Grounded Capacitors Research Articles

Voltage Differencing Gain Amplifier-Based nth-Order Low-Pass Voltage-Mode Filter

In this paper, a new active-C filter realizing the general [Formula: see text]th-order low-pass voltage transfer functions using [Formula: see text] voltage differencing gain amplifiers (VDGAs) is presented. In this realization minimum number of equal-valued grounded capacitors and [Formula: see text] active elements are used. Due to the adjustability of the transconductance of the VDGA with current, different gains can be realized using the same building block and a simple filter structure can be created. The filter which is composed of VDGA building blocks is suitable for integration and advantageous in terms of eliminating parasitic effects because all capacitors are grounded and the filter structure has no resistors. All simulations are performed on SPICE and the accuracy of this method is validated experimentally with commercially available products upon on-board circuit.

A new voltage mode quadrature oscillator using grounded capacitors: An application of CDBA

The paper realizes a single-resistance-controlled oscillator employing current differencing buffered amplifiers as active devices, and virtually grounded resistors and grounded capacitors as passive components. Operating in voltage mode, the designed circuit is capable of generating quadrature outputs along with an unambiguous control of oscillating frequency and condition of oscillation. Initially, practicality and feasibility of the design has been justified by the results obtained using PSPICE simulation software. Simulation results include time response and frequency response outputs generated by using the commercially available I.C. of CFOA, i.e. AD844, as well as by using the CMOS structure of active device employed. Later, hardware experimentation of the design has been included, for which AD844 along with standard components have been employed. Validating results have been obtained in both the cases.

Temperature‐dependent modeling and performance analysis of coupled MLGNR interconnects

AbstractThe temperature‐dependent circuit modeling and performance in terms of propagation delay, power dissipation, and crosstalk‐induced voltage waveform at the far end of victim line of multilayer graphene nanoribbon (MLGNR) interconnects have been analyzed at 22 nm technology node. A comparative performance analysis between MLGNR interconnects with resistance estimated using temperature‐dependent model and temperature‐independent model is examined. The results obtained are also compared with capacitively coupled interconnects of copper (Cu). The results show that as the temperature is varied from 300 K to 500 K, MLGNR has lower propagation delay and power dissipation as compared to Cu for 1 mm long interconnects. It is also observed that because of the dominance of both low resistance and ground capacitance compared to Cu, MLGNR has better crosstalk‐induced delay and voltage waveforms with rise in temperature at the far end of aggressor and victim line, respectively. Further, simulated results show an average relative improvement in propagation delay of 37.24% and corresponding improvement in power dissipation of approximately 19.59% by using a temperature‐dependent model in comparison to a temperature‐independent model of MLGNR resistance with interconnect lengths varying from 200 to 1000 μm. The reduction in the time duration of victim output pulse over these interconnect lengths also shows a significant improvement of approximately 35% by using temperature‐dependent model as against temperature‐independent model of MLGNR resistance.

Grounded capacitance multipliers based on active elements

In this study, we present two new grounded capacitance multiplier circuits based on a negative-type second-generation current conveyor (CCII-) and an inverting second-generation current conveyor (ICCII). The first proposed circuit consists of one CCII- and a voltage follower (VF) employing two NMOS transistors while the second proposed circuit is composed of an ICCII and an inverting voltage follower (IVF) including two NMOS transistors. Each circuit contains two resistors, and single grounded capacitor, which is attractive for integrated circuit realization. No active and passive component matching conditions are required for the realization of the proposed capacitance multiplier circuits. The simulation results are included to confirm the theory.

