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BQ25887EVM: BQ25887 TS-ADC and TDIE-ADC

Part Number: BQ25887EVM

Hi, 

My name is Babu. Regarding sensing the temperature we have TS pin and reading the value in the TS-ADC registers. can you tell me how these values are read and how can we convert these values into the temperature in degree Celsius?

What is a TDIE, I am unable to find any clear definition about this in the datasheet.

Could you please let me know how to convert these values in degree Celsius?

  • HI Babu,

    The TS pin voltage is proportional to thermistor resistance, which is proportional to battery temperature. The TS_ADC value reports the value as a % of REGN voltage.  You can use the app note at the link below to compute the battery temperature from this percentage:

    https://www.ti.com/lit/an/slua745/slua745.pdf

    The TDIE value is the temperature of the integrated circuit die/junction inside the chip's package. From internal die/junction temp, you can estimate external case temp and/or exposed pad temp using the thermal info in datasheet section 7.4. REG0x23-24 TDIE_ADC has 0.5C resolution so a register value of 0000000000000001 is 0.5C.  Please note that this 16-bit register is reported in 2's complement with the MSB (bit7) in REG0x23 being the sign bit.  So, if that bit is 1, you have to convert to the 2's complement value.   

    Regards,

    Jeff