STM32F302xx/STM32F303xx
Functional overview
3.7
Power management
3.7.1
Power supply schemes
●
V
, V = 2.0 to 3.6 V: external power supply for I/Os and the internal regulator. It is
SS DD
provided externally through V pins
DD
●
V
, V
= 2.0 to 3.6 V: external analog power supply for ADC, DACs, comparators
DDA
SSA
operational amplifiers, reset blocks, RCs and PLL (minimum voltage to be applied to
is 2.4 V when the DACs and operational amplifiers are used). The V voltage
V
DDA
DDA
level must be always greater or equal to the V voltage level and must be provided
DD
first.
●
V
= 1.65 to 3.6 V: power supply for RTC, external clock 32 kHz oscillator and backup
BAT
registers (through power switch) when V is not present.
DD
3.7.2
Power supply supervisor
The device has an integrated power-on reset (POR) and power-down reset (PDR) circuits.
They are always active, and ensure proper operation above a threshold of 2 V. The device
remains in reset mode when the monitored supply voltage is below a specified threshold,
VPOR/PDR, without the need for an external reset circuit.
●
The POR monitors only the V supply voltage. During the startup phase it is required
DD
that V
should arrive first and be greater than or equal to V
.
DDA
DD
●
The PDR monitors both the V and V
supply voltages, however the V
power
DDA
DD
DDA
supply supervisor can be disabled (by programming a dedicated Option bit) to reduce
the power consumption if the application design ensures that V is higher than or
DDA
equal to V
.
DD
The device features an embedded programmable voltage detector (PVD) that monitors the
power supply and compares it to the VPVD threshold. An interrupt can be generated
V
DD
when V drops below the V
threshold and/or when V is higher than the V
DD
PVD
DD PVD
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.
3.7.3
Voltage regulator
The regulator has three operation modes: main (MR), low power (LPR), and power-down.
●
●
●
The MR mode is used in the nominal regulation mode (Run)
The LPR mode is used in Stop mode.
The power-down mode is used in Standby mode: the regulator output is in high
impedance, and the kernel circuitry is powered down thus inducing zero consumption.
The voltage regulator is always enabled after reset. It is disabled in Standby mode.
Doc ID 023353 Rev 5
15/133
STMICROELECTRONICS [ ST ]
