BQ25120A Datasheet, PDF (24/67 Pages) Texas Instruments – Low IQ Highly Integrated Battery Charge Management Solution for Wearables and IoT

bq25120A
SLUSD08 – MAY 2017
www.ti.com
9.3.13 Input Current Limit Programming by External Components (ILIM)
The input current limit threshold is user programmable through an external resistor or through registers over I²C.
Set the input current limit using the ILIM pin by connecting a resistor from ILIM to GND using Table 4 for
guidance. If no ILIM resistor is connected and the pin is tied to GND, the default ILIM register value is used. The
external value is not valid once the device enters host mode.
MIN
0.048469388
0.09047619
0.146153846
0.19
0.285714286
0.380761523
ILIM
TYP
0.051020408
0.095238095
0.153846154
0.2
0.30075188
0.400801603
MAX
0.053571429
0.1
0.161538462
0.21
0.315789474
0.420841683
Table 4. ILIM Resistor Settings
KILIM
MIN
TYP
MAX
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
RILIM
(STANDARD 1%
VALUES)
3920
2100
1300
1000
665
499
UNIT
Ω
Ω
Ω
Ω
Ω
Ω
The device has register programmable input current limits from 50 mA to 400 mA in 50-mA steps. The device is
USB-IF compliant for inrush current testing, assuming that the input capacitance to the device is selected to be
small enough to prevent a violation (<10 µF), as this current is not limited.
9.3.14 Charge Current Programming by External Components (ISET)
The fast charge current is user programmable through an external resistor or through registers over I²C. Set the
fast charge current by connecting a resistor from ISET to GND. If no ISET resistor is connected and the pin is
tied to GND, the default ISET register value is used. While charging, if the charge current is using the externally
programmed value, the voltage at ISET reflects the actual charging current and can be used to monitor charge
current. The current out of ISET is 1/100 (±10%) of the charge current. The charge current can be calculated by
using Table 5 for guidance:
MIN
0.285714286
0.19
0.126666667
0.095
0.06462585
0.048469388
0.038076152
0.031456954
0.025956284
0.019
0.012666667
0.0095
0.006462585
0.004846939
ISET
TYP
0.30075188
0.2
0.133333333
0.1
0.068027211
0.051020408
0.04008016
0.033112583
0.027322404
0.02
0.013333333
0.01
0.006802721
0.005102041
MAX
0.315789474
0.21
0.14
0.105
0.071428571
0.053571429
0.042084168
0.034768212
0.028688525
0.021
0.014
0.0105
0.007142857
0.005357143
Table 5. ISET Resistor Settings
KISET
MIN
TYP
MAX
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
190
200
210
RISET
(STANDARD 1%
VALUES)
665
1000
1500
2000
2940
3920
4990
6040
7320
10000
15000
20000
29400
39200
UNIT
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
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