SMPS DESIGN USING TINY SWITCH

Hello jedlmotordrive,

TinySwitch-III is an incremental upgrade over our older generation TinySwitch-II. The main difference is a better thermal management; as you can see version III offers up to 20% higher power levels over version II. Also, another important benefit is the reduced power level in standby: version II dissipates under 250mW without bias winding, version III does the same thing with less than 150mW. There are some other differences less visible regarding internal logic control to improve the overall performance. The PCB design is not too different for these versions, I would recommend you to use TinySwitch-III.

Cheers,
PI_Crusher

Hello, I need to replace the IC TNY254 from an existing design. Looking in the page I found that TinySwitch 4 are available so, I would like to know if I can use it instead the old one and if I can use the same same transformer that the other one? 

http://productfinder.pulseeng.com/files/datasheets/P533.pdf

Hi Pamela,

Thank you very much for using Power Integrations product. For new designs we would recommend TinySwitch 4. For the transformer, it can be checked using the design tool PI Expert. What are the electrical specs and the size of the old transformer? Is it EE16? and what is the inductance of the old transformer? With these we can verify if it can be used for TinySwitch 4. Although practically speaking you can use it since the old part/design is less than the power capability of TinySwitch 4. However to be sure kindly provide the information needed like electrical input and output specs as well as the old transformer inductance and core size. You can also verify using the PI Expert link below:

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

Hope this helps. 

My company have a design using the TNY279P device. This has been in production for a number of years. We have a number of returnes where the device has failed catostrophically. Whilst the percentage is low (approx 0.1%), when it does fail it completely blows its top off. Is this unique? Is there anyone who could review the design and suggest any improvements to make the design more rugged? I believe the design is based on a P.I. reference design so there shouldn't really be an issue other than layout. Also, I have been unable to reproduce this failure mode in the lab so I don't know what causes it, and it is tolerant across the expected working temperature range and max/min loading.

Hello Leo,

Thanks for your help. The transformer that is used currently is P5001NL from Pulse Electronics. The leakage inductance for it is 180uH, according to the datasheet. The output is 12V and the input varies depend of the different voltage systems (120/240 1-phase, 208Y/120 3-phase and 240Y/120 3-phase). I hope this info can help you. 

http://products.pulseelex.com/product-details/p5001nl/228/

http://products.pulseelex.com/files/product_files/P533.pdf

Hi Pamela,

Thank you for the information provided. With that we suppose you can use the transformer. Should you have any concerns just kindly message us. 

Hi Chris,

Thank you very much for using Power Integrations product. With regards to your inquiry, could you please provide some schematic, electrical specs, reference design used, etc. that were used for your design so we can check and verify.