LP3925 Datasheet, PDF (13/51 Pages) Texas Instruments – High Performance Power Management Unit for Handset Applications

Startup and Shutdown Sequences
FIGURE 2. Startup and Shutdown Sequences
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The default, factory-programmed power-up sequence of the
PMU can be seen in Figure 2. Startup sequence is triggered
by setting PWR_ON or HF_PWR input high for 100 ms or after
500 ms is passed from the connection of a suitable voltage to
the charger input. Once this time has expired, the start-up
time slots begin. The programmable values of the startup and
shutdown time slots are available in the Default Operating
Settings section at the end of the datasheet. If the Idle state
has been reached from the Startup state, all regulators that
are enabled are on, and their outputs are defined by their
programmed register values. 450 µs in startup/shutdown di-
agram is the time needed for system to perform a shutdown
event.
Note: All the timings are limited by an internal oscillator’s
accuracy.
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