LM5176: The efficiency problem

Feng Xu

Part Number: LM5176

I am currently using LM5176 as a DC-DC controller and i am so confused that the relationship between compensation pole-zero and the circuit's efficiency in steady state.

When i enlarge the compensation pole to widen the bandwidth,the efficiency of steady state decreases about 1~2%,both of the previous and subsequent circuit are working in steady state.

Why ?

over 6 years ago

0 Jasper Li over 6 years ago

TI__Mastermind 46905 points

Hi Feng,
the engineer supporting this device is out of office now. the post is assigned to him. he will reply you after back to office next week

0 EricLee over 6 years ago in reply to Jasper Li

TI__Guru 58851 points

Hi Feng
There is no direct relationship between loop compensation and efficiency unless the system is stable. If you see an efficiency drop by changing the compensation pole, then it means that your system becomes unstable.
Regards,
EL

0 Garrett Roecker over 6 years ago

TI__Mastermind 21720 points

Hi Feng,

There should not be a correlation between the loop compensation and the efficiency of the circuit assuming the circuit is stable. It sounds like you might be having issue might be due to instablibity.

Please use the LM5176 quick-start calculator to ensure that your loop is stable.
www.ti.com/.../snvc208

Thanks,

Garrett

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LM5176: The efficiency problem