CMOS realization of single-resistance-controlled and variable frequency dual-mode sinusoidal oscillators employing a single DVCCTA with all-grounded passive components

In this paper, two new designs are proposed for sinusoidal oscillators based on a single differential voltage current conveyor transconductance amplifier (DVCCTA). Each of the proposed circuits comprises a DVCCTA combined with passive components that simultaneously provides both voltage and current outputs. The first circuit is a DVCCTA-based single-resistance-controlled oscillator (SRCO) that provides independent control of the oscillation condition and oscillation frequency by using distinct circuit parameters. The second circuit is a DVCCTA-based variable frequency oscillator (VFO) that can provide independent control of the oscillation frequency by adjusting the bias current of the DVCCTA. In this paper, the DVCCTA and relevant formulations of the proposed oscillator circuits are first introduced, followed by the non-ideal effects, sensitivity analyses, frequency stability discussions, and design considerations. After using the 0.35-μm CMOS technology of the Taiwan Semiconductor Manufacturing Company (TSMC), the HSPICE simulation results confirmed the feasibility of the proposed oscillator circuits.     

New canonic lossy inductor using a single CDBA and its application

A new lossy inductor (parallel R-L type) using single current differencing buffered amplifier (CDBA) is presented, which employs only two resistors and a grounded capacitor. The proposed lossy inductor is shown to be useful in realizing an oscillator circuit, which provides quadrature voltage outputs using only two CDBAs, three resistors and two grounded capacitors and offers independent control on condition of oscillation and frequency of oscillation up to a frequency of 61 MHz. Detailed non-ideal analysis including single-pole model for voltage and current gain has also been carried out. SPICE simulation results and experimental results based upon the CDBA constructed from commercially available IC AD844 have been included which confirm the practical workability of the proposed lossy inductor and quadrature oscillator circuit.     

基于高次谐波体声波谐振器的微波振荡器设计

基于高次谐波体声波谐振器(HBAR)的高品质因数(Q)值和多模谐振特性,设计了Colpitts和Pierce两种形式的微波振荡器。采用HBAR与LC元件组成谐振回路的方法,与放大电路构成反馈环路直接基频输出微波频段信号。Colpitts振荡器输出信号频率为980 MHz,信号输出功率为-4.92dBm,信号相位噪声达-119.64dBc/Hz@10kHz;Pierce振荡电路输出信号频率达到2.962GHz,信号输出功率为-9.77dBm,信号相位噪声达-112.30dBc/Hz@10kHz。     

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included.     

New voltage-mode universal filter and sinusoidal oscillator using only single DBTA

In this article, a new voltage-mode second-order universal frequency filter and sinusoidal oscillator using only single differential-input buffered and transconductance amplifier (DBTA) is presented. The proposed voltage-mode filter structure using single DBTA and four passive elements can provide all standard filter functions, i.e. low-, band-, high-pass, band-stop, and all-pass without changing the circuit topology and enables independent control of the quality factor Q using single passive element. The circuit requires the minimal number of active and passive elements with no conditions for component matching. By slight modification of the proposed filter structure, the new DBTA-based sinusoidal oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded passive elements. The proposed sinusoidal oscillator employs only grounded capacitors. The passive and active sensitivities of all the proposed circuit configurations are low. PSPICE simulations using a BJT realisation of DBTA and experimental results based on commercially available amplifiers OPA860 and MAX436 are included, which prove the workability of the proposed circuits.     

Four new oscillators using operational transresistance amplifier

In this paper, four new sinusoidal waveform generators based on the operational transresistance amplifier (OTRA) are presented. The first proposed circuit is a minimum component RC sinusoidal oscillator circuit with one OTRA and a few passive components. The second and third proposed circuits consist of one OTRA and a few passive components, among them two passive components are connected to ground. These circuits are able to control the condition of oscillation and frequency of oscillation independently. The fourth proposed quadrature oscillator circuit uses two OTRAs as main active building blocks and a few external passive components to generate the oscillations. The IC AD844AN is adopted to implement the proposed circuits on a laboratory breadboard with external passive components. Both the SPICE simulation and experimental results are given to verify the theoretical analysis of the proposed circuits.     

Novel voltage/current-mode quadrature oscillator using current differencing transconductance amplifier

This letter proposes a new realization of voltage/current-mode (CM) quadrature oscillator (QO) using Current Differencing Transconductance Amplifier (CDTA) as the active element. The proposed circuit employs canonic number of components, namely two CDTAs, one resistor and two grounded capacitors. The oscillator is capable of providing two explicit quadrature current outputs and two quadrature voltage outputs. Moreover, the circuit enjoys the advantage of independent control of condition of oscillation (CO) and frequency of oscillation (FO). The non-ideal analysis and sensitivity study of the circuit has been carried out and the circuit exhibits a good sensitivity performance. B2SPICE simulation results are included that validate the working of the circuit.     

