ACT8946AQJ203-T
Rev 1.0, 08-Jul-16
circuitry automatically reduces charge current in
order to prevent VVSYS from continuing to drop.
when the input is connected, disconnected, or both.
An interrupt is generated any time the input supply
is connected when INSTAT[ ] bit is set to 1 and the
INCON[-] bit is set to 1, and an interrupt is
generated any time the input supply is disconnected
when INSTAT[ ] bit is set to 1 and the INDIS[ ] bit is
set to 1.
Charge Current Programming
The ACT8946A'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.
INDAT[-] indicates the status of the CHGIN input
supply. A value of 1 indicates that a valid CHGIN
input (CHGIN UVLO Threshold<VCHGIN<CHGIN
OVP Threshold) is present, a value of 0 indicates a
valid input is not present.
When an interrupt is generated by the input supply,
reading the INSTAT[ ] returns a value of 1.
INSTAT [ ] is automatically cleared to 0 upon
reading. When no interrupt is generated by the
input supply, reading the INSTAT[ ] returns a value
of 0.
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 1.2V 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 responding to an Input Status Interrupt, it is
often useful to know the state of the ACIN input. For
example, in
a
dual-input charger application
When the voltage at ACIN is above the 1.2V
threshold, the charger operates in “AC-Mode” with a
charge current programmed by RISET, and the RISET
is given by:
knowing the state of the ACIN input can identify
which type of input supply has been connected. The
state of the ACIN input can be read at any time by
reading the ACINSTAT[-] bit, where a value of 1
indicates that the voltage at ACIN is above the 1.2V
threshold (indicating that a wall-cube has been
attached), and a value of 0 indicates that the
voltage is below this threshold (indicating that ACIN
input is not valid and USB supply input is selected).
RISET (kΩ) = 2336 × (1V/ICHG (mA)) - 0.205
With a given RISET then charge current will reduce 5
times when CHGLEV is driven low.
When ACIN is below the 1.2V threshold, the
charger operates in “USB-Mode”, with a maximum
CHGIN input current and charge current defined by
the CHGLEV input; 450mA, if CHGLEV is driven to
a logic-high, or 100mA, if CHGLEV is driven to a
logic-low.
Thermal Regulation
The charger features an internal thermal regulation
loop that monitors die temperature and reduces
charging current as needed to ensure that the die
temperature does not exceed the thermal regulation
threshold of 110°C. This feature protects against
excessive junction temperature and makes the
device more accommodating to aggressive thermal
designs. Note, however, that attention to good
thermal designs is required to achieve the fastest
possible charge time by maximizing charge current.
The ACT8946A's charge current settings are
summarized in Table 7.
Table 7: ACIN and CHGLEV Inputs
CHARGE
CURRENT
(mA)
PRECONDITION
CHARGE CURRENT
(mA)
ACIN CHGLEV
Charge Safety Timers
0
0
1
1
0
1
0
1
90
450
45
The charger features programmable charge safety
timers which help ensure a safe charge by
detecting potentially damaged cells. These timers
are programmable via the PRETIMO[1:0] and
TOTTIMO[1:0] bits, as shown in Table 8 and Table
9. Note that in order to account for reduced charge
current resulting from DCCC operation in thermal
regulation mode, the charge time-out periods are
extended proportionally to the reduction in charge
current. As a result, the actual safety period may
exceed the nominal timer period.
45
ICHG/5
ICHG
10% × ICHG
10% × ICHG
Note that the actual charge current may be limited
to a current lower than the programmed fast charge
current due to the ACT8946A’s internal thermal
regulation loop. See the Thermal Regulation section
for more information.
Charger Input Interrupts
Charger Timer Interrupts
The charger features the ability to generate
interrupts based upon the status of the charge
timers. Set the TIMRPRE[
TIMRSTAT[ ] bit to 1 to generate an interrupt when
In order to ease input supply detection and
eliminate the size and cost of external detection
circuitry, the charger has the ability to generate
interrupts based upon the status of the input supply.
This function is capable of generating an interrupt
]
bit to
1 and
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