Evaluation board accelerates design of remote wireless charging for smart buildings

Article By : Maurizio Di Paolo Emilio

Energous is partnering with e-peas to develop an evaluation board that combines e-peas' energy management IC technology with Energous' RF solution to support remote wireless charging applications.

Energous has announced a partnership with e-peas S.A., a developer of energy harvesting PMICs and ultra-low power microcontrollers, to develop an evaluation board that combines e-peas’ energy management IC technology with Energous’ radio frequency (RF) solution to support remote wireless charging applications.

In an interview with EEWeb, Stephen R. Rizzone, president & CEO and Cesar Johnston, chief operating officer & executive vice president of engineering, at Energous, highlighted the features and application opportunities for smart buildings, industrial IoT sensors, retail electronic displays and more. The combination of Energous’ WattUp and e-peas’ AEM technologies on an -integrated reference design will facilitate the deployment of new solutions.

WattUp & e-peas’ AEM30940

Belgian company e-peas provides energy harvesting and processing solutions to give infinite battery life to wireless devices, increasing the amount of energy harvested and dramatically reducing power consumption.

Energous’ WattUp wireless charging technology is based on RF technology, which provides a number of advantages for wireless charging, including the ability to be designed into small-format products and devices without flat surfaces. The technology supports at-contact and over-the-air wireless charging – reducing the positioning and interference issues with coil-based solutions. The simplicity of the architecture with a single amplifier and antenna makes it small enough to fit into various use cases. In terms of frequency, the solution is based on Energous’ 900MHz technology.

The functionality of the evaluation board mainly includes e-peas AEM30940, Supercap or a rechargeable lithium battery, a Smartbond DA14531 BLE SoC, ambient light sensor, and temperature/humidity sensors and an optional E-ink ultra-low-power display driver.


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Figure 1: Block diagram of the evaluation board


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Figure 2: Evaluation board by Energous and e-peas


“The Energous WattUp technology enables active wireless power charging which, at the core, is the deployment of either a single transmitter or a mesh of transmitters, depending on the size of the charging zone required, that can provide a 24/7 source of power. The WattUp PowerHub transmitter is designed to provide a broadcast charging zone that scales from a few centimeters to 5m and beyond,” said Energous’ Rizzone and Johnston. “When coupled with the power harvesting evaluation board jointly developed with e-peas, the combination can support a broad range of active, extended distance, harvesting applications including electronic display tags and sensors used in retail, building and industrial automation applications. In addition, the onboard BLE supplied by Dialog provides duplex connectivity from the edge of the network to the cloud to enable data gathering and management.”

e-peas’ energy harvesting IC solution – AEM30940 – is an integrated energy management circuit that extracts DC power from a piezo generator, a microturbine generator or any high-frequency RF input to simultaneously store energy in a rechargeable element and supply the system with two independent regulated voltages. The AEM30940 allows to extend battery lifetime and ultimately eliminates the primary energy storage element in a large range of wireless applications such as industrial monitoring, home automation, transportation and smart agriculture.

The AEM30940 harvests the available input current up to 110 mA. It integrates an ultra-low-power boost converter to charge a storage element, such as a Li-ion battery, a thin-film battery, a supercapacitor or a conventional capacitor. The boost converter operates with input voltages in a range from 50mV to 5V. With its unique cold-start circuit, it can start operating with empty storage elements at an input voltage as low as 380mV and an input power of just 3µW. The low-voltage supply typically drives a microcontroller at 1.2V or 1.8V. The high-voltage supply may typically drive a radio transceiver at a configurable voltage between 1.8V and 4.1V. Both are driven by highly efficient LDO (Low Drop-Out) regulators for low noise and high stability.

Configuration pins determine various operating modes by setting predefined conditions for the energy storage element (overcharge or over-discharge voltages), and by selecting the voltage of the high-voltage supply and the low-voltage supply. Moreover, special modes can be obtained at the expense of a few configuration resistors.

The chip integrates all the active elements for powering a typical wireless sensor. Five capacitors and two inductors are required, available respectively in the small 0402 and 0603 SMD formats. With only seven external components, integration is maximum, footprint and BOM are minimum, optimizing the time-to-market and the costs of WSN designs.

The WattUp technology used is a non-beamforming, single antenna, and single power amplifier (PA) design, which is based on an architectural approach that establishes a path for over-the-air charging for small-format devices. The goal is to create a ‘charging zone’ of one meter, extending to upwards of 5m and beyond, in front of the transmitting device, where multiple receivers such as smart glasses, hearing aids, and wearables can be charged simultaneously without any restrictions on positioning or orientation.

This article was originally published on EEWeb.

Maurizio Di Paolo Emilio holds a Ph.D. in Physics and is a telecommunication engineer and journalist. He has worked on various international projects in the field of gravitational wave research. He collaborates with research institutions to design data acquisition and control systems for space applications. He is the author of several books published by Springer, as well as numerous scientific and technical publications on electronics design.

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