BQ24072 Datasheet, PDF (7/38 Pages) Texas Instruments – 1.2A USB-FRIENDLY Li-Ion BATTERY CHARGER AND POWER-PATH MANAGEMENT IC

bq24072, bq24073
bq24074, bq24075
www.ti.com...................................................................................................................................... SLUS810A – SEPTEMBER 2008 – REVISED DECEMBER 2008
TERMINAL FUNCTIONS (continued)
TERMINAL
NAME
NO.
'72, '73 '74
I/O
'75
DESCRIPTION
TMR
Timer Programming Input. TMR controls the pre-charge and fast-charge safety timers. Connect TMR to VSS
14
14
14
I to disable all safety timers. Connect a 18 kΩ to 72 kΩ resistor between TMR and VSS to program the timers
a desired length. Leave TMR unconnected to set the timers to the default values.
Termination Disable Input. Connect TD high to disable charger termination. Connect TD to VSS to enable
TD
15
–
–
I
charger termination. TD is checked during startup only and cannot be changed during operation. See the TD
section in this datasheet for a description of the behavior when termination is disabled. TD is internally pulled
down to VSS with ~285 kΩ. Do not leave TD unconnected to ensure proper operation.
ITERM
Termination Current Programming Input. Connect a 0 Ω to 15 kΩ resistor from ITERM to VSS to program the
–
15
–
I termination current. Leave ITERM unconnected to set the termination current to the default 10% termination
threshold.
SYSOFF
–
System Enable Input. Connect SYSOFF high to turn off the FET connecting the battery to the system output.
–
15
I
When an adapter is connected, charging is also disabled. Connect SYSOFF low for normal operation.
SYSOFF is internally pulled up to V_BAT through a large resistor (~5 MΩ). Do not leave SYSOFF unconnected
to ensure proper operation.
ISET
Fast Charge Current Programming Input. Connect a 590 Ω to 3 kΩ resistor from ISET to VSS to program the
16
16
16
I/O
fast charge current level. Charging is disabled if ISET is left unconnected. While charging, the voltage at ISET
reflects the actual charging current and can be used to monitor charge current. See the SubSec2 1.1 section
for more details.
Thermal
Pad
There is an internal electrical connection between the exposed thermal pad and the VSS pin of the device.
–
The thermal pad must be connected to the same potential as the VSS pin on the printed circuit board. Do not
use the thermal pad as the primary ground input for the device. VSS pin must be connected to ground at all
times.
Table 1. EN1/EN2 Settings
EN2
EN1 Maximum input current into IN pin
0
0
100 mA. USB100 mode
0
1
500 mA. USB500 mode
1
0
Set by an external resistor from ILIM to VSS
1
1
Standby (USB suspend mode)
Copyright © 2008, Texas Instruments Incorporated
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