Taking a break from his usual prodding at suspicious AliExpress USB chargers, [DiodeGoneWild] recently had a gander at what used to be a good USB charger.
Before it went completely dead, the Anker 737 GaNPrime USB charger which a viewer sent him was capable of up to 120 Watts combined across its two USB-C and one USB-A outputs. Naturally the charger’s enclosure couldn’t be opened non-destructively, and it turned out to have (soft) potting compound filling up the voids, making it a treat to diagnose. Suffice it to say that these devices are not designed to be repaired.
With it being an autopsy, the unit got broken down into the individual PCBs, with a short detected that eventually got traced down to an IC marked ‘SW3536’, which is one of the ICs that communicates with the connected USB device to negotiate the voltage. With the one IC having shorted, it appears that it rendered the entire charger into an expensive paperweight.
Since the charger was already in pieces, the rest of the circuit and its ICs were also analyzed. Here the gallium nitride (GaN) part was found in the Navitas GaNFast NV6136A FET with integrated gate driver, along with an Infineon CoolGaN IGI60F1414A1L integrated power stage. Unfortunately all of the cool technology was rendered useless by one component developing a short, even if it made for a fascinating look inside one of these very chonky USB chargers.
That was a LOT more complicated than I expected. I’ll never complain about the price of these 120W chargers again. Thankfully I only own a cheap amazonbasics 65W. It feels light
They’re a really smart charger, different voltages on different ports with USB PD per port I think
Just from a quick glance, it looks like the secondary might actually be isolated from line voltage. That’s unusual for these Chinese chargers and makes it worth buying.
Most “Chinese chargers” have an isolated secondary. In fact, I don’t think I have seen one that isn’t. Sure, some I would consider unsafe, but to say that an isolated power supply is “unusual” is just bizarre – the vast majority are flyback based, which by definition is galvanically isolated. Also worth noting that Apple chargers are made in China – are these also “unusual” ?
The myth comes from chargers with unpolarized mains plugs and filter caps between primary neutral and secondary ground.
Most of the time people will stick a DMM between earth and USB ground and see high voltage, but don’t care to check that the short current is tiny.
This is Hackaday so China Bad, Chinese Bad, Asians Bad.
Same folks who have no problem using Chinese-made Intel, AMD, or Nvidia products. Heck, the same people never complain about Chinese-made parts in literally everything they build. That is until there’s a defect and suddenly is those darn Asians ruining their project.
I have 2 of those 65 watt amazon chargers. They are really solid. I use one with a soldering iron and definitely puts out close to 65 watts and heats up my iron quickly. The other one I use to charge up high capacity LIPO batteries connected to a Lipo charger that I use on my own DIY built drones. They are a great deal.
Why are companies still allowed to produce equipment that can’t be repaired? A single faulty part has rendered the entire PSU in to e-waste.
Sadly, even if it was perfectly repairable – say it literally came with a schematic in the box and philips screws and no potting – it would probably still be 1% or less of users who would repair it or have it repaired.
Heck, I bet 90% of chargers are thrown out intact because of being grungy or in a box in a company storeroom that nobody has the time to test all the gubbins in.
If anything, the world needs “anything not perishable or noxious or unsanitary, to refurbish/reuse by any takers, with no responsibility left to who puts anything in” bins in every recycling station.
Also consider this device is smaller than what would often be considered a spare or wear part you just replace in a vehicle or machine.
I’m not bothered that it has a single point of failure. What consumer electronic can handle an IC failure gracefully? Everything would be too expensive to be designed under the assumption that ICs fail and need redundancy. I’m also not too bothered it’s not repairable though it would be nice.
But the idea of “not trash” bins reminds me of the three Rs: recycle, reduce, reuse. The emphasis today feels like it’s just to recycle. It’s the only option of the three that fits corporate needs for more consumption. But the other two are what will really improve our lives most immediately and we have the most control over.
How much would you pay a repair technician per hour to work on this device, how much are the parts to repair it?
How much did the device cost to buy?
So you would be willing to pay twice the price for something (the additional costs of a design that facilitates repair) that will cost you three time the cost of the original unit to repair? Also, what makes you think enough customers would want that to warrant actually selling it? Companies don’t decide to produce throw-away electronics – their customers do.
All the stuff to make “e-waste” originally came from the ground. If you didn’t make it, you didn’t buy it, and it goes back into the ground, how does it affect you at all?
If you care that much about it, grab a shovel, head to your local landfill, and start a recycling program. If you’re not willing to do that, sit down and be quiet.
Automated production is cheap, manual labor to troubleshoot and repair isn’t. Even on a device that’s easily taken apart with no potting, it’s easy for a repair to cost twice as much as buying a new unit. Making repairs possible isn’t too hard, making repairs cheap enough that the devices actually get fixed is much harder.
The potting resin is a good idea in this case, compact chargers like this are physically thrown around and impacted all the time, you don’t want those heavy inductors and capacitors flapping in the breeze.
I have to imagine that the potting also helps conduct heat out of the unit better than if it were filled with air.
The transformer was interesting, and it was nice that he investigated it and showed the cutout.
As for waste, I wonder if that transformer is reusable if you carefully separate it, since it’s on a separate PCB.
I know DGW uses old parts and at least he got some capacitors and maybe some USB ports from it.
These transformers are very specific to this particular implementation. The PCB would only be useful if you are building pretty much the same SMPS.
In other words, a fully functional power supply for custom voltages is rendered useless because the voltages must be digitally negotiated by the device? I remember discussions not long ago where this was said to be an advantage of USB…