A high-precision low-voltage bipolar current mirror circuit and its compensation for stability

A current mirror circuit is widely utilized as an important building block in analogue signal processing circuits. This paper describes a high-precision low voltage bipolar current mirror circuit. Well known current mirror circuits, such as a simple current mirror and a Wilson current mirror, have a trade-off between low-voltage operation and accuracy of the current gain. The accuracy of the proposed current mirror is high in spite of low current amplification factor (β) of transistors and large current output (or a large number of the multiple output). The current mirror circuit can operate at a 1V or less supply voltage. The high accuracy is realized by negative current feedback with high gain. Thus, the stability of the circuit and compensation methods are discussed. PSPICE simulation shows that the proposed current mirror circuit compensated using Miller components composed of a capacitor and a resistor is stable and can operate at a 1V supply voltage.     

高精度宽范围可调的LED驱动控制器的设计与实现

本文提出一种新颖的高精度宽范围可调的LED恒流驱动控制器的设计,与传统的恒流驱动电路不同,该电路采用漏端电压固定的MOS管代替传统的镜像电阻,并加入运放负反馈结构来保证所有镜像器件的端电压完全相等,得到不受输出端负载电压影响的精确可调的输出电流。同时通过新颖的电流分段镜像（CSM）机制,优化了镜像MOS管的电气特性,从而保证了高精度输出电流的宽范围。基于该方案采用TSMC 0.6μm BCD工艺设计实现了一款面积为1.1×0.7mm2的三通道LED恒流源驱动芯片。投片测试结果表明,该LED驱动控制器工作状态良好,输出电流范围为5mA～60mA,电流精度的相对误差小于1%,通道间电流匹配的相对误差不超过1.5%。     

高保真音频功放器设计

针对高品质音频的需求,设计了一种高保真音频放大器。该音频放大器主要由信号放大电路、功率放大电路和有源滤波电路组成,其中信号放大部分采用场效应管及运算放大器。其受外界的干扰性较小,稳定性较高,放大倍数可达到20～30倍,随需要而进行调节。功放部分采用LM4766型芯片,采用差动放大电路对信号实现音频信号的放大,失真小于百分之零点一。滤波电路采用了二阶有源低通滤波电路,对输入的音频信号进行处理。该设计的音频功率放大器具有失真度小、增益可调、体积小等特点,具有较高的实用价值。     

Design and implementation of a high precision and wide range adjustable LED drive controller

This paper presents a novel high precision and wide range adjustable LED constant-current drive controller design. Compared with the traditional technique, the conventional mirror resistance is substituted by a MOSFET with fixed drain voltage, and a negative feedback amplifier is used to keep all mirror device voltages equal, so that the output current is precise and not affected by the load supply voltage. In addition, the electric property of the mirror MOSFET is optimized by a current subsection mirror (CSM) mechanism, thus ensuring a wide range of output current with high accuracy. A three-channel LED driver chip based on this project is designed and fabricated in the TSMC 0.6 μm BCD process with a die area of 1.1 × 0.7 mm~2. Experimental results show that the proposed LED drive controller works well,and, as expected, the output current can be maintained from 5 to 60 mA. A relative current accuracy error of less than 1% and a maximal relative current matching error of 1.5% are successfully achieved.     

一种宽动态范围跨阻放大器的设计

针对光电探测器的光电流信号弱、变化范围大的特点,设计了一种全新的检测光电流信号的跨阻放大器(TIA)电路结构,其检测电流信号范围为1.6 μ上A～1.6 mA,动态电流检测范围达到60 dB.通过在电路内部设计出两个增益可调、增益段不同的TIA,分别处理光电流的小电流段(1.6～50 μA)和大电流段(50 μA～1.6 mA),增益可调范围为56～96 dBΩ;通过外置输出电压饱和检测信号,选择所需工作的TIA及其增益段.该电路采用0.18 μm标准CMOS工艺的PDK进行电路设计、版图设计和仿真验证等.测试结果表明:在检测电流为1.6 μA时,输出电压为95 mV;检测电流为1.6mA时,输出电压为915 mV,与仿真结果相一致.电路瞬态特性良好,上升时间为5～10 ns,3.3V电压下功耗小于2 mW,各指标满足设计要求.     

