LM61440-Q1: Light Load operation (PFM)

ARUN Manikantan Indira

Part Number: LM61440-Q1

Hi, What will be the minimum switching frequency when operated in Auto mode- Light Load operation: (PFM). Will it be less than 200 kHz.

over 3 years ago

0 Elena Gao over 3 years ago

TI__Genius 13735 points

Hi ARUN,

From datasheet RT set frequency L_limit will be 180k and 200k as TYP. The lowest frequency should happens when ton=tonmin,toff=toffmax, ton calculator is (IPEK-MIN*L/(Vin-Vo)) ,

Elena

0 ARUN Manikantan Indira over 3 years ago in reply to Elena Gao

Prodigy 10 points

Hi Elena, Thanks for your reply. Is this formula applicable for PFM operation as well.

0 Elena Gao over 3 years ago in reply to ARUN Manikantan Indira

TI__Genius 13735 points

yes, and the limit is TON min. you could also try simulation with webench and check the light load condition.

Elena

Power management

Power management forum

LM61440-Q1: Light Load operation (PFM)