Parasitic Extraction for Heterogeneous Face-to-Face Bonded 3-D ICs

Face-to-face (F2F)-bonded 3-D ICs provide higher vertical interconnection densities and cost-effective solutions compared to face-to-back-bonded 3-D ICs. With a bumpless direct-copper-bonding process, the die-to-die distance is significantly reduced to enable a finer F2F via pitch. Unfortunately, this increases interdie parasitic components that require careful extraction. Heterogeneous 3-D ICs are built using dies from different design houses and foundries, potentially using different technology nodes. They again require accurate parasitic extraction across multiple dies and thus call for new computer-aided design methodologies with intellectual property protection. We, for the first time, provide a comprehensive study of three full-chip parasitic extraction methods for homogeneous and heterogeneous F2F 3-D ICs. The traditional die-by-die extraction ignores any interdie coupling and underestimates the total coupling capacitance by 35%. The holistic extraction that takes all dies into account provides the most accurate results at the cost of high layout-versus-schematic (LVS) complexity. The in-context extraction, taking only the interface layers from the neighbor dies, offers tradeoffs between accuracy and complexity. Our study shows that with only two interface layers, in-context extraction offers highly accurate and efficient extraction results with 0.9% error for the total ground capacitance and 0.8% for the total coupling capacitance.

A systematic realization of third-order quadrature oscillator with controllable amplitude

A systematic realization of third-order quadrature oscillator using a voltage-mode non-inverting lowpass filter and a voltage-mode inverting lossless feedback integrator is presented in this paper. The proposed circuit consists of two multiple-output differential voltage current conveyor transconductance amplifiers (MO-DVCCTAs), two grounded resistors and three grounded capacitors. The new circuit provides three quadrature voltage outputs, two high-impedance quadrature current outputs, and one high-impedance current output with controllable amplitude, simultaneously. When the input bias current of the first MO-DVCCTA is a modulating signal, the circuit can generate amplitude modulation or amplitude shift keying signals. The condition of oscillation and the frequency of oscillation can be controlled independently through grounded resistors. The proposed circuit only uses grounded capacitors and grounded resistors, which can be easily implemented as an integrated circuit. The experimental results and H-Spice simulation results are given to confirm the theoretical analysis.

Temperature-Dependent Modeling and Crosstalk Analysis in Mixed Carbon Nanotube Bundle Interconnects

The temperature-dependent circuit modeling and performance analysis in terms of crosstalk in capacitively coupled mixed carbon nanotube bundle (MCB) interconnects, at the far end of the victim line, have been analyzed with four different structures of MCBs (MCB-1, MCB-2, MCB-3 and MCB-4) constituted under case 1 and case 2 at the 22-nm technology node. The impact of tunneling and intershell coupling between adjacent shells on temperature-dependent equivalent circuit parameters of a multi-walled carbon nanotube bundle are also critically analyzed and employed for different MCB structures under case 1. A similar analysis is performed for copper interconnects and comparisons are made between results obtained through these analyses over temperatures ranging from 300 K to 500 K. The simulation program with integrated circuit emphasis simulation results reveals that, compared with all MCB structures under case 1 and case 2, with rise in temperature from 300 K to 500 K, crosstalk-induced noise voltage levels at the far end of the victim line are found to be significantly large in copper. It is also observed that due to the dominance of larger temperature-dependent resistance and ground capacitance in case 1, the MCB-2 is of lower crosstalk-induced noise voltage levels than other structures of MCBs. On the other hand, the MCB-1 has smaller time duration of victim output. Results further reveal that, compared with case 2 of MCB, with rise in temperatures, the victim line gets less prone to crosstalk-induced noise in MCB interconnects constituted under case 1, due to tunneling effects and intershell coupling between adjacent shells. Based on these comparative results, a promising MCB structure (MCB-2) has been proposed among other structures under the consideration of tunneling effects and intershell coupling (case 1).

