Wireless Charger TX : Efficiency

[devinpark]

Hi,

I want to know how the efficiency varies depending on the antenna misalignment.

WCT-15WTXAUTO has 3coil and its manual descries its efficiency as roughly >70%.

The efficiency varies depending on the gap(bwt TX & RX, assumed these antennas are well aligned)

Regarding the gap, the efficiency  looks proportional to (antenna diameter)/(vertical gap).

BTW I want to use only 1coil and want to know its efficiency depending on the misalignment ( this is, horizontal difference btw the center of TX/RX antennas not vertical gap)

We want to get  efficiency of 70%.

For this, how much misalignment is allowed?

Thanks and BR,

Devin

[TomasVaverka]

Hi Devin,

For the efficiency issue you mentioned above, it is something related to the active area for wireless charging.

We cannot refuse to charge an RX if the efficiency is below 70%.

So the area within which efficiency > 70% is surely within the active area.

In addition, the efficiency is a system issue, not related to TX only.That is, if the TX and RX resonance parameter match well, the efficiency would be higher.

Best regards,

Tomas

[devinpark]

Tomas,

Let me ask you about the Coil.

WCT-15WTXAUTO EVM(MP-A9 Topology) has a 3 Coil whose maker would be TDK.

But I'm not 100% sure because its BOM doesn't include any information about the coil.

BTW we want to make Single-Coil Module..

So we checked WCT-15W!COILTX. But its BOM also doesn't include the Coil Maker. There is no 15W TX coil in TDK website.

Can you suggest any proper single-coil for WCT-15WTXAUIO

I don't know well about coil but some spec would be important. For example, WPC Compliant TX Type( A9, A6,...), Output, etc.

 Thanks and BR,

Devin