Teardown: Wireless charger boosts output, alters orientation

Article By : Brian Dipert

One benefit to a wireless charging stand is less likelihood that you'll mis-place the mobile device to be charged.

Earlier this year, I dissected a single-coil 5-9W Qi wireless charging pad from Samsung, which laid flat on a horizontal surface, with the mobile device to be charged placed on top of it. This time, we’ll be looking at a 10W vertical (more accurately: 60° diagonal) charger from Seneo, which also acts as a stand. One benefit to this altered orientation is less likelihood that you’ll mis-place the mobile device to be charged … from past personal experience, it can be quite a bummer to wake up in the morning and realize that not only has your smartphone not recharged overnight, but its battery is even further drained. Plus, while the mobile device is recharging, you can still conveniently watch videos or otherwise use it; the Seneo charger supports both horizontal and vertical mobile device placement orientations.

I’ll start out with some overview shots:

See the micro USB port on the bottom of the charger’s back side view? It’s the “Achilles’ heel” reason why this teardown is happening at all. The charger works great when it’s supplied with reliable external power (several others are still in regular use in our household, in fact). The micro USB port on this particular unit has gotten flaky, only working at all when the cable-and-connector feeding are in specific orientations, and then not consistently.

At the bottom of the charger’s “foot” is what I suspect to be (we’ll soon see) a multi-segment LED array feeding a cluster of lightpipes. The LEDs output one of three colors; it’s light blue on initial power up:

Darker blue after a few seconds, if no mobile device is detected on the charger:

And green, if a mobile device is present (regardless of whether or not it’s fully charged):

Getting a closer look at that illumination assembly (along with the charging coils, ICs, and the like) requires cracking open the two halves of the product chassis. My first step is always to look below the underside rubber pads. A-ha! Screws!

The topside of the “foot,” on which the mobile device being charged rests, is also rubberized. It peels right off and, as suspected, there’s a translucent plastic piece underneath:

Four more screws are in obvious view, two at the top of the back side, and two others at the “elbow” joining the bottom and stand:

Remove all six and the two halves of the chassis pop apart with only a bit of flat-head screwdriver-as-lever encouragement. Here’s the back side of the top half, revealing the rear end of the lightpipe array:

On either side of it is another screw; remove them and the lightpipe comes into full view:

Now for the lower half of the chassis, which (IMHO) is far more interesting. First off, the dual charging coils:

That piece up at the top that looks like tape is, as far as I can tell, exactly that, pasted to a piece of adhesive rubber:

I’m a bit baffled as to what purpose it serves (readers?), since the coils are glued to a fibrous plastic-or-something backing, which is then glued to the chassis itself.

The bottom piece of backing popped away from the chassis intact, after some screwdriver-as-lever motivation. The top piece, not so much:

And what are the coils connected to? The PCB on the underside of the base, of course!

It was similarly glued to the chassis, and was easily detached. Those left-over metal pieces on either side, as far as I can tell, serve no electrical value; they’re simply there to give the base extra rigidity and weight.

The back side of the PCB is pretty boring (note, however, the separated halves of the micro USB connector, which I suspect is the root cause of its charging reliability woes):

The front side is much more interesting albeit ultimately frustrating. No amount of Google searching enabled me to identify even a single chip! Many of them match ones on this reference design, and the primary wireless charging controller chip (with “324” and “GZJT210” markings on consecutive lines) appears to be from STMicroelectronics, given the distinctive logo also stamped on the package. But I can’t find a reference to it anywhere on ST’s relevant product family page.

If any of you can help me ID any of the ICs on the board, I welcome your feedback in the comments. Thanks in advance!

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