While charging, the device continuously monitors battery temperature by sensing the voltage at the TS pin. A negative temperature coefficient (NTC) thermistor should be connected between the TS and GND pins (recommend: 103AT-2). If temperature sensing is not required in the application, connect a fixed 10-kΩ resistor from TS to GND to allow normal operation. Battery charging is allowed when the TS pin voltage falls between V_COLD and V_HOT thresholds (typically 0°C – 45°C). The temperature corresponding to these voltage thresholds can be modified by adding resistors in parallel and in series with the thermistor, as shown in Figure 7-3. If the TS pin indicates battery temperature is outside this range, the device stops charging, enters the STANDBY state, and blinks the STAT pin. Once battery temperature returns to normal conditions, charging resumes automatically.

Figure 7-3 TS Resistor Network For Modified Temperature Charging Window

In addition to battery temperature sensing, the TS pin can be used to disable the charger at any time by pulling TS voltage below V_{TS_ENZ}. The device disables the charger and consumes I_{SD_IN_TS} from the input supply. In order to minimize quiescent current, the TS current source (I_{TS_BIAS}) is duty-cycled, with an on-time of t_{TS_DUTY_ON} and an off time of t_{TS_DUTY_OFF}. After the TS pin pull-down is released, the device may take up to t_{TS_DUTY_OFF} to turn the I_{TS_BIAS} back on. After the source is turned on, the TS pin voltage will go above V_{TS_EN}, and re-enable the charger operation. The device treats this TS pin toggle as an input supply toggle, triggering Device Power Up From Input Source (Section 7.3.1).