Blog first published and contributed to Planet Analog
Continuing on from my previous blogs regarding wireless power & charging standards and comparing various stances on the wireless charging of electronic devices – today I want to discuss the respective positions on frequency.
I have written in the past about convenience for Consumers in wirelessly charging mobile devices. Some of the key factors are:
While the Consumer Electronics Association WG4 will deliver on the above, there is an on-going debate to select the right frequency.
Of course the Wireless Power Consortium has defined a specification for frequencies below 500 KHz. Such products have been shipping and proven to be safe and reliable.
At the same time, another working group called the A4WP is driving a specification for a frequency of 6.78 MHz – making it incompatible with products now shipping. In addition, the 6.78 MHz frequency has not yet been proven to meet safety and emission requirements, while is also expected to cost more.
Does it not seem obvious that Consumer Electronics Association WG4 select a frequency less than 500 KHz, which has been proven to meet the safety and emission standards, is the lowest cost for consumers, and is interoperable?
Let me now your thoughts.
In my post last week I started to examine issues around frequency selection for wireless power systems. This week I want to take the discussion a bit further and talk about the benefits (as we perceive) of using lower frequencies (in the kHz range) vs. higher frequencies (MHz) as an industry standard.
As the standards debate rages on, different parties continue to put forward their various interpretations on the ideal frequency range. Various standards utilize higher frequency ranges than others. PowerbyProxi, through the CEA working group, continues to argue that standards that use lower frequency ranges (kHz) are more appropriate based on what we believe is in the best interest for you – the consumer.
There are several factors that need to be taken into account.
Complexity. How complex is the device to manufacture. Controllers used for wireless power systems are far more complex at the MHz range ultimately impacting the cost of manufacture and thus the price that the end-consumer (you) pays.
Interference. As we as we are aware there are no wireless devices operating in the MHz range that meet EMC radiated emission compliance. What it means is that at the moment, there is no proof that they wont cause interference on other devices.
Other factors such as charging distance, transmission efficiency, thermal properties and form factor tend to be implementation specific or require further research to be able to draw clear comparisons.
On the balance of the research done so far, lower frequencies at the kHz allow for more user friendly and functional wireless power systems to be developed. Isn’t that ultimately what it should be all about?