Datasheet CN3165 (Consonance) - 10

CONSONANCE Selecting R1 and R2
The values of R1 and R2 in Figure 7 can be determined according to the assumed temperature monitor range and thermistor’s values. The Follows is an example: Assume temperature monitor range is TL～TH (TL＜TH＝; the thermistor in battery has negative temperature coefficient (NTC), RTL is thermistor’s resistance at TL, RTH is the resistance at TH, so RTL＞RTH, then at temperature TL, the voltage at TEMP pin is: At temperature TH, the voltage at TEMP pin is: We know, VTEMPL＝VHIGH＝k2×VIN (k2=0.8) VTEMPH＝VLOW＝k1×VIN (k1=0.45) Then we can have: R R (k − k ) R1＝ TL TH 2 1 (R − R )k k TL TH 1 2 R R (k − k ) R2＝ TL TH 2 1 R (k − k k ) − R (k − k k ) TL 1 1 2 TH 2 1 2 Likewise, for positive temperature coefficient thermistor in battery, we have RTH＞RTL and we can calculate: R R (k − k ) R1＝ TL TH 2 1 (R − R )k k TH TL 1 2 R R (k − k ) R2＝ TL TH 2 1 R (k − k k ) − R (k − k k ) TH 1 1 2 TL 2 1 2 We can conclude that temperature monitor range is independent of power supply voltage VIN and it only depends on R1, R2, RTL and RTH: The values of RTH and RTLcan be found in related battery handbook or deduced from testing data. In actual application, if only one terminal temperature is concerned(normally protecting overheating), there is no need to use R2 but R1. In this case it becomes very simple to calculate R1.
Recharge
After a charge cycle has terminated, if the charge current rises above 30% of the constant charge current, a new charge cycle will begin automatically.
Constant-Current/Constant-Voltage/Constant-Temperature
The CN3165 use a unique architecture to charge a battery in a constant-current, constant-voltage, constant temperature fashion as shown in Figure 3. Amplifiers Iamp, Vamp, and Tamp are used in three separate feedback loops to force the charger into constant-current, constant-voltage, or constant-temperature mode, respectively. In constant current mode the charge current delivered to the battery equal to 1188V/RISET. If the power dissipation of the CN3165 results in the junction temperature approaching 130℃, the amplifier Tamp will begin decreasing the charge current to limit the die temperature to approximately 130℃. As the battery voltage rises, the CN3165 either returns to constant-current mode or it enters constant voltage mode straight from constant-temperature mode. www.consonance-elec.com 10 REV 1.0