Precise Electronically Adjustable Oscillator Suitable for Quadrature Signal Generation Employing Active Elements with Current and Voltage Gain Control

A new oscillator suitable for quadrature and multiphase signal generation is introduced in this contribution. A novel active element, called the controlled gain-buffered current and voltage amplifier (CG-BCVA) with electronic possibilities for current and voltage gain adjustment is implemented together with a controlled gain-current follower differential output buffered amplifier (CG-CFDOBA) for linear adjustment of the oscillation frequency and precise control of the oscillation condition in order to ensure a stable level of generated voltages and sufficient total harmonic distortion. The parameters of the oscillator are directly controllable electronically. Simultaneous changes of two current gains allow linear adjusting of the oscillation frequency, and a controllable voltage gain is intended to control the oscillation condition. A detailed comparison of the proposed circuits with recently developed and discovered solutions employing the same type of electronic control is provided and shows the useful features of the proposed oscillator and utilized methods of electronic control. Behavioral models based on commercially available ICs have been used for experimental purposes. CMOS implementation of active elements was introduced and utilized for additional simulations and studies. Non-ideal analysis, Monte Carlo statistical evaluations of simulated models, and further analyses were performed for the exact determination of the expected results. Laboratory experiments confirmed the workability and estimated behavior of the proposed circuit as well.     

A Novel Single-Resistance-Controlled Sinusoidal Oscillator Employing Single Operational Transresistance Amplifier

A novel operational transresistance amplifier (OTRA)-based single-resistance-controlled sinusoidal oscillator (SRCO) is proposed. It uses single OTRA, three resistors and two capacitors. To the best knowledge of author, this is the first oscillator constructed with single OTRA. The oscillator circuit provides independent control of oscillation frequency without disturbing oscillation condition by a resistor. It has also low passive sensitivities. The oscillator circuit is insensitive to parasitic input capacitances and input resistances due to zero internally grounded input terminals of OTRA. PSPICE simulations are given to verify the theoretical analysis.     

Nanowatt operation of monolithic operational amplifiers†

A study was made of two micropowered operational amplifiers to determine degradation of unity gain frequency response, open-loop gain, and slow rate in amplifier circuits and maximum frequency of oscillation in Colpitts and Wein bridge oscillators as programmed. Quiescent current was reduced below specified operating levels into the nanoampere region.     

基于单个CDCTA的低压电控调谐电流模式多相位正弦振荡器的设计

提出了一种全新的电流模式多相位正弦振荡器电路。该电路仅使用一个电流差分级联跨导放大器(CDCTA)和接地无源元件,能产生n(n为奇或偶)个等相位差的电流信号,电路结构简单、工作电压低、输出阻抗高、振荡频率高,而且振荡条件和振荡频率独立可调。计算机CADENCE软件仿真和流片测试结果验证了理论分析的正确性。     

High-performance RF mixer and operational amplifier BiCMOS circuits using parasitic vertical bipolar transistor in CMOS technology

The electrical characteristics of the parasitic vertical NPN (V-NPN) BJT available in deep n-well 0.18-/spl mu/m CMOS technology are presented. It has about 20 of current gain, 7 V of collector-emitter breakdown voltage, 20 V of collector-base breakdown voltage, 40 V of Early voltage, about 2 GHz of cutoff frequency, and about 4 GHz of maximum oscillation frequency at room temperature. The corner frequency of 1/f noise is lower than 4 kHz at 0.5 mA of collector current. The double-balanced RF mixer using V-NPN shows almost free 1/f noise as well as an order of magnitude smaller dc offset compared with CMOS circuit and 12 dB flat gain almost up to the cutoff frequency. The V-NPN operational amplifier for baseband analog circuits has higher voltage gain and better input noise and input offset performance than the CMOS ones at the identical current. These circuits using V-NPN provide the possibility of high-performance direct conversion receiver implementation in CMOS technology.     

