LMR36503-Q1:LMR36503-Q1 rc snubber circuit resistance value and capacitor value recommendation

min jeong

Prodigy 10 points

Part Number: LMR36503-Q1

Tool/software:

안녕하세요,

현재는 컨트롤러 보드에 IC를 사용하여 전압을 48V에서 3.3V로 낮추고 있습니다.

컨트롤러 보드의 EMC CEV 테스트를 진행하는 동안, 노이즈가 벅 컨버터에서 발생한다는 것을 확인했습니다.

벅 컨버터의 스위칭 주파수를 확인해보니, 스위치가 꺼지면 파형이 불안정해지는 것을 발견했습니다.

저는 이 불안정성을 해결하고 싶습니다:

RC 스너버 회로를 사용하여 억제할 수 있나요?
그렇다면 적합한 저항기와 커패시터 값을 추천해 주시겠습니까?
추천할 만한 대체 솔루션이 있나요?

24 days ago

0 Niranjan Nair 24 days ago

TI__Genius 9600 points

Hi,

You can reduce the ringing by adding RC snubber. The values have to be determined experimentally (you can follow this reference : https://www.ti.com/document-viewer/lit/html/SSZTBC7)

Another option is to go for FPWM operation. This ensures that the device is in CCM throughout and this ringing will be absent. You can choose a device variant with PFM/FPWM selectable (with M in the name) and operate it in FPWM. However, frequency is fixed at 2.2MHz for these variants.

Regards,

Niranjan

0 min jeong 20 days ago in reply to Niranjan Nair

Prodigy 10 points

Thank you for your response. I was wondering if that switching waveform could be mitigated by using an RC snubber. If so, where would be the appropriate location to place the RC snubber?

0 Niranjan Nair 19 days ago in reply to min jeong

TI__Genius 9600 points

You can place an RC snubber on the SW node. The component values can be determined according to the article I linked above.

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LMR36503-Q1:LMR36503-Q1 rc snubber circuit resistance value and capacitor value recommendation