Choetech usb 5V 2.4A SMT0008



Official specifications:

• USB Ports: 1
• Type: Desktop
• Output Interface: USB
• Model Number: SMT0008
• Quality Certification: FCC,CE,RoHS
• Input: 100-240V/0.3A
• Power Source: A.C. Source
• Output: 5V/2.4A
• Support Quick Charge Technology: No
• Plug Type: EU,US
• Material: Anti-fire PC
• Feature 2: USB Charger
• Feature 3: Universal USB Charger
• Function 1: Charger for Phone
• Function 2: Smart Phone Charger
• Type : Charger for iPhone Samsung Xiaomi
• Function 4: Mobile Phone Charger
• Function 5: Travel Wall Charger
• Feature 4: Charger for iPad

I bought it from Aliexpress dealer: CHOETECH Flagship Store






The box contains the charger and instruction sheet.










Measurements

• Power consumption when idle is 0.06 watt
• Output is auto coding with Apple 2.4A as max.
• Weight: 38.2g
• Size: 83.4 x 42 x 22mm

Overload protection at about 2.6A for a 2.4A rated output is fine.
The regulation is a bit special with increasing voltage, this will work well with cheaper cables.



The output is about the same at 120VAC.
The efficiency is good in both cases.



There is no problem delivering rated current for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.



M1: 63,0°C, HS1: 69,6°C
HS1 is the rectifier chip.



M1: 60,0°C, HS1: 66,9°C
HS1 is the rectifier chip, M1 is the transformer.



M1: 42,3°C, HS1: 67,6°C
HS1 is the transformer.



M1: 42,2°C, HS1: 48,0°C



M1: 63,2°C, HS1: 70,0°C
HS1 is the rectifier chip.



Noise at 0.5A load is: 16mV rms and 591mVpp.



Noise at 1A load is: 27mV rms and 836mVpp.



Noise at 2.5A load is: 28mV rms and 821mVpp, rms is low, but peak-peak is high.




Tear down



Mounting the charger in my vice and whacking it with a mallet broke it open.



On this side is a fuse, a inductor between the two mains smoothing capacitors and a safety capacitor.
There is no opto coupler (The raising output voltage from the load sweep told me that).



The black fuse can easily be seen between the two mains input terminals. The output leads of the transformer is a bit extended for improved isolation.





The safety capacitor looks to be a real safety capacitor, the inductor is between the two black capacitors.



On this side of the circuit board is a bridge rectifier and a switcher (LP3783) and partial hidden below the white stuff a synchronous rectifier (LP3515). The last chip is the auto coding (RH7901A).






The isolation distance is good.

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



Conclusion

The usb power supply has good efficiency, lot of output power, the increasing output voltage will in many cases be an advantage, the safety is good, only minus is the peak noise.

I will call it a good usb charger.



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?