Wireless Charging Coil Array Solution?

[corynrobinson]

Does NXP offer a solution for large area wireless charging? More specifically, I’d like to implement something similar to WPC’s B1 coil array. The part I’m having trouble with is coil selection.

[Rixcyshah]

If you’re trying to implement something similar to a WPC B1-style coil array for a large charging surface, coil selection can definitely be tricky. From what I’ve seen in Qi designs, parameters like coil diameter, inductance (typically around a few µH), Q-factor, and coupling efficiency with the receiver are critical for stable power transfer. Many multi-coil pads use overlapping PCB coils or pre-wound litz wire coils combined with a controller that can dynamically select the active coil depending on the receiver position. In practice, designers often prototype with a few coil geometries first and then optimize spacing and shielding to reduce cross-coupling between adjacent coils. Another approach I’ve noticed is using ready made wireless charging coils that are designed for Qi transmitters, since they already have tuned inductance and consistent manufacturing tolerances. That can simplify early prototyping before committing to a custom PCB coil array.

[reyes]

Hi,

I suggest you to use the WCT1111 in B type (Multi-coil) solution, this way you will use only one chip to control multiple coils.

Please refert to the detali in below link:/external-link.jspa?url=https%3A%2F%2Fwww.nxp.com%2Fproducts%2Fpower-management%2Fwireless-power%2F1...https://www.nxp.com/products/power-management/wireless-power/15-watt-wireless-charging-transmitter-i...

I also recommend you to review the application note “Migration from A13 to B5 Wireless Charging Transmitter” in the link below, this App Note describes how to design a multiple coil wireless charger with the topology B5, which design has four PCB coils. This transmitter topology allows to connect two coils simultaneously to achieve better charging performance and active area efficiency for the case when the receiver is placed between two coils.

AN5059: https://www.nxp.com/docs/en/application-note/AN5059.pdf

Have a great day,

Jose

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[corynrobinson]

Thank you for those resources, however, I’m looking for a solution that provides a much wider charging area. B5 only supports 4 coils, but I’d like to implement something like 12 coils.

[reyes · Accepted solution]

Unfortunately there is no solution in the current NXP portfolio to support 12 coils.