LM5157-Q1: EMI performance curves as flyback

Rohan Shevade

Prodigy 75 points

Part Number: LM5157-Q1
Other Parts Discussed in Thread: LM5157EVM-FLY

I am trying to design a flyback converter using LM5157-Q1

Is there an EMI performance report of this IC used as a flyback?

My specs are:

Input: 8 to 18V

Output:+15,-8,+15,-8,+15,-8V @50mA each

over 2 years ago

0 Haroon Wardak over 2 years ago

TI__Genius 10385 points

Hi Rohan,

Thank you for using E2E forums, we have LM5157EVM-FLY that has similar design specs as you have requested and also here is the user guide for it https://www.ti.com/lit/ug/snvu770/snvu770.pdf?ts=1663063585685&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM5157-Q1 with some test reports also included in the manual.

There is also this link that helps with EMI reduction, but there is no EMI performance report for this IC as Flyback available for your case.

Hope this was helpful.

BR,

Haroon

0 Rohan Shevade over 2 years ago in reply to Haroon Wardak

Prodigy 75 points

Hi Haroon, Thank you for your response.

I need to design a similar power supply, but I want it to be in DCM mode. Can you share a calculator, or suggest what changes in the equation? I want DCM throughout the voltage range,
Mail: RohanSShevade@eaton.com

+1 Stefan Schauer over 2 years ago in reply to Rohan Shevade

TI__Mastermind 47141 points

Hi Rohan,

Until now the the Excel quickstart calculator does not support DCM mode for this device.

To best see the mode of operation and the expected waveforms in the SMPS components you can use the power stage designer:

https://www.ti.com/design-resources/design-tools-simulation/power-stage-designer.html

With visualizing the waveform through the inductor you can then easily identify the required inductor to have the preferred operation mode.

Best regards,

Stefan

0 Rohan Shevade over 2 years ago in reply to Stefan Schauer

Prodigy 75 points

Thank you Stefan! Got it! The tool is excellent.

Power management

Power management forum

LM5157-Q1: EMI performance curves as flyback