LM62435-Q1: the light load operation of LM62435

Torres Liu

Part Number: LM62435-Q1

Hi, Experts:

I am planning using LM62435-Q1 in my system, and I have a question about the light load operation.

in your spec, there are Diode emulation and frequency reduction , I understand Diode emulation , but I am nott familar with frequency reduction technology, could you help to explain it in details? which status do we use this techniques in? thanks

Thanks

Torres

over 3 years ago

0 Colin Chen over 3 years ago

TI__Mastermind 21361 points

Hi Torres:

At light load, because load current is low, the conduction loss is less dominant in total power loss and total power loss is mostly switching loss. As we known, switching loss is proportional to frequency, so frequency reduction technology will reduce power loss and improve efficiency.

B R

Colin

0 Torres Liu over 3 years ago in reply to Colin Chen

Prodigy 30 points

Hi, Colin:

Is this the same meangings as the skip mode at light load?

Thanks

Torres

0 Torres Liu over 3 years ago in reply to Torres Liu

Prodigy 30 points

Hi， Colin：

Please study the below information from th datasheet, Maybe it’'s not the same as our understanding. I understand your power switching loss theory.

I ever used many kinds of TI power parts and didn't met these kind of descriptions. so haven some issues. thanks

0 Colin Chen over 3 years ago in reply to Torres Liu

TI__Mastermind 21361 points

Hi Torres,

When device works in PFM mode, the average current IL is greater than Io at first, so Vout will rise. As a result, there is a small DC positive offset between fb and Vref, this will cause output of Comp decline and furthermore to decrease frequency in PFM mode.

B R

Colin

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LM62435-Q1: the light load operation of LM62435