SAN FRANCISCO – Wireless charging startup Energous is sampling an RF-to-DC rectifier IC designed to power smaller wearable and IoT devices that require up to 10 Watts over a 15 foot distance.
The IC is the center of Energous' WattUp platform, which connects devices via Wi-Fi and Bluetooth Low Energy at 2.4 GHz to 2.5 GHz as well as 5.8 GHz. Bluetooth locates the device in need of charging and focuses the radio waves to charge the devices automatically.
The ASIC is more reliable and twice as efficient as Energous’ original reference design while running over a larger range of power. The 3mm x 2mm chip integrates more components and requires a smaller battery, Energous CTO and Founder Michael Leabman told EE Times.
The size of Energous' ASIC package compared to a dime. The IC measures 3 mm x 2mm inside the package. Source: Energous
Energous’ IC supports four independent antenna inputs at up to 30dBm per port. Providing four independent ports will allow RF wireless charging to scale up to higher-power devices such as tablets and smartphones.
“Our antenna designs are unique because they’re thin, and we’ve manipulated the board by packing a lot of thin antennas in a small space without getting them de-tuned,” Leabman said.
Leabman outlined the same process for manipulating antennas on a PCB in Energous’ reference design. While those techniques took time and three iterations of silicon, creating an ASIC with cost-effective CMOS was the trickiest part of the wireless charging process.
“It’s very, very difficult [creating] the RF-to-DC conversion when you put it next to something if the antenna is metal,” Leabman said, though he declined to state whose CMOS process Energous uses. “Putting it into an IC takes away a lot of those issues.”
This may be Energous’ differentiating factor in an emerging wireless charging market that requires standardization. Energous joined the Power Matters Association’s Uncoupled Working Group to develop technical specifications for wireless power and charging based on non-magnetic technologies.
The future of wireless charging won’t simply by resonant or inductive-based magnetic technologies, the CTO said.
“Everyone has different technologies and different advantages,” he said, adding that 40W laptops and cars are better suited for coil-based systems. “We see a world where multiple technologies fit different needs. In a mobile world where devices are 10W or less, being able to be untethered where you can walk anywhere in a room is worth it.”
Leabman said Energous has more than 19 development agreements with unnamed consumer electronics companies, including “one of the top five consumer electronics companies” for products in late 2016 or early 2017.
— Jessica Lipsky, Associate Editor, EE Times