• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 177 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

BQ2973: BQ297XX Series Suitable as Secondary/System Side Protection?

Kyle Wagner
Prodigy 150 points
Part Number: BQ2973

Hello,

We are currently using an 18650 Lithium Ion battery with a built-in PCM for protection. In order to be single fault safe per UL standards, we are looking to add secondary protection on the system side. The BQ297XX series looks to be a great candidate, but I can't quite tell if this would be suitable as secondary protection. For example, if we were in an overdischarge situation (battery voltage too low) and the battery pack PCM kicked in, the BQ297XX would see 0V. Is it possible to recover from this kind of scenario? It appears the BQ297XX allows 0V charging, so I think we would be fine. Just wanted to confirm that this was a suitable application for this chip.

Thanks!

  • +1
    TI__Guru 54715 points

    Hi Kyle,

    While the BQ2973 has the zero volt charge mode it also has an inhibit to prevent charge of shorted cells.  See the data sheet section 9.4.7 0-V Charging Inhibit Function.  Unfortunately I don't expect the BQ297x to work for system side.  It seems you need a circuit powered by the charger to control its inputs from the protected cell so that if the battery protected the secondary circuit could still enable the battery voltage to provide recovery.