Datasheet

bq24072, bq24073

bq24074, bq24075, bq24079

www.ti.com

SLUS810I –SEPTEMBER 2008–REVISED JANUARY 2014

PIN FUNCTIONS (continued)

NO. I/O DESCRIPTION

NAME

'72, '73 '74 '75, '79

Timer Programming Input. TMR controls the pre-charge and fast-charge safety timers. Connect TMR to VSS

TMR 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

charger termination. TD is checked during startup only and cannot be changed during operation. See the TD

TD 15 – – I

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.

Termination Current Programming Input. Connect a 0 Ω to 15 kΩ resistor from ITERM to VSS to program the

ITERM – 15 – I termination current. Leave ITERM unconnected to set the termination current to the default 10% termination

threshold.

System Enable Input. Connect SYSOFF high to turn off the FET connecting the battery to the system output.

When an adapter is connected, charging is also disabled. Connect SYSOFF low for normal operation.

SYSOFF – – 15 I

SYSOFF is internally pulled up to V

BAT

through a large resistor (~5 MΩ). Do not leave SYSOFF unconnected

to ensure proper operation.

Fast Charge Current Programming Input. Connect a 590 Ω to 5.9 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 at

ISET 16 16 16 I/O

ISET reflects the actual charging current and can be used to monitor charge current. See the CHARGE

CURRENT TRANSLATOR section for more details.

There is an internal electrical connection between the exposed thermal pad and the VSS pin of the device.

Thermal The thermal pad must be connected to the same potential as the VSS pin on the printed circuit board. Do not

–

Pad 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)

Product Folder Links: bq24072 bq24073 bq24074 bq24075 bq24079