Chaichana, Amornchai
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Chaichana, Amornchai
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Chaichana, Amonchai
Chaichana, Amornchia
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amornchai.ch@kmitl.ac.th
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Item type:Publication, Single Active Element Based Electronically Controllable Capacitance Multiplier(2022-07-15); ; ; The realization of capacitance multiplier using the versatile active building block, namely voltage differencing differential difference amplifier (VDDDA) is presented in this paper. The realized capacitance multiplier is very simple consisting of one VDDDA, one MOS resistor (RM) and one grounded capacitor which is attractive for integration. The multiplication factor (KC) of the realized circuit can be electronically controlled via the bias current (IB) and control voltage (VC) without the need of any matching condition of active and passive element. Moreover, the multiplication factor can be adjusted to be more or less than one. The performances of the presented capacitance multiplier are verified through Pspice simulation using CMOS VDDDA in 0.18μm TSMC technology with ±0.9V power supplies. The multiplication factor is designed to be KC=2 by choosing VC=0.85V, IB=50μA and C=30 pF. The simulated multiplication factor is around 1.98. The simulated operational frequency range is around three decades (6.16 kHz-8.91MHz). The performances of the proposed circuit are also verified by the experiment using VDDDA implemented from the commercial ICs, AD830 and LM13700 with ±5V power supplies. The experiment is conducted under the same multiplication factor (KC=2) as the simulation by choosing RM=0.27 kω (1% passive resistor), IB=96.2μA and C=1nF. The experimental multiplication factor is around 2.06. The experimental operational frequency range is around three decades (1kHz-1.25MHz). By adjusting the bias current from 17.67μA to 400 μA, the experimental multiplication factor is controllable from 11.47 to 0.48. The percent deviation of the theoretical and experimental multiplication factor is lower than 5% when the value of bias current is greater than 39μA. These deviations stem from the effect of the parasitic capacitance and resistance in VDDDA. Moreover, the application example of the presented capacitance multiplier as the sinusoidal oscillator is presented. The performances of the presented oscillator verified via the experiment are well consistent with theoretical anticipation. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Voltage-Mode First-order Multifunction Filter with Electronic Controllability Using VDDDA(2025-01-01); ; This study presents the design of a three-input single-output voltage-mode first-order multifunction filter. The proposed filter comprises a single VDDDA as the active component, one grounded capacitor, and two resistors. The output voltage node has low impedance. The proposed filter provides three responses consisting of a low-pass (LP), a highpass (HP), and an all-pass (AP) by setting the voltage signal at the input voltage. The natural frequency (f<inf>0</inf>) and phase response are electronically controlled by the bias current (I<inf>B</inf>). This flexibility allows for precise tuning of the filter characteristics to meet specific application requirements. The passband gain of LP and HP filters can be adjusted using resistors R<inf>1</inf> and R<inf>2</inf> without affecting the f<inf>0</inf> or requiring an additional amplifier. The simulation and experimental results validate the functionality of the proposed filter as anticipated theoretically. This reliability is crucial for communications and signal processing applications, where accurate signal representation is paramount. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electronically Tunable Capacitance Multiplier Implemented Using a Single Active Element for Low-Frequency Biomedical Applications(2024-01-01); ; ; An active circuit designed for increasing a passive capacitor's capacitance to a noticeably larger level is called a capacitance multiplier. The article proposes the design of a grounded capacitance multiplier using an electronically adjustable active device called a voltage differencing differential difference amplifier (VDDDA). The proposed capacitance multiplier is a very compact structure that consists of just one passive resistor, one passive capacitor, and one VDDDA. The multiplication factor (KC) can be electronically controlled by adjusting the external bias current (IB) of VDDDA, which is convenient for microcontroller control in modern analog signal processing systems. To test the performance of the proposed capacitance multipliers PSpice simulation and experimentation using a VDDDA built from commercially available integrated circuits were utilized. To further illustrate the usefulness of the proposed capacitance multiplier, an application example in the lagged phase shifter with electronically adjustable phase shifts is shown and examined. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, MULTIPLE-INPUT SINGLE-OUTPUT VOLTAGE-MODE MULTIFUNCTION FILTER BASED ON VDDDAS(2023-12-01); ; ; In recent years, the voltage differencing differential difference amplifier (VDDDA) has been used in various analog signal processing circuit designs. A second-order multifunction filter with multiple-inputs and single-output (MISO) voltage mode using VDDDA as active elements is proposed in this paper. The structure of the proposed filter comprises two VDDDAs, two grounded capacitors, and two resisters. The proposed filter has a cascadability feature in a voltage-mode sys-tem, producing voltage input and voltage output at high and low impedance ports, respectively. It can offer responses for all-pass (AP), band-reject (BR), band-pass (BP), low-pass (LP), and high-pass (HP) filters without additional inverting and double gain amplifiers, as well as the matching conditions. Choosing the appro-priate input signals provides these five filter responses in the same circuit topology. With two VDDDAs, the bias currents can be utilized to electronically tune the natural frequency (ω<inf>0</inf>) independently from the quality factor (Q). Experimental results using available com-mercial ICs have supported the theoretical expectations and confirmed the practical operation of the proposed multifunction biquad filter.