BQ24072T_2 Datasheet, PDF (8/36 Pages) Texas Instruments – 1.5A USB-Friendly Li-Ion Battery Charger and Power-Path Management IC

bq24072T
bq24075T, bq24079T
SLUS937A – DECEMBER 2009 – REVISED APRIL 2010
www.ti.com
NAME
IN
PIN
NUMBER
bq24072T bq24075T
bq24079T
13
13
TMR
14
14
SYSOFF
–
15
TD
15
–
ISET
16
16
Thermal
–
--
Pad
TERMINAL FUNCTIONS (continued)
I/O
DESCRIPTION
I Input Power Connection. Connect IN to the external DC supply (AC adapter or USB port).
The input operating range is 4.35V to 6.6V. The input accepts voltages up to 26V without
damage, but operation is suspended. Bypass IN to VS with a 1mF to 10mF ceramic
capacitor.
I Timer Programming Input. TMR controls the pre-charge and fast-charge safety timers.
Connect TMR to VSS to disable all safety timers. Connect a 18kΩ to 72kΩ resistor between
TMR and VSS to program the timers to a desired length. Leave TMR unconnected to set
the timers to the default values.
I System Enable Input. Connect SYSOFF high to turn off the FET connecting the battery to
the system output. When an adapter is connected, charge is also disabled. Connect
SYSOFF low for normal operation. SYSOFF is internally pulled up to VBAT through a large
resistor (~5MΩ). Do not leave SYSOFF unconnected to ensure proper operation.
I Termination Disable Input. Connect TD high to disable charger termination. Connect TD to
VSS to enable 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.
I/O Fast Charge Current Programming Input. Connect a 590 Ω to 3 kΩ resistor from ISET to
VSS to program the fast charge current level. Charging is disabled if ISET is left
unconnected. While charging, the voltage ISET reflects the actual charging current and can
be used to monitor charge current. See the Charge Current Translator section of this
datasheet for more details.
– 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 must be connected to ground at all times.
Table 1. EN1/EN2 Settings
EN2
EN1
MAXIMUM INPUT CURRENT INTO IN
0
0 100 mA. USB100 mode
0
1 500 mA. USB500 mode
1
0 Set by external resistor from ILIM to VSS
1
1 Standby (USB suspend mode)
8
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