Electronically Tunable Current Controlled Current Conveyor Transconductance Amplifier-Based Mixed-Mode Biquadratic Filter with Resistorless and Grounded Capacitors

A new electronically tunable mixed-mode biquadratic filter with three current controlled current conveyor transconductance amplifiers (CCCCTAs) and two grounded capacitors is proposed. With current input, the filter can realise lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) responses in current mode and LP, BP and HP responses in transimpedance mode. With voltage input, the filter can realise LP, BP, HP, BS and AP responses in voltage and transadmittance modes. Other attractive features of the mixed-mode biquadratic filter are (1) the use of two grounded capacitors, which is ideal for integrated circuit implementation; (2) orthogonal control of the quality factor (Q) and resonance angular frequency (ωo) for easy electronic tenability; (3) low input impedance and high output impedance for current signals; (4) high input impedance for voltage signal; (5) avoidance of need for component-matching conditions; (6) resistorless and electronically tunable structure; (7) low active and passive sensitivities; and (8) independent control of the voltage transfer gains without affecting the parameters ωo and Q.

Novel Integrated CM Inductor for Single-Phase Power Converters With Reduced EMI

Ground leakage current and electromagnetic interference noise are important challenges during design of grid-connected power converters. Use of common-mode (CM) choke helps to mitigate these issues. A common practice is to use a separate CM filter and a differential mode LCL filter. In this paper, an integrated CM inductor (ICMI) is proposed in which the LCL filter boost inductor and the CM choke are combined into a single component. This results in a reduction in the number of magnetic components required to build the power converter. Steps involving design of the ICMI are provided. The proposed ICMI is fabricated in the laboratory. Experimental test are carried out on a 5-kW single-phase grid-connected power converter to validate the effectiveness of the proposed ICMI. The results show that the use of proposed ICMI along with an added ground capacitor in the power circuit as a CM filter can reduce the electromagnetic interference noise level up to 30 dB.

Voltage-mode biquadratic filters using single DDCCTA

This paper presents two voltage-mode universal biquadratic filters based on a single differential difference current conveyor transconductance amplifier (DDCCTA). Each of the proposed circuits comprises a single DDCCTA combined with passive components that can realize lowpass (LP), highpass (HP), bandpass (BP), bandstop (BS), and allpass (AP) filtering responses from the same configuration. The first proposed configuration can be used as either a high-input impedance single-input four-output multifunction filter or three-input four-output universal filter. The second proposed circuit with single-input five-output is slightly modified from the first proposed configuration that can simultaneously realize LP, HP, BP, BS, and AP filtering responses. The proposed circuits enjoy the features of orthogonal tunable of resonance angular frequency and quality factor, only using grounded capacitors, and low active and passive sensitivities. Experimental and H-Spice simulation results are given to confirm theoretical analyses.

New Fully-Uncoupled Current-Controlled Sinusoidal Oscillator Employing Grounded Capacitors

A new electronically-controllable fully-uncoupled sinusoidal oscillator, employing four second generation current-controlled conveyors (CCCIIs) and two grounded capacitors, is presented. The oscillation frequency and condition of oscillation are totally uncoupled and electronically adjustable. The circuit has low sensitivities and a high frequency stability factor. SPICE simulation results confirm the validity of the proposed oscillators.

Equivalent Noise Source: An Effective Method for Analyzing Common-Mode Noise in Isolated Power Converters

The interwinding capacitance of the transformer and the primary-side circuit nodes to ground capacitance are critical coupling path for common-mode (CM) noise in isolated power converters. In order to analyze the CM noise, the transformer interwinding capacitance is usually equivalent to lumped capacitance. In this paper, a generalized lumped capacitance model for constructing the CM noise equivalent circuit that is valid at low frequencies is derived. By simplifying the CM noise equivalent circuit based on Thevenin’s theorem, the equivalent noise source (ENS) for CM noise is proposed. The ENS is expressed by a linear combination of voltages in the converter, where the coefficients of these voltages are determined by transformer winding structure and the circuit configuration. With the help of ENS, the CM noise of the converter under different circuit configuration can be systematically analyzed and conveniently compared, which develops an effective reference for selecting a proper circuit configuration. Finally, the lumped capacitance model and the ENS for CM noise are verified by the experimental results.

