A wide dynamic range continuously adjustable CMOS current mirror

A novel circuit realization of a CMOS current mirror with wide input dynamic range and continuously adjustable gain is presented. The proposed current mirror is linear with respect to signal current in the strong inversion as well as in the subthreshold region of MOSFET operation. The gain is controlled by the same control signal in both regions. The circuit is analyzed using a numerical unified MOSFET model which covers both operating regions. The implemented current mirror is adjustable over more than eight decades of signal current     

Low-voltage CMOS adjustable current mirror

A novel scheme for an adjustable low-voltage CMOS current mirror is introduced. The proposed current mirror provides continuous gain adjustment, while it simultaneously features the attractive characteristic of low-voltage operation. The behaviour of the proposed topology has been experimentally verified through a first-order lowpass filter fabricated in AMS 0.35 μm CMOS technology.     

Tunable linear CMOS current mirror

Based on triode MOSFETs as tunable devices, a tunable linear current mirror is proposed, whose current gain is tunable over a wide range. Simulations show that, total harmonic distortion on the output current is within 2% for a tuning range of almost five octaves. Although the structure is in the form of an active-input current mirror, keeping the tuned MOSFETs in triode region significantly relaxes the stability problems of an active-input current mirror. This issue is revealed by theoretical analyses and further simulations are included for demonstration. An application example is also supplied.     

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.     

Miller compensation using current buffers in fully differential CMOS two-stage operational amplifiers

Several Miller compensation schemes using a current buffer in series with the compensation capacitor to modify the right-half-plane zero in fully differential two-stage CMOS operational amplifiers are analyzed. One scheme uses a current mirror as a current buffer, while the rest use a common-gate transistor as a current buffer. The gain transfer functions are derived for each topology, and approximate transfer-function coefficients are found that allow accurate estimation of the zero(s) and poles.     

Compensation in variable ratio current mirrors

The accurate control of the current ratio of a variable ratio bipolar current mirror is affected by the finite transistor current gain. Compensation for errors due to low current gain and mismatching of emitter efficiencies can be introduced to cancel these errors     

Modified current mirror with a `voltage-following? capability

A negative current mirror suitable for monolithic IC fabrication is described. It is unusual in that it is a `voltage-following? circuit in which the input-output offset voltage is small and only weakly dependent on operating conditions. A base-current compensation scheme enables the circuit to exhibit a current transfer ratio comparable with that of the `Wilson? current mirror.     

High-swing MOS current mirror with arbitrarily high output resistance

A new current mirror circuit scheme is proposed that allows an arbitrary number of transistors to be cascoded creating a current mirror circuit with maximum output voltage swing and very high output resistance.<>     

A novel highly accurate current mirror

A novel complementary metal-oxide semiconductor (CMOS) current mirror that can work in weak and strong inversion is proposed. The mirror is capable of accurately copying current in the nano-ampere range. The proposed scheme eliminates the DC matching error caused by the difference between drain-to-source voltages of both the input and output transistors. The proposed circuit was verified using ORCAD simulator in 0.8 μm CMOS process technology. Simulation results confirm the functionality and accuracy of the circuit.     

An integrated low power highly linear 2.4-GHz CMOS receiver front-end based on current amplification and mixing

A low power 2.4-GHz complementary metal oxide semiconductor (CMOS) receiver front-end using highly linear mixer based on current amplification and mixing is reported. In the proposed mixer, linearity is greatly improved by using current mirror amplifier and transconductance linearization using multiple gated transistors. Single IF direct conversion receiver (DCR) architecture is used to achieve higher level of integration and to relax the problem of DCR. The fully integrated receiver front end is fabricated in 0.18-/spl mu/m CMOS technology and HP3 of -9 dBm with a gain of 32 dB and noise figure of 6.5 dB are obtained at 8.8 mW power consumption.     

BiCMOS adjustable linear current mirror

Two novel BiCMOS adjustable gain linear current mirrors are presented. Variable gain is achieved by introducing a DC voltage into the control loop. Simulation and experimental results indicate that the gain is linear over several decades of signal current. The circuits are designed for maximum voltage swing with cascoded output to provide high output resistance     

A Schmitt trigger with current mirror feedback

The circuit of a simple trigger with positive feedback via the current mirror (with gain) and the resistive divider is proposed. The circuit operation is described and the hysteresis voltage is obtained. The basic design limitations are introduced. Both versions (CMOS and bipolar) are considered.     

