Current-mode Band-pass Filter Research Articles

Realization of a New Current Mode Second-Order Biquad Using Two Current Follower Transconductance Amplifiers (CFTAs)

A new circuit for realization of universal current-mode filter using current Follower Transconductance Amplifiers (CFTAs) is presented. The proposed circuit realizes current-mode low pass, high pass and band pass filter functions simultaneously with a single current source at the input. The band reject and all pass filters can also be obtained from the proposed circuit without any extra hardware. The proposed circuit employs three passive grounded elements and two CFTAs. Linear electronic control of natural frequency ω0 is available in the proposed circuit. The quality factor can be independently adjusted through grounded resistor. The proposed circuit employs two grounded capacitors and a grounded resistor along with two CFTAs. The grounded resistor can be replaced by an OTA based circuit for linear electronic control of quality factor Q0. The circuit exhibits low active and passive sensitivities for ω0 and Q0. Simulation results are obtained using PSPICE software which is in conformity with the theoretical findings.

Component reduced floating ± L, ± C and ± R simulators with grounded passive components

In this study, a novel immittance simulator circuit is proposed. The proposed circuit can simulate any one of the floating positive or negative inductor simulator (± L), positive or negative capacitor simulator (± C) and positive or negative resistor simulator (± R). It uses only one current backward transconductance amplifier (CBTA) and two grounded passive components. The proposed simulator can be tuned electronically by changing the transconductance value of the CBTA. Moreover, the circuit does not require any conditions of component matching. It has a good sensitivity performance with respect to the tracking errors and the passive components. The performance of the proposed immittance simulator is demonstrated on the fourth-order voltage- and current-mode band-pass filters by using Pspice simulations based on the 0.25 μm TSMC level-7 CMOS technology parameters.

GENERATION OF GROUNDED CAPACITOR ICCII-BASED BAND-PASS FILTERS

A new current-mode band-pass filter using the inverting second-generation current conveyor (ICCII) is introduced. The circuit is generated from a frequency-dependent negative resistance (FDNR)-C circuit realized using ICCII+. It is observed that a voltage-mode band-pass filter using two CCII+ has similar transfer function to this current-mode filter. The adjoint network theorem is used to demonstrate the transformation between the two circuits. Two new voltage-mode grounded capacitor band-pass filters using two ICCII are also introduced. The first voltage-mode circuit is generated from the FDNR-C circuit and employs two opposite Z polarity ICCII. The second voltage-mode circuit is obtained from the first circuit by relocation of the input and a grounded terminal. Two new additional grounded capacitor and grounded resistor current-mode band-pass filters with independent control on the filter Q are also introduced. Spice simulation results with 0.35 μm CMOS transistors model are included to demonstrate the practicality of the two ICCII- band-pass current-mode filter.

New Current-Mode Bandpass Filters Using Three Single-Output ICCIIs

New current-mode bandpass filters using three single outputs inverting second generation current conveyors (ICCII) are introduced. The first circuit uses two ICCII+ and one ICCII−, and realizes an inverting bandpass response. This circuit has one floating resistor and no independent gain control. The second circuit uses three ICCII−and realizes a noninverting bandpass response. The third circuit uses three ICCII+ and realizes also a noninverting bandpass response. The second and third circuits employ four grounded resistors and two grounded capacitors and have independent control onQand on the center frequency gain by varying a single grounded resistor. Spice simulation results using 0.5 um CMOS transistors are included to support the theoretical analysis.

Improved FGMOS-Based Low-Voltage Voltage Follower

The use of floating-gate MOSFETs (FGMOS) in designing low-voltage analog circuits is presented. A FGMOS based low-voltage voltage follower and its use in CCII structures is presented. Working of such CCII structures is ascertained by using them in current-mode and voltage-mode band-pass simulated filters.

High output impedance current-mode lowpass, bandpass and highpass filters using current controlled conveyors

Three new current-mode second-order filter configurations which employ one or two current controlled conveyors (CCCIIs) and three passive elements are presented. Each proposed filter can realize one of the bandpass, lowpass or highpass responses all at high impedance outputs. The proposed filters offer current-control of pole angular frequency ωo without disturbing the parameter ωo /Q. No component matching is required and all the passive and active sensitivities are low. PSPICE simulation results are given to confirm the theoretical analysis.

A new CMOS realization of a four terminal floating nullor (FTFN)

A novel circuit configuration for the realization of a four terminal floating nullor in CMOS technology is proposed. The circuit proposed combines the advantages of a cascade of common-source and common-gate amplifiers and a floating current source. PSPICE simulations show that the proposed circuit is suitable for wideband, accurate and wide dynamic range current-mode signal processing. The feasibility of the circuit is also tested successfully in a current-mode band-pass filter structure.

