仿真电流镜输入偏置电流的方法

仿真电流镜的输出偏置电流是很简单的.您只需加上输入电流和测量输出电流,再计算它们的差就行了.然而,输出偏置电流不等于输入偏置电流,尤其当电路不是1:1电流镜时.高度精确地仿真输入偏置电流是比较复杂的.假设您正在处理1:1电流镜,并且想知道需要什么样的输入电流来得到10μA输出电流.在理想情况下,假如输入偏置电流为零,则输入电流是10μA.然而,由于双极晶体管的β值有限、输出阻抗有限以及失配等原因,输入偏置电流不等于零.图1所示设计,仿真精度高,仿真时间短.     

Very accurate dynamic current mirrors

A highly accurate current mirror based on dynamic analogue techniques has been integrated and measured. This principle is insensitive to transistor mismatch and allows the reproduction of input current in any desired integer ratio, at the output.<>     

Ultra low-voltage CMOS current mirrors

In this paper we present an ultra low-voltage bidirectional and continuous time current mirror based on clocked semi-floating-gate transistors. The current mirror may be used with supply voltages down to 250 mV and frequencies up to several hundred MHz. The simulated data presented are obtained using the Spectre simulator provided by Cadence and valid for a 90 nm TSMC CMOS process.     

Gain programmable current mirrors based on current steering

A new and compact scheme for a programmable current mirror is introduced. It features linear gain continuously adjustable in a wide range. In such a scheme differential pairs are used as current steering elements in order to provide gain programmability. All mirror transistors operate in strong inversion. Implementation of a linear OTA/multiplier is discussed. Experimental verification of the proposed scheme is provided.     

Symbolic analysis of analog circuits containing voltage mirrors and current mirrors

The pathological elements voltage mirror (VM) and current mirror (CM) have shown advantages in analog behavioral modeling and circuit synthesis, where many nullor-mirror equivalences have been explored to design and to transform voltage-mode circuits to current-mode ones and viceversa. However, both the VM and CM have not equivalents to perform automatic symbolic circuit analysis. In this manner, we introduce nullor-equivalents for these pathological elements allowing to include parasitics and to perform only symbolic nodal analysis. The nullor-equivalent of the CM is extended to provide multiple-outpus (MO-CM). Finally, two active filters containing VMs, CMs and MO-CMs are analysed to show the usefulness of the models.     

A second current controlled current conveyor realization using Wilson current mirrors

The paper proposes a Wilson current mirror with double outputs and a bipolar second current controlled current conveyor (CCCII) circuit based on Wilson mirrors. The performance principle of the circuits is analysed and experiment results are given. The CCCII circuit has the following merits: high trace accuracy of voltage and current; high current output impedance; and good current stability.     

Power voltage current convertor using quasi complementary MOSFET current mirrors

A voltage current convertor is described having a quasi complementary class AB architecture that is particularly suited to implementation using discrete power MOSFETs. High-voltage mirror designs are presented, enabling the construction of sources with kilovolt compliance range, tens of watts of output power and greater than 100 kHz bandwidth. GΩ output impedance and distortion below 1% can be obtained with no trimming or transistor matching.     

A full-wave rectifier using a current conveyor and current mirrors

The realization of a full-wave rectifier using a current conveyor and current mirrors is presented. The proposed rectifier is composed of a voltage-to-current converter, a current mode full-wave rectifier, and a current-to-voltage converter. A voltage input signal is changed into a current signal by the voltage-to-current converter. The current mode full-wave rectifier rectifies this current signal resulting in the current full-wave output signal that is converted into a voltage full-wave output signal by one grounded-resistor. The theory of operation is described. The simulation and experiment results are used to verify the theoretical prediction. Simulated results show that the proposed rectifier yields the minimum voltage rectification to 94µV. Experimental results demonstrate the performance of the proposed rectifier for 50mV_peak signal rectification.     

Universal biquad filters using low-voltage current mirrors

Novel Single Input Multiple Output (SIMO) and Multiple Input Single Output (MISO) current-mode universal biquad topologies are introduced in this paper. The proposed topologies have been realized by employing low-voltage current mirrors as active elements. As a result, an absence of resistors is achieved in the derived filter topologies; also only grounded capacitors are required. The resonant frequency of the filters can be electronically controlled by an appropriate dc current. In addition, the derived filters offer the feature of orthogonal adjustment between the resonant frequency and Q factor. The behavior evaluation of the proposed filters has been performed through a test chip prototype fabricated in AMS 0.35 μm CMOS technology.     

