AAT2550
Total Power Solution for Portable Applications
and to maintain the integrity of the data timing for
the system, the pull-up resistor on the data line
Digital Charge Status Reporting
The AAT2550 has a comprehensive digital data
reporting system by use of the DATA pin feature.
This function can provide detailed information
regarding the status of the charging system. The
DATA pin is a bi-directional port which will read back
a series of data pulses when the system microcon-
troller asserts a request pulse. This single strobe
request protocol will invoke one of 13 possible return
pulse counts which the microcontroller can look up
based on the serial report table shown in Table 4.
should be low enough in value so that the DATA
signal returns to the high state without delay. If too
small a pull-up resistor is used, the strobe pulse
from the system microcontroller could exceed the
maximum pulse time and the DATA output control
could issue false status reports. A 1.5kΩ resistor is
recommended when pulling the DATA pin high to
5.0V. If the data line is pulled high to a voltage level
less than 5.0V, the pull-up resistor can be calculat-
ed based on a recommended minimum pull-up cur-
rent of 3mA. Use the following formula:
The DATA pin function is active low and should nor-
mally be pulled high to VADP. This data line may
also be pulled high to the same level as the high
state for the logic I/O port on the system microcon-
troller. In order for the DATA pin control circuit to
generate clean, sharp edges for the data output
VPULL-UP
3mA
RPULL-UP
≤
Number
DATA Report Status
1
2
Chip Over-Temperature Shutdown
Battery Temperature Fault
3
Over-Voltage Turn Off
4
Not Used
5
ADP Watchdog Time-Out in Battery Condition Mode
ADP Battery Condition Mode
6
7
ADP Watchdog Time-Out in Constant Current Mode
ADP Thermal Loop Regulation in Constant Current Mode
ADP Constant Current Mode
8
9
10
11
12
23
ADP Watchdog Time-Out in Constant Voltage Mode
ADP Constant Voltage Mode
ADP End of Charging
Data Report Error
Table 4: Serial Data Report Table.
1.8V to 5.0V
IN
RPULL_UP
IN
AAT2550
Status
DATA Pin
Control
GPIO
OUT
OUT
μP GPIO
Port
Figure 3: Data Pin Application Circuit.
20
2550.2006.07.1.0
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