BQ27Z561EVM-011: PWR LED turns on when battery is connected.

Wenlong,
I would encourage you not to focus on the power LED but to focus on getting the chip working. In my previous response to your post, i had requested that you placed a scope on the TS pin to ensure that it is pulsing to know if the chip if functioning. I do not believe that LED has anything to do with the functioning of the gauge IC

thanks
Onyx

Thank you for your reply, Onyx.

Could you give me some explanation about why there will be pulses on TS pin? From schematic, I see TS is connecting BAT- through the external thermistor as shown below:

On the datasheet (https://www.ti.com/lit/ds/symlink/bq27z561.pdf), it reads

"The NTC thermistor should be connected between VSS and the individual TS pin. The analog measurement is then taken via the ADC through its input multiplexer."

and

"The ADC multiplexer provides selectable connections to the external pins BAT, BAT_SNS, TS, the internal temperature sensor, internal reference voltages, internal 1.8-V regulator, and VSS ground reference input. In addition, the multiplexer can independently enable the TS input connection to the internal thermistor biasing circuitry, and enables the user to short the multiplexer inputs for test and calibration purposes."

Here is the function block diagram from datasheet(https://www.ti.com/lit/ds/symlink/bq27z561.pdf):

I am confused about why there are pulses on TS pin and we can test if the IC is damaged by observing TS pin. Could you give me more information?

Thanks,

Wenlong