WEBENCH® Tools/LM5022-Q1: why I can't set the switching frequency to 500K

Chris Zhao1

Part Number: LM5022-Q1

Tool/software: WEBENCH® Design Tools

Hi experts,

I am using WEBENCH to design a boost circuit, the input is 12V +-5%, and output is 54V/2.4A.

The tool will give me a result with a frequency of 248kHz, while I'm trying to use a higher one, 500KHz, but after clicking the Re-Create Design, I found the switching frequency was the same. it seems I couldn't change it, as there is a recommendation about 200k - 300k, can you tell me why?

Thanks

Chris

over 7 years ago

0 Chris Zhao1 over 7 years ago

Expert 1240 points

I ran a simple test, which set the frequency to 250KHz, within the range recommended, while the final switching frequency I got is like 225kHz, can you tell me why?

Thanks
Chris

0 Youhao Xi over 7 years ago in reply to Chris Zhao1

TI__Guru* 78080 points

I tried your design. You need to edit the schematic my changing the Rt resistor. If I change Rt to 31.4k, the Webench design is updated for ~498kHz (Sorry I did not remember the exact number but it is close to this).

0 Chris Zhao1 over 7 years ago in reply to Youhao Xi

Expert 1240 points

Thanks, I should just refresh the design, I had been recreating the design, that's why I got that problem.

Regards
Chris

0 Chris Zhao1 over 7 years ago in reply to Chris Zhao1

Expert 1240 points

By the way, can you tell me how to change the quantity of capacitors, e.g., I want to change the number of output capacitors from 3 to 4.

0 Gerold Dhanabalan - Online Design Tools over 7 years ago in reply to Chris Zhao1

TI__Genius 14455 points

Hi Chris,

We currently do not have this ability to change the quantity of capacitors . You can try this instead. You can go to "Select ALternate Parts" for Cout and you can see a pencil icon, that you can click to change the maximum value of Cout. You can increase this and click "Search". You will now be able to see more Cout capacitors. You can pick the caps that meet your requirement.

Regards,

Gerold

Power management

Power management forum

WEBENCH® Tools/LM5022-Q1: why I can't set the switching frequency to 500K