Voltage Regulator For Stm32F42Xxx And Stm32F43Xxx - ST STM32F405 Reference Manual

RM0090
regulator can be put either in main regulator mode (MR) or in low-power mode (LPR).
The programmed voltage scale remains the same during Stop mode:
•
In Standby mode, the regulator is powered down. The content of the registers and
SRAM are lost except for the Standby circuitry and the backup domain.
Note: For more details, refer to the voltage regulator section in the STM32F405xx/07xx and
STM32F415xx/17xx datasheets.
5.1.4

Voltage regulator for STM32F42xxx and STM32F43xxx

An embedded linear voltage regulator supplies all the digital circuitries except for the backup
domain and the Standby circuitry. The regulator output voltage is around 1.2 V.
This voltage regulator requires two external capacitors to be connected to two dedicated
pins, V
CAP_1
V or V
SS
package.
When activated by software, the voltage regulator is always enabled after Reset. It works in
three different modes depending on the application modes (Run, Stop, or Standby mode).
•
In Run mode, the main regulator supplies full power to the 1.2 V domain (core,
memories and digital peripherals). In this mode, the regulator output voltage (around
1.2 V) can be scaled by software to different voltage values (scale 1, scale 2, and scale
3 can be configured through VOS[1:0] bits of the PWR_CR register). The scale can be
modified only when the PLL is OFF and the HSI or HSE clock source is selected as
system clock source. The new value programmed is active only when the PLL is ON.
When the PLL is OFF, the voltage scale 3 is automatically selected.
The voltage scaling allows optimizing the power consumption when the device is
clocked below the maximum system frequency. After exit from Stop mode, the voltage
The programmed voltage scale remains the same during Stop mode (see
Section 5.4.1: PWR power control register (PWR_CR) for STM32F405xx/07xx
and STM32F415xx/17xx).
and V available in all packages. Specific pins must be connected either to
CAP_2
to activate or deactivate the voltage regulator. These pins depend on the
DD
RM0090 Rev 18
Power controller (PWR)
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