Lerkvaranyu, Somkiat

Preferred name

Alternative Name

Lerkvaranyu, S.

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School of Engineering

somkiat.le@kmitl.ac.th

Now showing 1 - 5 of 5

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Current-Mode Shadow Filter with Single-Input Multiple-Output Using Current-Controlled Current Conveyors with Controlled Current Gain
(2024-01-01)
Kumngern, Montree
;
Khateb, Fabian
;
Kulej, Tomasz
;
Kyselak, Martin
;
Lerkvaranyu, Somkiat
In this paper, a novel current-mode shadow filter employing current-controlled current conveyors (CCCIIs) with controlled current gains is presented. The CCCII-based current-mode shadow filters are resistorless and can offer a number of advantages such as circuit simplicity and electronic tuning capability. The proposed shadow filters offer five filtering functions, i.e., low-pass, high-pass, band-pass, band-stop, and all-pass functions, in the same topology. Furthermore, no component matching condition is required to realize all the transfer functions. The natural frequency and quality factor adjustment is possible by using the CCCII current gains without the need to use external amplifiers, all capacitors are grounded, and the filter terminals offer low-input and high-output impedance. To verify the functionality and feasibility of the new topologies, the proposed circuits were simulated using SPICE and the transistor model process parameters NR100N (NPN) and PR100N (PNP) from AT&T’s bipolar arrays ALA400-CBIC-R. The simulation results are consistent with the theory. The CCCII experimental setup was designed using commercially available 2N3904 (NPN) and 2N3906 (PNP) transistors with a supply voltage of ±2.5 V. The measurement results confirm the performance of the designed filters.
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An Ultralow-Power 0.5-V MI-OTA-Based Universal Filter for Efficient Low-Frequency Signal Processing
(2026-01-01)
Kulej, Tomasz
;
Kumngern, Montree
;
Khateb, Fabian
;
Lerkvaranyu, Somkiat
This work introduces novel universal filters implemented using multiple-input operational transconductance amplifiers (MI-OTAs). The MI-OTA is specifically designed for a minimal 0.5-V supply, achieving nano-watt level power dissipation, which positions the design as highly viable for demanding ultralow-power systems. The architecture employs a subthreshold, multiple-input, bulk-driven MOS configuration. This design not only extends the operational input voltage range but concurrently ensures minimal voltage and power consumption. The primary filter topology utilizes five MI-OTAs and two grounded capacitors to concurrently deliver all five standard filtering responses—low-pass, high-pass, band-pass, band-stop, and all-pass filter—from a single, fixed circuit structure. By integrating a sixth MI-OTA, the architecture becomes reconfigurable for operation in both voltage-mode (VM) and transimpedance-mode (TIM). This versatility yields both non-inverting and inverting transfer functions for all five fundamental responses, resulting in a total of 20 distinct output functions. This multifunctionality and power efficiency make the proposed designs exceptionally well-suited for low-frequency applications, such as bio-signal processing and sophisticated sensor interfacing circuits. Furthermore, a key feature is that the filter's natural frequency is electronically tunable across all responses. The MI-OTA was designed and simulated in Cadence Virtuoso, utilizing the TSMC 65-nm (1P9M) CMOS process. The device occupies a modest silicon footprint of 125 μm × 92 μm. Simulation results confirm a power dissipation of 150 nW at a 177-Hz cutoff frequency under the 0.5-V supply. Post-layout simulations verified the expected circuit performance. Finally, experimental validation was conducted using a discrete-component MI-OTA-based circuit built with the LM13700, thereby confirming the filter's correct operation.
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Atmospheric boundary layer observation by ground-based lidar at KMITL, Thailand (13° N, 100° E)
(2001-01-01)
Lerkvaranyu, Somkiat
;
Dejhan, Kobchai
;
Cheevasuvit, Fusak
;
Itabe, Toshikasu
;
Mizutani, Kohei
Tropospheric aerosols effects on climate in directly through various cloud formation, the lidar has been used to study the composition of many particles mixing in the atmosphere including to study the aerosol and cloud. Currently, it has many types of lidar systems depending on the purpose of measurements. In this report, the ground-based lidar system was established at King Mongkut's Institute of Technology Ladkrabang (KMITL), THAILAND to study and measure the aerosol in boundary layer and cirrus clouds in the tropopause region. The aerosol measurement is in the form of scattering ratio whereas the signal depolarization has been applied to identify layers of cirrus clouds. The lidar system consists of laser source (Nd:YAG) with second harmonic wavelength, 28 cm Schmidt-Cassegrain telescope, photomultiplier tube (PMT) and data acquisition system.
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TEC prediction with neural network for equatorial latitude station in Thailand
(2012-01-01)
Watthanasangmechai, Kornyanat
;
Supnithi, Pornchai
;
Lerkvaranyu, Somkiat
;
Tsugawa, Takuya
;
Nagatsuma, Tsutomu
This paper describes the neural network (NN) application for the prediction of the total electron content (TEC) over Chumphon, an equatorial latitude station in Thailand. The studied period is based on the available data during the low-solar-activity period from 2005 to 2009. The single hidden layer feed-forward network with a back propagation algorithm is applied in this work. The input space of the NN includes the day number, hour number and sunspot number. An analysis was made by comparing the TEC from the neural network prediction (NN TEC), the TEC from an observation (GPS TEC) and the TEC from the IRI-2007 model (IRI-2007 TEC). To obtain the optimum NN for the TEC prediction, the root-mean-square error (RMSE) is taken into account. In order to measure the effectiveness of the NN, the normalized RMSE of the NN TEC computed from the difference between the NN TEC and the GPS TEC is investigated. The RMSE, and normalized RMSE, comparisons for both the NN model and the IRI-2007 model are described. Even with the constraint of a limited amount of available data, the results show that the proposed NN can predict the GPS TEC quite well over the equatorial latitude station. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).
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0.5-V High-Order Universal Filter for Bio-Signal Processing Applications
(2025-04-01)
Kumngern, Montree
;
Khateb, Fabian
;
Kulej, Tomasz
;
Lerkvaranyu, Somkiat
In this paper, a novel multiple-input operational transconductance amplifier (MI-OTA) is proposed. The MI-OTA can be obtained by using the multiple-input bulk-driven MOS transistor (MIBD MOST) technique. The circuit structure is simple, can operate with a supply voltage of 0.5 V, and consumes 937 pW at a current setting of 625 pA. The proposed MI-OTA was used to implement a high-order multiple-input voltage-mode universal filter. The proposed filter can provide non-inverting and inverting low-pass, high-pass, band-pass, band-stop, and all-pass transfer functions to the same topology. In addition, it has a high input impedance and does not need any inverted input signals, so there is no additional buffering circuit. The proposed filter can be used for biological signal processing. The proposed MI-OTA and the second-order universal filter were simulated in Cadence using CMOS process parameters of 0.18 μm from TSMC to verify the functionality and performance of the new structures.

Lerkvaranyu, Somkiat

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