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Microelectronic Circuit Enhancements and Design Methodologies to Facilitate Moore’s Law – Part II
Published in Lambrechts Wynand, Sinha Saurabh, Abdallah Jassem, Prinsloo Jaco, Extending Moore’s Law through Advanced Semiconductor Design and Processing Techniques, 2018
Lambrechts Wynand, Sinha Saurabh
Highly dense capacitive structures are used specifically in power applications to achieve the minimum equivalent series resistance (ESR), with proposed structures provided in Villar et al. (2003). Since all capacitors (and inductors) used in electrical circuits, which include off-chip discrete components as well as on-chip integrated solutions, are not ideal and can in most cases be approximated as a perfect (ideal) device in series with a resistive element, the ESR is typically defined as an AC resistance and measured with standardized frequencies. ESR arises from losses in the dielectric substances, electrodes or other factors in addition to the capacitive properties of the component and additional parasitic inductance, denoted as the equivalent series inductance (ESL) resulting from the inductance of electrodes, leads or tracks on ICs. A simplified two-element equivalent model of the capacitor, which includes the ESR, is shown in Figure 8.16. This model will be discussed later in this section.
Review of Fundamentals
Published in Nihal Kularatna, Electronic Circuit Design, 2017
An ideal capacitor blocks DC, and its impedance is expected to drop with the inverse of the frequency based on the relationship XC = 1/2fπC. However, in practical devices the device behaves as a complex combination of the ideal capacitor, with value C and other components as in Figure 1.33a. In this figure Lc indicates the equivalent series inductance (ESL) and RC indicates the equivalent series resistance (ESR) composed of the lead resistances, electrodes, and terminating resistances, and these two values are important design parameters when the capacitor is expected to work at higher frequencies or in high-voltage situations, such as in power supply designs. Rac and Rdc represent the equivalent resistance due to AC dielectric losses and leakage resistance due to DC dielectric losses, respectively. Rac may vary nonlinearly with frequency and temperature, whereas Rdc may vary with temperature. Another annoying situation in some types of capacitors is the dielectric absorption property, in which the dielectric material does not become polarized instantly, causing a “memory effect.” This is represented by Rd and Cd and can be problematic in sample and hold circuits if the wrong capacitor type is selected. In such a situation, if the capacitor is charged, discharged, and left open, it will recover some of its charge due to the parasitic effect of Rd and Cd, known as the memory effect. Figure 1.33b shows a comprehensive equivalent circuit. Figure 1.33c shows the impedance versus frequency.
Magnetic field edge-effect affecting joint macro-morphology in sheet electromagnetic pulse welding
Published in Materials and Manufacturing Processes, 2020
Chengxiang Li, Yan Zhou, Xin Shi, Zhigang Liao, Jian Du, Ting Shen, Chenguo Yao
The discharge current flowing in the welding coil is the key electrical parameter in the EMPW process. The circuit module in COMSOL Multiphysics is used to build the discharge loop, and the current generated in the circuit module is the excitation source for the magnetic model. Figure 3 presents the simplified equivalent circuit of the EMPW platform, and it is a typical second-order RLC discharge circuit. C is the energy storage capacitance value. L is the loop equivalent inductance, including the coil inductance, the capacitor equivalent series inductance and the stray inductance of the line and the switch. R is the loop equivalent resistance, including the coil resistance, the capacitor internal resistance, and the equivalent resistance of the switch and the wire. The circuit model including a capacitor, a resistor and an inductor in the simulation is set according to Fig. 3.
A dynamic model of power metal-oxide-semiconductor field-effect transistor half-bridges for the fast simulation of switching induced electromagnetic emissions
Published in Mathematical and Computer Modelling of Dynamical Systems, 2019
D. Büchl, W. Kemmetmüller, T. Glück, B. Deutschmann, A. Kugi
To calculate the conducted emissions over a frequency range from several kilohertz up to multiple megahertz, the parasitic behaviour of the capacitors must also be taken into account. Manufacturers of capacitors provide detailed equivalent circuits, which consist of several parallel RLC circuits. To keep the model complexity low, a simplified lumped circuit model according to Figure 5 is utilized in this work. It will be shown later that this is sufficient for a rather accurate calculation of the EME, see also [16]. The filter and stabilization capacitors of the inverter are modelled by their capacitance , an equivalent series resistance and an equivalent series inductance .
An Indirect Current Phase Detection Method Applied to Automatic Phase Compensation Driver for 1Φ BLDC Fan Motor
Published in Electric Power Components and Systems, 2018
Zong-Hong Tang, Yie-Tone Chen, Chun-Lung Chiu, Ruey-Hsun Liang
The operational mode will enter mode B (Figure 2(b)) when the energy release current is exhausted. In this mode, due to the exhaust of energy release, the winding current will change the direction and the energy comes from DC source to excite the stator winding for torque generation. Furthermore, because S1 and S4 maintain conductive, the winding terminals a and b are tied to +Vc and ground respectively; hence, the winding voltage Vba is still negative and equal to −Vc (ignoring the voltage drops of power transistors). Based on the above description, the current in the conductive period of Figure 2 can be expressed as the sum of the forced and natural responses. where L and R are the equivalent series inductance and resistance of the stator winding respectively, Vemf is the back-EMF voltage, , and .