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TPS61194: Spread Spectrum with changing the switching frequency

tateo yamashiro
Guru 10890 points
Part Number: TPS61194

Hi,

We got a question from the customer about TPS61194.
Could you help us?

[Question]
They want spread spectrum with extenrnal synchronization. But the IC can't meet thier requirement. So they are considering changing the switching frequency by FSET pin with SYNC pin pulled up to VDDIO/EN.

- Are there any concerns for this usage?
- How much is the variation of the switching frequency at the over temperature?
  *fsw=300k to 500kHz

Best Regards,
tateo

  • 0
    TI__Intellectual 2140 points
    Hi Tateo,

    This thread has been assigned to Sungho who will be able to look into your questions on Monday and provide feedback.

    Regards,
    Angelos Tsiros
  • 0
    TI__Expert 4565 points
    Hi,

    Usage case os OK. Variation range of SW is based on internal OSC clk freq which has max +/- 7% over temp.
    BYW, I’m not sure about the switch on FSET connection. Rfset connection should be consistent, not dynamically switching.

    Please contact MLP automotive apps group via emails if you need more info.
  • 0 in reply to Sung Ho Yoon
    Guru 10890 points

    Hi, Thank you for your quick reply. Basically they change the switching frequency by external clock in order to avoid AM band noise. But the IC can't enable spread spectrum while the IC is synchronized external clock. So they are considering the function avoid AM band by changing RSET resistor. We will contact you soon by e-mail.

    Best Regards,
    tateo

  • 0 in reply to tateo yamashiro
    TI__Expert 4565 points
    The device can support self switched spread spectrum, but using external boost sync input, SW freq will just follow sync input.
    If system side can provide sync signal already implemented spread spectrum, it will be the best. Otherwise, using internal spread spectrum based on internal SW freq setting will be only option.