• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 63 subscribers
  • Views 1332 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.

bq51050b Ros and EN2

John Baek
Prodigy 100 points
Other Parts Discussed in Thread: BQ51050B, BQ51013B

Hi,

In the datasheet for bq51050b, the typical application schematics show a resistor from RECT to FOD. However, there is no mention of this resistor at all in the datasheet. What is the purpose of this resistor?


I want to use bq51050b as the only method of charging (i.e. no wired charging), but I am not sure what to do with the EN2 pin. I have AD grounded and AD-EN floating. Since AD is grounded, can I just ground EN2? I have EN2 connected to BAT for now, but I really don't want to keep it that way.

Thanks

  • 0
    TI__Prodigy 160 points

    Hello John,

    1. Ros is related to the FOD tuning of the device. More information about FOD can be found under the tools and software section of the bq51013b:  http://www.ti.com/product/BQ51013B/toolssoftware

    Unfortunately, the explanation in the bq51013b datasheet are not very well, too, but we are currently working on an updated version that is in process of release. 

    2. You can connect EN2 to GND. If AD is unused (floating or grounded) then wired power is disabled and EN2 can be grounded. In this case EN2 can even be high, low or floating. The result will be the same. However, best practice is to tie it to GND.

  • 0 in reply to Tobias Puetz (TP)
    Prodigy 100 points

    Thanks Toby.

    If I am using bq51050b and not bq51013b, do I need Ros?

  • 0 in reply to John Baek
    TI__Prodigy 160 points
    Sorry for the misunderstanding. I guided you to the bq51013b tools and software section, because there the FOD procedure / calibration is explained. The same guidelines also apply for the bq51050b.
    To answer your question: yes, you need Ros.
  • 0 in reply to Tobias Puetz (TP)
    Prodigy 100 points

    How critical is it to calibrate Ros using the method described in the user guide for the FOD calibration/tuning tool? The process described is long and the AVID calibration transmitter is expensive.

    I've already calculated Rterm and Rilim from guidelines in the bq51050b datasheet. Can I just use the default value in the bq51050bEVM for Ros (42.4k) and adjust it from there instead of using the FOD tool?

  • 0 in reply to John Baek
    TI__Prodigy 160 points
    If you don't tune your system, the RX might over or under report the amount of power your system is transmitting. This can lead to an unwanted shutdown or your TX.
    How do you intend to use this device? If you're using your TX and RX in a fixed closed system, then just placing a "random" value might work. But it might also not.

    Please also take a look at the application example in the bq51050b datasheet (page 29 and following). In section 10.2.1.2.3 there's a recommendation for RFOD before (!) tuning for the described application example.