Patent ID: 6859670
Filing Date: 2005-02-22
Classification: G05B

Abstract:
1. A method for predicting at least one transient response characteristic of a closed loop apparatus; said closed loop apparatus having an open loop impedance, a design load impedance, an output voltage and at least one inherent internal gain; the method comprising the steps of: (a) identifying an impedance scaling factor associated with said closed loop apparatus; said impedance scaling factor being expressed in terms including said open loop impedance, said at least one inherent internal gain, a gain variable and a phase variable; (b) vectorally establishing a first scaling value for said impedance scaling factor as a function of frequency while maintaining a first variable of said gain variable and said phase variable at a first working value to record said first scaling value for a plurality of frequencies; (c) vectorally establishing a second scaling value for said impedance scaling factor as a function of frequency while maintaining a second variable of said gain variable and said phase variable at a second working value to record said second scaling value for a plurality of frequencies; (d) creating a first reference tool relating said first scaling value with said second variable of said gain variable and said phase variable as a function of frequency; (e) creating a second reference tool relating said second scaling value with said first variable of said gain variable and said phase variable as a function of frequency; (f) identifying a combined impedance for said apparatus; said combined impedance involving said closed loop impedance, said at least one internal gain and said design load impedance; (g) determining a combined impedance response of said combined impedance as a function of frequency; (h) determining a characteristic frequency for said combined impedance response; said characteristic frequency occurring substantially at a peak value of said combined impedance response; (i) employing at least one of said first reference tool and said second reference tool to establish a first design value for one parameter of phase margin and said design load impedance for said closed loop apparatus at said characteristic frequency; (j) employing at least one of said first reference tool and said second reference tool to establish a second design value for the other parameter of phase margin and said design load impedance than said one parameter for said closed loop apparatus at said characteristic frequency; (k) vectorally establishing a transient multiplier factor for said closed loop apparatus; said transient multiplier factor being associated with said output voltage of said closed loop apparatus with said design load impedance as a function of frequency for selected values of phase margin; (l) creating a third reference tool relating said transient multiplier factor with said selected values of phase margin as a function of frequency; (m) employing said third reference tool to establish a third design value for said transient multiplier factor associated with said characteristic frequency and at least one of said first design value and said second design value; and (n) mathematically combining at least two of said first design value, said second design value and said third design value with a design step current according to a predetermined relation to establish transient voltage excursion of said output voltage in response to an applied step current substantially at said characteristic frequency.