Power Supply full range 5x18v/30mA

Posted by: Edson on 11/29/2012

Hi,

I develop a power supply with TOP244 and EFD30 core.

The power supply has 5 outputs with 18V/30mA and an input 22..240Vdc/ac.

The transformer was assembled just like an experience, I mean, with mistakes and success.

I think the consuption is too high and I would like to make sure that the transformer is correct.

I use the PIXIs Designer but I don't know if its correct.

So I'm sending the file, the schematic and the transformer construction in order to search for any mistake.

Thank you a lot.

Edson

Files

Power Supply_3.pdf (31.04 KB)

Transformer_4.pdf (414.59 KB)

Fonte 5 x 18V_30mA EFD30.pdf (30.36 KB)

Comments

Hi,

Looking into your PI Expert Design Sheet, you should change the following:

Limit your KI to 0.5 since your peak operating primary current Ip is 0.39A. Redo the transformer.

What is your current consumption? Please send me some numbers.

rgds..

Hi,

The current consumption is 240mAac with 145mA used at secundary of the transformer.

The number of the turns are similar but the indutance is different. The Design Sheet show 340uH and my transformer has 1700uH. I changed the indutance to 340uH but the circuit doesn't work.

Thank you

Edson

Hi Edson,

Please redesign the transformer with suggested KI and rewind a new transformer based on the new KI value.

The magnetics needs to be correct with low leakage before we can debug further.

rgds..

Hi Edson,

I have redesigned the transformer using PIXLs and attached. Please make a transformer according to this design sheet.

rgds

Hi,

First of all, thank you a lot for your help but I have some considerations above:

- I need to have 5 output with 18V/30mA and the power supply must work with 22Vdc and 22Vac.

- I didn't get more than 3 outputs in the Design Sheet so I used the total output power (150mW).

- I choose the EF30 Core because its high (less than 16mm) and, you can see the attached before, the transformer will have two outputs an the bias by wire not by pin. The lay-out of my product is ready for this.

- In your Design Sheet is mentioned that the power supply will work with 30VDC. Is it right?

Thank you

Edson

Hi Edson,

I used 30 VDC since you mentioned 22VAC in your earlier emails. You can change to 22 VDC. If your board is ready for EF30 core that you can re-design the transformer using the spread sheet I sent you.

rgds.