Matching circuits to lower Q value?

Discussion in 'The Projects Forum' started by Shocker33, Jun 11, 2015.

  1. Shocker33

    Thread Starter New Member

    Oct 28, 2013
    14
    0
    Hi,

    When i drive a signal in to a MOSFET driver, i notice that there is a substantial amount of overshoot and it rings.
    I also find that this is the case when i drive a MOSFET, but the overshoot is significantly higher and it rings for much longer.

    I assume this mean that my circuit/traces has a high Q factor.

    How do i go about determining the Q factor of the traces/circuit?
    And how do i go about designing matching circuits to solve this?

    I've read about matching circuits such as an LC matching filter but i feel massively lost.

    Thanks
     
  2. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Over shoot and ringing is a sign of poor grounding, lack of decoupling capacitors, and or poor layout. "Q" has nothing to do with it.
     
  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,535
    1,251
    99.9% - Think horses: Les is right.
    0.01% - Not zebras: In switching power supplies, the power device internal capacitances and package lead/trace inductances can form resonant circuits and ring at surprisingly high frequencies (hundreds of megahertz).

    ak
     
  4. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    This kind of problem is usually fixed by amputating mistakes, not adding complication.
     
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