BQ24292I Datasheet, PDF (26/42 Pages) Texas Instruments – I2C Controlled 4.5A Single Cell USB/Adapter Charger With Narrow VDC Power Path Management and USB OTG

bq24292i
SLUSBI4 – APRIL 2013
REGN
bq2429x
TS
RT1
RT2
RTH
103AT
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Figure 29. TS Resistor Network
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
TEMPERATURE RANGE TO
INITIATE CHARGE
CHARGE SUSPENDED
TEMPERATURE RANGE
DURING A CHARGE CYCLE
CHARGE SUSPENDED
VREF
V_LTF
V_LTFH
V_LTFH
CHARGE at full C
CHARGE at full C
V_HTF
AGND
CHARGE SUSPENDED
CHARGE SUSPENDED
Figure 30. TS Pin Thermistor Sense Thresholds
V_TCO
AGND
Assuming a 103AT NTC thermistor is used on the battery pack Equation 2, the value RT1 and RT2 can be
determined by using the following equation:
æ₁
1^ö
RT2 =
V_VREF
´ RTH_COLD
´ RTH_HOT
´ç
è
V_LTF
-
V_TCO
÷
ø
RTH_HOT
´
æ
ç
è
V_VREF
V_TCO
-
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
(2)
Select 0°C to 45°C range for Li-ion or Li-polymer battery,
RTH_COLD = 27.28 kΩ
RTH_HOT = 4.911 kΩ
RT1 = 5.52 kΩ
RT2 = 31.23 kΩ
26
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