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LM5141-Q1: LM5141-Q1 light road operation

Tomohiro Nagasawa58
Expert 1570 points
Part Number: LM5141-Q1

Dear support team

I want to know what kind of LM5141-Q1 light road operation mode.

Seeing datasheet, there is diode emulation and pulse skip are written. Are these the same? 

What are the conditions for releasing the pulse skip mode?

Regards

Tomonhiro Nagasawa

  • 0
    TI__Mastermind 23845 points
    Hi,

    The diode emulation mode is chosen through DEMB pin. If diode emulation mode is chosen, and there is no load at the output, then the part will skip cycle. But if you ask for definition, the diode emulation means that the diode will conduct but the switching frequency could be nominal switching frequency. Pulse skipping on the other hand, the frequency is less than nominal switching frequency.

    To release pulse skip mode i think is based on the output current or you use the FPWM mode therefore no skipping will happens and the part will operate in synchronous mode regardless of output current.

    Thanks
    -Arief
  • 0 in reply to Arief Hernadi
    Expert 1570 points

    Hello Arief-san

    Thank you for detailed explain.

    My customer make LM5141-Q1 prototype.

    Despite FPWM, the frequency is unstable and less than nominal switching frequency from light load to heavy load.

    I guess unstable operation is due to a bad pattern layout, but will the frequency change by bad pattern layout?

    Regards

    Tomohiro Nagasawa