Dear TI expert,
Currently i am use BQ77905 design one BMS, i use low temperature LiFePo4 cell, i want to under temperature -10 to protect and over temperature 55 to protect, but RTS_PU meet -10 under temperature protector, but can not meet over temperature 55 protector. How can i do?
Have a nice day!
Hello,
If you would like to adjust the temperature at which protections are triggered, you can select a different NTC thermistor which will produce different resistances corresponding to temperature than the default 103AT NTC that is 10kOhms at room temp. For example, the NTC you select could be 9kOhms at room temp.
I recommend reading through Section 9.1.1.5 in the BQ77905 datasheet: BQ77904, BQ77905 3-Series to 20-Series Ultra Low-Power Voltage, Current, Temperature, and Open-Wire Stackable Lithium-Ion Battery Protector datasheet (Rev. K) (ti.com).
Additionally, you could also select a different version of the device that has thresholds closer to your desired thresholds in combination with selecting a different NTC thermistor.
Best,
Andria
