Samsung 1 port EP-TA20EWE (Maybe fake)

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Official specifications: I got it from ebay dealer: swoy1753

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It was on a plastic bag inside an envelop.

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Measurements

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It can deliver 3.5A at 5V, that is rather high for a 2A charger.

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The output power is lower at 120VAC, but still well above the rated 2A

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At 9V it can deliver about 2.2A.

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And slightly lower with 120VAC input.

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The charger could deliver 9V at 1.66A for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp7350

M1: 73.0C, HS1: 80.5C

Temp7351

M1: 83.6C, HS1: 86.4C

Temp7352

M1: 70.3C, M2: 52.4C, HS1: 73.4C

Temp7353

HS1: 80.0C

Temp7354

M1: 44.4C, HS1: 79.7C

10ohm

At 0.5A the noise is 18mV rms and 529mVpp.

5ohm

At 1A the noise is 21mV rms and 467mVpp.

2ohm

At 2.5A the noise is 25mV rms and 410mVpp.

10ohmQC9V

At 0.9A the noise is 25mV rms and 635mVpp.



Tear down

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Putting a lot of pressure on the top of the charger with my vice made the lid pop out.

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On this side is the input fuse (F01), a MOV (TM01), a common mode coil, two mains smoothing capacitors (C01 & C02) with a inductor (L01/L02) between and a mains switching transistor (Q01).
There is the usual safety capacitor (CY01), partially isolated behind a plastic shield

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Here is the bridge rectifier made with four diodes (D01..D04), the mains switcher controller (U01), opto feedback (OP01), the protocol controller (U02) and a reference (U3: 431). The rectification is a normal diode (D21).

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The distance between mains and low volt side is about 5mm, this is on the low side.

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Because one PCB track goes under the opto couple the distance is down to 4mm there.


Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

These chargers are usually cheap imitations of the original Samsung, but I got a bit surprised when the QC only went to 9V (This is Samsung protocol) and the teardown shows a rather complex design with better isolation than many cheap chargers, but it is not good enough. The overload protection is at a too high level for a 2A charger.

I do not hope Samsung has ever sold this model, the isolation is not good enough.



Notes

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger
How does a usb charger work?