Two new multiple-mode (including voltage, current, transconductance, and transresistance modes) OTA-C universal biquad filters are proposed. The first proposed circuit uses only four operational transconductance amplifiers (OTAs) and two grounded capacitors. The second proposed circuit uses five OTAs and two grounded capacitors. Both the proposed circuits can realize voltage, current, transconductance, and transresistance mode universal filtering responses (low-pass, high-pass, band-pass, notch, and all-pass) from the same topology. The first proposed circuit uses the least number of components. This represents an attractive feature from a chip area and power consumption point of view. The second proposed circuit has no need of extra inverting and non-inverting amplifiers for special input signals. Moreover, both the proposed biquads still have (i) the employment of two grounded capacitors, (ii) cascadable connection of the former voltage-mode stage and the latter current-mode stage, and (iii) low sensitivity performance. H-SPICE simulation results confirm the theoretical analysis.

Multiple-Mode OTA-C Universal Biquad Filters

A novel electronically tunable mixed-mode universal biquad by using four single-output and one dual-output-operational transconductance amplifiers, two grounded capacitors is proposed. The proposed circuit has ability to realize voltage, current, transconductance, and transresistance mode, and can the following advantageous features: (i) realization of low-pass, band-pass, high-pass, notch, and all-pass filter responses from the same configuration, (ii) employment of only grounded capacitors ideal for integrated circuit implementation, (iii) orthogonal controlling of ? o and Q for easily electronic tunability, and (iv) low active and passive sensitivity performance. Finally, to verify our architecture, we have designed this analog filter chip with TSMC 0.35-μm 2P4M CMOS technology. This chip operates to 1 MHz and consumes 30.95 mW. The chip area of the analog filter is about 0.823 mm2.

Tunable mixed-mode OTA-C universal filter

In this paper a mixed-mode (input and output signals can be current or voltage) Kerwin–Huelsman–Newcomb (KHN) biquad with low-high input impedance and high-low output impedance depending on the type of the corresponding signal (current-voltage) is presented. The circuit is constructed using three differential voltage current conveyors (DVCCs), two grounded capacitors and three grounded resistors. The circuit simultaneously provides bandpass (BP), highpass (HP) and lowpass (LP) responses when the output is current and notch, BP and LP responses when the output is voltage. The notch and allpass responses can be obtained by connecting appropriate output currents directly without using additional active elements. Because of the low input and high output impedance of the circuit for current signals and the high input and low output impedance for voltage signals, it can be used in cascade for realizing higher-order filters. SPICE simulation results are given to verify the theoretical analysis. Copyright © 2008 John Wiley & Sons, Ltd.

A mixed-mode KHN-biquad using DVCC and grounded passive elements suitable for direct cascading

None of the recently reported voltage-mode versatile filters are digitally programmable for applications like the easy addition of current-mode filtering signals to do the synthesis. None of the recently reported analytical synthesis methods are used for the realization of a multifunction filter. Both the above two induced motivations of researches have been merged, developed, and solved in this brief on the voltage-mode operational transconductance amplifier (OTA)-C universal biquad filter, which still achieves many advantages like the employment of all single-ended-input OTAs, all grounded capacitors, and the least number of active transistor and passive component counts, in addition to having a controllable gain, a cascadable input terminal, and the absence of the need to impose component matchings

Analytical Synthesis of the Digitally Programmable Voltage-Mode OTA-C Universal Biquad

The transconductance and the transresistance modes might act as the bridge transferring from voltage-mode to current-mode and vice versa, respectively. A novel mixed-mode (including voltage, current, transconductance, and transresistance modes) biquad filter with one input and seven outputs or two inputs and eight outputs is presented. The proposed filter structure only uses a single fully differential current conveyor (FDCCII), three resistors and two grounded capacitors, which are the least components necessary for realizing voltage, current, transresistance modes all five standard filter functions and transconductance-mode band-pass, high-pass filter functions from eight output terminals. Moreover, the new mixed-mode biquad filter still enjoys (i) the employment of two grounded capacitors (attractive for absorbing shunt parasitic capacitance and ideal for IC implementation), (ii) orthogonal control of ω 0 and Q (easy for tunability), and (iii) high output impedance of three current outputs (good for cascadability). H-Spice simulation results verify the theoretical analysis.

Single FDCCII-based mixed-mode biquad filter with eight outputs

A novel mixed-mode biquad circuit is presented. The circuit uses six single-output- and one dual-output-operational transconductance amplifiers, two grounded capacitors; and can realize lowpass, highpass, bandpass, notch, lowpass-notch, highpass-notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. The parameters ωo and ωo/Q o enjoy independent electronic tunability. Simulation results are included.

A novel mixed-mode OTA-C universal filter

A new mixed-mode biquad circuit is presented. The circuit uses six single-output plus-type second-generation current-conveyors (CCII+s), a single dual-output CCII+, two grounded capacitors, eight resistors, at least two of them permanently grounded, and can realize lowpass, highpass, bandpass, notch, lowpass notch, highpass notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. The parameters ω0 and ω0/Q 0 enjoy independent electronic tunability. Simulation results are included.

A novel mixed-mode current-conveyor-based filter

A new mixed-mode biquad circuit is presented. The circuit uses five second-generation current conveyors, seven resistors, and two grounded capacitors and can realize lowpass, highpass, bandpass , notch, lowpass notch, highpass notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. The parameters ωo and ωo/Qo enjoy independent electronic tunability. Simulation results are included.

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A novel mixed-mode ccii-based filter

A novel mixed-mode biquad circuit is presented. The circuit uses six single-output- and one dual-output-operational transconductance amplifiers, two grounded capacitors; and can realize lowpass, highpass, bandpass, notch, lowpass-notch, highpass-notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. The parameters ? o and ? o / Q o enjoy independent electronic tunability. Simulation results are included.

Abdulwahab Bentrcia

Papers

A novel mixed-mode OTA-C universal filter

A novel mixed-mode current-conveyor-based filter

A novel mixed-mode ccii-based filter

"A novel mixed-mode OTA-C filter"