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SPECIAL REPORT: EVs
Eggtronic Enables GaN-Based Charging for EVs

By Maurizio Di Paolo Emilio

patented AC wireless power hybrid thanks to GaN technology. “The power can be between the two primary and secondary coils.
technology from Eggtronic is scaled up, reproducing the applicability for Once placed in close proximity, these coils
designed to increase the power large-scale applications such as electric- create a resonant transformer in the air with
A and efficiency of wireless charging vehicle charging,” he said. “Ninety-five resonant frequencies on the order of 100 kHz.
applications for home and automotive percent was achieved at a distance of 10 mm. The power transfer is constantly monitored
applications. [That’s] double what we could achieve with and controlled by system logic for varying
Igor Spinella, CEO and founder of Egg- the Qi standard — which, at 5 mm, is usually power requirements imposed by the device,
tronic, said the proprietary technology, no more than 70% efficient — representing a depending on its current state (for example,
dubbed E Watt, is supported by a GaN half- real breakthrough for inductive standards.” the completion of a battery-charging process).
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bridge and a dsPIC33 microcontroller. That The technology currently enables wireless
arrangement merges a conventional power QI STANDARD power transfer of up to 30 W with an operat-
adapter and Qi wireless transmitter, boosting The Qi system for wireless power transfer ing frequency of 100–200 kHz over a distance
efficiency to overcome challenges posed by consists of two basic modules — the base of up to 5 mm.
the Qi wireless power transfer standard. station and mobile device — as shown in
Traditional Qi wireless power is limited by Figure 1. The base station includes one or E WATT TECHNOLOGY
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distance (usually 5 mm) and maximum power more power transmitters capable of providing With about 200 patents and founded in 2012,
(up to 30 W). Overheating is another issue: wireless power transfer. It consists in principle Eggtronic specializes in energy conversion
After fast-charging, thermal protections of a power-conversion section and control and and wireless power. It has recently focused on
are activated that stop the charging. “Our communication units. The various subsystems various consumer designs through inductive
solution directs the magnetic field in the right have analog features responsible for driving and capacitive approaches. The company has
way, not only avoiding the problem of over- a primary coil and digital features controlling already raised more than US$20 million.
heating for the Qi standard but also offering the power-transfer process while communicat- “On the basis of the Qi standard, we are
compatibility with the new Apple 12, which ing with other parts of the system. already serving many automotive companies,”
is not Qi-certified,” said Spinella. That paves The mobile device includes a single power Spinella said. “We decided to increase the
the way “not only for automotive but also for receiver, which consists of a power- level of integration of our solutions in order
consumer applications,” he said. harvesting unit and control and commu- to launch our proprietary standards, [which
Spinella added that the new hybrid tech- nication units. On the same level as the are] able to increase performance and features.
nology with AC input does not require an transmitter are analog and digital subsystems Thus, we developed our own ASIC, entirely
AC/DC adapter and allows up to 95% effi- for process optimization. The actual power designed by us and manufactured by TSMC.”
ciency with power of up to 300 W and 40-mm transfer from the base station to the mobile E Watt is Eggtronic’s latest wireless tech-
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distances while reducing the overall size, device is achieved by inductive coupling nology (see Figure 2). It is powered directly
from AC without the need for an external
power supply. The hybrid wireless AC power
approach serves as both power supply and
wireless charger. “The goal was to get a prod-
uct that could be better than the equivalent
wired power supply unit,” said Spinella. “It is
certified as a power supply from an emissions
and safety point of view, and of course, it is a
wireless power transfer technology.”
E Watt uses GaN technology from
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Navitas Semiconductor. The decision to go
with GaN highlights silicon’s inability to pro-
vide adequate switching frequencies, which
are limited to about 100 kHz. The harder it is
driven, the more heat it generates, along with
complexity and cost. Meanwhile, low-
frequency magnetics are too slow when run-
ning at corresponding speeds. Hard-switching
topologies are one option, but they introduce
switching losses; when frequency is increased,
efficiency drops because of increased parasitic
inductance. Also, old topologies and legacy
control ICs can’t keep up.
Therefore, the first step was to address
Figure 1: A typical wireless charging system uses magnetic coupling between a primary the switch problem using GaN technology.
coil in the transmitter and a secondary coil in the receiver to transfer power and exchange Navitas’s GaNFast approach consists of a GaN
data. (Source: STMicroelectronics) switch — a field-effect transistor — with mono-

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