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BQ51050B: Is the data sheet of HPA689 available for the TX coil used in the bq51050bEVM development board

Star Xu
Genius 9645 points
Part Number: BQ51050B
Other Parts Discussed in Thread: BQ500210

Hi

Is there any data sheet of HPA689 for TX coil used in the bq51050bEVM development board?

Please provide the specific inductance value, Q value and DCR value.

Thanks

Star

  • 0
    TI__Guru* 76486 points

    Hello Star

    The HPA689 is our 19V input wireless power TX BQ500210 Evaluation board.  This design uses the standard WPC A1 coil built by several manufactures.

    One of them is Wurth Electronics, see P/N 760308101 for additional info.

  • 0 in reply to Bill Johns
    Prodigy 240 points

    Hi Bill! Thank you for your reply. Plus, Star, thank you for posting my question in E2E. Appreciated.

    One more question, is there any data sheet of HPA764 for RX coil used in the bq51050bEVM development board? I am looking forward to your reply. Thanks again for your help.

    Best regards from China,
    Zhetao Xie

  • 0 in reply to ZheTao Xie
    TI__Guru* 76486 points

    The coils used for EVM are 48mm X 32mm from Vishay or TDK, IWAS-4832FF-50 and WR-483250-15M2-G.  They are an older generation and may be harder to get, limited stock.

    Take a look a look at the below, in stock at Digikey

    1.) Wurth Electronics -- 760308103215 this is a 14.3uH coil 48mm X 32mm

    2.) TDK --- WR483265-13F5-G, this is a 10.1uH coil 48mm X 32mm

  • 0 in reply to Bill Johns
    Prodigy 240 points

    hello bill!

    Thank you for your reply. 

    I looked up the datasheet for coils IWAS-4832FF-50 and WR-483250-15M2-G and I found that their inductances were 10.5uH and 9.7uH.However, in bq51050b-EVM, the capacitance of the resonant capacitor is 183nf. The inductance should be 14uH according to the formula. This is quite different from the inductance value of the actual coil. Thus, I would like to know the answer to this question.

    Best regards from China,
    Zhetao Xie

  • 0 in reply to ZheTao Xie
    TI__Guru* 76486 points

    Hello

    The L value of the RX coil will increase when placed on the TX coil and in the case, this is Ls' values used for selecting Resonant capacitors.

    L value used in data sheet is free space with no metal around the coil. 

  • 0 in reply to Bill Johns
    Prodigy 240 points

    Hello Bill.

    Thank you again for your reply.I'm sorry to keep bothering you.But I still have a question to ask you.

    How do I choose the inductance of the RX coil when I have determined the resonant capacitance value?

    Or I should first determine the inductance of the RX coil when the RX coil is placed on the TX coil.

    Best regards from China,

    Zhetao Xie

  • 0 in reply to ZheTao Xie
    TI__Guru* 76486 points

    Hello Zhetao Xie

    For deciding the RX Coil, First determine the physical size of the coil.  This will be based on available area of the device.  Try to make the coil as large as possible, up to standard EVM coil which is 48mm X 32mm and about 15uH. 

    If the coil must be physically smaller try to keep the coil size greater than 20mm Round.  As the coil size is reduced L value will need to increase to off set poor coupling factor and inductance will increase to greater than 25uH.

    Tuning of the resonant capacitors is done after coil selection.  Also note that the Ls' value of coil is used to determine tuning.  This is a measure of the coil L when installed in the device case and mounted on TX.