A new true RMS-to-DC converter using up-down translinear loop in CMOS technology

In this paper a new true current-mode RMS-to-DC converter circuit based on a square-root-domain squarer/divider and simplified current-mode low pass filter is presented. The circuit is designed by employing up-down translinear loop and using of MOSFET transistors that operate in strong inversion saturation region. The converter offer advantages of two-quadrant input current, low circuit complexity, large dynamic range, low supply voltage (1.2 V) and immunity from the body effect. Moreover, the power consumption of the circuit for the maximum accepted input current is less than 100 μW and does not need extra biasing to inject current into transistors. The circuit has been simulated by HSPICE. The simulation results with 0.18 μm CMOS technology are seen to conform to the theoretical analysis and shows benefits of the proposed circuit. Simulation results show high performance of the proposed circuit.     

Current-controlled translinear impedance converter

A current-controlled impedance converter is described which is implemented using two translinear active devices: a current conveyor with unity gain and an adjustable differential current-mode amplifier. It has low parasitic input impedance and useful properties when the amplifier gain is near unity. To characterize the circuit, SPICE simulation results are given and discussed.     

A translinear-based true RMS-to-DC converter using only npn BJTs

A true rms-to-dc converter based on the explicit computation technique is proposed in this paper. Since the scheme utilizes translinear principle circuits to realize current-mode squarer, averaging and square root circuits, only npn bipolar junction transistors are required. The conversion circuit has wide-band frequency response and can be operated with single supply voltage at 2 V. PSPICE simulation and experimental results show good agreement with the theoretical predictions.     

具有快速动态响应的高稳定性电流型降压DC-DC转换器

提出了一种高稳定性的电流型DC-DC转换器.首先应用一种新型的电流型转换器的模型推导了控制环路的增益表达式,在分析其环路增益的基础上,提出了一种新颖的控制环路频率补偿的方法,从而使转换器的稳定性不受负载电流和电源电压变化的影响.其次应用这种新的频率补偿方法,使用0.5μm-CMOS工艺设计了一种电流模式的降压型转换器.仿真结果表明,该稳压器具有高度的稳定特性,其稳定性与负载和电源电压无关.并且由于这种新的频率补偿为环路提供了极高的带宽,所以该转换器具有优异的动态响应.其提供的全负载瞬态响应的建立时间小于5μs,过冲电压小于30mV.     

Adaptive Sliding-Mode Position Control for Piezo-Actuated Stage

The effect and design criteria of the input filter for buck converters with peak current-mode (PCM) control are researched using a novel system block diagram. With this diagram, a novel current loop transfer function is proposed to derive the design criteria that apply to designing the input filter. However, the input filter that is added to reduce electromagnetic interference will significantly change the dynamic property of the PCM-controlled buck converter. Therefore, the induced effect due to the input filter is examined. Finally, experimental results prove the accuracy of this deduction in both the circuit simulation and the circuit experiment.     

一种自适应斜坡补偿电路的设计与实现

提出了一种应用于电流型DC-DC转换器的自适应斜坡补偿电路.在分析斜坡补偿原理的基础上,提出了一种动态的斜坡补偿方法.该方法利用跨导线性环电路对补偿电流信号进行叠加,无需外加引脚引入输出电压,从而减小了芯片封装尺寸,以较少的电路使引入的斜坡补偿对系统带载能力和瞬态响应的负面影响减至最小.此电路采用UMC BCD工艺,在升压型DC-DC转换器2V转换8V的条件下,带载能力达到300mA,负载调整率为6.7mV/A.     

CMOS FTFN realisation based on translinear cells

A novel CMOS implementation of a four-terminal floating nullor (FTFN) is proposed. The presented FTFN circuit is based on two translinear cells and cascode current mirrors. It provides an alternative solution to differential amplifier-based FTFN circuits. Simulation results show that the proposed circuit is quite suitable for wideband, accurate and wide dynamic range current-mode signal processing. The feasibility of the circuit is tested on a current-mode bandpass filter structure     

New electronically tunable current-mode universal biquad filter using translinear current conveyors

In this study, a new electronically tunable current-mode universal filter with two inputs and two outputs employing one translinear current conveyor, one translinear current conveyor with controlled current gain and two grounded capacitors is presented. The proposed circuit offers the following attractive features: realisation of low-pass, band-pass, high-pass, band-stop and all-pass current responses from the same configuration; employment of the minimum active and passive components; no requirement of component matching conditions; independent current-control of the parameters natural frequency (ω_o) and quality factor (Q); low active and passive sensitivities; and high impedance output. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.     

Insensitive voltage-mode and current-mode filters with easily modifiable transfer functions

Two configurations for 2^nd order current-mode filters are introduced. The circuits, which exhibit low values for their active and passive sensitivies are implemented from two current conveyors. They are easily cascadable because they exhibit zero input impedance. Two voltage-mode implementations are then deduced from them. Depending on the passive components used, the circuit will be either a 2^nd order or a 3^rd order filter. Both the current-mode and voltage-mode implementations are characterized by easily modifiable transfer functions, without affecting ₀ and Q.SPICE simulation results, which confirm the theoretical analysis, are given and discussed for current conveyors implemented in a translinear form.     

Electronically tunable multiphase sinusoidal oscillator using translinear current conveyors

A new electronically tunable current-mode multiphase sinusoidal oscillator based on translinear current conveyors is presented. The proposed oscillator circuit, which employs only one translinear current conveyor and one grounded capacitor for each phase, can generate arbitrary N output current equal-amplitude signals that are equally spaced in phase (N being even or odd), all at high output impedance terminals. The frequency of oscillation and the condition of oscillation can be controlled electronically and independently through the bias current of the translinear current conveyor. The proposed structure also has simple circuitry, low-component count, and is highly suitable for integrated circuit implementation. The theoretical results were verified by PSPICE simulation. In addition, the modification of the N sinusoidal oscillators to construct a programmable multiphase oscillator is also discussed.     

