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LC VCO startup issue for different transient algorithms

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CHETHAN2323

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My LCVCO is converging .i.e. starting when I am not checking any transient algorithm. In this case, I am getting the required tuning frequency.

But when I turned on gear2 or gear2only algorithm, then my LC is not starting for any vcontrol signal. The oscillations are getting damped.

The same setup when I am doing transient simulation without checking algorithm in transient options, then my LCVCO is working perfectly.

Is it necessary that it shoul work with gear2 or gear2only algorithm?
What might be the reason for this ?
Can anyone please help me out with this?
 

But when I turned on gear2 or gear2only algorithm,
then my LC is not starting for any vcontrol signal.
The oscillations are getting damped.
It could be for gear2 as integral method.

The same setup when I am doing transient simulation without checking algorithm in transient options,
then my LCVCO is working perfectly.
It could be, since default interal method is trapezoidal rule for moderate accuracy setting.

Is it necessary that it shoul work with gear2 or gear2only algorithm?
hat do you want to mean ?

What might be the reason for this ?
Gear2 tends to suppress oscillation, so simulation with gear2 sometimes can not reach to steady state oscillation.
 

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This is showing you that oscillation has some kind of "hump"
to get over, to start, and the damping of the GEAR2 method
might be showing you what will happen if passives' Q or
actives' gain are lower than your models estimate.

PLL designers may include "sweeper" or "kicker" functions
to force their loop to closure. Bandgap designers always
(if they want to stay in the job) need startup circuits for
theirs. Maybe your oscillator should be no different. It's
not always practical to know whether a simulation method
outcomes discrepancy is really. solely about the numerical
goings-on, but you can know that you pounded a spike
through its neck, if you did.
 
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