Datasheet

DS10198 Rev 8 23/270
STM32L476xx Functional overview
60
Figure 3. Power-up/down sequence
1. V
DDX
refers to any power supply among V
DDA
, V
DDUSB
, V
DDIO2
, V
LCD
.
3.9.2 Power supply supervisor
The device has an integrated ultra-low-power brown-out reset (BOR) active in all modes
except Shutdown and ensuring proper operation after power-on and during power down.
The device remains in reset mode when the monitored supply voltage V
DD
is below a
specified threshold, without the need for an external reset circuit.
The lowest BOR level is 1.71V at power on, and other higher thresholds can be selected
through option bytes.The device features an embedded programmable voltage detector
(PVD) that monitors the V
DD
power supply and compares it to the VPVD threshold. An
interrupt can be generated when V
DD
drops below the VPVD threshold and/or when V
DD
is
higher than the VPVD threshold. The interrupt service routine can then generate a warning
message and/or put the MCU into a safe state. The PVD is enabled by software.
In addition, the device embeds a Peripheral Voltage Monitor which compares the
independent supply voltages V
DDA
, V
DDUSB
, V
DDIO2
with a fixed threshold in order to ensure
that the peripheral is in its functional supply range.
MSv47490V1
0.3
1
V
BOR0
3.6
Operating modePower-on Power-down time
V
V
DDX
(1)
V
DD
Invalid supply area V
DDX
< V
DD
+ 300 mV
V
DDX
independent from V
DD
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