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DV
CC
Voltage
V
CORE
SVS
_IT+
L
SVS
L_IT-
SVS
H_IT+
SVS
H_IT-
Time
BOR
PMM Operation
2.2
PMM Operation
2.2.1 V
CORE
and the Regulator
DV
CC
can be powered from a wide input voltage range, but the core logic of the device must be kept at a
voltage lower than what this range allows. For this reason, a regulator has been integrated into the PMM.
The regulator derives the necessary core voltage (V
CORE
) from DV
CC
.
The regulator supports two different load settings to optimize power. The high-performance mode is active
when:
•
The CPU is in active, LPM0, LPM1, or LPM2 modes
•
A clock source greater than 100 kHz is used to drive any module
•
An interrupt or DMA transfer is executed
•
JTAG is active
Otherwise, the low-power mode is used. The hardware controls the load settings automatically, according
to the criteria above.
2.2.2 Supply Voltage Supervisor
The high-side supervisor (SVS
H
) and the low-side supervisor (SVS
L
) oversee DV
CC
and V
CORE
,
respectively. The high-side supervisor (SVS
H
) is always active in all power modes. It can be disabled only
in LPM4.5 with SVSHE = 0. By default the low-side supervisor (SVS
L
) is enabled in active mode, LPM0,
LPM1, and LPM2. It can be disabled in LPM1 and LPM2 with SVSLE = 0. The SVS
L
is always disabled in
LPM3, LPM3.5, LPM4, and LPM4.5.
2.2.2.1
SVS Thresholds
As
shows, there is hysteresis built into the supervision thresholds, such that the thresholds in
force depend on whether the voltage rail is going up or down.
The behavior of the SVS according to these thresholds is best portrayed graphically.
shows
how the supervisors respond to various supply failure conditions.
Figure 2-2. High-Side and Low-Side Voltage Failure and Resulting PMM Actions
63
SLAU272C – May 2011 – Revised November 2013
Power Management Module and Supply Voltage Supervisor
Copyright © 2011–2013, Texas Instruments Incorporated