDR: Power Down Reset
BPOR: V
BAK
Power On Reset
WKUPN
LVD
V
DDA
3.3V
V
DDA
Domain
BKP PAD
Cortex-M33
VRFx: RF Power
5.3.1.
Battery backup domain
The Backup domain is powered by the V
DD
or the battery power source (V
BAT
) selected by the
internal power switch, and the V
BAK
pin which drives Backup Domain, power supply for RTC
unit, LXTAL oscillator, BPOR, and two pads, including PC14 to PC15. In order to ensure the
content of the Backup domain registers and the RTC supply, when V
DD
supply is shut down,
V
BAT
pin can be connected to an optional standby voltage supplied by a battery or by another
source. The power switch is controlled by the Power Down Reset circuit in the V
DD
/ V
DDA
domain. If no external battery is used in the application, it is recommended to connect V
BAT
pin externally to V
DD
pin with a 100nF external ceramic decoupling capacitor.
The Backup domain reset sources includes the Backup domain power-on-reset (BPOR) and
the Backup Domain software reset. The BPOR signal forces the device to stay in the reset
mode until V
BAK
is completely powered up. Also the application software can trigger the
Backup domain software reset by setting the BKPRST bit in the RCU_BDCTL register to reset
the Backup domain.