Design of Low Voltage Quasi-floating Self Cascode Current Mirror

In this paper, a modified structure of self-cascode structure is proposed. In the proposed structure, the MOSFET working in saturation mode is replaced by a Quasi-floating gate MOSFET by which the threshold voltage can be scaled, resulting in an increase in the drain-to-source voltage of other MOSFET operating in the linear region. The increased drain-to-source voltage results in a change in the operating region, which here is from linear to saturation regime. To exploit the performance of the proposed structure, the design of the current mirror circuit is shown in this paper. The proposed architecture when compared with its conventional design showed improvement in performance without affecting the other parameters. The complete design is done using MOSFET models of 180nm technology using Spice at supply dual supply of 0.5V.

Design of Low Voltage Low Power High Gain Operational Transconductance Amplifier

In this paper, a high gain structure of operational transconductance amplifier is presented. For low voltage operation with improved frequency response bulk driven quasi-floating gate MOSFET is used at the input. Further for achieving high gain the modified self cascode structure is used at the output. Compared to conventional self cascode the modified self cascode structure used provides higher transconductance which helps in significant boosting of gain of the amplifier. The modification is achieved by employing quasi-floating gate transistor which helps in scaling of the threshold which as a result increases the drain-to-source voltage of linear mode transistor thus changing it to saturation. This change of mode boosts the effective transconductance of self cascode MOSFET. The proposed operational transconductance amplifier when compared to its conventional showed improvement in DC gain by 30dB and also the unity gain bandwidth increases by 6 fold. The MOS models used for amplifier design are of 0.18µm CMOS technology at supply of 0.5V.

Analysis of Current Mirrors with Asymmetric Self-Cascode Association of SOI MOSFETs through SPICE Simulations

In this paper the performance of different architectures of current mirrors implemented with single SOI transistors and self-cascode transistors, both symmetric and asymmetric is evaluated. A comparison of current mirrors figures of merit, looking for the advantages of the asymmetric composite structure in relation to a single SOI MOSFETs and the symmetric self-cascode transistor is performed. This analysis has been carried out through analytical simulations, using common-source, Cascode and Wilson current mirrors architectures. It is shown that asymmetric configuration can provide larger output resistance even in the common-source current mirror than other architectures with conventional single transistors.