Design and implementation of a sliding-mode controller for digital low-dropout/linear regulators

This paper presents an approach to utilize of sliding-mode (SM) controller in digital low-dropout/linear regulators. Various design aspects, including the extraction of the regulator state-space model and sliding coefficients by considering the hitting, existence, and stability conditions are described. Moreover, the freeze control block is introduced as a solution to compensate the high frequency chattering phenomenon of SM, resulting in reduction of switching losses. In order to verify the statements, a quasi digital low-dropout/linear regulator (QDLDO) is implemented in a discrete form on a PCB. The circuit consists of the proposed current-mode current feedback amplifier (CFA)-based SM controller and switchedmode PMOS array driven by a bidirectional serial shift register, which is controlled by the SM controller. The results reveal that the controller detects the load changes rapidly, and eliminates the output limit-cycle oscillation, providing a robust and stable output voltage.Peer ReviewedPostprint (author's final draft

Design of broadband CNFET LNA based on extracted I-V closed-form equation

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A procedure of extracting a closed-form user-friendly I-V equation for short channel carbon nanotube field-effect transistors (CNFET) in the saturation region is presented by employing a relation between CNFET parameters meeting the experimental results. The methodology is based on the Stanford model and ballistic relation of one channel CNFET. In this regard, the ballistic relation is simplified to a closed-form I-V equation, and then, the parameters are estimated through the fitting algorithm by means of ICCAP and least square (LS) method, respectively, and the obtained equation is verified by the experimental results given in the literature. Additionally, an extended quantitative noise analysis is performed at the circuit level and the noise sources implemented in Verilog-A are added to the Stanford CNFET HSPICE model. Subsequently, with the accordance to the extracted I-V equation, a CNFET-based inductor-less broadband common-gate low noise amplifier (LNA) is designed theoretically and its results are confirmed in HSPICE based on the Stanford CNFET model, indicating a proper matching between analysis and simulation. The proposed CNFET-based LNA provides very high frequency bandwidth and also lower noise figure in comparison with its contemporary CMOS-based LNA, without any passive spiral inductor.Peer ReviewedPostprint (author's final draft

Design of broadband CNFET LNA based on extracted I-V closed-form equation

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A procedure of extracting a closed-form user-friendly I-V equation for short channel carbon nanotube field-effect transistors (CNFET) in the saturation region is presented by employing a relation between CNFET parameters meeting the experimental results. The methodology is based on the Stanford model and ballistic relation of one channel CNFET. In this regard, the ballistic relation is simplified to a closed-form I-V equation, and then, the parameters are estimated through the fitting algorithm by means of ICCAP and least square (LS) method, respectively, and the obtained equation is verified by the experimental results given in the literature. Additionally, an extended quantitative noise analysis is performed at the circuit level and the noise sources implemented in Verilog-A are added to the Stanford CNFET HSPICE model. Subsequently, with the accordance to the extracted I-V equation, a CNFET-based inductor-less broadband common-gate low noise amplifier (LNA) is designed theoretically and its results are confirmed in HSPICE based on the Stanford CNFET model, indicating a proper matching between analysis and simulation. The proposed CNFET-based LNA provides very high frequency bandwidth and also lower noise figure in comparison with its contemporary CMOS-based LNA, without any passive spiral inductor.Peer Reviewe