ACT81460
Rev 1.0, 18-Dec-2018
START POWER SEQUENCE State
such as fault conditions. Any changes to these registers
are lost when power is recycled. The default values are
fixed and cannot be changed by the factory or the end
user.
The START POWER SEQUENCE state is a transitional
state to power on the regulators. The IC is not intended
to operate in this state. When entering START POWER
SEQUENCE from the SLEEP and DPSLP states, the IC
transitions to the POWER ON state after all regulators
are in regulation.
Basic Non-Volatile – These are R/W and RO. After the
IC is powered, the user can modify the R/W register val-
ues to change IC functionality. Changes in functionality
include things like output voltage settings, startup delay
time, and current limit thresholds. Any changes to these
registers are lost when power is recycled. The default
values can be modified at the factory to optimize IC
functionality for specific applications. Please consult
sales@active-semi.com for custom options and mini-
mum order quantities.
When entering START POWER SEQUENCE from the
POWER OFF state due to an nPBIN press, the IC re-
mains in START POWER SEQUENCE until nPBIN is
released AND the regulators are in regulation. If nPBIN
is released before the regulators are in regulation, the
IC transitions back to the POWER OFF state. If nPBIN
is still pressed and the regulators enter regulation and
one of them has a fault before nPBIN is released, the IC
transitions back to the POWER OFF state.
When modifying only certain bits within a register, take
care to not inadvertently change other bits. Inadvert-
ently changing register contents can lead to unexpected
IC behavior.
When entering START POWER SEQUENCE from the
POWER OFF state due to a power cycle sequence, the
IC stays in START POWER SEQUENCE for 0.5s before
exiting to the ACTIVE state.
STATE MACHINE
The ACT81460 contains an internal state machine with
five internal states: POWER OFF, START POWER SE-
QUENCE, SLEEP/STANDBY, DPSLP (DEEP SLEEP),
and POWER ON.
POWER ON State
The POWER ON state is the main active operating state
when the input voltage is within the allowable operating
range and there are no faults. Each power supply and
load switch output can be programmed to be either ON
or OFF in this state.
POWER OFF State
The POWER OFF state is a PMIC “safe state” or “shut-
down” state. In this state, all the regulator outputs are
turned off. The user cannot configure any of the power
supplies to remain ON in the POWER OFF state and
this is therefore different from the SLEEP and DPSLP
states that allows users to configure these states via
firmware.
The ACT81460 enters the POWER ON state from
START POWER SEQUENCE with a normal nPBIN
startup, an I2C startup, or a power cycle sequence.
The IC can transition to the SLEEP and DPSLP states
with proper control of the I2C bits and external GPIO
inputs. It can transition to the POWER OFF state by set-
ting the I2C MR bit or by the nPBIN pin.
The ACT81460 enters POWER OFF at initial power on
when input power is applied to the IC and VIN is within
a valid range defined by the VIN_UV and VIN_OV
thresholds. nRESET is asserted low and all volatile and
non-volatile registers are reset to defaults. If the input
voltage drops below the VIN_UV threshold voltage, the
IC transitions from any other state to the POWER OFF
state. It is important to note that a transition to POWER
OFF due to VIN_UV returns all volatile and non-volatile
registers to their default states. The ACT81460 can also
enter POWER OFF from any other state due to an
nPBIN press that initiates the power off sequence. The
ACT81460 momentarily enters POWER OFF during a
power cycle sequence. The IC exits the POWER OFF
state when the I2C bit POWER OFF is cleared to 0, or
the nPB pin is pulled low for > 32ms
SLEEP State
The SLEEP state is a low power mode for the operating
system. Each output can be programmed to be on or off
in the SLEEP state. The outputs follow their pro-
grammed sequencing delay times when turning on or
off as they enter or exit the SLEEP state. Buck1/2 can
be programmed to regulate to their VSET0 voltage,
VSET1 voltage, or be turned off in the SLEEP state. The
Buck-Boost, LDOs, Load Switches, and Boost con-
verter can be programmed to regulate to their VSET0
voltage or can be programmed to be turned off. Note
that the LDOs, Load Switches, and Boost converter do
not have a VSET1 voltage.
The IC enters SLEEP state via I2C register bits SLEEP,
SLEEP EN, and SLEEP MODE, plus a GPIO input pin.
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Copyright © 2018 Active-Semi, Inc.
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