LM5180: The regulation issue for LM5180NGUR

Hi miyata

Did you refer to the equation(26) in the datasheet for the RFB selection?  And RSET is 12.1k in equation(26) as recommended in the datasheet.

Thanks

Hi Gui san

 Good day.

Of course. I referred to the  the equation(26) in the datasheet.

Rfb=(Vout+Vf)*Nps/Irset=(11V+0.41V)*1/0.1mA=114.1kΩ≒115kΩ

→Vout setting＝11.02V (Rset : 12kΩ)

And, I confirmed the Vout when I changed the  Rset from 12.0kΩ to 12.1kΩ.

But , Vout remained almost unchanged.

Hi Miyata

Will the Vo change if you add more load? Usually Vo is higher when no_load or very slight load.

Thanks

Hi Gui san

Good day.

Thank you for your advice.  I will confirm your idea.

Our output current spec is 0.1A/output. 

If we need to reduce the Vout , do you have any other ideas besides the following?

1.Adjust the Rfb

2.Decrease the value of bleeder resistor

Thank you.

Best regards,

miyata

Hi Gui san

Good day.

I confirmed the regulation in overload.

But, Our circuit keeps 11.5V until overcurrent protection point.

Please refer attached for detail.

Do you have any other reasons why the set voltage is not output??

20230711_Regulation Issue for LM5180NGUR.xlsx

Hi Miyata

Let me check and get back later.

Hi Miyata

What is the part number of the D252 and D253?

Thanks

Hi Gui san

We use PMEG60T10ELR(NEXPERIA) in D252/D253.

Hi Gui san

Thank you for your support.

I understood.