A MISO current-mode biquad filter using a minimum number of active and passive components

Multiple-input single-output low-input and high-output impedance current-mode biquadratic filter employing five modified CFTAs and only two grounded capacitors

This paper proposes a current mode universal filter circuit, employing two active elements along with four grounded passive components only. The derived circuit realizes all five filtering responses, i.e., low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP), simultaneously from high-impedance ports along with the input being fed to low-impedance port, thus making it a fully cascadable filter. In addition, the designed circuit exhibits independent tunability of its quality factor. With the idea of making the proposed filter fully integrable, a resistor-less approach of the configuration has also been discussed. By making slight modifications in the filter configuration, a current mode single-resistance-controlled quadrature oscillator circuit has also been derived. The ideal, nonideal, sensitivity and parasitic analysis have been conducted for the designed configurations. The functionality of the proposed structures is verified by PSPICE simulations using 0.18[Formula: see text][Formula: see text]m CMOS technology. The designs have also been verified using PSPICE macro-model of the commercially available IC, i.e., OPA860.

In this paper a new realization of electronically tunable current-mode Active-C biquad filter is presented. In the proposed current-mode biquad filter, only a single modified current conveyor transconductance amplifier (MCCTA) as active building block and two grounded capacitors as passive elements are used. The proposed filter can realize three filtering functions namely, low pass (LP), band pass (BP) and high pass (HP), simultaneously. It is also capable of realizing band reject (BR) and all pass (AP) responses. The pole frequency and quality factor of the proposed circuit can be electronically and orthogonally tuned via only biasing currents of the MCCTA. The theoretical results of the filter are verified by P-SPICE simulation where standard 0.25um CMOS process parameters from TSMC were used.

Synthesis of biquad filters using two VD-DIBAs with independent control of quality factor and natural frequency

A recently developed active element, namely Voltage Differencing Differential Voltage Current Conveyor (VD-DVCC), is employed in the design of electronically tunable mixed-mode universal filter. The filter provides low pass (LP), high pass (HP), band pass (BP), band reject (BR) and all pass (AP) responses in voltage-mode (VM), current-mode, trans-impedance-mode (TIM) and trans-admittance-mode (TAM). The filter employs two VD-DVCCs, three resistors and two capacitors. All the passive components employed are grounded. The attractive features of the filters include: (i) ability to operate in all four modes, (ii) use of grounded passive components, (iii) tunability of Q factor independent of pole frequency, (iv) high input impedance for VM and TIM mode, (v) high output impedance explicit current output for CM and TAM and (vi) no requirement for double/negative input signals (voltage/current) for response realization. The VD-DVCC is designed and validated in Cadence virtuoso using 0.18µm PDK at supply voltage of ±1V. The operation of filter is examined at 5.305 MHz frequency. The non-ideal gain and sensitivity analysis is also carried out to study the effect of process and components spread on the filter performance. The obtained results bear close resemblance with the theoretical findings.

This paper presents a systematic methodology for designing a voltage-mode multifunction biquad filter employing the commercially available active element, LT1228. The proposed topology adopts a three-input single-output (TISO) configuration. The circuit comprises a single LT1228, two capacitors, and three resistors, offering a highly compact design. The TISO biquad filter is capable of providing five fundamental filtering responses: low-pass (LP), band-pass (BP), high-pass (HP), band-reject (BR), and all-pass (AP) responses, within the same circuit architecture. Notably, these responses are achieved without the need for additional inverting amplifiers or reconfigurations of passive components. The parameters of the proposed filter, encompassing the natural (ω0 ) and quality factor (Q), are determined by electronic adjustment. Furthermore, we can adapt the proposed biquad filter to function as a current-controlled sinusoidal oscillator. The oscillation frequency is adjustable independently of the oscillation condition. We verified the performance and validity of the proposed circuits through PSpice simulations and experimental implementations in a laboratory setting. The proposed circuits hold immense significance for applications requiring precise signal generation and filtering, such as communication systems, test instrumentation, audio processing, automation and control systems.

