LM5122: Interleave issues

Hi Zoey,

Could you give me some time to test this myself, I am also very curious regarding this, but I need to arrange the setup for this test and I might need 2 to 3 days for that, because I will be on leave tomorrow, as soon as I get back I will test this and keep you updated.

Thank you

BR,

Haroon

Hi Haroon,

Thanks~ Hope for your reply！

Hi Zoey,

I will get back to you with updates as soon as possible.

BR,

Haroon

Hi Zoey,

Apparently the LM5122EVM-2PH has one single Vin pin for both of the inputs of the Master and slave devices, so I was not able to test this, but I think if the two input voltages were not equal there would be problems especially for the COMP pin, as normally the peak current detected at COMP pin should be equal for both devices, but if the input voltage of the two devices are not equal that would mean different peak currents at COMP pins and hence the load would be handled by one of the devices as opposed to being shared which would normally happen if the input voltage of the two devices were equal.

LM5170 is more suitable for different input voltages https://www.ti.com/lit/ds/symlink/lm5170-q1.pdf?ts=1649088364939&ref_url=https%253A%252F%252Fwww.google.com%252F#:~:text=The%20LM5170%2DQ1%20controller%20provides,by%20the%20DIR%20input%20signal.  

BR,

Haroon

Hi Zoey,

That is a problem as there are no LM5122EVM-1PH available here with me (in Freising) as well, I could try making changes to the 2PH EVM and try this test, but I will ask my supervisor first if they think it makes sense or not, and also see if it is even possible to make this change. I will keep you updated.

Regarding not using syncin and syncout in the interleave mode, it has to be used, because the syncout is basically the pin that causes the 180 degrees phase shift in the S-mode device by connecting it to the syncin pin of the S-mode device, without this phase shift we do not have the dual phase in our output, so syncin and out have to be used exactly the way it has been stated in the datasheet.

Yes, LM5170 is way more appropriate for the usage of two different different and not equal input voltage sources.

BR,

Haroon

Hi Zoey,

Could you please share the specs for the customers application, e.g.. Vin, Vout, Iout, Fsw.

Also, may I ask why is the customer interested in using two input voltage sources, instead of one, I thought this was just out of curiosity question, but could I know exactly what is that the customer is interested in doing?

BR,

Haroon