Comments on Understanding inductive ringing
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Understanding inductive ringing
For my own understanding I tried modelling switching off an inductive load without a freewheeling diode to observe ringing. This is the model I used:
1.) Are the two main components of the resonant circuit L1 and C_windings, where C_windings is the inherent capacitance between the two ends of L1, or are there more elements contributing to this effect that I have not placed in the circuit?
2.) Can ringing on digital signal lines also be represented in the same way, where L1 is the total inductance of the signal line and C_windings is the capacitance between the two ends of this signal line?
3.)Is adding a termination resistor on data lines essentially providing a path for the collapsing magnetic field of the line inductance that dampens the LC oscillation? (Path in red)
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are there more elements contributing to this effect that I have not placed in the circuit?
Well, you have a simulator and it should be really easy to remove C_windings and observe if the ringing frequency alters. If it does then there is another capacitor hidden away in your circuit (aka drain-source capacitance) that sets the new ringing frequency.
Can ringing on digital signal lines also be represented in the same way, where L1 is the total inductance of the signal line and C_windings is the capacitance between the two ends of this signal line?
No, because usually on digital signal lines the problem is one of reflections rather than resonance. It may look like resonance but, it's something else tied up in transmission-line theory.
Is adding a termination resistor on data lines essentially providing a path for the collapsing magnetic field of the line inductance that dampens the LC oscillation? (Path in red)
No, the resistor is there to prevent reflections returning back down the line. It's a transmission-line effect that we are normally dealing with here on digital signal lines.
Unfortunately if you haven't studied transmission lines (a big and difficult subject) you can easily mistake t-line effects for LC oscillations.
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