ACT5880
Rev 2, 03-Sep-13
rise far beyond a thermal threshold of nominal
100°C. The current reduction is about 50mA/°C for
die temperature over the threshold. This feature
prevents the ACT5880 from excessive junction
temperature and makes it more accommodating of
aggressive thermal designs without risk of damage.
When the thermal regulation reduces the current, it
takes longer time to charge the battery. The thermal
regulation is counted in end of charge detection,
which assures that the battery could be charged to
the same status as a normal charged battery when
the end of charge detected.
in fast-charge state, when the cell is charged with
the fast charge current, or a less current restricted
by the thermal regulation and power source
capability. Once the VVBAT reaches the battery
regulation voltage; the state machine jumps into
Top-Off State.
Table 11:
The State Transition Summary.
CURRENT
STATE
NEXT STATE
CONDITIONS
VCHGIN<VVBAT
Figure 17:
,
SUSCHG=1 or
(total charge timer
time-out)
The Charging Profile of the ACT5880 Charger.
Any state
Sleep
VVBAT
Precondition
ICHARGE
Battery Temp Out
of Range
Top-off
Any state
Temp-Fault
Pre-condition
Temp-Fault
Sleep
Suspend
Fast charge
(or floating)
Battery Temp is OK
Pre-condition timer
times-out.
Fast charge
regulation (current )
VBAT regulation
(voltage )
Time-Fault
Presumably battery
replaced.
Top-off start
(voltage )
Time-Fault
Sleep
Sleep
Precondition
threshold
(voltage )
SUSCHG=0, VCHGIN
valid and VVBAT<
End of charge
threshold
(current )
Fast-Charge
Fast-Charge
Top-Off
(BRV-200mV)
Precondition regulation
(current )
VVBAT>PTV, not
Temp-Fault.
Current =0
Pre-condition
Fast-Charge
t
Expended scale
VVBAT=BRV and not
(Total Charge Time-
Out )
Charger State-Machine
ICHG=IEOC and
not (Charge Time-
Out )
The I and V parameter changes, input condition and
the time-out outputs of 2 timers trigger the state
transitions.
Top-Off
Sleep
Sleep
Pre-condition
VVBAT<PTV
State Transition Table
Note: The PTV stands for pre-condition threshold voltage, the
BRV stands for battery regulation voltage, the ICHG stands for
charge path current and the IEOC stands for end of charge
current.
The LDO mode is a lonely state when the BATID
detection is configured and the BATID reads invalid.
The other states are subset available when the
BATID reads valid or the BATID detection is not
configured. Refer to Table 11 for transition details.
Top-Off State
In the Top-Off state, the cell is charged in constant
voltage mode where the VVBAT is regulated at
battery regulation voltage, which equals to the
charge termination voltage specified in battery
specification. The charge current goes less and less
from the fast charge current as the charging is on
and on, against the chemical and physical
composition changes in the cell. Once the charge
current goes less than the end of charge current
threshold, the state machine jumps into Sleep State
while the cell is recognized as full charged, the
state is also the state of Sleep.
Pre-condition State
When the VVBAT is less than the precondition
threshold voltage, the cell is charged at a reduced
current of either 45mA or 10% of the fast charge
current, whichever is the greater.
Fast-Charge State
When VVBAT is greater than the precondition
threshold and before it reaches to the battery
regulation voltage, or over 200mV falls down from
the battery regulation voltage, the charger operates
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