WEBENCH® Tools/LM5160: LM5160

user5139885

Part Number: LM5160

Tool/software: WEBENCH® Design Tools

Our isolated design based on LM5160 doesnt regulate correct on our pcb compared to webench. Webench suggest 649 ohm to FB (pin 8) for 5,6V out. In practise we need 4,9kohm. I have a Webench link that I can share?

over 6 years ago

0 Gerold Dhanabalan - Online Design Tools over 6 years ago

TI__Genius 14455 points

Hi,
Yes, please share you WEBENCH design to this email g-dhanabalan@ti.com
We will take a look and get back to you.
Regards,
Gerold

0 Gerold Dhanabalan - Online Design Tools over 6 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Genius 14455 points

Hi Henrik,

Thanks for sharing the design. The primary voltage of the design should be lower than ½ of Vinmin as per the datasheet. WEBENCH uses this to design the primary output voltage to be around 2.725V. This means that the coupled inductor needs to have a turns ratio ( NOT 1:1) to get the secondary Vout of 5V.

The turns ratio recommended by WEBENCH is 2.07. Because you are using a 1:1 coupled inductor, you have to adjust the primary voltage accordingly and that’s what is making you to change your feedback resistor value to a different value other than 649 ohm.

Please let us know if you have further questions.

Regards,

Gerold

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WEBENCH® Tools/LM5160: LM5160