Integrated-Circuit Fabrication. Active Devices in Integrated Circuits. Passive Components: Diodes, Resistors, and Capacitors. Bias Circuits. Basic Gain Stages. Analog Design with MOS Technology. Operational Amplifiers. Wideband Amplifiers. Analog Multipliers and Modulators. Voltage Regulators. Integrated-Circuit Oscillators and Timers. Phase-Locked-Loop Circuits. Integrated-Circuit Filters. Data Conversion Circuits: Digital-To-Analog Converters. Data Conversion Circuits: Analog-To-Digital Converters. Index.

Bipolar and MOS Analog Integrated Circuit Design

Two second-generation current conveyor (CCII+)-based resistance-capacitance (RC) square/triangular waveform generators, which have been derived from their voltage-mode op-amp-based schemes, with independent control of frequency are presented in this paper. Each configuration consists of two positive second-generation conveyors (CCII(+)-ldquoArdquo and CCII(+)-ldquoBrdquo), three resistors, and one floating capacitor that is responsible for better linearity. The frequency of the waveform generators can independently be adjusted with any passive device. The circuits were built with commercially available current feedback operational amplifiers (AD844) and passive components used externally and tested for waveform generation and tunability. The measured results included in the paper show excellent linear variation of frequency as compared with existing reported configurations over the range from 25 Hz to 260 kHz. The configurations that are suitable for very large scale integration (VLSI) realization find application in capacitive and resistive sensors and in neuro-fuzzy systems.

Current Conveyor-Based Square/Triangular Waveform Generators With Improved Linearity

The current paper presents a novel Schmitt trigger using two second-generation current conveyors and four resistors and its application as a relaxation oscillator. The performance of the proposed circuit is examined using Cadence and the model parameters of a 0.6µm CMOS process. The obtained results demonstrate excellent agreement with the theoretical values. The measured results based on commercially available current feedback operational amplifiers (AD 844 AN) are included and the non-idealities are also examined. The topology reports low sensitivities and has features suitable for VLSI implementation. Copyright © 2010 John Wiley & Sons, Ltd.

(The current paper presents a novel Schmitt trigger using two second-generation current conveyors and four resistors and its application as a relaxation oscillator. The performance of the proposed circuit is examined using Cadence and the model parameters of a 0.6 m CMOS process. The obtained results demonstrate excellent agreement with the theoretical values.)

A novel current conveyor-based Schmitt trigger and its application as a relaxation oscillator

This article presents the new current-mode counterclockwise (CCW) and clockwise (CW) Schmitt triggers based on multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA). The circuit descriptions are very simple, each construction consists of only single MO-CCCDTA, without any external passive element. The hysteresis and amplitude of the output current of each Schmitt trigger can be tuned independently/electronically by input bias currents. In addition, the output signals are independent of the thermal voltage (VT). The applications as a relaxation oscillator, triangular/square wave generator, pulse width modulation and monostable multivibrator are given here to display the usefulnesses of the presented Schmitt triggers. The PSpice simulation and experimental results are depicted, and agree well with the theoretical anticipation. The maximum power consumptions of CCW and CW Schmitt triggers are approximately 235 and 191 μW, respectively, at ±1.5 V supply voltages.

http://te.kmutnb.ac.th/~msn/stmcccdtaanalognew.pdf

Fully and electronically controllable current-mode Schmitt triggers employing only single MO-CCCDTA and their applications

This paper presents some interesting new applications in the field of analog signal processing focused on signal generation. A novel modifications of recently developed and studied family of active elements, called voltage differencing buffered amplifier (VDBA) and voltage differencing inverted buffered amplifier (VDIBA) are discussed. Our attention is focused on simple application of active elements like dual output VDBAs (DO-VDBAs) and fully balanced VDBAs (FB-VDBAs), where one or two z terminals and always voltage outputs of both polarities are present. The last modification of VDBA allows additional electronic control of voltage gain in frame of active element except standard transconductance control. Discussed active elements were used to build very simple multiphase oscillators with minimal complexity as a simple non-tunable alternative to classical conceptions utilizing lossy integrators in phase-shifted loop. Linearly tunable quadrature differential mode (balanced) oscillator or balanced simple triangle and square wave generator were chosen as other useful examples. Features of proposed circuits are discussed and selected examples verified and evaluated by computer simulations with appropriate low-voltage TSMC 0.18 m CMOS technology models.

