ETA-U90EWE 3 port charger

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Official specifications:
I got it from Ebay dealer lakeyx101

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No retail package for this charger, only a simple plastic bag.

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Very compact for a 3 port usb charger.



Measurements


ETA-U90EWE%20%231%20load%20sweep
ETA-U90EWE%20%232%20load%20sweep
ETA-U90EWE%20%233%20load%20sweep

All 3 outputs can deliver the same power and has the same over load protection. This is because they are in parallel.

ETA-U90EWE%202A%20load%20test

The 2A load test did not last 60 minutes as expected, but terminated after 23 minutes, because the usb power supply shut down. This shows the power supply has over temperature protection (good), but that it cannot deliver rated current.

ETA-U90EWE%201.8A%20load%20test

Reducing the current to 1.8A works much better, this time I could run for 60 minutes.

Temp1623

M1: 73,3C, M2: 69,5C, M3: 43,6C, HS1: 75,0C
The charger do get rather warm at 1.8A

Temp1624

M1: 59,2C, M2: 43,5C, HS1: 72,2C

Temp1625

HS1: 85,9C

Temp1626

HS1: 75,7C

Temp1627

M1: 55,1C, HS1: 65,4C

10ohm

There is some noise at 0,5A with 50mV rms and 1.1Vpp

5ohm

It does not get better at 1A with 73mV rms and 1.1Vpp

2.5ohm

And even more at 2A with 130mV rms and 1.3Vpp




Tear down

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The adapter contains two circuit board, one with the usb connectors and the usb coding and another for the power supply part.

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The power supply part looks very simple. It has a fuse, a rectifier bridge, a capacitor and a switching controller chip.
On the low volt side it only has a rectifer and a capacitor, there is no feed back.

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The scatches in the yellow tape on the trafo is worring, this means the usb board can touch and removes one isolation layer (not good).

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Here is a view of the rectifier diode and output capacitor.

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The usb board has the coding resistors on the backside and 3 usb connectors on the front side.

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The isolation is rather bad, C6 is mounted between the low volt side and the mains. This is NOT a safety capacitor.


The charger passed 2500 volt isolation test, but failed a isolation test with 5000 volt, this makes it doubtful to use with 230VAC mains. The fail made a shorted between mains and low voltage side (Very bad)!



Conclusion

The idea with a universal usb charger, that can charge most equipment is good enough, but it is not necessary with 3 ports for this, a single chip can make any port universal. The actual charging performance is fairly good, but I am a bit worried about the temperature.
The worst problem is, of course, the bad safety from the mains, especially because it fails with a connection from mains to low volt side.

Stay away from this one!



Notes

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger