10 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.
10.1 Application Information
A typical design is shown in
. This design uses the BQ25123 with external resistors for ILIM,
IPRETERM, and ISET. These are not needed if these values are set with a host controller through I
2
C
commands. This design also shows the TS resistors, which is also optional.
When powering up in default mode the battery voltage is the default for the part (4.2 V), the SYS output is the
default (1.8 V). External resistors set the charge current to 40 mA, the termination current to 10% (4 mA), and
the input current limit to 100 mA. If the I
2
C interface is used the part goes to the internal default settings until
changed by the host.
10.2 Typical Application
BQ25123
GND
HOST
SDA
SCL
INT
SW
BAT
MCU /
SYSTEM
-
+
NTC
TS
LS / LDO
<100mA
Load
IN
SYS
LSCTRL
VINLS
Unregulated
Load
PMID
IPRETERM
ISET
ILIM
IN
4.7 µF
`
2.2 µH
10 µF
1 µF
14
NŸ
14.3
NŸ
499
Ÿ
4.99
NŸ
4
NŸ
1 µF
1 µF
PG
CD
RESET
MR
Figure 10-1. Typical Application Circuit
SLUSCZ6A – JANUARY 2018 – REVISED MAY 2021
Copyright © 2021 Texas Instruments Incorporated
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