Class AB current-controlled resistor for high performancecurrent-mode applications

A class AB current-controlled grounded resistor based on a translinear loop implemented from bipolar transistors is described. Simulation results show that its value is tunable from 30 to ~100 kΩ with frequency responses up to 100 MHz and beyond. With 12.5 V supply voltages, the total harmonic distortion (THD) is <1% for peak to peak magnitudes of the input current >2.5 times the value of the control current. To illustrate its suitability, the results of a controlled amplifier, using this resistor and operating in current-mode, are also given     

A biochemical translinear principle with weak inversion ISFETs

A weak inversion region is shown to exist in ion-sensitive field effect transistor (ISFET) sensors. It is therefore proposed that the ISFET and its chemically sensitive (ChemFET) counterparts be used as translinear elements in the synthesis of novel biochemical input stages which perform real-time mathematical manipulation of biochemical signals. A Biochemical Translinear Principle using weakly inverted ChemFETs is presented. A low-power current-mode input stage circuit is presented as an application of the principle. This yields a linear relation between drain current and hydrogen ion concentration valid over four decades. This paper demonstrates an important and necessary step toward biochemical VLSI.     

Novel bipolar differential input/output current-controlled current source

A new bipolar differential input/output current-controlled current source (CCCS) is described. The basic cell consists of a translinear array of six transistors with two bipolar inputs, and is suited for the input stage of a differential current-mode operational amplifier.     

A Square-Root Domain Differentiator Circuit

Companding circuits are very useful blocks for realizing low-voltage, high-frequency analog systems. They are implemented using the translinear principle and the quadratic/exponential I-V characteristic of MOS/BJT transistor. In this paper, a Square-Root Domain differentiator is proposed. It is constructed from an appropriate input stage that converts the input current into a compressed voltage at a capacitor's node, and simultaneously senses the capacitor's current. The overall configuration of the differentiator also includes a current geometric-mean circuit and a multiplier, both based on a translinear loop. An attractive characteristic of the proposed circuits is their immunity to body effect. HSPICE simulation results were used for evaluating the behaviour of the differentiator.     

An improved sampled-data current-mode-control model which explainsthe effects of control delay

A new sampled-data model for the current-mode controlled buck converter includes for the first time the effects of delay in the pulse-width-modulator (PWM). Modified z-transforms are used in this new model for constant frequency trailing-edge modulation. Realistic amounts of delay are found to be particularly significant when the buck converter is operating in the continuous conduction mode near the discontinuous conduction mode boundary. The new model is used to predict the loop gain measurements obtained with the “digital modulator” and with conventional measurement techniques. It is shown that conventional loop gain measurement techniques are insufficient to measure the loop gain in this region of operation. It is also shown that the digital modulator can add a significant amount of delay, thereby altering the loop gain of the circuit being measured. Unlike the case of a continuous system, PWM delay is found to significantly alter the low-frequency loop gain magnitude of this sampled-data system. The new model predicts the boundary condition for sub-harmonic instability, and reduces to Ridley's current-mode control model for the case of zero delay. Experimental corroboration is presented     

Negative impedance converter with a translinear implementation

A new negative impedance converter circuit, which is a current inversion type (I-NIC), is described. The basic cell consists of a mixed translinear loop comprising two pnp and two npn bipolar transistors. This cell is used in conjunction with a constant current source and two complementary current mirrors. The characteristics and the properties of the practical realization are presented and discussed. A new bandpass filter, which is a current processing circuit, using the I-NIC and a current-controlled current source (CCCS) are also introduced. Experimental results are given.     

Low-Voltage CMOS Nonlinear Transconductors and Their Application to Companding Current-Mode Filters

Two novel nonlinear CMOS transconductors that can be employed for building CMOS current-mode filters are presented and their performances compared to formerly proposed topologies aimed at the same goal. The first one is based on a previous topology proposed by the authors, where a new biasing procedure leads to an improved performance for low supply voltages. The second one follows a novel approach, based on cascading a transresistor and a transconductor. The analysis is complemented with a more general approach based on the identification of translinear loops present in the circuit. Both nonlinear transconductors can operate at supply voltages as low as one V _GS plus two V _DS of a saturated MOSFET. CMOS current-mode filters based on these blocks are built following companding techniques, and their correct operation is validated by simulation and experimental results.     

Sinusoidal frequency doubler and full-wave rectifier usingtranslinear current conveyor

A simple circuit design technique for realising both a sinusoidal frequency doubler and a full-wave rectifier, employing a translinear current conveyor and current mirrors as active circuit elements, is proposed. The implementation method uses the inherited translinear loop of the translinear current conveyor to perform frequency doubling and rectification. The performance of the scheme is demonstrated by PSPICE simulations     

一种高精度电流检测电路的设计

针对常用电流模式的升压转换器结构,提出了一种高精度电流检测电路。该电路在保证响应速度的前提下,通过增加电路环路增益,降低误差源等方法,提高检测电路的电流检测精度。与其他结构电路相比,有结构简单,响应速度快,电流检测精度高的优点。基于Chartered的0.35μm的3.3V/13.5V CMOS工艺,使用Spectre仿真器,对该电路进行了仿真与验证。结果证明,在输入电压为2.5V～5.5V,电感电流为100mA～500mA,工作频率为1MHz的情况下,能够正常稳定工作,并且电流精度高达93%。