UGreen Dual USB Power Adapter CD104


Official specifications:
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I got it in a white cardboard box.


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The top output may only be rated for 1A, but it can deliver a bit above 4.5A, this is a bit high for the usb connector.


Same with the bottom output.


And it is no surprise that running them in parallel, the output current is the same, both at 120VAC


And 230VAC


Rated output is 3.4A and it can deliver that for at least one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.


M1: 61,2C, HS1: 70,6C
HS1 is the transformer.


M1: 44,5C, M2: 52,9C, HS1: 60,2C
HS1 is the rectifier diode, is is also the reason for the warm usb connector.


M1: 57,7C, M2: 54,4C, HS1: 61,8C
HS1 is again the rectifier diode. M1 is the switcher transistor or something close to it.


M1: 47,7C, HS1: 57,3C
HS1 is the switcher transistor or something close to it.


M1: 62,0C, HS1: 77,3C
M1 is the transformer and HS1 is due to the rectifier diode.


At 0.5A the noise is 13mV rms and 331mVpp.


At 1A the noise is 16mV rms and 305mVpp.


At 2.5A the noise is 18mV rms and 273mVpp.

Tear down


The glue was very strong on this one, I had to cut and break it open.


On the input side is a fuse (Red block), a common mode coil and an inductor. The switcher transistor can also be seen.
The transfor has flying leads to improve isolation,below the transformer is a safety capacitor.

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On the first picture the common mode could and the safety capacitor with all its approvals can be seen. The metal is a heatsink for the rectifier diode. On the second picture the fuse with the inductor behind it and the common mode coil can be seen.

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On the first picture the switcher transistor sits before the transformer. On the second picuture the recifier diode can be seen inside the heatsink. The heatsink also helps move current to the capacitors.


On this side is the bridge rectifier (BD1), the switcher controller (U1), the opto feedback (U2), the reference (U3:431) and two chips for auto coding (U4, U5).



The slot in the circuit board is great for safety, this means very good distance between mains and low volt side.
Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.


This power supply can deliver rated current, has auto coding, noise is acceptable, there is overload protection (It is a bit high, but not enough to be a serious problem), the safety looks good.

I will call it a good power supply.


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