Tunable Voltage-Mode Bandpass Biquad Synthesis Using NAM Expansion Method

The synthesis of voltage-mode parameter tunable biquadratic bandpass filters using grounded capacitors is presented. To easily construct high-order filters, the synthesis of voltage-mode cascadable tunable biquadratic bandpass filters is also indicated. The synthesis procedure is based on the nodal admittance matrix (NAM) expansion method using nullor–mirror pathological elements. The synthesis of filters using grounded capacitors is considered since it is helpful for easing the elimination/accommodation of various parasitic effects for monolithic integration. The Q factor of the derived filters can be adjusted without changing the natural frequency, so the high-Q bandpass filters are attainable. The workability of some synthesized circuits is verified by HSPICE simulations.

A First-Order Fully Cascadable Current-Mode Universal Filter Composed of Dual Output CCIIs and a Grounded Capacitor

In this paper, a new first-order current-mode (CM) universal filter employing two dual output second-generation current conveyors (DO-CCIIs), one resistor and a grounded capacitor is proposed. The proposed filter has low input and high output impedances; thus, it can be easily connected with other CM circuits. It can simultaneously realize first-order low-pass (LP) and all-pass (AP) responses and can provide high-pass (HP) response with interconnection of LP and AP responses. It can be tuned electronically by replacing with dual output second-generation current controlled conveyors (DO-CCCIIs) instead of DO-CCIIs and removing the resistor. It has only a resistor but no capacitor connected in series to X terminal of DO-CCII; accordingly, it can be operated at high frequencies. Also, it does not need any critical passive component matching conditions and cancellation constraints. A number of simulation results based on SPICE program are included to exhibit performance, workability and effectiveness of the proposed filter configuration.

小型化交指型LTCC带通滤波器设计

本文提出了一种基于LTCC技术的小型化交指型带通滤波器的设计方法，通过在交指线末端加载对地电容，压缩了谐振器尺寸，将对地电容布置在分立的空间中，避免了电容间的耦合干扰，引入非相邻谐振器间交叉耦合，在通带两端各产生一个零点，提高了边带抑制。设计了一款中心频率2.3 GHz，带宽200 M交指型带通滤波器，插损小于2.5 dB，通带波动优于0.5 dB，利用三维仿真软件HFSS建模及优化，并利用LTCC工艺加工制造，尺寸仅为3 mm × 2 mm × 1.5 mm，经测试，实际测试曲线与仿真曲线符合较好，验证了设计的有效性。 A method of designing miniaturized interdigital bandpass filter based on LTCC technology was proposed, through loading ground capacitance at the end of interdigital transmission line, com-pressed the volume of resonator, to arrange the ground capacitance in discrete space, avoided the coupling interference between themselves, then cross-coupling was introduced between nonad-jacent resonator, generated two transmission zeros on both sides of the passband and improved the sideband suppression. A interdigital bandpass filter with center frequency 2.3 GHz and bandwidth 200 M was designed, the insertion loss was less than 2.5 dB, passband fluctuation was better than 0.5 dB, HFSS was used to construct the 3D model and optimize the simulated results, then fa-bricated the filter with LTCC technology, the size was only 3 mm × 2 mm × 1.5 mm, the measured curves confirmed well with the simulated curves, verified the validity of the design.

Effect of transformer symmetry on intrabody communication channel measurements using grounded instruments

Transformers with one winding terminal symmetrical with respect to ground (capacitances between their terminals and ground are the same) are referred to as balun transformers, and are often used for decoupling in the measurements of the intrabody communication (IBC) system transmission characteristics. We measured IBC system amplitude and phase transmission characteristics using three types of galvanic decouplers: non-symmetric RF transformers, balun transformers with center tap grounded and balun transformers with center tap floating. Four possible electrode configurations (AA, AB, BA, and BB) and four electrode arrangements (GSGS, GSSG, SGGS, and SGSG), result in a total of 16 measurement scenarios for each of three measurement setups. We showed that the change in the measured amplitude for different signal and ground electrode arrangements while measuring with non-symmetric transformers is influenced by the transformer symmetry to the ground, and not the capacitive intrabody communication transmission characteristics. The change of the amplitude in case symmetric balun transformers are used is negligible for practical purposes.

