• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 64 subscribers
  • Views 608 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

min. switching frequency LM3150

Jan Zomerdijk25
Prodigy 30 points
Other Parts Discussed in Thread: LM3150

Hello everyone,

Can anyone tell me where I can find the minimum working frequency of the LM3150 part in the data sheet ?

The TI website (see link) states 200kHz but I cannot find that information in the data sheet and I don't understand why there is a minimum (technical reason) for a hysteretic controller. 

http://www.ti.com/product/lm3150?keyMatch=LM3150&tisearch=Search-EN

cheers,

Jan

  • 0
    TI__Guru 73235 points

    I think that the 200kHz is somewhat arbitrary.  Lower frequencies would require larger and bulkier inductors.

    FD

  • 0 in reply to Frank De Stasi
    Prodigy 30 points

    Hello Frank,

    Thank you for your reply and I agree regarding the influence on components when the switching frequency is low.

    However, I can think of numerous practical reasons why a converter needs to work in a specific frequency range.

    The link provided earlier states explicitly 200kHz as the lower frequency limit as if there is some sort of technical reason inside the chip.

    Furthermore, the data provided for the LM3150 seems to be inconsistent at the point of allowed frequency range when looking at the website ("min. 200kHz", see link provided earlier), the datasheet ("up to 1MHz", no lower limit provided) and the simple switcher product portfolio flyer ("up to 1MHz", no lower limit provided).

    I would like to use this IC but I want to know for sure that I can use the IC below 200kHz. Is it possible to get some more information ?

    Jan

  • 0 in reply to Jan Zomerdijk25
    TI__Genius 10115 points

    I have used the part before at 90Khz. I believe the 200Khz limit was put there because it was where they decided to end bench testing.  Also, the Ron setting becomes less accurate at the lower frequencies because the current is reduced.

    Regards,

    Marc

  • 0 in reply to Marc Davis-Marsh
    Prodigy 30 points

    Hello marc,

    Thank you for your answer. I'll continue with this part and keep the Ron issue in mind.

    Consider this question answered.

    regards,

    Jan