195V-265VAC to 6V/1.2A, 15V/300mA and -15V/300mA Design

Posted by: dhruv_electro on 01/05/2011

Hi There,

As I am newbie here. I am willing to design SMPS for mentioned design. I have tried designs attached with this post. In this design my VR1 becomes very hot when I connect mentioned load with the output and after some time it becomes burnout. Again I have already designed and used SMPS with 12V/500mA, 12V/500mA since 1.5 years so I am confident about transformer design and other aspects. I also have followed the instruction mentioned in this design and followed the datasheet of TNY268. So will you please help me that in any way VR1 stops getting hot.

Files

SMPS +6 +15 -15.jpg (76.9 KB)

SMPS +6 +15 -15_new.jpg (77.01 KB)

SMPS_0.jpg (231.88 KB)

SMPS 2.jpg (227.68 KB)

SMPS+6+12-12.xls (67.5 KB)

SMPS+6+15-15 new.xls (67.5 KB)

Comments

Hi,

The symptom that you have described suggests that the transformer has significant leakage reactance which is resulting in increased losses in VR1. It is also possible that the turns ratio of the transformer is resulting in excessive reflected voltage across the primary winding during the flyback cycle (VOR).

I suggest you download PIEXpert, which is a free software tool that we provide on our website. This tool can help you with the selection of components and also with transformer design.

Please use the link below to download PIExpert

http://www.powerint.com/en/design-support/pi-expert-design-software

Regards

PI-Sarek

Dear there,

Yes I have the latest version of the software and I am using it since last 1.5 years. I have designed both of these solutions in this software and then tested, which resulted in this problem. Additionally I have followed the construction of the transformer as suggested in the software. As I am using SMPS designed in this software since that much time I am well aware of the construction precautions of the transformer. But I really appreciate that you care to reply. Again will you help me to understand how to reduce this VOR?? I have tried two design of transformer suggested by software. I am attaching photo of both the design. Thanks again.

Since you have used PIExpert for this design,

I suggest you send us the PIExpert files so that we can help you better.

Thank you,

Regards

PI-Sarek

Dear Sarek,
I am trying to upload my .uda file form pi expert, but it shows me this error every time "The selected file SMPS +6 +15 -15.uds can not be attached to this post, because it is only possible to attach files with the following extensions: jpg jpeg gif png txt doc xls pdf ppt pps odt ods odp pdf." Will you tell me what should I do?? or say me your email.. i will send you directly.