Wireless charging poised to go the distance

The benefits of wireless battery recharging over a distance appeared about as likely as jet packs and flying cars until Dialog Semiconductor and Energous Corporation began their quest to cut the cords.

While consumers clearly love their smartphones, laptops and tablets, they equally detest the tangle of power converters and charger cables cluttering backpacks and briefcases from Bristol to Burbank. This love/hate relationship could be about to change if power technology companies Dialog Semiconductor and Energous Corporation successfully deploy their new WattUp® family of wireless charging solutions.

Wirelessly recharging mobile device batteries is hardly new. Existing wireless solutions typically employ coils to carry power to receiving devices; however, these have their limitations. According to Dialog Semiconductor’s Senior Director of Corporate Strategy, Mark Hopgood, it is precisely those limits that make the solutions developed by Energous Corporation with support from Dialog so compelling. Without charger mats, precise alignment or other persnickety requirements, the WattUp solution offers benefits that Hopgood says consumers expect: no clutter, and more importantly, no wires.

“I think wireless charging has not lived up to a lot of consumers’ expectations. In some cases it can be downright frustrating to find that your device has not charged because it wasn’t placed quite right on the charging mat. We believe this new solution is much closer to consumer expectations – it will be a difference they appreciate when it comes time to buy,” Hopgood said.

Dialog traces its roots back to 1981 and included times as a Daimler Benz AG subsidiary infused with CMOS and semiconductor technology from Silicon Valley’s International Microelectronic Products company; its expertise in power management electronics later extended into smartphones incorporating ARM processors. Work with LED power technology and sensors were later added as the company grew to multiple locations in the UK, Europe, Asia and the US. Dialog’s broad power-focused market appeal eventually led to a relationship with Energous Corporation that began in 2014 and was formalized with a partnership and cash infusion of (USD) $10 million in 2016 to support Energous’ development of its WattUp wireless technology.

Energous developed its WattUp technology that provides over-the-air power at a distance as an alternative to existing wireless recharging techniques including those of other AirFuel Alliance members. Although Energous and Dialog stress the wireless aspect of their technology enabling recharging at a distance, WattUp could be employed to create near field charging mats, but without the precise placement requirements some consumers find challenging.

Both companies believe most consumers will realize additional benefits as longer-distance charging applications become available, such as deciding when a device is ‘refueled.’ Consumers can choose priority devices for recharging, or let anything properly equipped sip power as needed. WattUp receiver technology can be incorporated in a very wide range of consumer products that can ultimately be charged from various types of WattUp transmitters. Even if WattUp devices are positioned in a wireless recharging mat in a near field application similar in appearance to existing systems, Hopgood said Energous’ core technology has important advantages.

“One of the things we looked at comparing coil based tech vs. Energous (WattUp) was the fact that the receiver coils tend to require a large diameter and an added physical dimension—a ‘z’ height thickness. Because of this, (coils) are often too big to be integrated into many products that could benefit from wireless charging. But if we reduce the footprint at the device level—which WattUp technology does, this translates into the antenna becoming nothing more than the tracking on a PCB; we can even use the same antenna for charging that you would use for Bluetooth,” Hopgood said.

Besides eliminating the coil that other wireless charging technologies depend upon, Hopgood said Dialog and Energous have worked to move from discrete components to integrated semiconductors that further reduce space and increase efficiency. At the same time, WattUp software is designed to ensure that charging waveforms are dynamically directed, focused and controlled via proprietary algorithms; for mid field and far field charging applications consumers can choose various control options including recharging when electricity rates are lowest.

Dialog and Energous have moved forward with their plans to further miniaturize key component technology with the announcement in January of their first jointly produced integrated WattUp wireless power transmit (Tx) IC, the DA4100. This new System-on-Chip (SoC) integrates an ARM Cortex-M0 along with RF power generator, power management and secure element functionality into a single 7x7mm device. It also features on-chip DC-DC conversion and embedded software, providing seamless integration to Dialog’s SmartBond™ family of highly integrated, low power BLE SoCs. The new DA4100 minimizes board space needed to implement, enabling smaller charging transmitters and simplifying overall design-in requirements.

Gordon Bell, VP of Marketing at Energous, said that the DA4100 is the backbone of all WattUp transmission designs including the near field transmitter that the US Federal Communications Commission (FCC) recently approved.

“We are engaged with a large number of product companies currently looking to incorporate the WattUp receiver technology into their devices. These companies would typically bundle a WattUp near field transmitter along with their product to offer devices that are charged wirelessly,” said Bell.

Bell elaborated that while many end use designs are possible using WattUp receiver technology, Energous and Dialog expect that WattUp-enabled transmitters will most likely appear in future consumer markets focused on two primary applications: standalone and embedded transmitters.

“Standalone transmitters have a single function to allow for wireless charging to WattUp-enabled receivers. A standalone near field transmitter would likely be a small charging pad included inside the box of many small electronics (replacing the USB cord and power brick typically bundled inside today). A standalone mid field transmitter may be incorporated into the dashboard of a car or may be a small device that sits on your desktop, allowing for charging in the 2-3 foot range. A standalone far field transmitter may look similar to a Wi-Fi access point installed on the wall or ceiling, allowing for wireless charging at up to 15 feet,” Bell explained.

“Embedded transmitters would be part of another product. For instance, the near field transmitter technology may be embedded into the top of a Bluetooth speaker, allowing you to charge small electronics simply by placing them on top of the speaker…. A desktop assistant type of product may offer mid field WattUp charging to other devices nearby. And the bezel of your TV may one day offer far field WattUp (utility), charging its own remote control, game controllers and other devices within 15 feet of your TV. All of these implementations would use the DA4100 as the backbone of the wireless charging function,” he concluded.

As the WattUp technology moves from development stages to design-in with lead customers, Dialog’s Mark Hopgood said that the change from coil-based wireless charging approaches and other technologies to antennas working with directed RF signals will affect consumer purchasing. The degree to which a consumer has adopted mobile devices and uses them away from mains power supplies could be decisive.

“There are so many gadgets that are a slave to a socket; WattUp technology has the potential to change the way we use our battery powered devices…let’s look at near field; at face value one might think that our technology doesn’t really add much advantage, but actually when you go from a coil to an antenna based system, you dramatically reduce the footprint and the cost, so just doing that opens up a whole new category of devices. Also, RF is less precious about positioning the device on the charge mat.

“The paradigm shift may occur that when you are using a device, you are sending just enough energy over the distance (using WattUp technology) to keep the devices topped-up. This could be done constantly…so you can reduce the size of the battery, or you can simply not worry about charging them again by keeping them under a managed constant charge. That is where the paradigm shift will occur that the consumer will appreciate,” he concluded.

While both Dialog and Energous could not share details regarding the original equipment manufacturers that are currently working to incorporate WattUp technology into future end user devices, they did indicate that product sampling and qualification tests were underway. The companies expect consumer devices incorporating WattUp wireless charging may begin appearing in some global markets later in 2017.