Hi Kash

Good day!

Thanks for your interest in using Power Integration product.

I would like to clarify that your output is 12V and 1A or 5V 1A?

Power Integration has a Design computation site that assist user in their design.
We call the website as PIExpert.
Please visit:
https://piexpertonline.power.com/site/login

There you can input the design requirement input and output then the spreadsheet will suggest the transformer design based on your requirements.

Thanks

Regards

PI-Chloe

Hi...Thank you for your feedback..
The output is 5VDC 1Amp.
I will try design using the PIExpert

Thanks

Hi..My design is live only and no nuetral/ground wire for 5vdc & 1amp output.
I have followed your advise to use PIExpert tools.
Thanks it showed me the solution by using LNK3204 device and EE16 bias transformer.
By referring your sample design DER-622 is quite similar but low current and different type of transformer.

Any idea for bias circuit from LNK3204 to bias transformer pins?

Thanks
Ashraf

Hi Kash,

Please elaborate your question. "Any idea for bias circuit from LNK3204 to bias transformer pins?"

Thanks
PI-Chloe

Hi..My idea at primary bias supply for bias winding pins 3 & 4 of transformer EE16 where pin 3 connected directly to source (S) pin LNK3204 and pin 4 to optocoupler Feedback (FB) pin. My questions:
1. Do i need to set any external biasing circuit to BP pin?
2. How to tighten the BP current?

hi Kash

In the absence of a Bias winding, the LNK3204 can operate. BP bias will be coming from the Drain. But this will result to a much higher no load input power.

The Bias winding can be use to bias the BP pin and optocoupler.

I suggest that you draw your circuit and let's discuss it.

Thanks

Regards

Patrick

Hi..please find my draft circuit as attached..
This draft is for PCB design board evaluation..
The output is 5VDC/1Amp and no Neutral/GND circuit.
Please advise ..

Thanks

Hi Kash,

Ok, much clearer now.
The aim to have an Isolated 5V Output.

You will be needing a additional winding to bias the opto and the BP pin.
You're schematic is correct.

R7 will determine the BP current. Please follow datasheet recommendation on page 6 "External Bias Resistor R5"

Thanks

Regards

PI-Chloe

Hi Chloe

Thank you very much for your feedback & advise very appreciated..
I will tune the R7 to to find the best BP current & follow the datasheet for R5.

Thanks & Regards
kash

Hi Chloe

I have questions what happen if I have 3 loads output & 3 TRIACs (as a relay) :
1. Do I need 3 units LNK304 too for each load?
2. Most probably need 3 or 4 fullwave rectifier, how the connection to Source pin LNK3204?

Regards
kash

Hi Kash,

Does the 3 loads output and 3 Triacs have common ground or isolated to each other?

Thanks

Regards

PI-Chloe

Hi Chloe

My idea is to common all the loads in one ground.
The TRIAC drive by Optoisolator to control the loads in one common ground too.

Regards
kash

Hi Kash,

If the load side have the same ground, you can use one Power Supply.
Just check the maximum load current of the loads. Check the LNK TN2 datasheet for the possible IC to use.

Thanks

Regards

PI-Chloe

Hi Chloe

Thank you very much for your kind support and advice.
I will start order for LNK T2 3204D-TL for my board evaluation.

Regards
Ashraf