topic Re: WCT-15WTXAUTO Wireless Charging in Wireless MCU

WCT-15WTXAUTO Wireless Charging

berniecheah — Fri, 16 Mar 2018 04:41:08 GMT

Hi,

My customer is testing the 15W wireless charging kit for automotive. I have a few questions to ask..

1. Can I get the spec of the coils (Including brand, thickness and coil thinness)? I could not find it from the document.

2. May I know what is the function for Temperature Sensing NTC B25/85 from the datasheet?

Re: WCT-15WTXAUTO Wireless Charging

reyes — Fri, 16 Mar 2018 17:32:34 GMT

Can I get the spec of the coils (Including brand, thickness and coil thinness)? I could not find it from the document.

[A1] We do not have a list of recommended coils, but we do have an application note which explain the coils used for wireless charging: http://www.nxp.com/docs/en/application-note/AN4866.pdf

Here are some examples of what you can find on the market:

https://product.tdk.com/info/en/catalog/datasheets/wlc_rx_wr222230-26m8-g_en.pdf

https://product.tdk.com/info/en/catalog/datasheets/wlc_rx_wr303050-15f5-g_en.pdf

https://product.tdk.com/info/en/catalog/datasheets/wlc_tx_wt1005690-12k2-a6-g_en.pdf

May I know what is the function for Temperature Sensing NTC B25/85 from the datasheet?

[A2] NTC B25/85 is the Beta value measured between two temperature endpoints (25C and 85C).

Re: WCT-15WTXAUTO Wireless Charging

berniecheah — Mon, 19 Mar 2018 07:28:57 GMT

Hi,

Regarding below answer,

NTC B25/85 is the Beta value measured between two temperature endpoints (25C and 85C).

So what is the purpose of this circuit in the nxp design? To detect temperature of transmitter? Is this temperature sensing compulsory in this design?

And also may I know what is the purpose of the Q factor detection in this schematic?

Thanks & Regards,

Bernie Cheah

(Field Application Engineer)

WPG Malaysia Sdn. Bhd.

• Office : (04) 642 9500 ext: 11670

• Mobile : (016) 451 2052

Re: WCT-15WTXAUTO Wireless Charging

reyes — Mon, 19 Mar 2018 16:09:44 GMT

Hi Bernie,

About the temperature sensing question, you mentioned “what is the purpose of this circuit in the nxp design?”. Can you please specify which circuit you are referring to? Please send me the link of the documentation you are working with.

Typically, the embedded temperature sensor read the temperature of the internal device which is used for internal calibration and compensation, but it can also be used for ambient temperature measurement.

Check Application Note AN3031 for more detailed information: https://www.nxp.com/docs/en/application-note/AN3031.pdf

Regarding the purpose of the Q factor detection in this schematic, Q factor (Quality factor) is defined as the Q factor of Test Power Transmitter #MP1’s Primary Coil at an operating frequency of 100 kHz with RX positioned on the interface surface and no FO nearby.

On section 4.7 of the WCT101XAV31A User Guide you can find more detailed information about this quality factor: https://www.nxp.com/docs/en/user-guide/WCT101XAV31AUG.pdf

Regards,

Jose

Re: WCT-15WTXAUTO Wireless Charging

berniecheah — Mon, 19 Mar 2018 16:29:40 GMT

Hi Jose,

Thank you very much for the information! It was very helpful.

We are actually working on the WCT-15WTXAUTO design. Currently having the ready kit with us and studying it in case we need to modify any changes before production.

Thanks & Regards,

Bernie Cheah

(Field Application Engineer)

WPG Malaysia Sdn. Bhd.

• Office : (04) 642 9500 ext: 11670

• Mobile : (016) 451 2052