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UCC2813-1-Q1: Synchronized to Spread Spectrum clock

Part Number: UCC2813-1-Q1


We got a question from the customer about UCC2813-x-Q1.
Could you help us?

They are considering using spread spectrum clock for external clock synchronization. Are there any concerns for this usage?

Best Regards,

  • Tateo,

    Thanks for the interest here.

    That configuration could work. If they were designing to do , for example, 100kHz fixed frequency and then want to do +/-10kHz around that 100kHz for frequency dithering they should just be cautious to use the RtCt for the frequency target for 90kHz(low end of the dither range). the clock can only speed up the frequency, not slow it down.

    For current mode control they may also need to adjust what they are doing with the slope compensation because this will change the internal ramp from a triangle to a triangle with sharp peaks(each edge of the clock will raise the ramp signal quickly to the threshold instead of the normal ramp it had before).

    Alternatively, they could also do this dither by providing current injection at the intersection point of Rt and Ct but that might be more complicated. I've seen still other methods of providing specific sawtooth waveform like here:

    I think their method is simplest in general though.