BQ24297 Datasheet, PDF (30/48 Pages) Texas Instruments – I2C Controlled 3A Single Cell USB Charger

bq24296
bq24297
SLUSBP6A – SEPTEMBER 2013 – REVISED OCTOBER 2013
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When the TS fault occurs, the fault register REG09[2:0] indicates the actual condition on each TS pin and an INT
is asserted to the host. The STAT pin indicates the fault when charging is suspended.
VREF
V_LTF
V_LTFH
TEMPERATURE RANGE TO
INITIATE CHARGE
CHARGE SUSPENDED
TEMPERATURE RANGE
DURING A CHARGE CYCLE
CHARGE SUSPENDED
VREF
V_LTF
V_LTFH
CHARGE at full C
CHARGE at full C
V_HTF
AGND
CHARGE SUSPENDED
CHARGE SUSPENDED
V_TCO
AGND
Figure 31. TS Pin Thermistor Sense Thresholds in Charge Mode
VREF
V _BCOLDx
( -10ºC / 20ºC)
Temperature Range to
Boost
Boost Disable
Boost Enable
V _BHOTx
(55ºC / 60ºC / 65ºC)
Boost Disable
AGND
Figure 32. TS Pin thermistor Sense Thresholds in Boost Mode
Assuming a 103AT NTC thermistor is used on the battery pack Figure 31, the value RT1 and RT2 can be
determined by using the following equation:
RT2 =
V_VREF
´ RTH_COLD
´ RTH_HOT
æ
´ç
è
1
V_LTF
-
1
V_TCO
ö
÷
ø
RTH_HOT
´
æ
ç
V_VREF
è ^VTCO
-
ö
1_÷
ø
-
RTH_COLD
´
æ
ç
è
V_VREF
V_LTF
ö
- 1_÷
ø
V_{VREF - 1}
RT1 =
V_LTF
1₊ 1
RT2 RTH_COLD
Select 0°C to 45°C range for Li-ion or Li-polymer battery,
RTH_COLD = 27.28 kΩ
RTH_HOT = 4.911 kΩ
30
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