On the back of the recent release of our resonant Proxi-2D EVK Development Kit, this video looks to provide a bit more insight into the technology behind the transmitter and receiver.
The EVK Development Kit includes ten key components packaged in two layers. Aside from the transmitter and receiver units, the kit includes, two 2mm spacers, a Power supply for the Tx, USB to Serial cable, Adaptor board, Ribbon cable, Mini USB cable and IEC power cord.
Setting up the Transmitter:
Setting up the transmitter for use is as simple as connecting the provided power cable.
The Tx consists of a single controller circuit board and coil array. At the front there are three LED indicators that designate different operating states. The center red LED indicates when power is being supplied to the transmitter. The Blue LEDs on the either side will indicate if the when the board is scanning for devices and when charging is occurring.
At initial start up, the transmitter will perform an initial Board scan to detect any receivers that are on the surface of the pad. Once powered, the board will continuously perform a loop detection to check if an object has been placed on, or removed from the transmitter pad. A board scan is performed whenever the loop detection detects a receiver being placed on the charging surface. This scan is highlighted by both blue LEDs flashing for three seconds. During this process a Digital ping is performed on each coil in the Transmitter array to check whether there is a receiver present.
Depending on where a receiver is placed, an LED will stop flashing and remain on – indicating that power is being transferred to a receiver. The transmitter will enter Resonant mode if a Proxi-2D receiver is detected, otherwise it will enter Inductive or Qi mode if a Qi version 1.1 receiver is detected.
Resonant Receiver module:
The Receiver module itself consists of an Rx coil and circuit board placed inside a plastic sleeve or enclosure. A series of five labeled LED indicators on the circuit board designate the amount of power being transferred to the receiver as well as the mode of operation. In this instance the receiver is operating in Resonant mode and is receiving 5Watts of power from the transmitter.
The Rx receives a signal from the Proxi-2D Tx which will inform it to switch to Resonant mode, otherwise it will assume that it has been placed on a Qi Transmitter and will operate in Inductive or Qi mode.
Extended Z Height Testing:
Included within the kit are two 2mm clear spacers. These spacers enable for users to test the system at three different Z heights or coil to coil distances – 3mm, 5mm and 7mm. The different spacing is achieved by simply inserting spacers between the Rx and Tx boards. The system will perform in the exact same manner at the different heights.
In our next video we will explain how to set up the system for testing and highlight the functionality of our unique control application software.
The Wireless Power World Shanghai 2012 was held last month on Sept 12 -13 where many of the leading companies presented and attended.
It was evident at the show that all companies and industry groups are now driving to a common set of objectives addressing the fundamental needs of consumers. These consist of spatial freedom, simultaneously charging multiple devices, and addressing a wide power range for devices from smartphones to tablets and PCs. Spatial freedom is the new term for “loosely coupled” and more intuitive than the prior technical term.
Although the Wireless Power Consortium (WPC) was first in creating an interoperable specification to start the market, the adoption has been slow. Some of the basic limitations for consumers have been the “tightly coupled” or non-spatial freedom requiring consumers to precisely align their device on a charging pad, charging only one device at a time, and power to charge only a smartphone. While on my travels throughout Asia last month, I discovered that a number of tier 1 OEMs decided not to supply WPC based products not only due of those limitations but also because of unacceptable performance for low efficiency and generating too much heat.
There are now 3 industry groups driving these common objectives: WPC, A4WP, and the Consumer Electronics Association Working Group 4 (CEA WG4). The CEA WG4, where PowerbyProxi is one of the leading contributors, was formed over one year ago and took the lead in defining an interoperable specification for what the rest of the industry is now recognizing as the fundamental needs.
PowerbyProxi demonstrated working products and technologies at the Wireless Power World Shanghai 2012 which deliver the ultimate in spatial freedom and the ability to charge multiple devices simultaneously with its Proxi-3D and Proxi-2D charging platforms as well as the most miniaturized receivers that can fit into AA batteries.
Let me now your thoughts.
Coupling is a term widely used in discussing wireless power systems – it refers to a coupling coefficient ‘k’ which defines how well a transmitter and receiver are magnetically “linked” as a percentage. Generally something like transformers have extremely high coupling coefficients approaching 100%.
Technically, tightly coupled systems are interpreted as having high or transformer like coupling coefficients while loose coupling is interpreted as systems with low coupling coefficients. There is some debate around the cut-off for high and low – 50% is one proposed transition point.
From a usability perspective I would define tightly coupled as a system which requires some form of mechanical alignment to fix orientation and transmission distance. This can be done via a magnet or a mechanical alignment feature on the transmitter and receiver. A loosely coupled system would allow complete flexibility of orientation / misalignment in a 2D target zone. A 2D target zone would be a planar area such as a matt (i.e. Proxi-2D), which can wirelessly charge devices imbedded with a receiver that is a few cm above it.
Systems like the Proxi-3D which enables receivers to work in a three dimensional target zone with an omni-directional receiver are what a user may call as beyond loosely coupled!
In my opinion the usability definition is more relevant for anyone buying the system as really the technical definition is really just a means to an end – the end being ensuring customers don’t have to carefully align their devices with a wireless charger.