A circuit scheme to control current surge for RFID-NVM pumps

This paper presents a new circuit scheme to control the current surge in the boosting phase of an radio frequency identification-nonvolative memory pump. By introducing a circuit block consisting of a current reference and a current mirror, the new circuit scheme can keep the period-average current of the pump constantly below the desired level, for example, 2.5μA. Therefore, it can prevent the rectified supply of the RFID tag IC from collapsing in the boosting phase of the pump. The presented scheme could effectively reduce the voltage drop on the rectified supply from more than 50% to even zero, but could cost less area. Moreover, an analytical expression to calculate the boosting time of a pump in the new scheme is developed.     

Voltage controlled oscillators using complementary current mirror inverter

Complementary current mirror inverters have large bandwidth, small time delay but small gain whereas complementary inverters have high gain but large time delay. Ring oscillators have been realised using a combination of both types of inverter to achieve stable high frequency oscillation. Voltage controlled oscillators were obtained by tuning the frequency of oscillation with supply voltage.<>     

Extremely low threshold current operation in 1.5-μm MQW-DFBlaser diodes with semi-insulating InP current blocking region

Threshold current operation of 1.5 mA was achieved for 1.5-μm multiple-quantum-well distributed feedback (MQW-DFB) laser diodes (LDs) with semi-insulating current blocking layers entirely grown by metalorganic vapor phase epitaxy (MOVPE). Such low-threshold current is attained by reducing leakage current and mirror loss in the laser structure. The required bias current for achieving several gigahertz bandwidth is markedly reduced due to the enhanced differential gain and low threshold current. Due to the reduced lasing delay time in such low threshold LDs, up to 5-GHz zero-bias current modulation, with a clear eye opening, is successfully demonstrated     

A modified current mirror with level shifting capability and low input impedance

A current mirror with DC level shifting capability and low input impedance is described. The input impedance can be varied over a limited range without significantly altering the current gain of the circuit, and lateral p-n-p transistors can be used to provide reasonable performance up to a few megahertz.     

A power efficient gain enhancing technique for current mirror operational transconductance amplifiers

In this paper, a power efficient voltage gain enhancing technique is described. This technique is suitable for the amplifiers which use current starving method for gain enhancement (explained in the text). The proposed technique makes use of the current which conventionally goes to ground, through a parallel path. In this paper, the new technique is demonstrated for current mirror type of operational transconductance amplifier (OTA). Simulation results show that gain improves by a factor ~2, while consuming the same power as conventional OTA. The added advantage of this technique is that it does not affect the voltage swing while increasing the gain. Compared to the conventional current starving technique, the proposed technique also improves the noise performance and settling speed of the amplifier. The results are compared with the conventional technique, in terms of gain, settling and noise performance. A comparison of FoM (MHz.pF/mA), with other amplifiers, is given at the end as well.     

5.2 GHz SiGe HBT upconverter using active-inductor LC current mirror

A compact 5.2 GHz upconversion micromixer using the 0.35 /spl mu/m SiGe HBT technology is demonstrated. A bandpass and area-saving LC current mirror using the active inductor is incorporated to increase the conversion gain. The demonstrated upconverter has conversion gain of -3.5 dB, OP/sub 1dB/ of -10 dBm, and OIP/sub 3/ of 0 dBm.     

A feedforward technique with frequency-dependent current mirrorsfor a low-voltage wideband amplifier

A feedforward technique using frequency-dependent current mirrors for a low-voltage wideband amplifier is presented. In the conventional single-stage wideband amplifiers, the folded cascode structure is used. However, the common-gate transistor requires an additional V_{DS sat} and reduces the available output voltage range. In this study the cascode structure is avoided; instead, a frequency-dependent current mirror, whose input impedance becomes higher for a higher frequency, is used to form the feedforward path from the input of the current mirror with a feedforward capacitor. This technique is effective to improve a 100 MHz-1 GHz frequency characteristic of the amplifier. The amplifier has been fabricated using the standard 0.8 μm CMOS process. The phase margin is improved from 46-66° without sacrificing the unity gain frequency of 133 MHz compared with the amplifier without this technique. The amplifier operates at 2.5 V power supply voltage and consumes 12 mW     

Low supply voltage high-performance CMOS current mirror with low input and output voltage requirements

This paper presents a scheme for the efficient implementation of a low supply voltage continuous-time high-performance CMOS current mirror with low input and output voltage requirements. This circuit combines a shunt input feedback and a regulated cascode output stage to achieve low input resistance and very high output resistance. It can be used as a high-precision current mirror in analog and mixed signal circuits with a power supply close to a transistor's threshold voltage. The proposed current mirror has been simulated and a bandwidth of 40 MHz has been obtained. An experimental chip prototype has been sent for fabrication and has been experimentally verified, obtaining 0.15-V input-output voltage requirements, 100-/spl Omega/ input resistance, and more than 200-M/spl Omega/ (G/spl Omega/ ideally) output resistance with a 1.2-V supply in a standard CMOS technology.