• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 410 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

bq24640EVM charge current

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: BQ24640EVM, BQ24640

Hello,

bq24640EVM charge current is 2A(min) on User's guide P.3.
Could you please let me know this reason ?

Since Viset range is 0V~2V and we can use external voltage for Viset, I think that we can use this EVM at the charge current under the 2A.
(also, we can change the divider and Rsns resistor)

Best Regards,
Ryuji Asaka

  • 0
    TI__Expert 5565 points
    You are right in that there is no reason why the bq24640 (or the EVM) can't be used for currents <2A. However, if you want to optimize charging current accuracy for <2A, you will have to change the Rsense resistor to something larger than 10mOhms. If you look at page 5 of the datasheet under the "current regulation" section, you will see that for a sense voltage of <20mV the charging accuracy drops of quickly. With a 2A current and 10mOhm Rsense on the EVM, the EVM is able to maintain +/-5% charging accuracy. Any current <2A will result is worse accuracy, which is the reason for the minimum charging current of 2A for the EVM.

    If you would like to use the EVM for a charging current <2A, you will need to change the Rsense resistor (R2) for better current accuracy as well as change the resistor divider on ISET (R18 and R21) to reflect 2A.