Design and implementation of a sliding-mode controller for digital low-dropout/linear regulators
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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.
CitationBaheri, J., Saberkari, A., Khorgami, O., Alarcon, E. Design and implementation of a sliding-mode controller for digital low-dropout/linear regulators. "IEEE transactions on circuits and systems II: express briefs", 20 Març 2018, vol. 65, núm. 12, p. 1889-1893.