微波信号调制电路设计与实现

在智能微波开关的发射电路中,对高频微波信号采用了低频和中频两级调制的方法。为避免现场多对智能微波开关之间的相互干扰,首先用37～51 Hz分8级可调的低频高占空比方波信号调制21 kHz固定频率的中频信号,再用该信号调制10 GHz的高频微波信号。在信号调制的同时,用低频信号控制MOS管对高频微波模块的DC-DC供电电源反馈回路进行干预,使DC-DC电路工作于最佳状态,输出电压峰值平稳,避免了高频发射模块间歇式工作对电源电路输出的影响,提高了智能微波开关的测量精度和工作的可靠性。设计结果与理论分析结果比较接近,达到了设计要求。     

High gain power switching using field controlled thyristors

A technique for high gain power switching using field controlled thyristors is described. This technique uses a MOSFET connected in series with the FCT to control the current flow. The circuit exhibits normally-off behavior and is capable of operation at high voltages. The current through the FCT can be turned on and off by the application of a low voltage gate signal to the MOSFET. Turn-on and turn-off times of less than 1 μs have been observed at a current gain of over 30. The new gating technique offers the advantage of the large operating current density of the FCT even at high breakdown voltages and the high input impedance of the MOS gate used to trigger the device during power switching.     

Worn-out oxide MOSFET characteristics: Role of gate current and device parameters on a current mirror

In this work, the influence of gate oxide wear-out and breakdown (BD) on MOSFET output characteristics has been studied for short and long channel transistors. The experimental curves have been fitted to the BSIM4 model and have been introduced in a circuit simulator to study the effect of the oxide wear-out and BD in an analog circuit such as a current mirror. The results show important variations in the behaviour of the current mirror especially for the long channel transistor.     

Design and research of an LED driving circuit with accurate proportional current sampling mode

An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ±10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving 1C will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.     

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.     

一种新型偏置电路的CMOS亚阈型电压基准源

文章设计了一种工作在亚闽值状态下的CMOS电压基准源,分析了MOSFET工作在亚闽区的电压和电流限定条件。电压基准源可提供与工艺基本无关近似零温度系数的基准电压。为了提高电路的电源抑制比,该电路采用了共源共栅电流镜结构。该结构采用了一种新型的偏置电路．使得电流镜各级联管均工作在饱和区边缘而不脱离饱和区,提高输出电压摆幅,得到有较高恒流特性的基准电流。该电路采用0,6μmCMOS工艺,通过Spectra仿真,可工作在2V电压下,输出基准电压1.4V,温度系数为17×10^-6（V／℃）。     

大功率半导体激光器驱动电路

为实现30 W连续掺Yb光纤激光器,设计一种大功率（10 A）半导体激光器（LD）的驱动电路,该恒流源电路采用功率场效应管作电流控制元件,运用负反馈原理稳定输出电流,正向电流0 A～10 A连续可调,纹波峰值为10 mV,输出电流的短期稳定度达到1×10-5,具有过流保护、防浪涌冲击的功能。实际应用在30 W连续掺Yb光纤激光器中,结果表明该驱动电路工作安全可靠。     

A bulk-driven quasi-floating gate FVF current mirror for low voltage,low power applications

This paper introduces a new low-voltage, low-power FVF current mirror circuit. The bulk-driven (BD) technique is employed to achieve extended input voltage swing and low supply voltage. Besides, the quasi-floating gate (QFG) is used to achieve high frequency performance. The merging of (BD) and (QFG) appear as a good and attractive solution to improve the circuit performance with reduced supply voltage. Benefiting from the interesting properties of (BD-QFG) MOSFET (MOST) technique, the proposed FVF current mirror circuit exhibits superior performance compared to other previously reported works. The workability of the proposed circuit has been verified through ELDO simulator based on a 0.18 μm USMC process. It achieves an enhanced bandwidth (2.7 GHz), low power consumption (79.33 μW), a low input impedance (130 Ω), and high output impedance (9.5 G Ω) from a low supply voltage (0.8 V). Monte Carlo simulation is also carried out, which proves the robust performance of the proposed circuit against mismatches. An application of the proposed current mirror is presented in the form of the current comparator to ensure the workability of the proposed BD-QFG current mirror.     

