ACT5880
Rev 2, 03-Sep-13
curves. The top-off portion of curves, which is in
shorter period comparing to the fast charge period,
are plotted with expended time scale for showing in
detail.
Figure 16:
The Battery Installation Detection Circuit.
CHGIN
ACT5880
Summary of Key Specifications
Battery
Assembly
RIDUP
Table 10:
The Key Specification of the Charger Block.
BATID
RID
PARAMETER
VOLUME
TYPE
Battery Regulation
Voltage (V)
Refer to Figure 16, the RID is known as battery
identification resistor in many commodity battery
pack designs, which is also used to identify the
battery model for the system. The resistance of RID
could be specified by ordering the battery pack, or
be whatever the commodity battery packs have, for
examples, the Nokia BLB-2 has a 68kꢀ resistor and
the Nokia BLC-2 has a 75kꢀ resistor. The RIDUP is
recommended to pull up to CHGIN, whose
resistance is derived from the thresholds and the
suitable charging voltage range.
4.10 to 4.40 Programmable
90 to 1000 Programmable
Fast Charge Current
(mA)
End-of-Charge Current
Residual Ratio
10.00%
180 to 300
2.8
Fixed
Total Charge Time-out
(minutes)
Programmable
or Disabled
Pre-condition Threshold
(V)
Fixed
Fixed
Pre-condition Current
(mA, or %/Fast Charge
Current)
The battery installed detection works only when
there is suitable charging voltage applied on the
CHGIN, no power loss occurs if not attaching onto
an external power source. When there is an
external power available at the CHGIN, the logic
level at the BATID decides if to operate as a normal
CCCV charger or to operate in LDO mode, in which
the charger regulator works like a LDO for
outputting the battery regulation voltage. When the
voltage the CHGIN is higher than the "No Battery
Installation Level" specified in the electrical
characteristics table, the charger is in LDO mode,
the maximum charge current still works to limit the
maximum output current.
45mA or
10%
Pre-condition Time-out
(minutes)
Programmable
or disabled
40 to 80
Operation Voltage (V)
UVLO Voltage (V)
4.2 to 6
3.1, 4
Fixed
Programmable
Over Voltage Threshold
(V)
6.3 to 6.9
Programmable
Input Voltage Range (V)
Regulation Die Temp(°C)
Hot Threshold, %
0 to 7
140 max.
34.9
Fixed
Fixed
Fixed
Fixed
When the battery does not have an ID resistor,
ground the BATID with a resistor to force the logic
level is equal to battery installed for normal charge
operation; Or connect it to an I/O of the system to
allow the system to control the logic level.
Cold Threshold, %
74.8
Charge Current Sharing
The charge current may go into the battery or the
load, decided by their dynamic impedances. During
Top-off state or floating, the fast voltage regulation
loop puts most current into the charger path until
the charge path current reaches the fast charge
current limit, reduces the AC current into battery.
This prevents the battery from aging caused by
continuous passing AC current.
CC/CV Charging Profile
The core of the charger is a state machine which
manages the state transitions for the CC/CV
charging with a precondition state. The state
machine waits for the available condition for
operation. If the input power is available and battery
is detected, it monitors either the voltage at VBAT
or the current through the charge path, and
regulates either the current or the voltage, as the
profile showed in Figure 17. The profile is showed
in time plane with typical I and V change to time
Thermal Regulation
The ACT5880 has an internal thermal feedback
loop that reduces the charge current when
necessary to ensure the die temperature does not
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