A novel circuit for dead angle compensation in the DC-to-DCconverter controlled by a magnetic amplifier

A novel circuit for compensating the dead angle in the DC-to-DC converter controlled by a magnetic amplifier is presented. The proposed circuit suppresses the dead angle so that the core loss may be reduced. The behavior of this circuit is explained analytically and a condition for compensation is derived theoretically. By adding this compensation circuit, excellent control characteristics of the converter are obtained without spoiling the current surge suppression characteristics of the magnetic amplifier     

A low-voltage sense amplifier with two-stage operational amplifier clamping for flash memory

A low-voltage sense amplifier with reference current generator utilizing two-stage operational amplifier clamp structure for flash memory is presented in this paper, capable of operating with minimum supply voltage at 1 V. A new reference current generation circuit composed of a reference cell and a two-stage operational amplifier clamping the drain pole of the reference cell is used to generate the reference current, which avoids the threshold limitation caused by current mirror transistor in the traditional sense amplifier. A novel reference voltage generation circuit using dummy bit-line structure without pull-down current is also adopted, which not only improves the sense window enhancing read precision but also saves power consumption. The sense amplifier was implemented in a flash realized in 90 nm flash technology. Experimental results show the access time is 14.7 ns with power supply of 1.2 V and slow corner at 125 ℃.     

A novel current-mode multiphase sinusoidal oscillator using MO-CDTAs

This article presents a novel current-mode multiphase sinusoidal oscillator. The oscillator can produce two groups of n output currents and one group of 2n output currents (n being even or odd) with equal amplitude and equal-phase space. The circuit only uses one multi-output current differencing transconductance amplifier and one grounded capacitor for each section, and is easy to integrate. Its oscillation condition and frequency can be electronically tuned linearly and independently, and its outputs possess high impedance. It is important that the multi-frequency oscillation in the oscillator is studied and a method for eliminating unnecessary oscillation is given. In addition, the inverting amplifier with the automatic gain control is employed to reduce the distortion of output signals. Finally, the frequency error is analysed and the simulated results are illustrated.     

Hybrid parametric amplifier

The letter proposes a hybrid parametric amplifier in which the signal circuit is a travelling-wave structure and the idling circuit is resonant. A simple expression for the available gain per section is calculated together with typical circuit values.     

High-output-impedance current-mode multiphase sinusoidal oscillator employing current differencing transconductance amplifier-based allpass filters

This article presents a multiphase sinusoidal oscillator using current differencing transconductance amplifier (CDTA)-based allpass filters. The oscillation condition and oscillation frequency can be orthogonally controlled. The proposed circuit provides 2n – phase signals (n≥2) that are equally spaced in phase and of equal amplitude. The circuit requires one CDTA, two resistors and one capacitor for each phase and no additional current amplifier. Owing to high-output impedances, the proposed circuit enables easy cascading in current-mode configurations. The effects of the nonidealities of the CDTA-allpass sections were also studied. The results of PSpice simulations are presented, demonstrating their consistency with theoretical assumptions.     

A dual-phase-controlled dynamic latched amplifier for high-speedand low-power DRAMs

A dual-phase-controlled dynamic latched (DDL) amplifier for a differential data transfer scheme designed to achieve both high speed and low power in DRAMs is described. This circuit reduces the excessive operating margin caused by device fluctuations by using a pair of dynamic latched amplifiers, controlled by a dual-phase clock, to automatically correct the output data. Two circuit technologies are used in the DDL amplifier to achieve 200-MHz operation in a 1-Gb SDRAM using 0.13-μm technology: a cycle-time-progressive control circuit that increases the operating frequency and a shared DDL amplifier technique that reduces the area penalty of the DDL amplifier. These techniques and circuits reduce the access time to 10 ns, which is 1.2 ns less than that of the conventional dynamic amplifier, while also reducing the operating current to less than 10% that of the static amplifier     

Clocked power control circuit for inductively powered devices

Inductively powered devices are finding increasing use in many applications, such as biomedical implants and radio frequency identification (RFID) tags. In these systems, because of transmitter and receiver movements, the receiver coil may get close to the transmitter coil, which results in more than needed power delivered to the receiver load. This increases heat dissipated in the receiver circuit. In order to avoid overheating the receiver in such a high magnetic field (short coil separation distance) condition, the received power should be monitored and controlled. This paper introduces a clocked power control circuit integrated in the implant receiver, which is an independent, automatic power adjustment solution to limit heat dissipation with response to the coil separation distance. In this circuit, the rectified voltage across the load is monitored, and converted to a digital representation to selectively detune the receiver inductor-capacitor (LC) tank. To demonstrate this concept, a design example applied to inductively powered implants is given. Measurements on the prototype with a varied coil separation distance validate the desired power control functionality. Less power dissipation is achieved for the receiver compared to no power control condition.