Showing 3 results for Najafi Aghdam
M. Abarzadeh, F. Eshaghi, E. Najafi Aghdam,
Volume 14, Issue 1 (March 2018)
Abstract
This paper proposes an improved control method based on modified Delta-Sigma Modulator (DSM) to enhance transient response and improve harmonic contents of buck DC-DC converter. The main advantages of the proposed method are improving the output voltage frequency spectrum, correction of the output voltage harmonic contents and sideband harmonics, reduction of switching noise peaks at the output voltage, operating buck converter in continuous current mode independent of load current, significant reduction of inductor current ripple, improving the transient response of buck converter and correction of the input current harmonics. This progress is achieved by applying improved control method based on proposed forgetting function to enhance transient response of buck converter and also by using modified DSM to improve harmonic spectrum of the output voltage and reduce inductor current ripples. The simulation results confirm performance and feasibility of the proposed system.
T. Azadmousavi, H. Faraji Baghtash, E. Najafi Aghdam,
Volume 14, Issue 2 (June 2018)
Abstract
This work introduces a new and simple method for adjusting the gain of current mirror. The major advantage of the proposed architecture is that, unlike the conventional variable gain current mirror, it does not need the change of the biasing current to adjust current gain. Therefore, the power dissipation remains constant in all of the gain settings. In addition, the proposed variable gain current mirror have linear-in-dB gain control characteristic, simple structure, and small occupied area. The gain of the current mirror can be simply varied from 1.3dB to 21dB while the 3-dB bandwidth of the circuit remains around 12.3MHz or 33.6MHz at operation frequency range of 1.9MHz-14.2MHz and 6.6MHz-40.2MHz respectively. The proposed circuit draws negligible power of 6.9µW from 1.8V supply voltage. The simulation results of designed variable gain current mirror in 0.18μm standard CMOS technology confirms the effectiveness of the proposed circuit.
T. Azadmousavi, H. Faraji Baghtash, E. Najafi Aghdam,
Volume 15, Issue 2 (June 2019)
Abstract
A power efficient gain adjustment technique is described to realize programmable gain current mirror. The dissipation power changes over the wide gain range of structure are almost negligible. This property is in fact very interesting from power management perspective, especially in analog designs. The simple structure and constant frequency bandwidth are other ever-interesting merits of proposed structure. The programming gain range of structure is from zero up to 18dB under operating frequency range from 72 kHz to 173 MHz. The maximum power dissipation of designed circuit is only 3.1 µW which is drawn from 0.7 V supply voltage. Simulation results in 0.18 µm CMOS TSMC standard technology demonstrate the high performance of the proposed structure.
