WiFi and Bluetooth are great techniques to unlock our portable devices from cables, except the power cord, right? Some vendors are ready with a new technology that allows charging of mobile phones or other small devices without wires. Is it Buck Rogers or what?
Powercast (Pittsburgh, PA) says it has a solution for wirelessly delivering portable devices. The technology is reliable, FCC-approved (safe), and is ready for delivery later this year, Powercast technology uses an RF wave to transfer power for use of the device. According to Keith Kressin, Vice President of Sales and Marketing, the technology has an efficiency of better than 50% (the amount of power transferred compared to the amount actually used, so every 2 watt power consumption uses the device more than 1 watt of energy).
The efficiency is inversely proportional to the distance between the transmitter and the receiver. In less than 3 feet, the efficiency is about 70%. The waste that is wasted can be used to heat frozen food, huh, no, just joking.
Powercast uses a signal in the 900 Megahertz band to move the power to the device being loaded. Other devices in the same band will not interfere with the operation; In fact, the Powercast receiver consumes some power near this frequency that comes into its periphery. However, this technology can not completely replace a standard charger for most devices. It can lower charge over a period of time so that the power output rate decreases dramatically dramatically for low power devices.
The concept behind the Powercast product is not new. The problem is that transmitted power in this way mirrors different surfaces and changes the signal. The Powercast solution is a receiver that acts as a radio broadcast to many frequencies at the same time.
The maximum power transmission is a few watts at a distance of 3 feet (maximum power is 15 watts). It should be enough to charge most mobile phones to a 50% level of 12 hours. This speed is ideal for mobile phones, wireless keyboards / mice, medical implants like pacemakers and other small devices. The technology is currently not capable of supporting higher power consuming devices like laptops, which currently use significantly more power than the Powercast system can deliver.
Phillips will be the first to market a product using the Powercast system later this year. The first product will be a light stick for low power application. For this application, the device will not have a battery on board, but will continuously receive power from the Powercast system. If you had asked me seven months ago if possible I would have said, do you dream? Did you smoke something? says Govi Rao, Vice President of Solid State Lighting at Phillips.
A Powercast system currently costs less than $ 10 to manufacture. In many devices, implementation of a Powercast solution is cheaper than implementing a battery, and its also more green-friendly green.
An alternative to Powercast technology is inductive charging. If you have a Sonicare electric toothbrush, you already have an inductive charging system. An inductive system is efficiently a transformer, but inductive charging is more less contact than wireless. This system requires a very close connection between charger and device, as efficiency drops sharply at slightly short distances. Powermat is one of several companies that develop a cushioning system that you would put under the device to be charged, and it could support higher power devices like laptops. The system currently has power consumption of approximately 90 watts.
The Wireless Power Consortium was launched this year in Hong Kong to develop standards so that charging systems and consumer devices will be able to communicate. This is important so that the transmitter only sends power when a consumer unit is present and at the appropriate output power. This will improve safety and efficiency. Founding members of the consortium are Logitech, National Semiconductor, Philips Electronics, Sanyo, Shenzhen Sang Fei Consumer Communications and Texas Instruments.