Input Bias Current Research Articles

Experimental characterization and modeling of the improved low frequency response of a current modulated bulk RSOA slow light based microwave phase shifter

The enhancement of the low frequency gain response of a microwave phase shifter based on slow light in a TO-can packaged bulk reflective semiconductor optical amplifier, by using forced coherent population oscillations achieved by simultaneously modulating the input optical power and bias current, is experimentally demonstrated. The beat-signal gain improvement ranges from 35 to 0dB over a frequency range of 0.5–3.5GHz, thereby improving the noise performance of the phase shifter. Tunable phase shifts of up to 55° are possible over this frequency range. Simulations that show good agreement with experiment, based on a wideband dynamic model that includes spontaneous emission and band structure based calculations of the amplifier active region material, are also presented.

Radiation Degradation Modeling of Bipolar Operational Amplifier Input Offset Voltage in LTSpice IV

Integrated circuits are used in electronic equipment of spaceships. Therefore, they are impacted by ionizing radiation during space mission. It leads to electronic equipment failures. At present operational amplifiers are base elements of analog electronic devices. Radiation impact leads to degradation of operational amplifiers input stages. Input bias current increasing and input offset voltage drifts are the results of ionizing radiation expose of operational amplifiers. Therefore, space application electronic equipment fails after accumulation of limit dose. It isn’t difficult to estimate radiation degradation of input bias currents of bipolar operational amplifiers, but estimation of dose dependence of input offset voltage drift is more complex issue. Schematic modeling technique based on Gummel–Poon transistor model for estimation of input offset voltage drift produced by space radiation impact was experimentally verified for LM324 operational amplifier and presented in this work. Radiation sensitive parameters of Gummel–Poon model were determined using 2N2907 bipolar pnp transistor.

Analyses of ionization radiation damage and dose rate effect of bipolar voltage comparator

In order to investigate the dose rate effect and the radiation response of the voltage comparator, a group of bipolar voltage comparators are irradiated by 60Co at high-and low-dose rates under different bias conditions. The results show that many of the parameters for the voltage comparator subjected to ionization radiation, such as power current, input bias current, input offset voltage, and output voltage, are degraded to a certain extent; the irradiation response of the voltage comparator is severely affected by bias condition. What is more, the same type of circuits manufactured from different companies exhibit different dose rate effects; the reasons for the degradation are discussed by analyzing the experiment results. The mechanism for the formation of dose rate effect is also analyzed from the annealing characteristics. The results obtained in this paper are not only useful for the applications of the radiation hardness device, but also helpful for its design.

A Current-mode Electronically Controllable Multifunction Biquadratic Filter Using CCCIIs

This article presents a current-mode multifunction biquadratic filter performing completely standard functions low-pass, high-pass, band-pass, band-reject and all-pass functions. The circuit principle is based on second-generation current-controlled current conveyor (CCCII) with three input terminals and one output terminal. The features of the circuit are that, the pole frequency can be electronically tuned via the input bias currents. The circuit topology is very simple, consisting of merely 2 CCCIIs and 2 grounded capacitors. Without any external resistor and using only grounded elements, the proposed circuit is very comfortable to further develop into an integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation. The total power consumption is approximately 1.87mW at ±1.5V power supply voltages.

A Current-mode Electronically Controllable Multifunction Biquadratic Filter Using CCCIIs

This article presents a current-mode multifunction biquadratic filter performing completely standard functions low-pass, high-pass, band-pass, band-reject and all-pass functions. The circuit principle is based on second-generation current-controlled current conveyor (CCCII) with three input terminals and one output terminal. The features of the circuit are that, the pole frequency can be electronically tuned via the input bias currents. The circuit topology is very simple, consisting of merely 2 CCCIIs and 2 grounded capacitors. Without any external resistor and using only grounded elements, the proposed circuit is very comfortable to further develop into an integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation. The total power consumption is approximately 1.87mW at ±1.5V power supply voltages.

Universal Biquadratic Filter Employing Single Differential Voltage Current Controlled Conveyor Transconductance Amplifier

This paper presents new realizations of second order voltage mode and current mode universal filters based on a recently reported active element, called the differential voltage current controlled conveyor transconductance amplifier (DVCCCTA). The proposed circuits do not use external resistor. The filter circuits provide all the responses without changing the circuit topology. All the capacitors are virtually grounded. The use of grounded capacitors makes the circuit suitable for monolithic implementation. The pole frequency and quality factor can be adjusted independently with the input bias currents. The non-ideal analysis and the sensitivity analysis have been included. Both the active and passive sensitivities are not more than unity. The filter performances are verified using the PSpice simulations which agree well with theoretical value. 

