Sandeep Dhar

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The paper describes a closed-loop controller for adaptive voltage scaling (AVS) where the supply voltage to a standard-cell ASIC is dynamically adjusted to the minimum value required for the desired system speed. The controller includes a clock generator that provides a low-jitter clock to the ASIC at all steady-state operating points and through(More)
We investigate the magnetic properties of epitaxial GaN:Gd layers as a function of the external magnetic field and temperature. An unprecedented magnetic moment is observed in this diluted magnetic semiconductor. The average value of the moment per Gd atom is found to be as high as 4000 micro(B) as compared to its atomic moment of 8 micro(B). The long-range(More)
This paper describes an adaptive power management architecture to reduce power consumption in digital filters. The proposed approach combines two low-power techniques which utilize supply voltage reduction. The first technique, multiple voltage distribution (MVD), attempts to reduce power consumption by assigning reduced supply voltages to circuit modules(More)
Reverse body biasing (RBB) is often used to reduce the leakage power of a device. However, recent research has shown that if this applied RBB is too high, the leakage power can actually increase due to the contribution of Band-to-Band Tunneling (BTBT) currents. Hence, there exists an optimal RBB value at which the leakage is minimum. This optimum point can(More)
Unlike the Si-SiO2 interface, the SiC-SiO2 interface has large defect densities. Though nitridation has been shown to reduce the defect density, the effect of H remains an open issue. Here we combine experimental data and the results of first-principles calculations to demonstrate that a Si-C-O bonded interlayer with correlated threefold-coordinated C atoms(More)
The paper describes a switching regulator system for adaptive voltage scaling (AVS) where the supply voltage to a digital VLSI chip is dynamically adjusted to the minimum value required for the desired system speed. The control loop includes a variable-frequency Watkins-Johnson switching DC-DC converter and a model of the critical path delay of the(More)
The current work directly relates valve dynamics to the compressor energy efficiency. Majority of the previous studies have focused on reducing pressure losses due to valve geometry, towards improved compressor performance. On a complimentary note, analyzing the valve ‘flutter’ leads to a holistic valve development methodology. Traditionally, pressure(More)
Pressure-actuated reed valves play an important role in the compression process of a refrigerator compressor. The material properties and geometrical parameters of the valve and geometrical properties of valve port determine the flow coefficient which in turn impacts the compressor efficiency. Also, the moving mass of the valve and its stiffness governs the(More)
Brake systems in trucks are crucial for ensuring the safety of vehicles and passengers on the roadways. Most trucks in the US are equipped with S-cam drum brake systems and they are sensitive to maintenance. Brake defects such as leaks are a major cause of accidents involving trucks. Leaks in the air brake systems affect braking performance drastically by(More)
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