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TPS55287: spread spectrum dithering above 2.2MHz possible?

Cor Los
Prodigy 50 points
Part Number: TPS55287

Tool/software:

Hi,

with TPS55287 i was aiming for 2.14MHz fsw, but spread spectrum dithering would introduce a triangular waveform which modulates the oscillator frequency by ±7% of the nominal frequency. So i would end up with 1.99MHz-2.29MHz,  and would be above the max allowed 2.2MHz.

Still possible or should i aim for a lower nominal switching frequency if i want to use spread spectrum dithering?

also the the EVM uses ~700Hz dithering frequency at 400kHz fsw, should i also aim for 700Hz dithering frequency with a fsw > 2Mhz or is a higher dithering frequency better?

Thank you in advance

  • +1
    TI__Genius 15160 points

    Hi Cor,

    1.You can keep the 2.14MHz, the maximum switching frequency will not limit dithering frequency.

    2.For the 700Hz dithering frequency, you can keep it at first and adjust it according to EMI test result.

    Regards,

    Mulin