BQ24072T_2 Datasheet, PDF (25/36 Pages) Texas Instruments – 1.5A USB-Friendly Li-Ion Battery Charger and Power-Path Management IC

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bq24072T
bq24075T, bq24079T
SLUS937A – DECEMBER 2009 – REVISED APRIL 2010
é₁
1^ù
R7 =
V_IN
´ RCOLD ´ RHOT
´ _{êëVCOLD}
-
V_HOT
ú
û
RHOT
´
é _VIN
êë_VHOT
-
ù
1_ú
û
-
RCOLD
´
é _VIN
êë_VCOLD
ù
- 1_ú
û
(2)
Where:
V_COLD = 0.25 X V_IN
V_HOT = 0.125 X V_IN
RHOT is the expected thermistor resistance at the programmed hot threshold, RCOLD is the expected thermistor
resistance at the programmed cold threshold. If the value of R6 is less than 100kΩ, R3 must be added to protect
the IC from 28V inputs. If R6 is greater than 100kΩ, R8 does not need to be used.
Adapter
V COLD
+
V_HOT
+
IN
R61
TS ^{R 8}
TEMP
PACK+
Not necessary
in all
applications
R7
PACK-
bq240xT
Figure 35. NTC Monitoring Function
For applications that do not require the TS monitoring function, set R6 = 200kΩ and R7 = 49.9kΩ to set the TS
voltage at a valid level and maintain charging.
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