LM3647 Datasheet, PDF (16/17 Pages) National Semiconductor (TI) – Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries

4.5 Recommended dimensioning for the NTC
The voltage at TEMP-input must be between 2.2V and 0.5V
for the charger to start. While charging the voltage, must stay
between 3.0V (maximum temperature) for Li-Ion, or 3.15V
(maximum temperature) for Ni-Cd/Ni-MH, and 0.5V (mini-
mum temperature) or the charger will register a temperature
fault and abort the charge. These voltages correspond to the
upper and lower limits for the battery pack temperature.
When no NTC is used the TEMP-input pin must be biased to
a voltage level between 2.2V and 0.5V.
Typical configuration curve, (NTC characteristics: 3kΩ @ 25°C, β=3988:
3.5
3
2.5
2
1.5
1
0.5
0
-10 -5 0
5 10 15 20 25 30 35 40 45 50
Temperature in °C
16
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