
DocID024597 Rev 5
155/1830
RM0351
Power control (PWR)
198
contents of the registers, SRAM1 and SRAM2.
•
In Stop 1 and Stop 2 modes, the main regulator is off and the low-power regulator
(LPR) supplies low power to the V
CORE
domain, preserving the contents of the
registers, SRAM1 and SRAM2.
•
In Standby mode with SRAM2 content preserved (RRS bit is set in the PWR_CR3
register), the main regulator (MR) is off and the low-power regulator (LPR) provides the
supply to SRAM2 only. The core, digital peripherals (except Standby circuitry and
backup domain) and SRAM1 are powered off.
•
In Standby mode, both regulators are powered off. The contents of the registers,
SRAM1 and SRAM2 is lost except for the Standby circuitry and the backup domain.
•
In Shutdown mode, both regulators are powered off. When exiting from Shutdown
mode, a power-on reset is generated. Consequently, the contents of the registers,
SRAM1 and SRAM2 is lost, except for the backup domain.
5.1.7 VDD12
domain
VDD12 is intended to be connected with external SMPS (Switched-mode Power Supply) to
generate the V
CORE
logic supply in Run, Sleep and Stop 0 modes only.
VDD12 pins correspond to the internal V
CORE
powering the digital part of Core, RAMs,
FLASH and peripherals. This improves significantly power consumption gain from 50% or
more depending of the SMPS performances.
The main benefit occurs in Run and Sleep modes whereas in Stop 0 mode, the gain is less
significant.
The
shows a schematic to understand how the internal regulator stops supplying
V
CORE
when an external voltage VDD12 is provided.
As VDD12 shares the same pin as output of the internal regulator, applying a slightly higher
voltage (typ50 mV) on the VDD12 blocks the PMOS and the regulator consumption
is negligible.
Figure 10. Internal main regulator overview
A switch, controlled by chosen GPIO, is inserted between the SMPS output and VDD12.
There are two possible states:
•
Connected: Switch is closed so SMPS powers VDD12
•
Disconnected: Switch is open and VDD12 is disconnected from SMPS output
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