BQ24161B_15 Datasheet, PDF (22/52 Pages) Texas Instruments – bq2416xx 2.5A, Dual-Input, Single-Cell Switched-Mode Li-Ion Battery Charger with Power Path Management and I2C Interface

bq24160, bq24160A, bq24161
bq24161B, bq24163, bq24168
SLUSAO0F – NOVEMBER 2011 – REVISED JULY 2014
www.ti.com
Feature Description (continued)
V_HOT = 0.30 × V_DRV
Where R_HOT is the NTC resistance at the hot temperature and R_COLD is the NTC resistance at cold temperature.
For the bq24160, bq24161B, bq24163, and bq24168, the WARM and COOL thresholds are not independently
programmable. The COOL and WARM NTC resistances for a selected resistor divider are calculated using the
following equations:
RCOOL =
RLO ´ 0.564 ´ RHI
RLO - RLO ´ 0.564 - RHI ´ 0.564
(3)
RW ARM =
RLO ´ 0.383 ´ RHI
RLO - RLO ´ 0.383 - RHI ´ 0.383
(4)
V_{BAT(REG) 1 x Charge/}
DISABLE -140 mV 0.5 x Charge
V_DRV
bq2416x
TS COLD
+
TS COOL ₊
TS WARM ₊
TS HOT
+
V_DRV
RHI
TS
TEMP
PACK +
RLO
PACK -
Figure 14. TS Circuit
9.3.15 Thermal Regulation and Protection
During the charging process, to prevent chip overheating, the bq2416xx monitors the junction temperature, T_J, of
the die and begins to taper down the charge current once T_J reaches the thermal regulation threshold, T_REG. The
charge current is reduced to zero when the junction temperature increases about 10°C above T_REG. Once the
charge current is reduced, the system current is reduced while the battery supplements the load to supply the
system. This may cause a thermal shutdown of the bq2416xx if the die temperature rises too high. At any state,
if T_J exceeds T_SHTDWN, the bq2416xx suspends charging and disables the buck converter. During thermal
shutdown mode, the buck converter is turned off, all timers are suspended, and a single 128μs pulse is sent on
the STAT and INT outputs and the STATx and FAULT_x bits of the status registers are updated in the I²C. A
new charging cycle begins when T_J falls below T_SHTDWN by approximately 10°C.
22
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