Low voltage current mirrors with enhanced bandwidth

This paper presents an improved low voltage cascode and flipped voltage follower (FVF) based current mirror with the enhancement of the bandwidth obtained by using a compensation resistor between the gates of the primary transistor pair. In this technique a carefully determined resistance is used in the diode connected MOS transistor of the current mirror for enhancing the bandwidth. Active realization of the compensation resistance using MOS operating in the triode region has also been applied to both the cascode and FVF based current mirror circuits. The proposed circuits have been simulated using PSpice for 0.25 μm CMOS technology and the obtained results are compared with their uncompensated topologies to show their effectiveness.     

Analysis and improvements of accurate dynamic current mirrors

The possibility of realizing highly accurate dynamic current mirrors based on dynamic analog techniques and improvements thereof is considered. These current mirrors, which memorize the input current, are insensitive to transistor mismatch, whereas for conventional current mirrors, the accuracy is limited by the achievable matching. Different current mirror structures are presented, the interfacing parameters are shown, and their influence is explained. The dominant transients occurring during switching are shown. Improvements which allow for increases in the performance of dynamic current mirrors are proposed, and experimental results are shown     

Linearisation of high-ratio, wide-range bipolar current mirrors

A new design strategy for implementing bipolar current mirrors with a high input to output ratio and a wide current range is presented. The strategy is based on a known area efficient topology. The new strategy improves the linearity of the current mirror at high currents.<>     

Algorithmic analogue/digital convertor based on current mirrors

An algorithmic analogue/digital convertor using current rather than voltage as the signal is proposed. A 6-bit prototype was fabricated using a standard 3 μm CMOS process. The circuit exhibited a sampling rate of 200 kHz while only requiring 0.38 mm² of chip area and 4.65 mW of power, making it well suited for use in larger VLSI systems     

Accurate switched-current ladder filters based on active current mirrors

Describes the design of switched-current ladder filters based on active current mirrors, and the dependency of the filter characteristic on current mirror implementation from both simulations and prototype measurements. Experiments show that the proposed current mirror improvements are necessary for meeting a given filter specification.<>     

CMOS current mirrors with reduced input and output voltagerequirements

A CMOS current mirror with lower than V/sub DS(sat/) input voltage requirement is presented. It is shown that the structure can be modified to provide cascode-type output resistance for output voltages even lower than 2V/sub DS(sat/). The topology of the proposed current mirror allows low distortion operation from a single 1.5 V supply, which makes it attractive for low-voltage applications     

Worst case estimate of mismatch induced distortion in complementaryCMOS current mirrors

Mismatching between the MOS transistors in a current mirror causes harmonic distortion. In a complementary class AB current mirror, mismatching of threshold voltages, geometries and transconductance parameters causes a distortion which cannot be eliminated by circuit techniques but which can be reduced by careful device matching. In this Letter, the author presents a worst case estimate of the harmonic distortion introduced by device mismatch     

A 6-bit digital to analogue converter based on current mirrors

In this article, a digital to analogue converter (DAC) based on multi-weighted current sources is proposed. This research requires only three kinds of current sources for a 6-bit DAC. The proposed DAC is implemented by 0.18?µm CMOS technology. The post-layout simulations of integral nonlinearity and differential nonlinearity are 0.076 and 0.099?LSB, respectively. The core area of the chip is 640?µm². The DAC consumes 3.5?mW at the sample rate of 1.6?GHz with a supply voltage of 1.8?V. The specifications of the proposed DAC make it suitable for a portable device.     

Novel CMOS pipelined A/D convertor architecture using current mirrors

A novel current source-based CMOS pipelined A/D convertor architecture is presented. Compared to previous switched-capacitor realisations, the proposed architecture offers significant advantages in terms of power consumption, accuracy, simplicity and silicon area.<>     

Highly linear micropower class AB current mirrors using Quasi-Floating Gate transistors

A design approach to achieve low-voltage micropower class AB CMOS cascode current mirrors is presented. Both class AB operation and dynamic cascode biasing are based on the use of Quasi-Floating Gate transistors. They allow high linearity for large signal currents and accurately set quiescent currents without requiring extra power consumption or supply voltage requirements. Measurement results show that dynamic cascode biasing allows a wider input range and a linearity improvement of more than 23 dB with respect to the use of conventional biasing. A THD value better than −35 dB is measured for input amplitudes up to 100 times the bias currents. Two class AB current mirror topologies are proposed, with slightly different ways to achieve class AB operation and dynamic biasing. The proposed current mirrors, fabricated in a 0.5 µm CMOS technology, are able to operate with a supply voltage of 1.2 V and a quiescent power consumption of only 36 µW, using a silicon area <0.025 mm².     

Compact log-domain current mode integrator with hightransconductance-to-bias current ratio

A current mode, class AB, MOST log-domain integrator with high transconductance-to-bias current ratio is presented. Large and small time constants are achievable, maintaining a low bias current and low capacitance