BQ27542-G1: counting number of charging and FCC calculation

Danny Kwon

Intellectual 1900 points

Part Number: BQ27542-G1

Could you check below question of gauging?

1. As i know there is charging counting function in fuel gauge. If charging is finish, does the number of count increase regardless of battery voltage ?

2. Generally, after full charging there is automatical discharge. So user does recharge. In case of recharge, does the # of count increase?

3. Could you share the detail document or equation which describe the calculation of FCC?

over 8 years ago

0 Onyx Ahiakwo over 8 years ago

TI__Guru* 76230 points

hi Danny,

The cycle count is based on accumulated discharge and not charge. ps see page 32 of the TRM

For the FCC question, see attached pdf

slua364[1]_theory and Imp of IT battery fuel-guaging algorithm.pdf

thanks

Onyx

0 Danny Kwon over 8 years ago in reply to Onyx Ahiakwo

TI__Intellectual 1900 points

Thank you for update.

Got additional question from customer to clarify the question.

1. If the threshod of cycle count is 1000mA, what is the nubmer of count in below case?

case1: After full charging ( 1000mA)-> discharged to 500mA

case2: After full charging (1000mA)-> discharged to 500mA -> charged to 1000mA

0 Onyx Ahiakwo over 8 years ago in reply to Danny Kwon

TI__Guru* 76230 points

Hi Danny,
I believe the cycle count will remain as what ever the previous value was given that you haven't had 1000mAh of passed discharge yet.

thanks
Onyx

0 Danny Kwon over 8 years ago in reply to Onyx Ahiakwo

TI__Intellectual 1900 points

To clarify the question, i modified value as below. could you check again?

1. If the threshod of cycle count is 1000mA, what is the nubmer of count in below case?

case1: After full charging ( 1100mA)-> discharged to 500mA

case2: After full charging (1100mA)-> discharged to 500mA -> charged to 1100mA

case3: 500mA -> Charged to full charging ( 1100mA)

0 Onyx Ahiakwo over 8 years ago in reply to Danny Kwon

TI__Guru* 76230 points

Hi Danny
1. after charge-1, after discharge remains 1
2. after charge 1, after discharge remain 1. after charge 2.
3. 0

I would encourage you to run tests to verify this is the case.
thanks
Onyx

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BQ27542-G1: counting number of charging and FCC calculation