An Active-Only Temperature-Insensitive Current-Mode Biquad Filter Based on Differentiator Structures Employing CCCCTAs

This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.

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

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.

CMOS-based current-controlled DDCC and its applications to capacitance multiplier and universal filter

This paper presents design of an active building block for analog signal processing, named as current-controlled differential difference current conveyor (CCDDCC). Its parasitic resistances at X-terminal can be controlled by an input bias current. The proposed element is realized in a CMOS technology. It displays usability of the new active element, where the maximum bandwidth of voltage and current followers are around 1 GHz, 100 MHz, respectively. The THD is obtained around 0.8% within 0.6 Vp–p input range. The power dissipation of a CCDDCC at 10 μ A biased current is obtained around 1.35 mW with ± 1.25 V power supplies. In addition, grounded capacitor-based floating capacitance multiplier and current-mode (CM) multiple-input single output (MISO) second-order universal analog filters are included as the applications. For realization of a grounded capacitor-based floating capacitance multiplier, it employs three CCDDCCs and one grounded capacitor without resistor connections. The capacitance can be tuned electronically through the bias current. The filter offers the simultaneous realization five type standard filter responses. The quality factor and the frequency response parameters can be independently tuned. The non-ideal effects of the developed structures are examined. SPICE simulation results of proposed CCDDCC and its applications are also presented.

Current-controlled current differencing transconductance amplifier and applications in continuous-time signal processing circuits

This article presents the design for a basic current-mode building block for analogue signal processing, named as Current Controlled Current Differencing Transconductance Amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. As it can be applied in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a bipolar technology and its performance is examined through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 65 MHz. The CCCDTA performs low-power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, a current-mode multiplier/divider and floating inductance simulator are included. They occupy only single CCCDTA.

Current-mode squaring, square-rooting and vector summation circuits

Abstract This paper presents new current-mode squaring, square-rooting and vector summation circuits based on the second generation current controlled conveyor (CCCII). Consisting of only CCCIIs as active elements not requiring any external passive elements, all of the proposed circuits are capable of high frequency operation and well suited for IC fabrication. Moreover, the circuits performances are insensitive to temperature and their gains can be easily adjusted by varying the input bias current of CCCII. Finally, the simulation results of the proposed squaring, square-rooting and a two-input vector summation circuits are depicted to confirm the theoretical analysis.

Fully Differential AC-Coupling Networks: A Comparative Study

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Fully differential ac amplifiers can easily be designed by placing an ac-coupling network in front of a fully differential dc amplifier. Such a network, however, must have a high common-mode rejection ratio (CMRR) to keep the overall CMRR high. In principle, passive ac-coupling networks that include no grounded components have an infinite CMRR, but they must provide a path for input bias currents. This paper analyzes how component tolerances limit the CMRR and affect the transient response of three different ac-coupling networks. To evaluate these networks in real conditions, the common-mode input impedance and bias currents of the ensuing differential amplifier are considered. Experimental results confirm the theoretical predictions. </para>

Cascadable Current-Mode Biquad Filter and Quadrature Oscillator Using DO-CCCIIs and OTA

This article introduces a circuit which can function both as a quadrature oscillator and as a universal biquad filter (lowpass, highpass, bandpass). When the circuit functions as a universal biquad filter, the quality factor and pole frequency can be tuned orthogonally via the input bias currents. When it functions as a quadrature oscillator, the oscillation condition and oscillation frequency can be adjusted independently by the input bias currents. The proposed circuit can work as either a quadrature oscillator or a biquad filter without changing the circuit topology. The amplitude of the proposed oscillator can be independently controlled via the input bias currents. The proposed oscillator can be applied to provide amplitude modulated/amplitude shift keyed signals with the above-mentioned major advantages. The circuit is very simple, consisting of four dual-output second generation current controlled current conveyors (DO-CCCIIs), one operational transconductance amplifier (OTA), and two grounded capacitors. Without any external resistors and using only grounded elements, this circuit is therefore suitable for IC architecture. PSPICE simulation results are depicted here, and the given results agree well with the theoretical analysis. The power consumption is approximately 7.32 mW at ±2.5 V supply voltages.