Current Controlled Current Differencing Buffered Amplifier: Implementation and Applications

A new four terminal current‐controlled active element is introduced, where parasitic resistances at two current input ports are controlled leading to the definition of current‐controlled current differencing buffered amplifier. Bipolar implementation and as application current‐mode band‐pass filter circuits are proposed. Simulation results using real device parameters are included, which show device bandwidth of 35 MHz, low total harmonic distortions, and tuning over a wide current range.

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.

CMOS four terminal floating nullor design using a simple approach

In this study a simple approach for design of four terminal floating nullor (FTFN) is introduced and two new CMOS FTFN topologies are proposed using the approach from suitable CMOS negative current conveyor (CCII−) structures. The performance of the proposed circuits was tested by Pspice computer simulation program. The feasibility of the proposed circuits was shown on a current-mode band-pass filter example constructed using one of the proposed CMOS FTFN circuits. The simulation results are given to confirm the predicted theory.

Current-mode band-pass ladder filters using OTAs

A design method of current-mode (CM) band-pass ladder filters is presented. The proposed method is based on the simulation of the passive RLC ladder networks using current-mode biquad blocks. Three scaled impedance functions are chosen to generate the biquadratic transfer functions. Based on these scaled impedance functions, three CM band-pass filters are obtained and implemented using OTAs. As an example, a sixth-order Chebyshev band-pass filter is designed and simulated using HSPICE.

High-frequency high-Q BiCMOS current-mode bandpass filter and mobile communication application

The design of a tunable high-frequency fully integrable current-mode bandpass filter is presented using a complementary high-performance BiCMOS process. The new architecture of this filter is based on impedance simulation and employs current controlled conveyors. The Q-factor and the center frequency can be electronically controlled with dc bias currents over a broad range of values, thus allowing easy tuning of this filter. An application to a mobile communication IF receiver channel centered at 85 MHz and with 1-MHz bandwidth based on the cascade of two identical second-order bandpass cells has been designed. Measurements show very interesting frequency performance (f/sub 0/ tunable in the range 30-120 MHz and Q from 1-140) in conjunction with low power consumption (25 mW for the fourth-order filter with /spl plusmn/2.5 V supplies).

Cascadable Current-Mode Biquads

New procedures are presented that yield cascadable, opamp based current-mode biquads from voltage-mode biquads without the use of voltage-mode to current-mode transformations. The opamps in the resulting current-mode circuits can be replaced by current-mode devices, such as current conveyors, producing circuits that are fully current-mode. The procedures are applied to several multi-opamp voltage-mode circuits to achieve current-mode lowpass, highpass, bandpass, notch, and allpass filters. The procedures are also applied to a single opamp circuit. Experimental results are given.

Current-mode band-pass filters with Q-magnification

The authors present a new architecture that, for a second-order band-pass filter operating in current-mode, allows one to modify the quality factor without changing its center frequency f/sub 0/. This is obtained by adding an auxiliary current-mode amplifier to the initial configuration of the filter. The resultant value of the Q-factor depends on the gain of this amplifier. SPICE simulation and experimental results, obtained from current-mode filters previously described, are given to confirm the theoretical analysis.

Current-mode lowpass and bandpass filters using the operational amplifier pole

This paper proposes a circuit configuration for realizing current-mode lowpass and bandpass filters using the operational amplifier (op.-amp.) pole. The circuit simultaneously realizes lowpass and bandpass transfer functions using an op.-amp., three resistors and a capacitor. The effects of the paras tic poles (i.e. second and third poles) of the op.-amp. on the gain of a lowpass filter are also presented. Since the circuit uses the op.-amp. pole, it is suitable for high frequency operation.

Brief communication Current-mode highpass and bandpass filters using the operational amplifier pole

A circuit configuration for realizing current-mode highpass and bandpass filters using the operational amplifier (op.-amp.) pole is proposed. The circuit simultaneously realizes highpass and bandpass transfer functions using an op.-amp., two resistors and a capacitor. The effects of parastic poles (i.e. second and third poles) of the op.-amp. are also presented. Since the circuit uses an op.-amp. pole, it is suitable for high frequency operation.

Insensitive current-mode bandpass implementations-based nonideal gyrators

Two equivalent implementations for a nonideal gyrator designed from two current conveyors are described. From these basic implementations, two new configurations for second-order current-mode bandpass filters, which exhibit reduced active and passive sensitivities, are deduced. For one of them an additional transfer (low-pass or high-pass) is also available on the circuit. SPICE simulation results are given and discussed for the conveyors implemented in a translinear form. They confirm the validity of the theoretical analysis and underline the high performances of the filters.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Insensitive current-mode bandpass filter implemented from two current conveyors

Two configurations for second order bandpass filters with current transfers are introduced. The circuits, which exhibit reduced values for the active and passive insensitivities, only use four passive components and necessitate two current conveyors. SPICE simulated results, which confirm the theoretical analysis, are given and discussed for current conveyors implemented in a translinear form.