dielectric dependent capacitor non-linearity 01 PUBLIC

A demonstration of the distortion introduced due to the effect of the voltage dependence of the dielectric constant of Y5V capacitors.

The signal across an ideal capacitor is shown for reference.

This model is scaled for a 100V working capacitor.

Has convergence problems. Use dielectric dependent capacitor non-linearity 02 instead:

[circuitlab]wb4qg4[/circuitlab]

A demonstration of the effect of the voltage dependence of the dielectric constant of Y5V capacitors.

The capacitor is a charge conserving non-linear capacitor modelled using a behavioural ideal DC transformer.

VCVS1 measures the voltage across the capacitor.

Iabs1 full wave rectifies the output of VCVS1, V(diff), to keep the input to the behavioural source, VN1, that generates the control parameter for the behavioural capacitance, V(N1), positive.

The output of Iabs1 is converted to a voltage, V(x), and lowpass filtered to help convergence.

V(N1) is the capacitance control parameter used to scale the capacitance value of C1, by controlling the "turns ratio" of the DC transformer in Iintsec1 and Isec1.

NOTES: i) This model assumes that the capacitor is being used at low enough frequencies that time delays of the various physical effects that contribute to dielectric constant variation vs. voltage are negligible compared to the period of the applied signal.

ii) The model is inaccurate for voltage swings of much more than 45V pk-pk. This is thought to be a convergence problem with the behavioural sources.

For an illustration of the capacitance variation vs DC bias of Y5V dielectric capacitors, see:

For more detailed background of the physics of capacitor behaviour see:

www.novacap.com/PdfFiles/tech_brochure.pdf