ACT5880
Rev 2, 03-Sep-13
SINGLE-CELL LI+ BATTERY CHARGER
The charger circuit in the ACT5880 deploys the
constant current and constant voltage scheme for
charging, with pre-condition charging and
suspending. Most parameters for CC/CV control is
programmable, together with the battery installed
detection, the adaptor charging detection, the
battery thermal condition, the die temperature
regulation, the charging time-out counters and the
LDO mode operation, it composes an autonomic-
able, flexible yet powerful battery management sub
system, which satisfies most applications.
precondition finishes, which reduces the time to
wait before start. Additionally, the ACT5880
provides a LDO mode for starting system without
battery.
Figure 15:
The Power Path of the Charger in the ACT5880.
Joint-node
Charger
Control
System
Load
Program and Manipulate
Most of the charging profile control parameters are
programmed by writing respective registers though
the I2C interface. The charge states, the logic inputs
are read and the charge behavior is manipulated
through the same interface by reading or writing
respective bits.
The ACT5880 provides rich of programmability and
effective solutions for dealing with these issues
against system designer's trade-off. The ACT5880
has a pre-condition timer and a total charge timer for
safe charging of a weak/dead battery, and it does not
start the system until the battery voltage is charged
to high enough voltage. The ACT5880 itself is
designed to start at as low voltage as the pre-
condition finishes, which reduces the time to wait
before start. Additionally, the ACT5880 provides a
LDO mode for starting system without battery.
Most programming and manipulation are done with
one time access to respective register. For
changing the battery regulation voltage and the fast
charger current, which are safe related, an enable
bit, the ENVISET[ ] register has to be set firstly, to
avoid the accidental change. Refer to the
REGISTER AND BIT DESCRIPTIONS section for
more details.
When the current goes into load is bigger than the
current threshold for end of charge detection, the
charging termination may never happen. The
system operates in this situation, is known as long
cord powered time operation. In this situation the
system could program the charger to output at a
slightly lower voltage for safe floating.
Power Path Management
The ACT5880 has simple power path management.
Refer to Figure 15, the charger only has one
controlled path for pre-condition charging, fast
charging and providing power to the load. By any
time, the regulated voltage and regulated current
apply to the load and the battery simultaneously.
The load directly pours current from the battery or
from the charge path, provides the most efficient
way of using the energy stored in the battery.
Adaptor Input Detection
The ACIN is the detection of adaptor charging input,
which is a logic input with precise logic thresholds.
A resistor divider can be used for sensing the
voltage applies at the adaptor input receptacle for
simple detection. Ref to the "USB Charging" and
"Dual Input and USB-OTG Paths" for detection of
USB adaptor.
This is the most common path management in
cellular phone and smart phone designs. Few
issues need to be carefully designed for the
optimizing use of this path management:
1.Start from a weak/dead battery;
2.Charging termination.
Battery Installed Detection
A grounded resistor in battery assembly is desired
together with the BATID of the ACT5880 for the
battery installed detection. The BATID is a logic
input with higher voltage precise logic thresholds ,
please refer to the SINGEL-CELL LI+ CHARGER
ELECTRICAL CHARACTERISTICS table for more
details.
The ACT5880 provides rich of programmability and
effective solutions for dealing with these issues
against system designer's trade-off. The ACT5880
has a pre-condition timer and a total charge timer
for safe charging of a weak/dead battery, and it
does not start the system until the battery voltage is
charged to high enough voltage. The ACT5880
itself is designed to start at as low voltage as the
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