LM5156-Q1: LM5156-Q1 schmetic review

Hi Kygo,

thank you for supporting the LM5156

Can you please check the given spec above:

I think it should be

Vin 12 -18 V

Vo 5 V

What is 4. referring too ? I might miss the history.

Thanks,

 Stefan

Hi Stefan

Thank you for the feedback!

Please help confirm the design ,THX

1. The Vin is 12V and Vo is 18V !!! (It's mean 12V boost to 18V)

2. What is 4. referring too ? I might miss the history.

--> No history here , the below SCH have changed some parameter value of the element now .(The change is "R5 change to 10ohm" But the SCH has not changed yet)

Hi Stefan

More support need !

Please review the Layout of the LM5156-Q1! THX

PPB-22181-10-A04A-1101-B.pcbPPB-22181-10-A04B_11141320.pdf

Hi Kygo,

some feedback on the Schematic:

- Inductor might be too small from the current rating, peak inductor current is 5.24 A. Please consider this (plus some margin) for saturation current rating of the inductor. Wenn considering the max current limited by the sense resistor the peak current can go up to 10A)

- compensation and loop stability does not look OK. Changing R11 to 2.5k looks much better

You can also check this with the Quickstart calculator which can be found on the product page.

Do you know which software for the PCB has been used - just tried Altium but it was not able to open the file?

Best regards,

 Stefan

Hi Stefan

Thank you so much

For PCB software , it is PADS , please refer to below link for free PADS Viewer

https://resources.sw.siemens.com/en-US/download-pads-professional-layout-browser?cmpid=12938&gclid=CjwKCAjw8JKbBhBYEiwAs3sxNyci5dEGpcm03XuwjjePBfuKsaeaTkO7mWfz94S_Xk8UTne6INgSPxoCrlUQAvD_BwE

HI Kygo,

Thanks for the info.

please allow me 2-3 days for the review.

Best regards,

 Stefan

Hi Stefan

Thank you so much!

Looking forward to your feedback!

Hi Stefan

Thank you !

Customers currently use this version for the first version board !

And we just tested the  first version board today!

We face a issue is 

When we give the Vin , and the output is  no-load , but the LM5156 will burn!!!

Can you suggest me the test and debug steps? I will verify them to find out the root cause! THX

Hi Kygo,

at initial startup, i would add a small load to the output and then limit the input current to a level that the system should be able to work.

In this mode the power supply should startup - but if now you should be able to measure into the system without immediately destroying a component.

Then check the individual nodes and try to find out what is working or not, e.g.

Does VOUT come up.

What is the switch node doing?

Each pin of the controller - does it have the expected signal or voltage level.

Best regards,

 Stefan