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Original question:

BQ25101: Indicate presence of power

BQ25101: Indicate presence of power

PATRICK FREY
Prodigy 60 points
Part Number: BQ25101


Hello thanks a lot for the answer .

We want use now  the provided solution with Pin TS .

The idea is to tied this PIN directly to the CPU ADC . And we are afraid that this could lead to measurement errors because of the current drawn from the ADC input.

Do you thing that this solution is ok ? Or should we amplify the signal before measuring it ?

Thank you for the quickly answer 

  • 0
    TI__Guru* 76816 points
    Load on the TS pin from CPU ADC, possible error in circuit due to current draw--The TS pin current source is 50uA and reducing the current due to an external load will cause some error. The error can be calculated based on the additional current draw from the load then compared with system requirements.
    If the load is constant the NTC network can be adjusted to compensate for the error.
  • 0 in reply to Bill Johns
    Prodigy 60 points
    What is the effect on the BQ25101 if we steel current to feed the ADC of the CPU? What is the charging curve of the chip ? Is it linear with the NTC voltage? or is there a trigger?
  • 0 in reply to PATRICK FREY
    TI__Guru* 76816 points

    Updated

    The circuit is a 50uA current source into a 10k NTC developing a voltage at the TS pin. The TS pin voltage is monitored by a series of voltage comparators planned for 60C, 45C, 10C and 0C.
    If the current is reduced voltage is reduced and the trip point will move lower. But reduced current can be corrected for by adding a resistor.
    Current into the ADC would need to be stable.