Watch for These Two Problems in Your Qi Wireless Charging Project

Display portlet menu

Watch for these two problems in your Qi wireless charging project

man pulling smartphone from pocket

As a future-proofed and widely available open standard, Qi wireless charging is a hot technology. Engineers are actively incorporating it in applications from hospitality to automotive. Wireless charging, however, replaces cords with coils—and with that comes a few common design challenges.

Luckily, specifications for the Qi standards tell you what features your project needs to have in order to pass the test for the standard. It even offers some suggestions on how to approach your design.

But an actual implementation? That’s not dictated – and therefore it’s not always deeply understood. With varying understanding comes variances in how it’s implemented.

Here are two of the most common problems engineers face in integrating Qi in their projects.

Communication protocol woes

There’s a specific communication protocol between transmitters and receivers in the Qi standard. This protocol is the key to interoperability between devices and the charging pads with which they are communicating.

The transmitter should emit an AC signal across its coil, which is then magnetically coupled with the receiver coil to provide DC output. This closed loop has to function correctly, otherwise there will be problems when you go to test and certify your Qi project.

Although the load modulation method between the device and charging pad should be simple, engineers sometimes run into complications with errors being sent, information transmitted at the wrong time between the transmitter and receiver, or data decoded incorrectly or at the wrong time in the process. All of these issues will hinder effective charging.

The takeaway: Ensure that none of the hardware in your design hinders the communication protocol between coils.

Abnormal temperature increases

With induction now happening between the coils, small metallic parts could reach higher temperatures – and fast—through induction heating. Any Qi tested hardware needs Foreign Object Detection (FOD), which is meant to identify if any metal object in that field could be subject to the adverse effects of induction heating.

Check especially for the magnetic field flow between the transmitter and receiver. Insufficient magnetic shields, often crafted out of aluminum, can poorly interact with aluminum battery case covers and cause abnormal heat generation.

The takeaway: Pay special attention to your FOD detection system so that engineers can detect and prevent overheating within their hardware.

Feedback, testing is key

If you’re running into some problems, find like-minded makers who are working on similar projects through online communities or in your own backyard. If you need more help, get a third party testing system or a strategic partner to get your Qi project off the ground and into the hands of customers.

Related Articles
Electronic circuit board
Batteries are key to charging options
July 6, 2018
Learn how having an understanding of the pros and cons of charging and battery options is key to realizing the full potential of your new product.
person holding smartphone on coffee table
3 levels of Qi testing
November 14, 2017
See how the Qi Sniffer and Qi Certified Product Testers can help you test and certify your Qi products.
charging cell phone in automobile
How to get your Qi project certified by the Wireless Power Consortium
November 14, 2017
By aligning with the Wireless Power Consortium and Qi standard—the way big name brands like Apple, Samsung and Avnet have—you can help verify the quality of your product to new customers.
Bill Amelio, Avnet CEO
Qi standard is for more than just smartphones
By Bill Amelio   -   November 14, 2017
I’m not alone in my suspicion that the engineering world will soon follow a singular standard for wireless charging: the Qi standard. I think it would be the right move—and its impact would extend far beyond the charging of mobile phones.
energy harvesting concept with green batteries sprouting from the ground
Powering the Internet of Things via Energy Harvesting
March 27, 2017
The push is on to add Internet capability to everything—often called the Internet of Things (IoT)—and the challenge for design engineers is to figure out how to power each of these IoT nodes.
nurse checking person wearing health monitoring system on wrist
Internet of Things: Designing Sensor-Based Devices with Coin Cell Batteries
March 11, 2017
A popular vision of the Internet of Things (IoT) is that it will comprise billions of sensors gathering information about their local environment and transmitting that data back to servers in the cloud. Such data will be compiled, analyzed and shared
Using Programmable Logic to Build Power-Efficient Systems
March 8, 2017
The successful implementation of the Internet of Things (IoT) requires new thinking about how to power connected devices.
colorful tunnel
AC/DC Supplies: Design and Make, or Just Buy?
March 8, 2017
How to implement the ubiquitous AC/DC supply is a complicated decision with many factors and perspectives, ranging from technical to regulatory ones.
chart depicting device power states
Power Management Techniques for Low-Energy IoT Devices
March 7, 2017
With the rise of the Internet of Things (IoT), embedded designers are, more than ever, focusing their attention and efforts on system energy usage.
man drawing schetch of an electric car attached to a battery
Technologies and Components for Designing Electric Vehicles
March 6, 2017
Hybrid electric vehicles (HEVs) such as the Toyota Prius and the Chevy Volt and electric vehicles (EVs) such as the Nissan Leaf, BMW i3 and Tesla Model S are growing in popularity amid concern for global warming.
Related Events
USB Type-C and Power Delivery
Date: September 5, 2019
Location: Webinar
Why Smart Gate Drive Optocouplers?
Date: May 23, 2019
Location: Webinar
Why Portable Electronics Perform Better with SIMO PMICs
Date: February 27, 2019
Location: Webinar