Wireless Power Solution Needed

[PNada.3]

Wireless Power Requirements:

-Require 5W on Receive side

-Active Part Number and industrial temp rated

-Air Gap: 20 to 30mm but ideally up to 40mm

-Coil Size: 50mm or smaller is ideal, room to adjust size as needed

-Don’t need to be compliant with any other standards but product will need to get FCC/CE certified, ideally don’t want to be able to charge anything else but priority is ease of design

-Not very concerned about efficiency

-Chip cost is a big consideration

Questions:

-Looking to run a device directly off power from the RX coil (no battery in device), are there any potential issues with this?

-Transfer distance depends on many things including the coils used but how reasonable power transmission over this air gap distance? What are the many factors contributing to wireless power transmission distance?

-Can I use a higher power transmitter such as 15W to get longer distance even if I only need 5W?

-Is the STWBC86 the best choice for this application or can you suggest other options?

[willzhou · Accepted solution]

Q:Looking to run a device directly off power from the RX coil (no battery in device), are there any potential issues with this?

A:It can be used but it is depends on the powering behavior of product - mainly the current jumps.

Dear Customer Q:Transfer distance depends on many things including the coils used but how reasonable power transmission over this Air Gap distance? What are the many factors contributing to wireless power transmission distance?

A:For this requirement, it is necessary to increase the coil space and input voltage. For detail solution, it is needed to do the simulation in dedicated software.

Q:Can I use a higher power transmitter such as 15W to get longer distance even if I only need 5W?

A:Usualy it is not possible, because the analog ping is defined by Qi standard. If the TX is supporting 15W, it means EPP (extended power profile) this is available after negotation. The behaviour of ping is the same for 5W (BPP) and 15W (EPP) TX.

Q:is the STWBC86 the best choice for this application or Can you suggest other options?

A:It could be possible to use it with higher input voltage to TX and TX coil with bigger dimension. This is specific request and for this application, the coil simulation is needed and then the real debug setup.