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High-order chebyshev notch filter based on MO-OTA and its application in Biosensor
(2021-05-19)
Srisamranrungrueang, Siradanai
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Wongprommoon, Natapong
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Prommee, Pipat
This paper presents a high-order notch filter based on multiple output OTA (MO-OTA). The signal flow graph (SFG) method is applied as a design procedure based on the RLC prototype. The RLC Chebyshev low-pass filter is used as an original prototype. The network transform is applied to convert the LPF to a notch filter. From the SFG, the denormalized network can be replaced by integrators and differentiators. The current-mode lossy and lossless types of integrator and differentiator are realized by using CMOS MO-OTA and grounded capacitor. A simple and low-complexity structure is achieved and constructed by 9 MO-OTAs and 6 grounded capacitors. The stop-band frequency between 10Hz-1kHz can be electronically tuned by the bias current between 1-100 μA. The low power supply ±0.75V is required which consumes the power 15mW at 100μA bias current. An application in ECG signal with power line interference (PLI) removal is included.
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Low-voltage low-pass and band-pass elliptic filters based on log-domain approach suitable for biosensors
(2019-12-02)
Prommee, Pipat
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Wongprommoon, Natapong
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Kumngern, Montree
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Jaikla, Winai
This research proposes bipolar junction transistor (BJT)-based log-domain high-order elliptic ladder low-pass (LPF) and band-pass filters (BPF) using a lossless differentiator and lossless and lossy integrators. The log-domain lossless differentiator was realized by using seven BJTs and one grounded capacitor, the lossy integrator using five BJTs and one grounded capacitor, and the lossless integrator using seven BJTs and one grounded capacitor. The simplified signal flow graph (SFG) of the elliptic ladder LPF consisted of two lossy integrators, one lossless integrator, and one lossless differentiator, while that of the elliptic ladder BPF contained two lossy integrators, five lossless integrators, and one lossless differentiator. Log-domain cells were directly incorporated into the simplified SFGs. Simulations were carried out using PSpice with transistor array HFA3127. The proposed filters are operable in a low-voltage environment and are suitable for mobile equipment and further integration. The log-domain principle enables the frequency responses of the filters to be electronically tunable between 10k Hz–10 MHz. The proposed filters are applicable for low-frequency biosensors by reconfiguring certain capacitors. The filters can efficiently remove low-frequency noise and random noise in the electrocardiogram (ECG) signal.
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High-order bp filter using biquad log-domain method
(2018-07-02)
Wongprommoon, Natapong
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Manositthichai, Narongsak
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Prommee, Pipat
High-order band-pass ladder filter based on Log-domain biquad functions is presented in this paper. High-order ladder filter is designed from RLC ladder filter prototype based on two types of biquad log-domain filters. Log-domain lossy and lossless integrator concepts are used to realize biquad log-domain filter in each type. Log-domain lossy integrator is easily realized by using 7 transistors and 1 grounded capacitor and log-domain lossless integrator is also easily realized by using log-domain lossy integrator by adding feedback to the input which consists of 8 transistors and 1 grounded capacitor. By adjusting bias current the frequency responses the filter can be obtain between 100 kHz and 100 MHz. This filter operates in transistor level which is suitable for operating in high frequency operation. A commercial array BJT technology is used in PSpice simulation.
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Log-domain high-order low-pass and band-pass filters
(2017-09-01)
Prommee, Pipat
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Thongdit, Preecha
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Angkeaw, Krit
Continuous time current-mode high-order low-pass and band-pass filters based on the log-domain concept are presented in this paper. The passive RLC ladder networks are used as the prototype to achieve the proposed filter by simulating the RLC network synthesis method. The achieved filters have inherited the good sensitivity performance from the RLC passive prototype. Fifth-order RLC ladder low-pass filter and sixth-order RLC ladder band-pass filter are used as prototypes and the signal flow graph (SFG) technique is used for the synthesis. The SFG can identify group of integrators and several signal paths. Log-domain lossy and lossless integrators based on BJT technology are deployed to achieve the integrators for realization of proposed filters. The simulations were carried out and the results exhibited several features which are in agreement with the RLC prototype. The frequency response of filters along 100 kHz to 10 MHz can be electronically tuned through 5–500 µA of bias currents. The THD lower than 1% of LP and BP filters were measured at 10 MHz input. The multi-tone tested was included in the paper for verifying the performance of proposed LP and BP filters. The intermodulation distortions around −50 dB and −60 dB were also investigated for the proposed LP and BP filters.
