Mohd. Samar Ansari

Multi output filter and four phase sinusoidal oscillator using CMOS DX-MOCCII

A current mode versatile first-order filter section with single input and multiple outputs is realised. The realisation uses one dual-X second generation current conveyor, two grounded resistors and two grounded capacitors. The realised current mode section provides low-pass, high-pass and all-pass responses at different outputs. The all-pass section is then cascaded with a current mode non-inverting integrator to realise a current mode four-phase sinusoidal oscillator. The current mode outputs are resistively loaded to achieve the four phase voltage mode sinusoidal outputs. All the realisations were designed and then verified using PSPICE. Experimental verification of the proposed filter sections using commercially available AD844s further confirms the validity of the theory.

Biphase amplifier based precision rectifiers using current conveyors

A novel and simple circuit for precision rectifier using second-generation current conveyor (CCII) is presented in this article. The circuit basically uses a CCII-based voltage mode bi-phase amplifier, which has been used as full-wave and half-wave rectifiers. To switch the bi-phase amplifier from non-inverting to inverting mode, a MOSFET and a CCII-based comparator has been used. The circuit exhibits precision rectification over a wide range of operation and can also be implemented using commercially available ICs such as the AD844. The proposed circuits have been simulated using CMOS implementation of current conveyor with effective results.

DVCC-based Electronically Tunable First-Order Current-mode Filters

The advent of differential voltage current conveyor (DVCC) has opened up new avenues in analog circuit design. In the present work, a DVCC has been employed to design currentmode first-order continuous-time analog filters. Parameter tunability is achieved by the use of a two-MOSFET electronic resistor which exhibits variation in resistance in accordance with a control voltage. The proposed circuits are amenable for monolithic integration by virtue of the fact that only MOSFETs and grounded capacitors are utilized. Circuit simulations using PSPICE yielded promising results.

Digitally Programmable Voltage-Mode Universal Biquadratic Filter

A single input multi-output voltage mode universal biquadratic filter has been presented. The circuit incorporates digital programmability employing three plus-type differential voltage current conveyors (DVCCs), two grounded capacitors and three resistors. The circuit exhibits high input impedance realizes all the standard filter functions having orthogonal control of cut-off frequency and quality factor. Parameter tunability is achieved by the use of a 3–bit digital control word. The proposed circuits are amenable for monolithic integration by virtue of the fact that only grounded capacitors are employed. Circuit simulations using PSPICE are in perfect agreement with the theoretically predicted results.

Digitally programmable first-order current mode continuous-time filters

The advent of differential voltage current conveyor (DVCC) has opened up new avenues in analog circuit design. However, a feature that is lacking in DVCC-based circuits is the non-availability of external control over circuit performance. To overcome this disadvantage, a new Digitally Controlled DVCC (DC-DVCC) has recently been proposed. In the present work, the DC-DVCC has been employed to design digitally programmable current-mode first-order continuous-time analog filters. Parameter tunability is achieved by the use of a 3-bit digital control word. The proposed circuits are amenable for monolithic integration by virtue of the fact that only grounded components are employed. Circuit simulations using PSPICE yielded promising results.

Digitally-programmable fully-differential current-mode first-order LP, HP and AP filter sections

Analog signal processing in the current-mode regime offers several advantages over its voltage-mode counterpart. Although, current-mode circuits exhibit better noise performance, fully-differential topologies may be employed to improve the noise cancellation,on account of their common-mode rejection properties. This paper presents fully-differential, first-order, low-pass, high-pass and all-pass filter sections operating in current-mode. The recently introduced Digitally Controllable Differential Voltage Current Conveyor (DC-DVCC) has been chosen as the active building block. Programmability of the filter characteristics through a digital control word is demonstrated.

Current-mode electronically-tunable Schmitt Trigger using single 65nm ±0.75V CMOS CDTA

A current-mode electronically-tunable Schmitt Trigger circuit is presented. The analog building block used is a new Multiple-Output CDTA (MO-CDTA) which is designed and implemented at 65 nm CMOS technology node. The proposed circuit employs only a single MO-CDTA and no passive components thereby making it attractive for integration. The operation of the proposed Schmitt Trigger was verified by using SPICE simulations. Electronic tunability of the hysteresis characteristics was also explored with good results. A simple application of the proposed Schmitt Trigger, in the form of a current-mode clock generator is also presented.

A novel current-mode non-linear feedback neural circuit for solving linear equations

A novel current-mode neural circuit employing non-linear feedback to solve a system of simultaneous linear equations is presented. The circuit has an associated transcendental energy function that ensures fast convergence to the exact solution while enjoying a resistor-less implementation. The hardware complexity of the proposed scheme compares favourably with existing voltage-mode neural circuits for the same task. PSPICE simulation results are presented for a chosen set of equations and are found to be in agreement with the algebraic solution.

Electronically Tunable Resistor-less Universal Filter in ±0.5V 32nm CNFET

CMOS technology faces significant challenges at channel lengths below 45 nm. Carbon nanotube-based electronics has emerged as a viable prospect for extending the saturating Moores law. This paper presents a resistor-less voltage-mode universal filter designed with a CNFET-based CCCII and two capacitors. The performance of the filter circuit has been evaluated using HSPICE.

High Performance Precision Rectifier for Analog Signal Processing

This paper presents two improved precision rectifiers, each employing two active elements and two MOS transistors. The new circuits are advantageous when compared to the most recent work [5] by enjoying high input impedance and resistor-less realization, which makes them ideal for CMOS implementation. High precision and wide frequency operation of the circuits is shown along with parasitic insensitivity. The dual-X current conveyor based novel circuits have useful analog signal processing applications and are verified through extensive computer simulations. General Terms Analog Signal Processing, Current Conveyors.