Over the last 6-8 months, my teammates at WiPower have pointed to a drastic increase in my usage of a short yet profound word – “subtleties” – for good reason.

Technology development companies, such as WiPower and others in the wireless power space, spend a lot of brainpower and resources coming up with innovative technologies to enhance the way we live. In these years of development, novel electronic systems are created and patented. For most technology development companies, this is where the engineering slows and business development picks up – sell the underlying technology to companies that will productize it.

What can often occur with this business model is the “missed expectations” or “broken promises” phenomena – where the “subtleties” of taking a technology into a product stage are not as straight-forward as expected.

Take for example a small subset of the subtleties involved in creating wireless power products:
1. EM considerations: The electromagnetic fields emitted by a transmitter and coupled into a secondary coil are dependent on the environment that the product is in. For wireless power systems with flat coils, this involves inventing new types of materials with the right EM characteristics and very thin form factors, and creating processes to manufacture them.
2. Thermal management: Electronics dissipate heat. When integrated inside of a phone or other portable device, this heat must be well managed. However, most typical heat management techniques can no longer be used because they involve metal – something that interferes with wireless power signals.
3. Manufacturing: When moving from the prototypes displayed at CES to manufacturing 100,000 units cost-efficiently, the tuning of wireless power systems becomes quite difficult – the inherent variability in electronic components makes the tuning necessary for each unit different.

WiPower has had the good fortune to take its core technology and develop it into products for mass-production. Through this process, the team has been able to design a core wireless power technology that inherently solves the product issues many other wireless power technologies face. For me, this has resulted in a high level of confidence in our team’s ability to execute robust and cost-efficient wireless power systems for virtually any portable electronic device.

Thanks,
Ashish
(Product Development)

Last Monday, the Wireless Power Consortium released their “0.95″ technical specifications and revealed a new logo. The logo designates that a product is compatible with their wireless charging standard. Similarly, the well-established “WiFi” logo denotes interoperability between wireless local area network (WLAN) devices communicating via IEEE 802.11 specifications. Unlike the widely accepted “WiFi” logo, the Wireless Power Consortium’s “Qi” logo lacks any semblance of intuitiveness. The Wireless Power Consortium chose “Qi” because it means “vital energy” in Chinese. I have a slight suspicion that the average consumer will fail to see the natural relationship between the “Qi” logo and wireless power. “WiFi” is simple and intuitive…and it sounds like wireless! Based on initial reactions (one blogger asked, “Does anyone else see this and see someone seated, hands on knees, boaking his guts up?”), others seem to agree that “Qi” is obscure and overcomplicated.

The Wireless Power Consortium’s technical specifications follow this trend with their overly-complicated receiver specifications. Their specifications require digital communication between the transmitter and the receiver. The receiver must send a digital signal to the transmitter to indicate that it is a compatible receiver and to specify its power requirements. Additionally, the receiver provides an error signal to a proportional-integral-derivative (PID) controller on the transmitter. All of these complexities are unnecessary. No communication requirements exist with WiPower’s technology. We use the principles of magnetic induction to detect appropriate loads. There is no communication module or PID controller required. This allows us to maintain low component counts, low BOM costs and therefore, low cost points.

Thanks,
Ed
(Electrical Engineer)

You might have to be technical to appreciate this one…

One of the challenges of designing an inductive power system is managing the voltage and current levels at the output of the receivers. Too much voltage and the end device will break, too little and it will not activate. At a given output voltage, the current level is self-regulating based on the instantaneous power requirement of an end device, but it is still desirable to have over-current protection for safety reasons. A switching voltage regulator is the solution.

Voltage regulators convert a given input voltage to a desired output voltage and are used in virtually all electronic devices. Buck voltage regulators are used to step-down voltages while boost voltage regulators step-up voltages. Buck-boost regulators, as you might guess, step-up or step-down. These regulators are available through a wide variety of vendors including Texas Instruments, National Semiconductor, Linear Technologies, Maxim, International Rectifier, and Fairchild Semiconductor.

All of our receivers work with off-the-shelf voltage regulators without requiring any support circuitry – an electronics enthusiast or undergraduate engineering student could design receivers for our transmitters. Our engineers work predominantly with buck voltage regulators and during the selection process, we are concerned with three primary factors:

1. Input voltage range: Switching voltage regulators enable efficient conversion from very high to very low voltages. The LM5005 by National Semiconductor can step down an input voltage from 75V to 1.23V. The receiver-side rectified DC voltage is not always stable (the secondary coil can be thought of as a non-ideal voltage source having a relatively high source impedance) and the input voltage rating should provide a significant level of margin. If voltages are nominally 25 volts, a 50 volt regulator is recommended.

2. Efficiency: The efficiency is critical. Our engineers design products that must stay cool despite being crammed into tiny form-factors that are devoid of air-flow, and have no space for heat sinks or any elaborate thermal management system. Sadly, even today, few people prefer to use high efficiency parts for environmental reasons because of the cost involved. High efficiency parts are expensive. Low efficiency parts are cheap. That said, we can usually convince our customers to use high efficiency parts for thermal reasons.

3. Form-factor: Devices are small and getting smaller. One of the keys to reducing form-factor is shrinking the size of the discrete components that surround the voltage regulator. This is accomplished by operating at high frequency. Increasing frequency reduces efficiency. A voltage regulator operating at 100kHz might be 95% efficient, but at 800kHz, might be 80% efficient. Fortunately some modern, low-cost, buck regulators with high input voltage ratings can have integrated switches with very fast switch times. This minimizes switching losses thereby preserving high efficiency operation at high frequency.

Let us know if you have questions!

Thanks,
Ryan
(President)

It’s interesting to take a step back and listen to what people say about wireless power.  If I had a dime for every time I heard a comment about wireless power that was completely inaccurate, I would be… well to be quite honest, I would not be writing this blog.  I suppose this is inherent with many, if not all new technologies and as such I’d like to take a minute to set the record straight on four common misconceptions:

1.  Yes – the transmitter must be plugged in!

All wireless power systems consist of a transmitter and a receiver.  Similar to WiFi, where wireless routers must be plugged into the wall, so must wireless power transmitters.  Why, you ask?  Because while we are good, we cannot defy the fundamental principles of the conservation of energy (yet).

2.  No – wireless power systems will not harm you.

Unlike hot dogs, inductive wireless power systems will not cause cancer.  Nor will they affect your cognitive abilities, respiratory function, or any other bodily functions.  WiPower’s wireless power system is completely safe and has passed the FCC’s regulatory standards.

3.  Yes – inductive wireless power transmission is not new technology.

The fundamental concepts of electromagnetism were first documented by Nikola Tesla in the late 1800′s.  Over the past decade, the technology has been commercialized in several consumer products, most commonly in the electric toothbrush.  As outlined by our CEO in a recent Product Design & Development article, what differentiates WiPower’s technology is the flexibility and ease of use provided to consumers.

4.  No – all inductive power systems are not created equal, and therefore not interoperable.

Though each of the companies in the inductive power space utilize similar technology, there are substantial differences that do not allow interoperability.  The frequency, for one, is different between systems rendering one transmitter compatible only with its receivers.  As such, you cannot take a Palm Pre and place it on a WiPower charging pad, nor can you take a WiPower enabled product and place it on your toothbrush charger (well you can, just don’t expect it to charge).

If you have more questions (myths or otherwise), please contact info@wipower.com

Thanks,

Henoch

(Business Development)