用于功率MOSFET的新型栅电荷测试电路

栅电荷是用于衡量功率MOSFET开关性能的重要参数,通常采用在栅极输入电流阶跃信号的方法来测量。一种新型的栅电荷测试电路被提出,该测试电路使控制信号从MOSFET的源极输入,从而消除了控制信号对栅极输入电流的影响。因为输入电流太小不能直接测量,测试时采用测量电压阶跃信号的方法来衡量电流阶跃信号的性能。与以往的测试电路对比结果表明,该电路可以使MOSFET栅极输入的电流更接近于理想的电流阶跃信号,该信号上升时间小于100 ns,并且上升后稳定,因此提高了栅电荷测量的准确度。     

MAGFET based current sensing for power integrated circuit

A new on-chip non-invasive integrated current sensing, compatible with standard CMOS technology, has been developed, using a 1.2 μm BiCMOS ALCATEL technology, to sense the current in the drain side of a power MOSFET. The circuit is based on a split-drain magnetic sensor, implemented on the same chip of an integrated gate driver for a power MOSFET. A CMOS biasing circuit with a differential current output is also developed. The simulation results of the current sensing show a conversion gain of 1.25 mV/mT.     

Neural network based MOSFET channel length and width decision method for analogue integrated circuits

The channel length and width of a MOSFET are two important parameters selected by the experience of the integrated circuit designer. Since drain current of a transistor is directly adjusted by the aspect ratio, the wrong selection of these parameters changes the circuit characteristics. In this work neural networks are used to decide the most suitable selection of channel length and width of MOSFET. Both p-channel and n-channel transistors are modelled by multi layer perceptron (MLP) neural network and the channel length and width are predicted by MLP. MOSFET level 3 is modelled by MLP, training and test data are obtained from HSPICE design environment with YITAL 1.5μ parameters. Developed network is tested with the current mirror and the differential amplifier circuits. Estimated aspect ratios for each transistor are compared with the HSPICE simulation results.     

一种兼顾速度和功率损耗的硅探测器模拟前端电路设计

提出了一种兼顾速度和功率损耗的增益可调模拟前端电路,适用于硅探测器。该电路主要由快速电荷灵敏放大器、整形器以及可调节主要参数的控制系统组成。其中快速电荷灵敏放大器由低噪音场效晶体管（JFET）和电流反馈运算放大器构成,以确保较高频率和较短上升时间。整形器为五阶复数滤波器,能够提供较高的对称脉冲。通过实验验证了其可行性,在电容小于100 pF的范围内,实现了6种可调增益且兼顾了速度和功率损耗,电荷灵敏放大器上升时间为12ns,功率损耗为96mW。当探测器电容为40 pF时,等效噪音电荷（ENC）均值为180e-。     

一款隔离的低成本的直流电流检测电路

文中提出了一款简单的直流电流采样、隔离电路,利用抗浪涌电路（热插拔电路）MOSFET的导通电阻作为采样电阻,经过单电源运放组成的信号放大电路,和555时钟芯片组成的幅-频转换器转变为脉冲信号,通过光耦隔离,送入后级的监控电路。实验验证了其可行性。     

A new empirical nonlinear model for sub-250 nm channel MOSFET

An empirical nonlinear model for sub-250 nm channel length MOSFET is presented which is useful for large signal RF circuit simulation. Our model is made of both analytical drain current and gate charge formulations. The drain current expression is continuous and infinitely derivable, and charge conservation is taken into account, as the capacitances derive from a single charge expression. The model's parameters are first extracted, prior the model's implementation into a circuit simulator. It is validated through dc, ac, and RF large signal measurements compared to the simulation.     

一种基于DC/DC变换器的LED驱动电路的设计

提出一种基于电流模式DC/DC变换器的驱动控制电路。该电路可以与恒流电路结合在一起,用作LED驱动。电路由误差放大器、斜坡信号产生电路、电流采样与叠加电路以及PWM比较器四部分构成。采用华虹BCD350工艺进行仿真验证,结果显示,电路成功实现了电流采样信号与斜坡补偿信号的叠加,在Vea信号的控制下,输出了控制功率管关断的PWM脉冲信号。