Noman Tasadduq

Electronically tunable capacitance multiplier and frequency-dependent negative-resistance simulator using the current-controlled current conveyor

Electronically tunable capacitance multipliers and a frequency-dependent negative-resistance (FDNR) are presented in this article. The multiplying factors of the capacitance multipliers and the value of the FDNR are tunable by adjusting the bias current of a plus-type current-controlled current-conveyor (CCCII+). The feasibility of obtaining temperature-independent capacitance multiplication factors is explored and the SPICE simulation results included.

A novel single-input multiple-output current-mode current-controlled universal filter

Abstract A novel current-controlled current-mode universal filter is presented. The circuit uses six second-generation current-controlled conveyors and two grounded capacitors. The circuit enjoys independent control of the parameters ω 0 and ω 0 / Q 0 , low active and passive sensitivities and can simultaneously realize all the five basic filter transfer functions. SPICE simulation results are included.

A complementary metal–oxide semiconductor digitally programmable current conveyor

SUMMARY A second-generation current conveyor with digitally programmable current gains is presented. A current division network with zero standby power consumption is utilized in two different ways to provide both gain and attenuation of the second-generation current conveyors current transfer characteristics. The proposed topology overcomes several drawbacks of the previous solutions through affording a more power and area efficient solution while exhibiting relatively wider tuning range and bandwidth. A variable-gain amplifier and a two-integrator-loop filter biquad providing low-pass and band-pass responses are given as application examples. A modified two-integrator-loop topology is developed to offer independent control of the pole frequency and quality factor without disturbing the passband gain. Simulation results obtained from a standard 0.18 µm complementary metal–oxide semiconductor process are given. Copyright

Universal Current-Controlled Current-Mode Filter Using the Multiple- Output Translinear Current Conveyor

Universelles stromgesteuertes Filter vom Stromquellentyp auf Basis des translinearen Stromfiberträgers mit Vielfach-Ausgang Abstract A new current-mode universal filter is proposed. The filter uses three multiple-output current-controlled translinear current-conveyors (CCCII) and can simultaneously realise towpass, highpass and bandpass responses. Realisation of notch and allpass responses is feasible. The parameters a*,, (oo/Q0. and the bandpass gain can be controlled by adjusting the bias currents of the CCCIIs. The proposed circuit enjoys low sensitivities.A new current-mode universal filter is proposed. The filter uses three multiple-output current-controlled translinear current-conveyors (CCCII) and can simultaneously realise lowpass, highpass and bandpass responses. Realisation of notch and allpass responses is feasible. The parameters ω 0 , ω 0 /Q 0 . and the bandpass gain can be controlled by adjusting the bias currents of the CCClls. The proposed circuit enjoys low sensitivities.

A Highly Linear Fully Integrated Powerline Filter for Biopotential Acquisition Systems

Powerline interference is one of the most dominant problems in detection and processing of biopotential signals. This work presents a new fully integrated notch filter exhibiting high linearity and low power consumption. High filter linearity is preserved utilizing active-RC approach while IC implementation is achieved through replacing passive resistors by R-2R ladders achieving area saving of approximately 120 times. The filter design is optimized for low power operation using an efficient circuit topology and an ultra-low power operational amplifier. Fully differential implementation of the proposed filter shows notch depth of 43 dB (78 dB for 4th-order) with THD of better than -70 dB while consuming about 150 nW from 1.5 V supply.

A novel three inputs and one output universal current-mode filter using plus-type CCIIs

A novel current-mode current-conveyor based universal filter with three inputs and one output is presented. The circuit uses six plus-type second-generation current-conveyors (CCII+), six grounded resistors and two grounded capacitors. The circuit enjoys the following advantageous features: independent grounded-resistance control of the filter parameters, realisation of all the basic filter functions, low passive sensitivities and high output impedance. Experimental results are included.

Optimal Low Power Complex Filters

Realizations of voltage-mode and current-mode complex filters based on transconductance, transresistance, and current amplifiers for intermediate frequency (IF) applications are systematically developed. Various amplifiers are realized utilizing the second generation current conveyor (CCII) to promote comparisons at device levels. The adopted approach shows that the most efficient designs in terms of the number of active components are current-mode filters based on the transconductance and current amplifiers. As an application example, a 4th-order complex filter based on the CA is designed for low-IF Bluetooth receiver. Fabricated in a standard 0.18 μm CMOS technology, experimental results show that the proposed design offers improved characteristics over the available solutions in terms of power consumption and spurious-free dynamic range (SFDR). The filter exhibits in-band SFDR of 65.8 dB while consuming 1 mW.

A class of digitally programmable n th-order filters

A family of new high-order filters capable of providing all filter functions without changing the circuit topology is proposed for integrated circuit applications. The proposed filters are based on simple active elements, namely, digitally controlled current amplifiers (DCCAs) and unity gain voltage buffers (VBs). Gains of DCCAs are digitally programmed to adjust the coefficients of transfer functions. R2R ladders are also utilized to increase the tuning flexibility of the proposed filters. A filter replicating the famous KHN biquad is extended to realize general nth-order filters. Comparison with the recent works shows that the proposed approach results in more efficient realizations compared with its counterparts based on other current-mode active elements. Experimental results obtained from a fourth-order filter implemented using devices fabricated in a 0.35-µm CMOS process are provided. Copyright

Realizations of CMOS fully differential current followers/amplifiers

Three CMOS realizations of fully differential current followers (amplifiers) are presented. Their various characteristics are determined and evaluated. In general, the proposed circuits exhibit low input resistances, high output resistances, and low common-mode gains. However, interesting differences showing the advantages and disadvantages of each topology are highlighted. Simulation results obtained using 0.18µm CMOS models are provided.

A CMOS low power current-mode polyphase filter

A new CMOS polyphase filter based on current followers is presented. Adoptions of such relatively simple building blocks and a filter structure employing minimum number of active elements, have lead to low power solution. The proposed filter is used to construct a 6th-order polyphase fully differential filter suitable for Bluetooth low-IF receiver. Experimental results show that the proposed design satisfies the selectivity and dynamic range specifications of Bluetooth while consuming relatively low power of 2.38mW.