Electronically Controllable Current-Mode Universal Biquad Filter Using Single DO-CCCDTA

This article presents a three-input two-output current-mode universal biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based-on a dual output current controlled current differencing transconductance amplifier (DO-CCCDTA). The features of the circuit are that the bandwidth and pole frequency can be tuned electronically via the input bias currents and that the circuit description is very simple, consisting of merely a single DO-CCCDTA and two grounded capacitors. Additionally, each function response can be selected by suitably selecting input signals. Without any external resistors and using only grounded elements, the proposed circuit is very suitable to further develop into an integrated circuit. PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is approximately 1.81 mW at ±1.5 V power supply voltages.

Current controlled current conveyor transconductance amplifier (CCCCTA): a building block for analog signal processing

This article presents a basic current-mode building block for analog signal processing, namely current controlled current conveyor transconductance amplifier (CCCCTA). Its parasitic resistance at current input port can be controlled by an input bias current. It is very suitable for use in current-mode signal processing, which is becoming more popular than voltage mode. The proposed element is realized in a bipolar technology and the performances are examined through PSPICE simulations, displaying usabilities of the new active element. The CCCCTA performs tuning over a wide current range. The description includes some examples as a current-mode universal biquad filter, voltage-mode universal biquad filter, a grounded inductance simulator, a current-mode multiplier/divider and an oscillator. They occupy only a single CCCCTA.

Improved Fully Differential Analog Filters

This paper proposes two novel design techniques that improve the performance of fully differential filters built by coupling two equal single-ended filters. These filters usually reach a high common-mode rejection ratio (CMRR) without using tightly matched passive components but may become unstable because of common-mode signals. Previously proposed techniques to solve these problems, based on resistor or capacitor T-networks, reduce the CMRR. The two techniques proposed overcome this tradeoff. The first technique improves the stability of the filter common-mode gain by adding damping resistors that do not modify the desired differential frequency response or the CMRR. The second technique, which is particularly valuable when a path for input bias currents must be provided, uses a resistor network to estimate the common-mode voltage of the input and uses it as common ground voltage for the filter.

Low-offset BiCMOS Current Controlled Current Differencing Buffered Amplifier (CC-CDBA) and Applications

This article presents the design for a basic current mode building block for analog signal processing, called Current Controlled Current Differencing Buffered Amplifier (CC-CDBA). Its parasitic resistances at two current input ports can be controlled by an input bias current. The output current and voltage offset are quite low. The proposed element was realized in a BiCMOS technology and the voltage follower in the element is modified to achieve high performance properties. Its performances are examined through PSPICE simulations. In addition,examples as a current-mode multiplier/divider and current amplifier are included, compared to the conventional CC-CDBA implementation. They disclose performances of the proposed CC-CDBA superior to previous CC-CDBA.

Degradation of Power Bipolar Operational Amplifiers in a Mixed Neutron and Gamma Environment

Power operational amplifiers were irradiated in a mixed neutron and gamma radiation environment. These experiments showed that the degradation of the power operational amplifiers shares a great deal of characteristics with that of the low signal devices (e.g., shift of the input offset voltage, increase of the input bias currents, and degradation of the frequency behavior). However, other phenomena were observed without equivalence in the family (linear dependence of the inverse of the quiescent current on the neutron fluence, more significant degradation of the negative output current and collapse of the primary operational amplifiers). These phenomena were explained from the special characteristics of the output stage, optimized to provide a current of several amperes. Finally, even though power devices are especially sensitive to radiation damage, some of the tested devices are suitable for radiation levels on the order of 5 ldr 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> - 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> n ldr cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> in case the whole electronic system, in which the device is integrated, is carefully designed.

CMOS current-controlled current differencing transconductance amplifier and applications to analog signal processing

This article presents design of a basic current-mode building block for analog signal processing, named as current-controlled current differencing transconductance amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. Owing to working in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a CMOS technology and is examined the performance through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 311 MHz. The CMOS CCCDTA performs low power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, floating inductance simulator and quadrature oscillator are included. They occupy only single CCCDTA.

Three-Input Single-Output Electronically Controllable Dual-Mode Universal Biquad Filter Using DO-CCCIIs

This article presents a dual-mode (voltage-mode and current-mode) universal biquadratic filter performing completely standard functions: lowpass, highpass, bandpass, band-reject, and allpass functions, based on plus-type dual-output second-generation, current controlled, current conveyor (DO-CCCII+). The features of the circuit are that the bandwidth and natural frequency can be tuned electronically via the input bias currents: the circuit description is very simple, consisting of merely 2 DO-CCCIIs and 2 capacitors: the circuit can provide either the voltage-mode or current-mode filter without changing circuit topology. Additionally, each function response can be selected by suitably selecting input signals with digital method. Without any external resistors, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is approximately 1.81 mW at±1.5 V supply voltages.