Ring oscillator frequency vs supply voltage variation

Discussion in 'General Electronics Chat' started by anhnha, Jan 14, 2016.

  1. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    As you may know, the oscillating frequency of ring oscillator changes significantly with supply voltage variation.
    Are there methods to reduce this effect?
     
  2. dannyf

    Well-Known Member

    Sep 13, 2015
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    Fixed the supply voltage?

    This effect allows them to be used as vco.
     
  3. DickCappels

    Moderator

    Aug 21, 2008
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    Probably, the key would be to make a stage with a delay that has only a small dependency on power supply voltage, and that would be highly dependent on the topology of the inverters in your oscillator.

    If you were to change the inverter to latches clocked by a stable (example: quartz) clock source, taking the outputs from NOT-Q there would be little dependency on the power supply voltage.
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    By any chance would you have a schematic of the circuit you have in mind so some specific comments can be made?
     
  5. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Thanks for the help.
    No, supply voltage varies a lot. So I need to fix frequency.
    I am using the inverter topology as below. Are these some ways to reduce the dependency?
    I can't use quartz here so it would be difficult.

    Ring oscillator.PNG
     
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