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GD32L23x User Manual
65
3.3.
Function overview
Figure 3-1. Power supply overview
provides details on the internal configuration of the PMU
and the relevant power domains.
Figure 3-1. Power supply overview
PMU
CTL
FWDGT
IRC32K
NPLDO/
LPLDO
LXTAL
RTC
WKUPF
IRC16M
HXTAL
PLLs
POR/PDR
BPOR
ADC
Backup Domain
NRST
PA0
PC13
PA2
PB2
PC6
V
DD
Domain
WKUPx
WKUPR
V
DD
V
BAT
Power Switch
3.3V
V
BAK
AHB IPs
1.1V Domain
APB IPs
SLEEPING
SLEEPDEEP
1.1/0.9V
LVD: Low Voltage Detector
NPLDO: Normal power Voltage Regulator
POR: Power On Reset
PDR: Power Down Reset
BPOR: V
BAK
Power On Reset
WKUPN
LVD
DAC
V
DDA
3.3V
V
DDA
Domain
IRC48M
BKP PAD
Cortex-M23
LPLDO: Low power Voltage Regulator
3.3.1.
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 and BPOR, and three pads, including PC13 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.
The clock source of the Real Time Clock (RTC) circuit can be derived from the Internal 32KHz