LM25122-Q1: LM25122-Q1 issue with dual phase configuration.

Hello Sabir,

Thanks for using the e2e forum.
Would it be possible to share the parameters for VIN, VOUT, max LOAD and the schematic if possible?
You can also add the name of the 700W reference design.

Based on this we can look into the design and look for the root cause.

Thanks and best regards,
Niklas

Vin 12v Vout 32v for now but will be using 36v finally. Output current 10 amps. Input max 30amps.

Reference design PMP11769

Also the schematic is same as the reference design. 

Hi Sabir,

Thanks for confirming the ref design number and the specs.
The PMP11769 design has been built and tested, so I do not expect that there is something wrong with the reference design.
I would compare the reference design schematic with your schematic to see if there are any differences.
Was the layout also copied without any changes?

If you can confirm both schematic and layout are identical to the reference design, it might be helpful to measure some signals on the board and share the waveforms.
You initially mentioned the secondary controller side does not share any current. Is this controller not turning on at all, or is it switching?

Thanks and best regards,
Niklas

Indeed i too thought it should not be the case. Second controller works ok. On second controller When load is increased i can see frequency on sw(20) pin latching. Only this pin behaves like this. All other pins hace frequencies same as master controller. 

Sorry pin20 is bst. 

send me your email address i will share my schematic and design files if needed

Hi Sabir,

Just for clarificaiton, you see abnormal behavior on the SW pin (pin 18) at higher loads?
As SW is an input pin, I would assume the driver signal must be off then.

You can send me the design files via a private message here in e2e.

Best regards,
Niklas

I clarified above. It was my mistake that i said sw. Pin 20 is the problem. Bst pin bootstrap. 

I tried to send you files via private msg but it asks for url. I don't know how to do that. 

I have files on my device. 

I am unable to add pdf and gerber files in private messages. Please guide me. 

Hi Sabir,

BST also is an input pin. If the voltage is abnormal here, you might need to check if the correct caps are placed at BST and VCC. In the schematic, these are C89 and C97.

You should be able to attach files simply via drag and drop. If this is not working, you can send me a single text message to start the chat instead. Then I will give you my mail information there.

Best regards,
Niklas

sent you private message please check

Thanks for your message.
I sent my reply via private message as well.

Best regards,
Niklas