The operation and configurability of the TS function varies from charger to charger. The BQ25180’s TS function is implemented as a current driven TS sensing. This means that a fixed current source biases an external resistor network placed at the TS pin with I_{TS_BIAS}. The NTC’s temperature dependent resistance correlates the resistance, and therefore voltage, at the TS pin with the battery pack temperature. This voltage is then compared with a series of reference voltages to determine the temperature range within which the battery pack is operating. Although these reference voltages are tuned to work with NTC thermistors with a specific Beta (β) and calibrated impedance, additional resistors can be placed to allow the use of NTCs with different β values and calibrated impedance with minimal error. The TS application is described in Figure 1-2.