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bq51050b: most simple schematic

Manuel Walter
Prodigy 130 points
Other Parts Discussed in Thread: BQ500211A, BQ51050B

Hello,

As a diploma thesis I'm currently implementing a wireless power system using bq500211A and bq51050B. Due to problems we already ordered the bq500211AEVM. Since our RX ist not working, neither with the TX-EVM nor with our system, we decided to build another RX, but only with the really neccesary stuff. Can you provide a schematic for bq51050B which is as simple as possible? So to say without NTV, FOD, Adapter and so on?

Thank you in advance

Manuel

  • 0
    TI__Mastermind 32350 points

    Hi Manuel,

     Please use the EVM and remove all the jumper and test points. The Pots, you can replace them with the fixed resistor based on your design requirements. Please use the BOM provided in the user’s guide as well. Let us know if you specific questions.

     -Tahar  

  • 0 in reply to Tahar Allag
    Prodigy 130 points

    Hi Tahar,

    thank you for your answer. I've got another question according to the bq51050b:
    When I limit I_Bulk with R_ILIM to 1A, the connection to the TX is aborted very often, but immediately reinitiated. When I limit I_Bulk to 500mA, connection is stabile. Could overheating be a reason for this? The IC gets about 80°C warm bevore the connection is aborted. When using a charge current of 500mA the IC's temperature is at about 60°C, just as mentioned in the datasheet. 

    Thank you

    Manuel

  • 0 in reply to Manuel Walter
    TI__Mastermind 32350 points

    The issue is the wpc1.1 compliance. Both the bq51050b and 211A are wpc1.1 compliance and they are not calibrated for it yet in your design. pls calibrate Ros and RFOD according to your final design configuration.

  • 0 in reply to Tahar Allag
    Prodigy 130 points

    Thank you for the fast answer!
    How do I calibrate these resistors? At the moment we are using ROS = 42,2 kOhm and RFOD = 187 Ohm (188 wasn't available), just as recomended in the datasheet. Does that mean there is no possibility to build a 1A test charger without implementing the foreign object detection?

    Kind Regards

    Manuel

  • 0 in reply to Manuel Walter
    Prodigy 130 points

    Me again.

    I have monitored the communication sent by the RX and there is no End Power Packet. It seems like the connection is aborted without any logical reason. Now my next question: In the bq51050BEVM schematic you are using a zener-diode (D2) and parallel capacitor (C20, 1.0 uF) parallel to the capacitor C3 of the schematic in the datasheet of the bq51050b. Between those there is the resistor R15 (1k). What is the use of R15, D2 and C20?

    Kind regards

    Manuel

  • 0 in reply to Tahar Allag
    Prodigy 10 points

    I have been experiencing the exact same issue as Manuel. I have also been told to calibrate these but I have heard no instruction on what exactly that means or how I would go about calibrating them. Can you please elaborate?

  • 0 in reply to Ashley Miller
    TI__Mastermind 32350 points

    Hi

     

    You need to tune resonant caps on AC1 and AC2 pin (Cs and Cd caps )according the wpc1.1 requirements.

     

    Also, if FOD (Foreign object detection) is needed for wpc1.1, the RFOD and the ROS needs to be calibrated as well.

     

    For more details, please contact the local TI sales office.

  • 0 in reply to Tahar Allag
    Prodigy 170 points

    Hi, I am New In wireless charging, but before going into I would like to get answer for question:  can I use bq51050b with coil with size about 15mm x 15mm ?

  • 0 in reply to Patryk Grabowski
    TI__Expert 7730 points

    Yes, it is possible to use a 15mm x 15mm coil with bq51050b but you will need to tune the resonant capacitance according to the inductance of your coil. The below design tool can help you with it.

    http://www.ti.com/lit/zip/sluc566

    What is your output current level?

    Thanks,

    Wenjia