BQ24161B_15 Datasheet, PDF (21/52 Pages) Texas Instruments – bq2416xx 2.5A, Dual-Input, Single-Cell Switched-Mode Li-Ion Battery Charger with Power Path Management and I2C Interface

www.ti.com
bq24160, bq24160A, bq24161
bq24161B, bq24163, bq24168
SLUSAO0F – NOVEMBER 2011 – REVISED JULY 2014
Feature Description (continued)
9.3.14 External NTC Monitoring (TS)
The I²C interface allows the user to easily implement the JEITA standard for systems where the battery pack
thermistor is monitored by the host. Additionally, the bq2416xx provides a flexible, voltage based TS input for
monitoring the battery pack NTC thermistor. The voltage at TS is monitored to determine that the battery is at a
safe temperature during charging. The bq24160, bq24160A, bq24161B, bq24163, and bq24168 enable the user
to easily implement the JEITA standard for charging temperature while the bq24161 only monitors the hot and
cold cutoff temperatures and leaves the JEITA control to the host. The JEITA specification is shown in.
1°C
0.5°C
4.25 V
4.15 V
4.1 V
Portion of spec not covered by TS
Implementation on bq24160
T1
(0°C)
T2
(10°C)
T3 T4
T5
(45°C) (50°C) (60°C)
Figure 13. Charge Current During TS Conditions
To satisfy the JEITA requirements, four temperature thresholds are monitored; the cold battery threshold (T_NTC <
0°C), the cool battery threshold (0°C < T_NTC < 10°C), the warm battery threshold (45°C < T_NTC ≤ 60°C) and the
hot battery threshold (T_NTC > 60°C). These temperatures correspond to the V_COLD, V_COOL, V_WARM, and V_HOT
thresholds. Charging is suspended and timers are suspended when V_TS < V_HOT or V_TS > V_COLD. When V_WARM >
V_TS > V_HOT, the battery regulation voltage is reduced by 140mV from the programmed regulation threshold.
When V_COLD > V_TS > V_COOL, the charging current is reduced to half of the programmed charge current.
The TS function is voltage based for maximum flexibility. Connect a resistor divider from DRV to GND with TS
connected to the center tap to set the threshold. The connections are shown in Figure 20. The resistor values are
calculated using the following equations:
RLO =
V_DRV
´ RCOLD ´ RHOT ´
é
ê
1
-
1ù
ú
ë ^VCOLD ^VHOT û
RHOT ´
é
ê
ë
V_DRV
V_HOT
ù
- 1_ú - RCOLD ´
û
é
ê
ë
V_DRV
V_COLD
ù
- 1_ú
û
(1)
RHI =
V_DRV
V_COLD
-1
1
1
+
RLO RCOLD
(2)
Where:
V_COLD = 0.60 × V_DRV
Copyright © 2011–2014, Texas Instruments Incorporated
Submit Documentation Feedback
21
Product Folder Links: bq24160 bq24160A bq24161 bq24161B bq24163 bq24168