This paper describes the design of multifunction second order voltage-mode filter using the voltage differencing differential difference amplifier (VDDDA) as active element. The internal construction of VDDDA based on the 0.25um TSMC CMOS technology is used for simulation and testing. The proposed filter is sort of three inputs-single output (TISO) multifunction filter. It consists of single VDDDA, single resistor and two capacitors that is suitable to fabricate into monolithic chip. The filter can provide five standard functions namely, lowpass (LP), bandpass (BP), highpass (HP), band-stop (BS) and allpass (AP) responses, in the same circuit topology. Each filter response can be selected by digital method. The natural frequency and quality factor can be electronically tuned that is attractive for micro-computer or microcontroller controllability. The proposed filter was supplied by ±1.25 V source. The simulated results using PSpice simulation agree well with expected theoretical analysis.

A low power current controllable single-input three-output current-mode filter using MOS transistors only

This research paper contains a new electronically tunable current-mode biquadratic universal filter using a new active building block; current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA). The proposed filter provides the following important and desirable features: (i) One can use only one CCDDCCTA and two capacitors; (ii) One can get low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) current responses from the same configuration without any alteration; (iii) Passive components are grounded, which ease the integrated circuit implementation; (iv) Responses are electronically tunable; and (v) Sensitivity is low. Moreover, the non-ideality analysis shows that the parasitic passive components can be compensated for the proposed circuit. The functionality of the design is verified through SPICE simulations using 0.25 μm CMOS TSMC technology process parameters. Simulation result agrees well with the theoretical analysis.

This paper presents a single VDTA based Mixed Mode type Biquad filter. The proposed Transadmittance Mode (TAM) type Biquad filter configuration employed single voltage differencing transconductance amplifier (VDTA) as an active building block, three passive element namely one grounded resistor, one grounded capacitor and one floating capacitor. The proposed transadmittance Mode multifunction Biquad filter configuration is presenting transadmittance mode type four basic standard filter functions low pass, high pass, band pass, band reject or band stop or band eliminate filter responses. These four type filter responses are realizing simultaneously with the selection of single input voltage signal. The proposed Transadmittance Mode multifunction Biquad filter configuration has more advantageous features such as low active and passive sensitivities, low power supply voltage, low power consumption, low quality factor, very low power consumption, more electronic tunability, higher linearity and required small area of the chip. The performance of the proposed configuration has been verified through PSPICE simulation using 0.18μm CMOS Technology process parameters.

The paper presents novel current-mode (CM) quadrature oscillators (QOs) created using the recently proposed active building block (ABB), namely the current controlled current differencing transconductance amplifier (CCCDTA). Two circuits have been proposed and both of them employ minimum components, namely one multipleoutput CCCDTA (MO-CCCDTA) and two grounded capacitors. One of the proposed circuits is suitable to be used as a very low frequency oscillator (VLFO) and the other circuit provides non-interactive CO and FO control and could be used as a variable frequency oscillator (VFO). Both the circuits provide explicit quadrature current outputs. Non-ideal analysis, sensitivity study are provided and PSPICE simulations have been included which verify the workability of the circuit.

The commercially available IC LT1228 is an interesting active device due to its advantage features, such as a fast transconductance amplifier, a wide bandwidth over a wide range of voltage gain, low total harmonic distortion (THD), high impedance differential input, etc. The single-input triple-output (SITO) voltage-mode (VM) multifunction biquadratic filters using ICs, LT1228s are introduced in this research. This circuit design provides the three-filtering functions, low-pass (LP), high-pass (HP), and band-pass (BP), without changing the circuit architecture. It comprises three LT1228s, four resistors, and two capacitors connected to the ground. The low impedance voltage output nodes are HP and BP responses. The quality factor (Q) and the pole frequency (ω0) can be electronically and orthogonally tuned by altering the third LT1228’s bias current (IB). The PSPICE simulation and the experiment are verified to describe the circuit operation.

This paper presents a possible usage of the voltage differencing transconductance amplifier (VDTA) for the design of an electronically tunable single-input five-output voltage-mode universal filter. The presented filter is constructed using two VDTAs, two capacitors and two resistors that are all grounded. The circuit simultaneously realizes lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) filtering responses, without changing the circuit topology. The circuit is capable of providing an independent electronic control of the natural angular frequency (ω0) and the quality factor (Q) through the transconductance gains of the VDTAs. By simply adjusting the transconductance ratio, a high-Q filter can also be obtained. Because of the high-input impedance of the circuit, it is advantageous for cascade connection. To support the theoretical analysis, the properties of the designed filter have been verified by PSPICE simulation results.

A current-mode analog multiplier/divider based on CCCDTA

Current-mode electronically tunable biquadratic filters consisting of only CCCIIs and grounded capacitors