Other Parts Discussed in Thread: BQ25798, BQ34Z100
We have a power system which includes a fuel gauge (BQ34Z100PW-G1) and charger (BQ25798RQMR) that both have inputs for a battery pack thermistor. What is the best way to connect our battery pack's thermistor to this system?
The BQ34Z100-G1 has the thermistor's negative terminal (THR-) connected to pin 11 (P6/TS) and the thermistor's positive terminal (THR+) connected to pin 7 (REG).
The BQ25798 uses a voltage divider from pin 4 (REGN) of the device to pin 16 (TS). The divider is 5.23kOhms for the top resistor; 30.1kOhms for the bottom resistor in our design.
We've used zero-ohm jumpers to set the path of the thermistor either to the fuel gauge or charger. It looks like the fuel gauge can give us a resistance reading and thus an actual temperature estimate. But the charger seems to only tell if the thermistor is "in range" for the charger to perform its duties.
Which device gives a more accurate reading of the thermistor's value?
We'd like to use the reading from just one device to simplify our design. For example, if the BQ34Z100-G1 gives an accurate temperature estimate, how can we use this estimate to tell the charger that value? -or at least tell the charger that the temperature is "in range?"
Please advise. Thanks,