Interview with Powercast: Solving Remote Wireless Charging Challenges

Parent Category: 2021 HFE

By Tom Perkins

HFE spoke with Dr. Charles Greene, Chief Operating and Technical Officer of Powercast Corp., on March 9. The company is located in Pittsburgh, PA. Charles has been with them for his entire career, about 18 years.

When the company was formed a small team set out to develop true wireless power solutions that could both eliminate batteries and enable completely untethered devices that require no wires or charging surfaces.  It was obvious to everyone at an initial meeting that long-range wireless power, or power over distance that could remotely charge enabled devices, would be revolutionary for many industries and products. The team spent several years refining its wireless charging technology – which transmits a radio frequency (RF) whose energy can be “harvested” to power devices embedded with a small receiver. They entered the market in early 2007. The target devices are mainly those having low power consumption, not cell phones or smart phones.

Powercast has since helped customers solve many remote wireless charging challenges, powering their wireless sensor networks, waterproof designs, reusable smart bands, RFID tags and many other commercial and industrial devices, and in 2017 launched solutions designed to power consumer electronics devices.  Devices benefitting from this technology include untethered headsets, keyboards with low-capacity batteries, and mouse controllers. Along the way, the company has accumulated awards and created significant intellectual property (IP) surrounding RF-based wireless power, including dozens of patents worldwide and numerous patents pending.

Where enabled devices automatically charge when within range of a transmitter, Powercast’s contactless charging technology provides over-the-air power at a distance to multiple devices – no wires, charging mats or direct line of sight needed. A transmitter sends RF energy to Powercast’s Powerharvester® receiver embedded in a device, which converts it to direct current (DC) to directly power that device or recharge its batteries. A unique application is providing power to embedded devices in rotating machinery. Also, applications where heat exceeds what conventional batteries can withstand, and powering embedded electronic sensors in sports related objects like baseballs and cricket balls having no external connection port.  Operation is across a wide RF power range as low as -17 dBm (.02 mW). Frequencies used are anywhere between 10 MHz and 6 GHz in compliance with applicable regulations. Frequencies such as 915 and 2.4 GHz are particularly emphasized in the U.S. whereas the 868 MHz European Low Power Network (LPWAN) is employed in Europe.

The Powerharvester receivers are designed to convert RF to DC. Up to 80 percent efficiency has been achieved. Two long-range transmitters pair with the Powerharvester receivers to serve different markets. Powercast’s 80-foot-range Powercaster® transmitter was FCC- and ISED-approved in 2010 (FCC ID: YESTX91501, IC #: 8985A-TX91501) for commercial and industrial applications. Powercast’s smaller PowerSpot® transmitter for consumer electronics can be a standalone charger, or be built into other consumer products that then become “PowerSpots” able to charge multiple enabled devices around them. The power spot device measures approximately 7” H x 2” W x 1” Thick.

The goal is for consumers to simply place enabled items for recharging within range of a PowerSpot in their home or public places. Recently they have even developed schemes to transfer energy via spread-spectrum techniques. Dr. Greene emphasized that the “holy grail” of this business is energy density. There are many emerging applications including medical wearables, embedded electronics in certain types of balls used in sports, “smart” credit cards, and “charging lighted packaging” in grocery stores to attract buyer’s attention, yes you heard it here first! Their products are available through leading electronics distributors.