Teardown: Wireless charger with a magnetic personality

Article By : Brian Dipert

Take a conventional Qi charger. Beef up its output (for compatible to-be-charged devices, at least). Add magnets. Now buy it and tear it apart. That, in a nutshell, is today's editorial piece.

With every iPhone generation, with varying degrees of success, Apple strives to come up with at least one “killer” new feature that will motivate not only potential Android switchers but also iOS upgraders. For the iPhone 12, there were (at least) two: first-time 5G connectivity, and the underlying motivation for this particular teardown, MagSafe.

Long-time Apple hardware owners may already be familiar with the term; beginning with the introduction of the Intel x86-based MacBook in 2006, it was the quick-release means by which power got delivered to Apple’s portable computers:

The concept was cool, albeit proprietary; no longer would tripping over the power cord send your laptop flying across the room. MagSafe went through two initial generations, with MagSafe 2 dimensionally smaller than its predecessor (an adapter bridged the gap for legacy power “brick” owners). Beginning in 2015, however, Apple phased it out in favor of non-proprietary (albeit non-quick-release) USB-C. As of 2021, however, it’s back (alongside USB-C), now named MagSafe 3; some good ideas thankfully don’t die, they just doze off for a while.

The iPhone 12, released in October 2020also offers magnet-augmented power connectivity, specifically associated with its wireless charging capabilities, and implemented in-phone via a set of powerful magnets around the charging coil and behind the glass back. You can, for example, use MagSafe to attach a Qi-based supplemental battery pack to the iPhone 12. For that matter, putting power aside for a second, you can also leverage MagSafe to mate the iPhone 12 with a gimbal or other bracket in a secure but easily removable fashion. But, returning to the power theme, the primary touted advantage was the ability to connect the phone with a Qi charger, either horizontally or vertically (the latter without requiring a “shelf” underneath the phone), and with optimum-efficiency positioning.

To date, I’ve torn apart both horizontal- and (near) vertical-orientation traditional Qi chargers (two in the latter case, come to think of it), so I was curious to see what a magnet-augmented pad might look like inside. Last July, Amazon had an EuSeneo (also sometimes referred to as iSeneo, and the parent company is Seneo…got that?) WaveCharger 228 magnetic wireless charger on sale for $7.99; even better, it was 15W output-capable when paired with Apple devices, more powerful than any of the other chargers I’d previously dissected.

Speaking of Apple, Seneo was seemingly careful to not call it “MagSafe”, presumably because the company didn’t have a license to use Apple terminology, although at least some of Seneo’s retail partners weren’t so scrupulous. And speaking of retailers, you won’t find it on Amazon’s website anymore; mine was sold by third party named “Yuze us” which seems to have fallen victim to Amazon’s purge around that same time. You can still find it on Walmart’s site, however, although it’s out of stock (at $12.94) as I write this. Thanks to its publication longevity there, however, I’m able to share the following unique descriptive excerpt with all of you:

Cat-paw Size – Dimension of the Seneo wireless charger is as small as cat paw, and the thickness is thinner than your phone, it is no pawblem to put the wireless charger in pocket and go.

Meow. You’re welcome.

Before diving in, I’ll share one more “stock” image, that of a conceptual teardown:

And now let’s see how close reality matches up to the marketing, as-usual beginning with some outer box shots:

Inside is the charger (currently within a protective “baggie”), two pieces of literature, and one half of the “pasteable design” listed in one of the earlier box shots (i.e., a 3M adhesive pad). Along with, as usual, a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes:

I’m only showing nine of the twelve total documentation “panels” in the following photos, focusing on the ones that include English verbiage:

Now let’s see what’s inside that baggie:

The charger topside is temporarily protected by a sheet of peel-away translucent plastic (perhaps obviously, you’ll need to remove it in order for the charger to operate at peak efficiency). It’s also USB C-based, although unlike with Apple’s own conceptually similar MagSafe Charger, Seneo nicely also includes a USB A-to-C adapter for folks with legacy wall warts and such. And did I mention that Seneo’s charger was only 1/5 the price of Apple’s? That said, Apple’s MagSafe Charger is firmware-updateable, which counts for something (???).

Flipping the Seneo charger and adapter over:

There’s a pre-installed matching 3M adhesive pad underneath, a bit of an odd implementation decision (IMHO). It’s a bit better than it might seem at first glance, because it’s actually attached to the removable silicon case surrounding the charger, not to the charger itself:

Still, what if I wanted to use the silicon case to, for example, protect a wood-top desk or other piece of furniture from being scratched by the charger, but not the adhesive pad to hold it in place? A bit more cosmetic flexibility via a second separate adhesive pad in the box instead of pre-attaching it would seemingly be the preferable packaging approach. But I nitpick.

Onward. Here’s the charger backside, sans silicone case:

And frontside, sans protective plastic:

Initially popping it open was pretty easy. A few seconds’ worth of heat gun application to the (presumed glued) top, followed by a fingernail under the “lid”, got me inside straightaway:

Here’s our first glimpse of the solitary charging coil, with a slew of magnets around its circumference:

The next step was a bit more work, but only a bit. My trusty flat head screwdriver acting as a lever arm got the plastic ring holding the magnets in place loose straightaway:

Those are some wicked strong magnets:

And (normally) holding them in place rattle-free is a circle of metal underneath them:

At this point, extracting the PCB was easy, after peeling off a dallop of glue:

I have no idea why the circular area underneath the PCB is reflective, and I have no idea whose receding hairline is reflected in it (sigh):

Here’s one more look at the coil, sans surroundings:

And here’s the PCB it’s sturdily glued to:

Notable components include, in the center, an IC labeled:


whose identity eludes me, in spite of abundant Google research. If I had to wager a guess, however, I’d suspect it was a STMicroelectronics wireless charger transmitter controller; the company has a longstanding habit of cryptically marking its chips. That said, the other IC above and slightly to the left of it is no less mysterious:


Reader insights into the functions and manufacturers of these chips are, as always, welcome!

In search of anything I could definitively ID, I turned my attention to the QR code-stamped sticker:

But the only thing below it was a bland albeit, hefty-sized capacitor. Oh well.

Over to you for your thoughts in the comments, readers!


This article was originally published on EDN.

Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.


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