Hello,

Im using LinkSwitch II - LNK615DG for my design.

Problems:

When i connect this circuit to AC mains - 230VAC. Bridge diode and fuse Blows.
I replaced MB8S with General purpose diodes 1N4007 and i started circuit with series test lamp setup.
Now the circuit shows output of 1.8 ~ 2.45 VDC and is not stable.

Kindly help me debug the circuit as i don't have Variac and working at 230VAC is highly dangerous.

Thanks in advance.

Design Reference:
3.25 W CV/CC Charger Using LinkSwitchTM-II
That Meets New 2011 European Standards.

 

Its a Transformerless psu, so unless you want to have it closed down stick a transformer on the input first,

So what is the chip T1 doing, is it a smpsu type, also U1?

 

Its a Transformerless psu, so unless you want to have it closed down stick a transformer on the input first,

So what is the chip T1 doing, is it a smpsu type, also U1?

Its custom made Hi freq Transformer . with specs same as given in design data.
T1 is EE16 Transformer.
U1 is LNK605/615DG

Design is same as shown in image below.

 

So if the output voltage is low it will be set by the reference fb pin, or bpm have you replaced the chip as well?

 

So if the output voltage is low it will be set by the reference fb pin, or bpm have you replaced the chip as well?

Yes, I did.
I have built two same modules.
One gives no output at all while other gives low voltage.

 

Check D5,6

 

Hi, Dodgydave.

I changed my transformers. Now the issue is output goes upto 8V.

I think i have problems with feedback loop of the transformer.