Atilla Uygur

Low-voltage current differencing transconductance amplifier in a novel allpass configuration

In this paper, a CMOS realization of the current differencing transconductance amplifier in the low voltage is presented. The proposed circuit can operate in supply rails down to plusmn0.75 V. In the input stage, flipped voltage followers are used to obtain very low input resistances and a few tens of ohms of input resistances are achieved. Then, the proposed circuit is employed in a novel allpass configuration. To verify the correctness of the realization, SPICE simulation results are also supplied

An ultra low-voltage, ultra low-power DTMOS-based CCII design for speech processing filters

In this study, an ultra low-voltage, ultra low-power dynamic threshold voltage MOS transistor (DTMOS)-based CCII design has been presented. The proposed circuit operates under ±0.2 V symmetric power supply. Consisting of only eight transistors, it consumes only 214 nW power while all transistors are working in the subthreshold region. It has a 570 kHz 3 dB-bandwidth from X terminal to Y terminal for the voltage gain. TSMC 0.18 μm process technology is used in the design of CCII block which is then employed in a band-pass filter configuration. In order to further investigate its performance, real speech signals are fed to the filter and close agreement is found between theoretical study and simulated responses.

An ultra low-voltage ultra low-power memristor

Memristor can provide new approaches especially in nonlinear & chaotic circuit design. Since no commercially available memristor exist until yet, obtaining of a practical implementation which behaves as a memristor, is very important from the point of view real-world circuit design. In this work, an ultra low-voltage ultra low-power DTMOS-based design of memristor is presented. A new ultra low-voltage, ultra low-power operational amplifier and a new ultra low-voltage, ultra low-power multiplier are also proposed to use in the realization. Our design is composed of these two type active blocks using CMOS 0.18μm process technology with symmetric ±0.25V supply voltages. Characteristics and performance of our design is verified by PSPICE simulations. Total power consumption of the proposed memristor is found as just 4.3μW which is suitable for ultra low-power consumption. The simulation results show that our design provides the characteristics of memristor accurately and it could be a viable and convenient option especially in low-voltage low-power memristor based chaotic applications.

MOS-only third order butterworth filter with DTMOS tuning technique for high frequency applications

In this paper, a new low-voltage, MOS-only, third order low-pass filter is proposed. The core circuit consists of only three MOSFETs and their parasitic gate to source capacitances as passive elements. Using TSMC 0.18μm technology parameters, the circuit with all biasing elements included consumes just 0.69mW for a cut-off frequency higher than 200MHz under a single supply of 1.8V. Non-ideal effects have been investigated and dynamic threshold voltage MOS (DTMOS) tuning technique has been developed for the filter circuit to suppress the non-idealities. Resulting circuit is capable of operation at high frequencies with low power consumption due to the usage of significantly less number of transistors than conventional active block-based filtering circuits.

0.4V OTA design using DTMOS transistors for EEG data processing

In this study, an ultra low-voltage low-power operational transconductance amplifier (OTA) is proposed. Dynamic Threshold Voltage MOS (DTMOS) transistors are utilized in the design for using very low supply voltages efficiently. The proposed OTA circuit is employed in a fourth-order band-pass filter topology which is used in EEG data processing with the help of SPICE and MATLAB programs. It is found that simulations are in close agreement with the theoretical calculations.