ACT8810QJ62C-T View Datasheet(PDF) - Active-Semi, Inc
Part Name
Description
MFG CO.
'ACT8810QJ62C-T' PDF : 54 Pages View PDF
ACT8810
Rev 9, 15-Nov-12
ActivePathTM CHARGER
FUNCTIONAL DESCRIPTION CONT’D
two current-limited nSTAT0 and nSTAT1 outputs
that can directly drive LED indicators or provide a
logic-level status signal to the host microprocessor.
Dynamic Charge Current Control (DCCC)
The ACT8810's ActivePath Charger features
Dynamic Charge Current Control (DCCC) circuitry,
which continuously monitors the input supply to
prevent input overload conditions. DCCC reduces
the charge current when the VSYS voltage
decreases to VDCCC and stops charging when VSYS
drops below VDCCC by 1.5% (typical).
The DCCC voltage threshold is programmed by
connecting a resistor from DCCC to GA according
to the following equation:
VDCCC = 2 × (IDCCC × RDCCC)
(2)
Where RDCCC is the value of the external resistor,
and IDCCC (100µA typical) is the value of the current
sourced from DCCC.
Given the tolerances of the RDCCC and IDCCC ,the
DCCC voltage threshold should be programmed to
be no less than 3.3V to prevent triggering the
UVLO, and to be no larger than 4.4V to prevent
engaging DCCC prematurely. A 19.1k (1%), or
18.7k (1%) resistor for RDCCC is recommended.
Charger Current Programming
The ACT8810's ActivePath charger features a
flexible charge current-programming scheme that
combines the convenience of internal charge
current programming with the flexibility of resistor
based charge current programming. Current limits
and charge current programming are managed as a
function of the ACIN and CHGLEV pins, in
combination with RISET, the resistance connected to
the ISET pin.
ACIN and CHGLEV Inputs
ACIN is a logic input that configures the current-limit
of ActivePath's linear regulator as well as that of the
battery charger. ACIN features a precise 1.25V
logic threshold, so that the input voltage detection
threshold may be adjusted with a simple resistive
voltage divider. This input also allows a simple, low-
cost dual-input charger switch to be implemented
with just a few, low-cost components.
When ACIN is driven to a logic high, the ActivePath
operates in “AC-Mode” and the charger charges at
the current programmed by RISET,
ISET (mA) = KISET × 1V/(RISET (kΩ) +0.031) (3)
where KISET = 628 when CHGLEV is driven to a
logic high, and KISET = 314 when CHGLEV is driven
to a logic low.
When ACIN is driven to a logic-low, the ActivePath
circuitry operates in “USB-Mode”, which enforces a
maximum charge current setting of 500mA, if
CHGLEV is driven to a logic-high, or 100mA, if
CHGLEV is driven to a logic-low.
The ACT8810's charge current settings are
summarized in the table below:
Table 19:
ACIN and CHGLEV Inputs Table
ACIN CHGLEV
CHARGE
CURRENT
ICHG (mA)
PRECONDITION
CHARGE CURRENT
ICHG (mA)
0
0
90mA or ISET 90mA or 12%ISET
(Smallest one) (Smallest one)
0
1
450mA or ISET
(Smallest one)
12% × ISET
1
0
50% × ISET
12% × ISET
1
1
ISET
12% × ISET
Note that the actual charging current may be limited
to a current that is lower than the programmed fast
charge current due to the ACT8810’s internal
thermal regulation loop. See the Thermal
Regulation and Protection section for more
information.
Battery Temperature Monitoring
The ACT8810 continuously monitors the
temperature of the battery pack by sensing the
resistance of its thermistor, and suspends charging
if the temperature of the battery pack exceeds the
safety limits.
In a typical application, shown in Figure 11, the TH
pin is connected to the battery pack's thermistor
input. The ACT8810 injects a 100µA current out of the
TH pin into the thermistor, so that the thermistor
resistance is monitored by comparing the voltage at
TH to the internal VTHH and VTHL thresholds of 0.5V
and 2.5V, respectively. When VTH > VTHL or VTH < VTHH
charging and the charge timers are suspended. When
VTH returns to the normal range, charging and the
Innovative PowerTM
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
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www.active-semi.com
Copyright © 2012 Active-Semi, Inc.
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