Patent ID: 8407637

Claim:
A method for analyzing the electrical stability of an active circuit intended to operate in a predetermined frequency domain according to a predetermined linear or non-linear operating condition, comprising: starting from a physical model provided by a CAD-type software tool for the circuit, determining a frequency response of the circuit in the form of an evolution of the transfer impedance I(f) or the transfer admittance A(f) of the circuit as a function of the frequency, the frequency describing a discrete analysis frequency band and the frequency response corresponding to the linearization of the circuit around the solution in a steady state, recording the transfer impedance or admittance I(f) or A(f) in the form of a first discrete function of the module (M) of the impedance or admittance as a function of the analysis frequency (f) and a second discrete function of the phase (φ) of the impedance or admittance as a function of the analysis frequency (f), dividing the analysis band (B) into sub-bands, each sub-band surrounding a different local extremum of the module (M) of the transfer impedance or admittance I(f) or A(f), ordering the set of sub-bands following a sequence while assigning a rank to each sub-band, in an elementary identification step, for a sub-band having a fixed rank (rang_sb) and a predetermined transfer function order (n): identifying a transfer function (TFI ranf — sb (n)) having the predetermined order (n) close in terms of a functional distance to the transfer impedance or admittance (I rang — sb (f)) restricted to the fixed-rank sub-band when the frequency describes the fixed sub-band, wherein: for a sub-band having a fixed rank (rang_sb), the method comprises a step for automatically determining a transfer function ((TFI ranf — sb (n_opti)) adapted to the stability analysis, the automatic determination step being carried out in the form of an identification loop parameterized according to an increasing current transfer function order (n) and implementing the elementary identification step in which the predetermined order is the order of the current transfer function, in that each elementary identification step implemented in the identification loop comprises a step consisting of calculating a phase error function errφ(n) as being the set of phase errors described when the frequency describes the fixed-rank sub-band, the phase error at a given frequency being the difference between the phase of the second function and the identified transfer phase, and determining a norm for the error function, and in that the path of the identification loop is stopped when a norm of the phase error function has exceeded a predetermined phase error threshold value, and in that it comprises a step consisting of determining the electrical stability of the circuit from the positions of the poles and the zeros of the transfer function identified in the automatic determination step.