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Original question:

BQ76930: BQ76930 incorrect pack voltage vs cell voltage measurement

BQ76930: TS pin as ADC port to measure pack battery

Wentao Zeng
Prodigy 590 points
Part Number: BQ76930
Other Parts Discussed in Thread: BQ76940, ISO1540

We want to use two BQ76940 + ISO1540 to build 26S system. Now we want to save one isolation device and use TS pin to measure pack battery, then send voltage value to MCU through ISO154X.

Do you think if it available and which TSX we can use? any other suggestion for measure independent pack voltage  

  • 0
    TI__Guru 54715 points

    Hi Wentao,

    The BQ76940 does not have a way to remove the thermistor bias from the TSx input during measurement.  Since TS1 is the input referenced to VSS it would be the input to use.  You could switch the signal to the TS1 pin similar to figure 7 of the data sheet, and this may also serve as your wake up signal, you would need a signal on your isolated side to control this.  Calculation and calibration would be needed, we do not have guidance on this use of the pin.

    You might also consider an I2C output ADC on the isolated side of the bus although that would use another component, I'm not familiar with that product line, see http://www.ti.com/adc for more information.