Voltage Differencing Buffered/Inverted Amplifiers and Their Applications for Signal Generation

A triangular/square-wave generator with current-controllable frequency and amplitude is presented. The generator utilizes operational transconductance amplifiers as switching elements. A prototype circuit built with commercially available components exhibits less than 2% nonlinearity in its current-to-frequency transfer characteristic from 1 to 10 kHz and -150 ppm//spl deg/C temperature coefficient of frequency over 15/spl deg/C to 35/spl deg/C. The circuit also displays wide sweep capability and good linearity of current to amplitude. The application of the circuit to a current-controllable saw-tooth waveform generator is also presented.

Triangular/square-wave generator with independently controllable frequency and amplitude

A monostable multivibrator with current-controllable pulse width and height is presented. The circuit utilizes three operational transconductance amplifiers (OTAs) as switching elements. Two of them compose a Schmitt trigger and the other forms an integrator. The theory of operation is presented and experimental results are used to verify theoretical predictions. A prototype circuit built with commercially available components exhibits less than 4.4% nonlinearity in its current-to-pulse width transfer characteristic from 200 to 1600 /spl mu/s and 20 ppm//spl deg/C temperature coefficient of width over 0/spl deg/C to 75/spl deg/C. The circuit also displays good linearity of current-to-pulse height and 1200 ppm//spl deg/C temperature coefficient of height.

Current-controllable monostable multivibrator using OTAs

A new bipolar linear transconductor for low-voltage low-power signal processing is proposed. The proposed circuit has larger input linear range and smaller power dissipation when compared with the conventional bipolar linear transconductor. The experimental results show that the transconductor with a transconductance of 50 μS has a linearity error of less than 0.02% over an input voltage range of ′2.1 V at supply voltages of ′3 V. The power dissipation of the transconductor is 3.15 mW.

A low-voltage low-power bipolar transconductor with high-linearity

공정(process:P), 전압(voltage :V), 그리고 온도(temperatuire:T) 변화에 영향을 적게 받고 디지털적으로 주파수 보정이 가능한 CMOS RC 발진기를 설계하였다. 이 발진기는 4개의 스위치, 2개의 비교기와 커패시터, 래치(latch) 회로로 구성된다. 동작원리는 좌우 2개의 CMOS 스위치에 의해 커패시터에 공급전압 VDD로 충전, (VDD-VR) 전압까지 방전, 그리고 비교기에서 충·방전 시간을 검출하여 래치회로로 보내어 발진을 시키는 것이다. 발진기에서 사용되는 방전전류, 비교기의 바이어스 전압, 그리고 보정회로의 바이어스 전류가 공급전압과 온도에 영향을 적게 받도록 바이어스 회로를 설계하였다. 또한, 공정변화에 대한 영향을 줄이기 위해 디지털적으로 저항값을 가변시켜 발진주파수를 보정시켰다. 시뮬레이션 결과, 제안한 RC 발진기의 발진주파수는 공정(T) 변수, 공급(V) 전압변화, 온도(T) 변화에 대해서 최대 ±2% 이내의 변화율을 갖고 있다는 것을 확인하였다. 제안한 회로는 0.35㎛ CMOS 공정 파라미터를 사용하여 설계 및 검증하였으며, 공급전압이 3.5V일 때 소모전력은 2㎽를 나타낸다. 

Hyeong-Woo Cha

Papers

Triangular/square-wave generator with independently controllable frequency and amplitude

Current-controllable monostable multivibrator using OTAs

A low-voltage low-power bipolar transconductor with high-linearity

Design of CMOS RC Oscillator with Low PVT Effect and Digitally Frequency-calibrated

New temperature-independent bipolar voltage reference circuit with its output controllable