%0 Journal Article
%T Ultra-Low-Voltage Low-Power Bulk-Driven Quasi-Floating-Gate Operational Transconductance Amplifier
%A Ziad Alsibai
%A Salma Bay Abo Dabbous
%J Advances in Electronics
%D 2014
%R 10.1155/2014/402840
%X A new ultra-low-voltage (LV) low-power (LP) bulk-driven quasi-floating-gate (BD-QFG) operational transconductance amplifier (OTA) is presented in this paper. The proposed circuit is designed using 0.18£¿¦Ìm CMOS technology. A supply voltage of ¡À0.3£¿V and a quiescent bias current of 5£¿¦ÌA are used. The PSpice simulation result shows that the power consumption of the proposed BD-QFG OTA is 13.4£¿¦ÌW. Thus, the circuit is suitable for low-power applications. In order to confirm that the proposed BD-QFG OTA can be used in analog signal processing, a BD-QFG OTA-based diodeless precision rectifier is designed as an example application. This rectifier employs only two BD-QFG OTAs and consumes only 26.8£¿¦ÌW. 1. Introduction In the late sixties, the Radio Corporation of America (RCA) and then General Electric (GE) came out with the operational transconductance amplifier, hereafter called OTA. The name means essentially a controllable resistance amplifier. OTA is a key functional block used in many analog and mixed-mode circuits. It is a special case of an ideal active element, and its implementation in IC form makes it indispensable today in discrete and fully integrated analog network design. The ideal OTA as shown in Figure 1 can be considered as a differential voltage-controlled current source (DVCCS); its transconductance ¡° ¡± represents the ratio of the output current to the differential input voltage, that is, . This transconductance is used as a design parameter and it is usually adjustable by the amplifier bias current . The benefit of this adjusting possibility is acquiring the ability of electronic orthogonal tunability to circuit parameters. It could be noted that tunability has a main role in integrated circuits, especially to satisfy a variety of design specifications. Thus, OTA has been implemented widely in CMOS and bipolar and also in BiCMOS and GaAs technologies [1]. Figure 1: Ideal operational transconductance amplifier, (a) symbol and (b) equivalent circuit. The OTA is similar to the standard operation amplifier (OPA) in the sense of infinite input impedances, but its output impedance is much higher and that makes OTA more desirable than any ordinary amplifier. Recently, the multiple-output-OTA (MO-OTA) has been introduced and used, on par with the ordinary operation amplifier, as a basic block in many applications, particularly for realizing universal filters which are able to implement several second-order transfer functions with a minimum of adjustments. The literature provides numerous examples of OTA-based biquad structures, as well as active
%U http://www.hindawi.com/journals/aelc/2014/402840/