STM32L471RG datasheet(21/218 Pages) STMICROELECTRONICS

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STM32L471xx

Functional overview

3.9.3

Voltage regulator

Two embedded linear voltage regulators supply most of the digital circuitries: the main

regulator (MR) and the low-power regulator (LPR).

•

The MR is used in the Run and Sleep modes and in the Stop 0 mode.

•

The LPR is used in Low-Power Run, Low-Power Sleep, Stop 1 and Stop 2 modes. It is

also used to supply the 32 Kbyte SRAM2 in Standby with RAM2 retention.

•

Both regulators are in power-down in Standby and Shutdown modes: the regulator

output is in high impedance, and the kernel circuitry is powered down thus inducing

zero consumption.

The ultralow-power STM32L471xx supports dynamic voltage scaling to optimize its power

consumption in run mode. The voltage from the Main Regulator that supplies the logic

(VCORE) can be adjusted according to the system’s maximum operating frequency.

There are two power consumption ranges:

•

Range 1 with the CPU running at up to 80 MHz.

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Range 2 with a maximum CPU frequency of 26 MHz. All peripheral clocks are also

limited to 26 MHz.

The VCORE can be supplied by the low-power regulator, the main regulator being switched

off. The system is then in Low-power run mode.

•

Low-power run mode with the CPU running at up to 2 MHz. Peripherals with

independent clock can be clocked by HSI16.

3.9.4

Low-power modes

The ultra-low-power STM32L471xx supports seven low-power modes to achieve the best

compromise between low-power consumption, short startup time, available peripherals and

available wakeup sources:

STM32L471RG датащи(PDF) 21 Page - STMicroelectronics