PLL phase shifter

Discussion in 'The Projects Forum' started by ako, Jun 12, 2009.

  1. ako

    Thread Starter Member

    Mar 14, 2009
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    Hi All,Is it possbible to phase shift by 180% a 150-250kHz variable frequency PWM signal with a duty cycle of 40-60%using a single supply voltage LM565 PLL?Complete newbie badly needs help on this one. Thanks..
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Wouldn't it be easier to run the signal through an inverter? Or change the control? A 50% duty cycle remains 50%, 60% becomes 40%, and so on.
     
  3. ako

    Thread Starter Member

    Mar 14, 2009
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    I need the signal for interleaving purposes which is variable frequency, and a change in duty cycle wouldn't be right anymore.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Draw up a 60% duty cycle PWM signal on graph paper. Do a 180 deg. phase shift on it. See if that hasn't made it a 40% duty cycle signal.
     
  5. ako

    Thread Starter Member

    Mar 14, 2009
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    I think some kind of signal delay is what I'm looking for right now. Does phase shift always mean a change in duty cycle (assuming that D is not 50%)? Really confused about this topic.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    A 180 deg phase shift simply inverts the signal. Signal delay is different. What kind of delay are you after?
     
  7. hgmjr

    Moderator

    Jan 28, 2005
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    You say 180%. Do you really mean 180 degrees?

    hgmjr
     
  8. ako

    Thread Starter Member

    Mar 14, 2009
    10
    0
    180 degrees. Sorry.. The kind of delay that is implemented in interleaving PWM IC's in which the duty cycle is preserved. Only that in my case its variable frequency. Can a PLL do the job?
     
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