• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 797 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.

BQ501210: FOD and PMOD resistors

LS84
Prodigy 115 points
Part Number: BQ501210

Hi,

we are testing our design and the BQ501210 development kit with several receivers.

We've realized that "starting" the charge requires to have the coils too close to each other. However, once it is started the coils can be taken appart and the charge still continues.

In our design we have about 6mm gap which should not be a problem. However, the behaviour seems not to be very stable.

We are afraid that it is due to the FOD and PMOD resistors. Is there any guideline/process to choose these values?

I've read that removing these resistors mean that the design will not be WPC1.2 compliant anymore.

Even if it is not WPC1.2 compliant will the charger still work with WPC 1.1 receivers?

What would be the risk if PMOD and FOD are disabled?

Thanks in advance and kind regards,

LS84

  • 0
    Prodigy 115 points
    Just to complete this question.
    I've tried to disable FOD and PMOD, by removing FOD, PMOD and FOD_CAL resistors and it works better.
    However, it is extremely still very sensible to the coil alignment at the beginning of the detection.
    Once it starts charging the distance and alignment of coils seems less problematic.
    I would really appreciate to have more insights about how the power transfer starts.
    Is it possible that the initial handshake between Rx and Tx requires a very good alignment?
    Is it possible to work around this handshake to force the initial charge?

    Thanks in advance,
    LS84
  • 0 in reply to LS84
    TI__Guru 65716 points
    If the coils are small coil alignment will be difficult and possibly require a mechanical alignment aid. This could be decal on the TX and TX or indention in the plastic case.
    The issue with start up is due to RX voltage at RECT pin increasing above UVLO -- see FAQ TX trouble shooting guide.