LM3478: Bust Mode or Pulse skip at light load

K.Hamamoto

Part Number: LM3478
Other Parts Discussed in Thread: LM5155

I saw some E2E post regarding the behavior at light load. There are mentioned about such as Pulse skip and Burst mode.

Which does this device have Burst Mode or Pulse Skip mode?

In my understanding, Burst mode is the behavior is repeating some pulse and long low state. On the other hand,Pulse skip mode is the behavior is repeating one pulse(min pulse) and the long low state.

To be more exact, the both behavior is a little different.But the both behavior is to improve the efficiency at light load.

Best Regards,

Koji Hamamoto

over 6 years ago

0 Garrett Roecker over 6 years ago

TI__Mastermind 21720 points

Koji,

Thanks for reaching out with your question.

The LM3478 operates like with multiple pulses at light load and then waits for the output voltage to decay. If you need less ripple at light load the LM5155 will operate in pulse skipping mode at light load.

Thanks,

Garrett

0 K.Hamamoto over 6 years ago in reply to Garrett Roecker

Guru 12155 points

Hi Garrett,

I am sorry for the delay in my response.　

I understand the behavior of this device at light load. I need to suggest adding the dummy load or suggesting LM5155.

Regards,

Koji Hamamoto

0 Garrett Roecker over 6 years ago in reply to K.Hamamoto

TI__Mastermind 21720 points

Koji,

Either changing to the LM5155 or adding a dummy load will reduce the ripple on the output.

Thanks,

Garrett

0 K.Hamamoto over 6 years ago in reply to Garrett Roecker

Guru 12155 points

Thank you!

Power management

Power management forum

LM3478: Bust Mode or Pulse skip at light load