IP5389

V1.23

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as a short circuit or an abnormal open circuit.

Table 20

Battery charging voltage settings

Note: 3.65V refers to lithium iron phosphate battery and corresponding turn-off voltage is 2.75V.

12.15

NTC Function and Threshold Selection

IP5389 integrates NTC function, which can detect battery temperature. After IP5389 is powered on, NTC

pin outputs 80uA current at high temperature and 20uA current at low temperature, and generates voltage

through external NTC resistor.The IC internally detects the voltage of the NTC pin to determine the current

battery temperature.

ADC

RNTC=10K

B=3380

NTC_ADC

20uA / 80uA

Figure 13

NTC circuit

IP5389 discharges 80uA current on the NTC_MODE pin. If this pin is connected with different resistors,

different voltages can be obtained. The IC will detect the NTC_MODE voltage and select different NTC

functions according to the NTC_MODE voltage.Note that the accuracy of the external resistance should

be 1% and the voltage of NTC_MODE should be in the middle of the judgment range. When the voltage

of NTC_MODE exceeds all judgment ranges, the chip will recognize the circuit as a short circuit or an

abnormal open circuit.

Figure 14

NTC threshold selection

Resistance from VSET

to GND(ohm)

VSET (theoretical

voltage) (mV)

VSET Voltage

judgment range (mV)

Corresponding

battery type

27k

2160

1750~2550

4.2V

18k

1440

1220~1750

4.3V

13k

1040

860~1220

4.35V

9.1k

728

600~860

4.4V

6.2k

496

384~600

4.15V

3.6k

288

216~384

3.65V