Mohsenkma
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Hello,
I simulate a switch-cap LC VCO in 2.4 GHz. It works well in transient simulation. I let the transient simulation to run for a long time to be sure that oscillation is stable. In PSS simulation with harmonic balance engine, I’ve got this error: Matrix is singular. I’ve tried some solutions: reducing reltol to 1e-6, increasing the number of harmonics to 32, setting the accuracy defaults to conservative and increasing tstab but the problem doesn’t solve. The state of switches doesn’t change during the simulation. Matrix singular error is always detected at the nodes which are connected to a switch. Here is a part of the output log: . . . sweeppss-000_pss: time = 48.1 ns (92.5 %), step = 974.7 fs (1.87 m%) sweeppss-000_pss: time = 50.7 ns (97.5 %), step = 507.7 fs (976 u%) The Estimated oscillating frequency from Tstab Tran is = 2.23231 GHz . Tstab: runs at least 165 timesteps per cycle, MaxStep=2.71495e-12
=============================================== `sweeppss-000_pss': time = (52 ns -> 52.448 ns) =============================================== sweeppss-000_pss: time = 52.01 ns (2.54 %), step = 1.044 ps (233 m%) . . . sweeppss-000_pss: time = 52.44 ns (97.5 %), step = 744.3 fs (166 m%)
MultiThread info: 7 new work threads created Pinning node: 274, harm: 1, name: I6.SW41.net19, value: (0.147438, -0.563566)
Notice from spectre during periodic steady state analysis `sweeppss-000_pss', during Sweep analysis `sweeppss'. Use new Arnoldi routine
============================== Harmonic balance ============================== Important HB parameters: RelTol=1.00e-06 abstol(I)=1.00e-12 A abstol(V)=1.00e-06 V ResidualTol=1.00e+00 LTE_Ratio=3.50e+00 Steady_Ratio=1.00e+00 MaxNewtonIter=100
Warning from spectre during periodic steady state analysis `sweeppss-000_pss', during Sweep analysis `sweeppss'. WARNING (SPECTRE-16001): Sweep iteration for `Vctrl' = 0 terminated prematurely because of the following error(s): Error found by spectre during periodic steady state analysis `sweeppss-000_pss', during Sweep analysis `sweeppss'. ERROR (SPECTRE-11005): Matrix is singular (detected at `I6.SW50.net17').
Analysis `sweeppss-000_pss' was terminated prematurely due to an error.
How can I solve the problem? Thank you,
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