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Original question:

UCC2895: ucc2895

UCC2895: Under what circumstances will the overlapping uncertain states in the figure appear?

Gabriel Wang1
Genius 4425 points
Part Number: UCC2895

Dear Sir

Attatched the Pin 13 & Pin 14 's waveform .

The following 13 - and 14-pin theories should be complementary. Under what circumstances will the overlapping uncertain states in the figure appear?

Sch:

A811AV07A.pdf

  • 0
    TI__Guru* 77495 points

    Hello,

    I reviewed your schematic and you have setup voltage amplifier into a voltage follower configuration and have your own discrete feedback scheme.

    So comp should be the same as EA+.

    So COMP is demanding maximum duty cycle and drops to zero volts because your compensation network demands it.  The A and B pulses are synchronized to the master clock.  The duty cycle is controlled by phase shifting out C and D.  When you demand 0% duty cycle the C and D pulses will be phase shifted from 180 degrees to zero degrees.  This will make the C or D pulse look to be on/off for more than 50% duty cycle.  This is what your waveforms are showing.  

    Regards,