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BQ500212A: FOD error stops charging process

jean raymond barbeau
Prodigy 65 points
Part Number: BQ500212A
Other Parts Discussed in Thread: BQ51013B

Hello


we use the TI bq500212A,  but we can't charge because as soon as the load starts we have a FOD and the charge stops.
By disabling the FOD_CAL and the FOD, the charging seems to be correct. This seems to be a calibration problem, please, could you tell us how to calibrate the IQ charger?

BR

J.Raymond Barbeau

  • 0
    TI__Guru* 75786 points
    An FOD fault can be caused by several issues:
    1.) Calibration of the TX, internal losses are not compensated for with FOD_CAL or FOD (Threshold) set too low.
    2.) Problems with TX measurements of input voltage and input current used for FOD loss calculation.
    3.) Higher than expected loss in the TX power section due to coil, resonant capacitors or layout.
    4.) Industrial design of the case with metal near the TX coil.
    5.) RX not correctly reporting received power due to issues with RX FOD calibration
    6.) Metal near the RX coil resulting in FOD loss.

    Is your bq500212A design a new design that you are testing?
    Which RX are you using for test?
  • 0 in reply to Bill Johns
    Prodigy 65 points
    Yes, it is a new design based on EVB schematic an bom, so the layout is different. We used a custom handset based on BQ51013B. We made tests inside and outside the metal housing case but we got a fod each time.
    BR
    J.Raymond Barbeau
    CAMEON
    FRANCE
  • 0 in reply to jean raymond barbeau
    Prodigy 65 points

    Hello,

    We try to charge our handset and we got a led fault indicator, please could explain us more precisely than in a DS what it means as FOD and PMOD are disabled?

    Thanks

    BR

    J.Raymond Barbeau

  • 0 in reply to jean raymond barbeau
    TI__Guru* 75786 points
    FOD fault is set when the difference between Power the TX calculated it sent to RX is greater than the power the RX reported it received. See FOD and PMOD info in the FAQ section.

    The TX will calculated power sent to RX based on input power and calculated power conversion loss for a given operating point.
    The RX will tell the TX how much power it has received, this is a digital word the RX sends to TX.
    Difference between the two is loss and if this exceeds the values set by LOSS_THR (bq500212A Pin 43) a fault is set.
    To disable FOD function pin 43 should be open.

    The RX will calculate the amount of power that it receives based on the output power using ILIM current.
    ILIM will also feed the FOD pin to generate the digital word set to TX.
  • 0 in reply to Bill Johns
    Prodigy 65 points
    Thanks.
    Do you think that USB Interface Adapter Evaluation Module can help us to diagnose our problem?
    BR
    J.Raymond Barbeau
  • 0 in reply to jean raymond barbeau
    TI__Guru* 75786 points
    Yes -- I will contact you offline with more info