Energous’ technology promises charging of devices such as Smartphones, within a room or within around 3m of a charging point, with no connections to the hand-held or wearable device and with no requirement to lay it on a charging pad or mat.
Details of Energous exact technology have so far been sketchy, but the company says it is using the same radio bands as WiFi and other wireless communications standards therefore, GHz RF. Within the operational range of the charging point (Energous calls the space a pocket) a compatible device is found and authorised for charging. Eventually devices may be native-Wattup-compatible: demonstrations so far seen are reported as requiring add-on Wattup cradles to add the charging function. Once identified, a phased-array of transmitting antennae form an RF beam that is focussed on the target device, and that tracks it if it moves. That RF is received, rectified and used as the power source. Nothing is revealed so far about exact frequency or frequencies (fixed? hopping? ultra-wideband?) or modulation schemes (CW? Pulsed?) or if the receive end of the link also needs a phased antenna array.
Other questions that will immediately occur to engineers include, how much power can actually be delivered in this way a figure of 10W has been seen but it is not clear if this is the power available, or transmitted. And; what end-to-end efficiency is possible? Again, reported figures of 20% (mains-socket to battery terminal) for prototypes have been mentioned, with Energous expressing confidence that this can be raised. Inevitably, questions of safety will arise, even if power levels are modest.
Energous is playing in a space where Witricity has already staked a claim; this MIT spin-off company proposed magnetic resonance rather than RF as a means of sending power over a free-space distance (a standard called Rezence has support from some high-profile names) and has been associated with higher power levels such as EV and HEV charging.
All of this, and more, is expected to be clarified as Energous moves closer to market; the deal with Dialog is specifically targeted at wearables and may therefore fit in a niche where required power levels are low, modest efficiency is acceptable and safety concerns minimised.
The formal announcement says that; Dialog Semiconductor has agreed to a joint collaboration with Energous Corporation, developer of WattUp, a disruptive wire-free charging technology for electronic devices that provides power at a distance with complete mobility under full software control. Dialog and Energous will develop reference designs to engage customers and further evaluate the market for wire-free power.
Our collaboration with Dialog Semiconductor will provide consumer electronics manufacturers with a superior technology that will differentiate their products with the freedom of charging without wires, said Stephen R. Rizzone, CEO of Energous Corporation. By optimising WattUp with Dialogs SmartBond connectivity and power management technology, OEMs will be able to seamlessly and rapidly integrate wire-free charging and remote management right into their devices.
Source: http://www.electronics-eetimes.com/en/is-free-space-wireless-charging-viable-dialog-thinks-it-s-worth-a-try.html?cmp_id=7&news_id=222922105&vID=209&page=0
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