+ Post New Thread
Results 1 to 9 of 9
  1. #1
    Full Member level 1
    Points: 965, Level: 7

    Join Date
    Oct 2010
    Posts
    117
    Helped
    0 / 0
    Points
    965
    Level
    7

    Question about comparator

    Does response time of a comparator in the datasheet means the time it takes the output to see the change of the input? and the slew rate is the time for the output to change its state?

    if i am correct about the response time, is there a way to improve it?

    thank you

  2. #2
    Full Member level 3
    Points: 1,267, Level: 8
    eklikeroomys's Avatar
    Join Date
    Oct 2010
    Location
    South Africa
    Posts
    151
    Helped
    40 / 40
    Points
    1,267
    Level
    8

    Re: Question about comparator

    I think you are correct about the response time, and the slew rate is the rate of change in voltage with respect to time (dv/dt). You can probably improve the response time by increasing the gain of the comparator. Are you constructing your own comparator or are you using an off-the-shelf comparator?



    •   Alt18th May 2011, 09:27

      advertising

        
       

  3. #3
    Full Member level 1
    Points: 965, Level: 7

    Join Date
    Oct 2010
    Posts
    117
    Helped
    0 / 0
    Points
    965
    Level
    7

    Re: Question about comparator

    Yes, i am using a LM339 comparator, will it help if I increase the closed loop gain (positive feedback) ?



  4. #4
    Full Member level 3
    Points: 1,267, Level: 8
    eklikeroomys's Avatar
    Join Date
    Oct 2010
    Location
    South Africa
    Posts
    151
    Helped
    40 / 40
    Points
    1,267
    Level
    8

    Re: Question about comparator

    For what purpose are you using the comparator? In order to use the LM339 as a voltage comparator, there should be no closed loop circuit.



    •   Alt18th May 2011, 12:50

      advertising

        
       

  5. #5
    Full Member level 1
    Points: 965, Level: 7

    Join Date
    Oct 2010
    Posts
    117
    Helped
    0 / 0
    Points
    965
    Level
    7

    Re: Question about comparator

    Hi, I would like to use it as a schmitt trigger.



  6. #6
    Full Member level 3
    Points: 1,267, Level: 8
    eklikeroomys's Avatar
    Join Date
    Oct 2010
    Location
    South Africa
    Posts
    151
    Helped
    40 / 40
    Points
    1,267
    Level
    8



  7. #7
    Full Member level 1
    Points: 965, Level: 7

    Join Date
    Oct 2010
    Posts
    117
    Helped
    0 / 0
    Points
    965
    Level
    7

    Re: Question about comparator

    i read it through but it doesn't tell anything about the response time.



    •   Alt19th May 2011, 07:19

      advertising

        
       

  8. #8
    Full Member level 3
    Points: 1,267, Level: 8
    eklikeroomys's Avatar
    Join Date
    Oct 2010
    Location
    South Africa
    Posts
    151
    Helped
    40 / 40
    Points
    1,267
    Level
    8

    Re: Question about comparator

    What is your concern with the response time if I may ask?



  9. #9
    Advanced Member level 4
    Points: 10,068, Level: 24
    leo_o2's Avatar
    Join Date
    Sep 2004
    Location
    China
    Posts
    1,324
    Helped
    276 / 276
    Points
    10,068
    Level
    24

    Re: Question about comparator

    If you use IC, the only way to improve speed is reduce the capacitance for output and input nodes.



--[[ ]]--