This paper presents a low-voltage low-dropout voltage (LDO) regulator achieving a high power supply rejection (PSR) performance over a wide frequency range. A simple PSR enhancing circuit (PSRE) establishing a power noise (ripple) cancellation mechanism to avoid power noise passing through the power MOS transistor. A LDO regulator adopting the proposed PSRE was designed using a 1-V 90 nm CMOS process to convert an input of 1.2 V-0.8 V to an output of 0.85 V-0.5 V at a load current range of 0-100 mA. Post-layout simulations show that a PSR is above −57 dB at 1 MHz while the output spike during a 0.1 mA-100 mA load transient test is only 14 mV.
In this study, the dynamic analysis of a domestic high speed rotor bearing system in turbo machines by using global assumed mode with different polynomial is investigated. This system consists of rotating multi flexible shaft, rigid disks and stiffness bearing effects. The analysis includes the whirl speeds, critical speeds, and mode shapes. The Global Assumed Modes Method (GAMM) and Finite Element Method (FEM) are employed to model the rotor-bearing system, and the accuracy of the results is discussed. With the application of GAMM, similarity transformation of different types of polynomials and interval has been investigated. The results show that using different polynomial function in GAMM have similar results, and which are also be agreed with the FEM. The results also show that the number of polynomial can be increased as the interval of the assumed mode function is altered. Consequently, the convergence of higher order modes will be more accurate.
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