• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 64 subscribers
  • Views 1098 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.

BQ24610: Differences in bq2461x series

Sven Pauli
Prodigy 40 points
Part Number: BQ24610
Other Parts Discussed in Thread: BQ24616, BQ24618, BQ24650, BQ24617, BQ24703, BQ2970

Hi,

I am trying to find my way through TI's battery charger portfolio.

I am designing a small hand-held device that is easily fed by a single cell battery (preferably NiMH or Li+). It has 3.3V system voltage and only draws a few hundred milliamps. Charging should be fool-proof, preferably from common power sources such as a wall adapter or a USB port. A wider input voltage range (e.g., industry standard 24V) would be eligible. Also within the scope of being fool-proof is the fact that the device is very likely to be inadvertently left switched on after use.

So far I found out about the above mentioned bg2461x series of ICs. Yet I am having a little trouble sorting them out. This is what I think I found so far:

  • bq24610 - the base model.
  • bq24616 - the same, but with a JEITA charging temperature profile.
  • bq24618 - the same, but with slightly lower input voltage range, catering for 5V USB power supply.
  • bq24650 - alien, for solar MPPT.
  • bq24617 - no Idea, seems to be sort of bq24610 with lower input voltate range.

Especially the bq24617 strikes me a bit. What is special about it?

Nonetheless, I am mostly worried about deep discharging (thus damaging) the battery in case the operator forgets to switch off the device after use. From reading the datasheets it is not quite clear to me whether the above ICs provide a means of disconnecting the system load (BATDRV signal) when the battery is discharged to a certain level. For comparison the bq24703 has a BATDEP signal and for my understanding it automatically switches over to AC power in case the depletion level is hit. Yet it seems to only do so if an AC adapter is present.

To conclude, my questions would be:

  • What is the matter with bq24617?
  • Is there any deep discharge protection?
  • What other ICs could be a better match for this application?

Thank you very much!

Yours,

Sven

  • 0
    TI__Genius 10240 points

    Hi Sven,

    Please refer to the Device Comparison Table on the BQ24610 datasheet page 3. http://www.ti.com/lit/ds/symlink/bq24617.pdf

    As there is a discharge path from battery to the SYSTEM through the body diode of the FET between the battery and the SYSTEM, the charger can't stop the discharge. General speaking, the battery pack should have the deep discharge protection.

  • 0 in reply to ezhao
    Prodigy 40 points

    Eric,

    thank you for the reply.

    The comparison table you mention is the exact table I have drawn my overview from. However, it does especially not clarify what's special about the bq24617 device, despite of the lower input voltage range. I also cannot make out the difference from the rest of the datasheet. Is it that the bq24617 was released first and then bq24610 was released as an improved version?

    I actually was thinking of a back-to-back configuration on the BATDRV pin. But I realize that it would disconnect the IC itself, obviously.

    Does TI offer a battery management IC that comprises deep discharge protection? Otherwise, what would be a reasonable part to integrate with these charger ICs - one of the bq2970 series ICs?

    Best regards,

    Sven

  • 0 in reply to Sven Pauli
    TI__Genius 10240 points

    Hi Sven,

    From the table, BQ24617 has lower OVP threshold to address some customer requirements. We have 1S battery chargers with deep discharge protection, not for multi-cell battery chargers. However, the feature is not intended to replace the pack protector circuit, which should have a threshold much higher than deeply discharged protection threshold.

  • 0 in reply to ezhao
    Prodigy 40 points

    Eric,

    Hrm. There will probably be no distinct pack protection circuit - this application will use the bare cell.

    This in turn brings me to the conclusion that in my rather-low-power application it is probably more reasonable to integrate a battery protection circuit altogether with a charger and a voltage regulator into my application. I.e., the single cell is fed through the protection IC and powers the voltage regulator that supplies the application. This should be safe in terms of battery damage. Then a separate charger IC connects to the application end of the protection IC as well for charging.

    The case when external power for charging is supplied and the application is switched on at the same time may be addressed by tapping off the application voltage regulator behind the charger IC's sense resistor, so the charger IC only sees the true current into the cell.

    Regards,

    Sven

  • 0 in reply to Sven Pauli
    TI__Mastermind 24075 points

    Hi Sven,

       Here is an overview of our protectors portfolio: http://www.ti.com/power-management/battery-management/protectors/overview.html

       If you have any questions regarding the protectors, feel free to create a new thread with the specified part number.