Elimination of the effect of bottom-plate capacitors in C-2C DAC using a layout technique

An efficient layout technique is proposed to eliminate the effect of the bottom-plate capacitors in a C-2C Digital to Analog Converter (DAC). Using this technique, the bottom-plate capacitors of 2C capacitors in the C-2C structure are placed in parallel with 1C capacitors. Then, the effect of the bottom plate capacitors is nulled by modifying the size of the main 1C capacitors. Hence, avoiding the complexity of calibration, this technique can preclude the effect of the bottom-plate to ground capacitance. Statistical simulations prove that the proposed technique is robust to non-ideal effects such as mismatch or parasitic capacitors. A 10-bit C-2C DAC is modeled in COMSOL Multiphysics using the TSMC 90nm technology parameters to demonstrate the proposed method. Simulation results prove that the peak of INL and DNL are improved by factors of 66 and 116 compared to the conventional C-2C DAC. Moreover, using this technique multi-layer capacitors can be used along with MIM capacitors to increase the capacitance density. In a 90nm CMOS technology, the area of the capacitors in a 10-bit C-2C DAC is reduced by more than 63%.

New current-feedback operational-amplifier based sinusoidal oscillators with explicit current outputs

Using a unified representation for the two current-feedback operational-amplifiers (CFOAs) based sinusoidal oscillators, new structures and circuits of this type are systematically discovered. Three catalogues for three different structures with each structure realizing 17 oscillator circuits are presented. Some of the new circuits are enjoying the attractive features of using grounded capacitors and/or independent/orthogonal tuning for the frequency and condition of oscillation. However, the classification of independent/orthogonal tuning may be misleading as it is based on using the Barkhausen criterion. Therefore, it is shown that using the roots of the characteristic equation of a specific oscillator circuit; while not leading to accurate results, may avoid any misleading conclusion regarding the orthogonal tuning of the frequency and condition of oscillation. Experimental results using the AD844 CFOA are included.

Enhanced Grounded Capacitor Multiplier and Its Floating Implementation for Analog Filters

A current-mode capacitor multiplier using a differential amplifier with exponential current scaling is presented. The proposed circuit consists of a reduced implementation of a multiplier based on differential amplifiers with decreased need for parameter matching compared with a conventional structure, thus reducing the power consumption and silicon area. It includes an exponential current scaling scheme to provide a large multiplication factor. Additionally, the differential input stage offers the capability to implement a floating realization for bidirectional applications. The circuit operates with a minimum supply of a gate–source voltage and two saturation voltages of a transistor, making it suitable for low-voltage applications. Experimental results from a fabricated prototype in 0.5-μm technology show the operation of the grounded and floating realizations, as well as their performance when implemented in a second-order low-pass analog filter.

Emulation of a constant phase element using operational transconductance amplifiers

The concept of emulating a constant phase element by an active scheme is presented in this work. Starting from a novel setup where the characteristics of the element could be easily derived, the emulation of the constant phase element is performed through a scheme that employs a differentiator and a voltage-to-current converter. The implementation of this scheme is done using operational transconductance amplifiers as active elements and uses grounded capacitors. The proposed emulator is accurate over five decades of frequency from (0.1 to 10 kHz) and offers independent electronic tunability of the constant phase element (i) magnitude (ii) phase angle and (iii) bandwidth of operation. Constant phase element designs currently available in the literature rely on using fixed passive RC ladder networks and thus lack flexibility and tunability. The behavior of the proposed design is verified through post-layout simulation results using Cadence and the 0.35 μm CMOS process Design Kit provided by the Austrian Micro Systems.