Experiencing when using wireless charging. T
Today, there are only a couple of different wireless charging standards used. The traditional systems are using straight forward inductive coupling, which is working similar to a transformer. These systems require close proximity between the Power Transmit Unit (PTU) and the Power Receiver Unit (PRU) which means, that the transmitter coil and the receiver coil have to be well aligned in the x and y position and the Z-height is limited to a few mm. Qi and PMA are the most known brand names representing these systems and require an individual power transmitter for each receiver unit.
Secondly there are magnetic resonance systems such as “Rezence” also referred to as A4WP (Alliance for wireless power) allow a much larger spatial freedom in all three axis and can also handle multiple receivers on a single transmitter. The transmitter can be on top of the table or it can be mounted underneath the table top, making installation of the technology a breeze.
As all these standards are competing in the market space today and will continue for some time in the future, NXP developed a dual mode receiver unit.
This demo shows that this solution can be used on Qi or A4WP transmitters to charge mobile device with around 5 to 6 W. We managed to integrate a solution into the same space as the previous Qi-only solution the cover was equipped with originally.
If I place the phone properly on a Qi charger, in this case I am using NXP’s single chip low cost Qi transmitter, you’ll see that the phone starts to charge. To show the difference between the two charging systems, I’ll move the phone so that the alignment is not perfect and you’ll notice, that the charging stops.
Taking it off the Qi charger and placing it on our latest A4WP/Rezence PRU, you can also see that phone starts charging again. In contrast to the tightly coupled Qi charging system, the loosely coupled A4WP systems allows a significant special freedom which means I can move the phone within the charging area without disrupting the charging process.
Along with our multi-mode receivers we also have A4WP only solutions as well. All of them are foot print compatible. We have solutions that can efficiently deliver power from 300mW to 20W.