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Active-only variable-gain low-pass filter for dual-mode multiphase sinusoidal oscillator application
(2017-01-01)
Prommee, Pipat
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Manositthichai, Narongsak
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Khateb, Fabian
This research presents an active-only low-pass (LP) filter whose pole frequency and gain are independently tunable by means of bias current manipulation. The realization of the proposed LP filter required one operational amplifier, two operational transconductance amplifiers, and two MOS transistors. The multiphase sinusoidal oscillator (MSO) was subsequently realized by cascading n LP filters (n = 3) and loop-backing the output of the last LP filter to the input of the first LP filter. Simulations were carried out and the results revealed that the MSO could simultaneously achieve low impedance voltage and high impedance current outputs without the circuit topology alteration. The frequency of oscillation and the condition of oscillation could also be electronically tuned without disturbing each other. Furthermore, the sinusoidal signal of the MSO exhibited relatively low total harmonic distortion of about 0.8% at 2.75 MHz. To verify, a prototype of the active-only LP-based MSO (n = 3) was constructed and experiments were performed. The experimental findings were agreeable with the simulation results.
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Accurate tunable current-mirror and its applications
(2008-12-01)
Somdunyakanok, Montri
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Pattanathadapong, Thanate
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Prommee, Pipat
This paper proposes an accurate electronically tunable current-mirror circuit based on translinear type-A (Polarities Alternative) topology. This circuit is realized by only 6 transistors with BJT technology. A shunt-feedback buffer principle is used in order to regulate its emitter voltage of translinear part. For current mirror behavior, output and input currents are identical with a small error. Current-gain can be obtained by adjusting the ratio of the 2 particular current sources. This proposed circuit is using only 6 transistors for the simple structure. The analysis of input, output resistance and current-gain are depicted. An extra transistor is added for maintained the transfer minimum error which is also proposed. The constant bandwidth more than 40MHz of various current-gains can be obtained. From current output mathematic function, several applications such as current multiplier, current divider and tunable current mirror are certainly performed. Other applications are raised to confirm realistic applicable including squaring and square- rooting circuits. All characteristics and performances are carried out by PSpice for confirm their well operations. © 2008 IEEE.
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Low-component-count current-mode universal filter based on active-only lossy and lossless integrators
(2008-12-01)
Somdunyakanok, Montri
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Angkeaw, Krit
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Prommee, Pipat
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Kumngern, Montree
An universal current-mode active-only filter using the biquadratic transfer function is proposed. The proposed circuit is realized by lossy and lossless integrators with minimize active components count without external passive elements. The different kinds of filter functions as lowpass, highpass, bandpass and band-reject response can be obtained without changing circuit topology. The proposed circuit implementation is realized by using MOS transistors, CMOS MO-OTAs, and CMOS OPAMPs. The parameters ω<inf>p</inf> can be tuned electronically through adjusting the transconductance gains of the OTA or electronic resistor power supplies. The simulation results are given by PSpice. © 2008 IEEE.
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Realization of OTA-C current-mode universal filter based on two type integrators loop
(2007-12-01)
Prommee, Pipat
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Somdunyakanok, Montri
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Angkeaw, Krit
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Dejhan, Kobchai
A universal current-mode active filter based on 2 types of integrator, lossy and lossless integrators, is presented. The biquadratic transfer function is obtained by the two integrators loop. The proposed circuit employs only 2 multiple output OTAs (MO-OTA) and 3 capacitors. The parameter Q<inf>P</inf> can be wide-range tuned independent from the ω<inf>P</inf> either changing of capacitor and transconductance gains. Moreover, the four different kind filter functions as lowpass, highpass, bandpass and band-reject response can be also obtained without changing circuit topology. The parameters ω<inf>p</inf> can be electronically tuned through adjusting the transconductance gains of the OTAs. The simulation results have been carried out by PSpice. © 2007 IEEE.

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