STM32L431 datasheet(21/200 Pages) STMICROELECTRONICS

21 / 200 page

DocID028800 Rev 1

21/200

STM32L431xx

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 16 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 STM32L431xx 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.

•

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 STM32L431xx supports seven low-power modes to achieve the best

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

available wakeup sources:

By default, the microcontroller is in Run mode after a system or a power Reset. It is up to the

user to select one of the low-power modes described below:

•

Sleep mode

In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can

wake up the CPU when an interrupt/event occurs.

•

Low-power run mode

This mode is achieved with VCORE supplied by the low-power regulator to minimize

the regulator's operating current. The code can be executed from SRAM or from Flash,

and the CPU frequency is limited to 2 MHz. The peripherals with independent clock can

be clocked by HSI16.

•

Low-power sleep mode

This mode is entered from the low-power run mode. Only the CPU clock is stopped.

When wakeup is triggered by an event or an interrupt, the system reverts to the low-

power run mode.

•

Stop 0, Stop 1 and Stop 2 modes

Stop mode achieves the lowest power consumption while retaining the content of

SRAM and registers. All clocks in the VCORE domain are stopped, the PLL, the MSI

STM32L431 数据表(PDF) 21 Page - STMicroelectronics

STM32L431 数据表(HTML) 21 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载