Transformer choice RD159

Hi,

I am using a schematic identical of RDR-159 with LNK603DG.

https://ac-dc.power.com/design-support/reference-designs/design-examples/rdr-159-24-w-charger/

The secondary load will be less than 2.4W ( close to 1W).

I'm looking for a standard transformer that matched the design requierement. I found this transformer :

http://katalog.we-online.de/pbs/datasheet/760871113.pdf

I'm  worry about the input #1 winding inductance. I plan to use the #4 winding to be the voltage feedback and the bias. I'm aware that R3 and R4 must be adapted. The #2 and #3 winding will be used in serial.

Do you think this transformer can fit in this design ?

Thank you for your help

Hi,

No answer was received yet. Please, help.

Have a nice day

Hi,

I would recommend you to use PIxls for transformer design. This transmer datasheet is missing the core details.

I would recommend you get the core details and input in the PIxls file.

In that you can be absolutely sure that the transformer will work.

You can download PIExpert/PIxls software at following location.

https://ac-dc.power.com/design-support/pi-expert/

Regards,

PI-NANO

Hi PI-NANO,

First, let me thank you for your answer.

I do know the transformer is a EE16 type. It that what you ask for when you metionned core details ?

I tried to use PI expert, but not like the name, I'm not :) and I get confused created a design. In fact, every time lnk623 come out rather than lnk603...

I will keep looking for the solution but would you mind, please, to explain me what information of core details is needed ?

Regards,

I have finaly find the right table to parameter all transformer parameter : Pixis designer.

It seams that primary inductance is too low (1310uH), so the frequency is too high... I look with several manufacturer and it seams that 2.8mH requiered is not a common value, isn't it ?

Or should I concider the input filter inductance within the primary inductance ?

Regards

Hi,

PIExpert is a tool which does all the optimisation and gives you the schematic. Where as PIxls is a tool where you will have lot of handles to optimize the transformer design.

Both PIExpert and Pixls comes with the software that you download on our website.

You can use these tools online as well by creating account on Power Integrations website.

Here is the link for online log in.

https://piexpertonline.power.com/site/login

Once you log in,

1. You can create new design and

2. Go to select flyback under LNK-II device and

3. Select Pixls

4. Chosend device change to LNK603 from Auto Under Enter Linkswitch -II variables

5. Select EE16 core for transformer and enter all your specifications

6. You can oiptiomize the design once you create the spreadsheet

The value of L depends on power current limit, frequency of operation aand power delivery requirement for a given core. You can play with these parameters find a suitable solution to your design.

If you need any design help please contact one of our field offices in your geographical region.

https://ac-dc.power.com/sales/

Regards,

PI-NANO

Hi,

Your comment conforts me in my effort today :). In fact, I spent all day with PIXis and start to feel confortable with those tools.

By the way, thank a lot for your support.

I got a bit confuse with the L inductance typ. but now I understood that is strongly related the load at supply ouput.

For question about my design, I will contact the support offices now.

Still, I wondering about the DCON parameter which I should decrease to 2.5us in order to reach the correct NS which match my transformer. What does it means ? In an other word, does it means my transformer with lnk603 can't be use for such a little power ?

Please, find attached the PIXis file.

Hi,

The device used in RD-159 uses auxilary winding voltage in order sense the output voltage. 

The minimum value for DCON is limited to 4.5 μs to ensure that under light loads when the feedback winding is sampled, 2.5 μs after the internal MOSFET is turned off, the output diode is still conducting. 

Please go through the application note for more details

https://ac-dc.power.com/sites/default/files/product-docs/an44.pdf

Regards,

PI-NANO