Need some help in stablizing the overshoot.

Discussion in 'General Electronics Chat' started by nepdeep, Jan 30, 2013.

  1. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    Hi,
    I have the circuit like this....and have the problem of overshoot...could anybody recommend me how can i configure the circuit to remove the overshoot.? overshot.png
     
  2. toffee_pie

    Active Member

    Oct 31, 2009
    162
    7
    clamping diode?
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    Is the ground side of R5 connected?
    I see an open line between R5 and the ground symbol.
    If R5 is not connected to ground, there will be no attenuation.

    Bertus
     
  4. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    I was just trying out different things....the circuit works without the R5 connected....

    and clamping diode would definitely not seem to solve the problem
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Why do you have all those inductors in your circuit?
     
  6. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    Those are the parasitic inductances due to the connecting wire
     
  7. tindel

    Active Member

    Sep 16, 2012
    568
    193
    Looks to me that your feedback loop is under-damped (google it).

    Have you tried to slow down the rise time (slew rate) of the input voltage to see if it goes away?

    Have you tried changing the values for R3 and C1?

    Have you read the datasheet thoroughly? Read it again. Try the 'capacitance on the inverting input' section. Verify there's no parasitic capacitance there. Also read the 'slew rate' section - this may be your problem. Still have the problem? Read the datasheet again!
     
    nepdeep likes this.
  8. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    When you measured your signal with the oscilloscope was the probe properly grounded?
     
  9. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    There is a finite loop speed. How fast is the op amp?

    I can't see time markers. How wide is the overshoot transient?

    Forcing the rise time slower probably would reduce the overshoot.

    The main problem is the inductor that the FET is driving stores energy. Even when you cut drive to the FET, the inductor's energy has to dump.
     
  10. crutschow

    Expert

    Mar 14, 2008
    13,018
    3,235
    Post your .asc file.
     
  11. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    nope..it wasnot ope
     
  12. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
  13. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Ground the scope probe (not just the scope) and you will observe a huge difference.
     
Loading...