Voltage-Controlled Capacitor—Feasibility Demonstration in DC–DC Converters

Zhang, Lujie; Ritter, Andrew; Nies, Craig; Dwari, Suman; Guo, Ben; Priya, Shashank; Burgos, Rolando; Ngo, Khai D. T.

doi:10.1109/tpel.2017.2666478

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…Consistent with this view is the conclusion that (4) is the more correct expression than (6) for the voltage-dependent capacitance [6]- [8]. Another view is that (6) is only appropriate for small signals, whereas (4) should be used for large-signal analyses [9]. It was also shown that (4) and (6) can be equated by using different definitions for C(V), which are the definition of total capacitance C(V) = Ct = Q/V in (4) and the definition of differential capacitance C(V) = Cd = dQ/dV in (6) [10]- [12].…”

Section: Introductionmentioning

confidence: 98%

The Correct Equation for the Current Through Voltage-Dependent Capacitors

et al. 2020

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Two different equations for the current through voltage-dependent capacitances are used in the literature. One equation is obtained from the time derivative of charge that is considered as capacitancevoltage product: dQ/dt=d[C(V)V]/dt=C(V)[dV/dt]+V[dC(V)/dt]. In the second equation, the term V[dC(V)/dt] does not exist: dQ/dt= C(V)[dV/dt]. This paper clears the ongoing confusion caused by the difference between these two equations. We use the voltage-dependent parasitic capacitance of a commercial Schottky diode in reverse bias mode to test experimentally both equations. The result is that it is incorrect to add the term V[dC(V)/dt] in the first equation with the measured capacitance. We also perform a theoretical analysis, which shows that the differential capacitance, C(V)=dQ/dV, in the correct current equation corresponds to the physical parameters of the diode capacitance.

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Section: Introductionmentioning

confidence: 98%

The Correct Equation for the Current Through Voltage-Dependent Capacitors

et al. 2020

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“…Despite the increase in the coupling factor k from 1% to 10% and the implementation of hysteresis losses, the calculations deviate from the measurements for higher values of Uc2RMS. A possible explanation would be that the measurement of the nonlinear capacitors used in this work, according to Section 2.1 , is no longer valid for higher AC voltages [ 25 , 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Consistent and Efficient Modeling of the Nonlinear Properties of Ferroelectric Materials in Ceramic Capacitors for Frugal Electronic Implants

Olsommer

Ihmig

2020

Sensors

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In recent years, the development of implantable electronics has been driven by the motivation to expand their field of application. The main intention is to implement advanced functionalities while increasing the degree of miniaturization and maintaining reliability. The intrinsic nonlinear properties of the electronic components, to be used anyway, could be utilized to resolve this issue. To master the implementation of functionalities in implantable electronics using the nonlinear properties of its electronic components, simulation models are of utmost importance. In this paper, we present a simulation model that is optimized in terms of consistency, computing time and memory consumption. Three circuit topologies of nonlinear capacitors, including hysteresis losses, are investigated. An inductively coupled measurement setup was realized to validate the calculations. The best results were obtained using the Trapezoid method in ANSYS with a constant step size and a resolution of 500 k points and using the Adams method in Mathcad with a resolution of 50 k points. An inductive coupling factor between 7% and 10% leads to a significant improvement in consistency compared to lower coupling factors. Finally, our results indicate that the nonlinear properties of the voltage rectifier capacitor can be neglected since these do not significantly affect the simulation results.

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“…In general, the nonlinear characteristics of the ferroelectric materials in MLCCs are rather considered as a disadvantage. However, there exist approaches that attempt to turn this nonlinearity into a benefit [27][28][29][30]. The most important application for ferroelectric materials is certainly in memory devices, such as ferroelectric random-access memories [31].…”

Section: B Mlcc Modeling Approachesmentioning

confidence: 99%

“…Experimentally determined polynomial coefficients are used to model the nonlinear properties of ferroelectric materials without considering the underlying physics [38,39]. SPICE models of voltage-dependent ferroelectric MLCCs are also reported in the literature [27][28][29]40]. Such models are popular among developers in the field of power electronics as they are readily available, user-friendly, and quick to set up and run [40].…”

Section: B Mlcc Modeling Approachesmentioning

confidence: 99%

Physics-Based Modeling of Ferroelectric Hysteresis for Ceramic Capacitors in Inductively Coupled Microstimulators

Olsommer,

Ihmig,

Rizzello

2024

IEEE Trans. Power Electron.

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In this paper, we present a physics-based model for nonlinear and hysteretic ferroelectric capacitors in inductively coupled microstimulator circuits. The purpose of this model is to predict the system's dynamic response as a function of the dielectric material properties, with the aim of optimizing the performance in passive power control applications. We describe the workflow starting from the extraction of the dielectric material properties of commercial ceramic capacitors to the implementation into the physics-based model of the overall circuit. Selected capacitors were experimentally characterized at frequencies above 100 kHz by means of both small signals (5 mVrms, ±25 VDC and ±40 VDC) and large signals (±25 VAC and ±40 VAC). Our results show that the developed model is well suited for accurately predicting the circuit's stimulation current for highly nonlinear capacitors and exhibits higher precision compared to commonly used models based on differential capacitance. Preliminary in vitro measurement results are finally described to provide proof of concept of the envisioned modelbased passive power control in implantable microstimulators.

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Voltage-Controlled Capacitor—Feasibility Demonstration in DC–DC Converters

Cited by 10 publications

References 11 publications

The Correct Equation for the Current Through Voltage-Dependent Capacitors

The Correct Equation for the Current Through Voltage-Dependent Capacitors

Consistent and Efficient Modeling of the Nonlinear Properties of Ferroelectric Materials in Ceramic Capacitors for Frugal Electronic Implants

Physics-Based Modeling of Ferroelectric Hysteresis for Ceramic Capacitors in Inductively Coupled Microstimulators

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