Valueline USB AC charger VLMP11955B

DSC_5788

Official specifications:
DSC_5773

I got it in a plastic bag.

DSC_5789 DSC_5790 DSC_5791 DSC_5792

DSC_5793




Measurements

Valueline%20USB%20AC%20charger%20VLMP11955B%20230V%20load%20sweep

This small adapter can deliver the rated current and a bit more (the overload protection looks fine).

Valueline%20USB%20AC%20charger%20VLMP11955B%20120V%20load%20sweep

It works about the same on 120VAC

Valueline%20USB%20AC%20charger%20VLMP11955B%20230V%20load%20test

No problems running one hour at 1A.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp3418

M1: 64,6°C, HS1: 78,8°C
HS1 is the transformer.

Temp3419

M1: 54,9°C, M2: 55,6°C, HS1: 60,6°C

Temp3420

M1: 57,4°C, HS1: 64,8°C
HS1 is the transformer.

Temp3421

M1: 61,3°C, HS1: 67,5°C


10ohm

At 0.5A the noise is 36mV rms and 384mVpp.

5ohm

At 1A the noise is 40mV rms and 317mVpp.

2.5ohm

At 2A the noise is 56mV rms and 410mVpp.


Tear down

DSC_7557

My vice and a mallet could open it.

DSC_7559

The plastic shield inside the box is used for isolation between mains and low volt side.

DSC_7560

At the mains input there is a fuse and a blue safety capacitor. Between the two capacitors is an inductor with shrink wrap around. The mains switcher transistor (Q1) is next to the transformer. The transformer has wires to the low volt side, where the rectifier diode is placed.

DSC_7562

The fuse (F1) is next to the mains input wire.

DSC_7563

Here the inductor between the two mains capacitors can be seen. One of the capacitors has shrink wrap on top of the plastic isolation.

DSC_7564

From this side the rectifier diode and the transformer can be seen.

DSC_7565

One of the capacitors is mounted on top of the usb connector and has heat shrink on its legs.

DSC_7561

This side contains a bridge rectifier (DB1) and the mains switcher controller. There is four resistor for coding the usb output (R15..R18).


DSC_7566

DSC_7568

Safety distance looks good.

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



Conclusion

Generally this small charger looks well designed and with good performance, the noise is slightly high.



Notes

Charger was supplied by Pro backup (probackup.nl)

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