BQ25120A Datasheet, PDF (23/67 Pages) Texas Instruments – Low IQ Highly Integrated Battery Charge Management Solution for Wearables and IoT

www.ti.com
bq25120A
SLUSD08 – MAY 2017
9.3.11 Default Mode
The default mode is used when there is no host, or I²C communication is not available. If the externally
programmable pins, ILIM, ISET, and ITERM have resistors connected, that is considered the default mode. If any
one of these resistors is tied to GND, the default register settings are used. The default mode can be entered by
connecting a valid power source to V_IN or the RESET bit is written. Default mode is exited by writing to the I²C
interface.
9.3.12 Termination and Pre-Charge Current Programming by External Components (IPRETERM)
The termination current threshold is user programmable through an external resistor or through registers over
I²C. Set the termination current using the IPRETERM pin by connecting a resistor from IPRETERM to GND. The
termination can be set between 5% and 20% of the programmed output current set by ISET, using Table 3 for
guidance:
Table 3. IPRETERM Resistor Settings
IPRE_CHARGE and ITERM
MIN
TYP
(% of ISET)
MAX
5
10
15
20
KKIPRETERM
RIPRETERM
(STANDARD 1%
VALUES)
UNIT
MIN
TYP
MAX
RECOMMENDED
RIPRETERM
180
200
220
15000
Ω
180
200
220
4990
Ω
180
200
220
1650
Ω
180
200
220
549
Ω
Using the I²C register, the termination current can be programmed with a minimum of 500 µA and a maximum of
37 mA.
The pre-charge current is not independently programmable through the external resistor, and is set at the
termination current. The pre-charge and termination currents are programmable using the IPRETERM registers.
If no IPRETERM resistor is connected and the pin is tied to GND, the default values in the IPRETERM registers
are used. The external value can be used in host mode by configuring the IPRETERM registers. If the external
ICHG setting will be used after being in Host mode, the IPRETERM registers should be set to match the desired
external threshold for the highest ICHG accuracy.
Termination is disabled when any loop other than CV is active.
Copyright © 2017, Texas Instruments Incorporated
Product Folder Links: bq25120A
Submit Documentation Feedback
23