MOS-only design automation and a simple agile MOS-only BP/LP filter design
In this work, a systematic of the automation in the result of the re-obtained small signal parameters based on SPICE is presented for MOS-Only circuits. Accuracy of the re-obtained parameters was improved by re-formulating in the basis of SPICE and CADENCE-SPECTRE. Moreover, piece-wise polynomial regressive models are presented for gds, gm and Ids-Also, performance of the models are compared with conventional expressions. Success of the given MOS-Only design automation based on re-obtained small signal parameters is verified with an examplary new agile filter.
Techniques for improving the accuracy of geometric-programming based analog circuit design optimization
We present techniques for improving the accuracy of geometric-programming (GP) based analog circuit design optimization. We describe major sources of discrepancies between the results from optimization and simulation, and propose several methods to reduce the error. Device modeling based on convex piecewise-linear (PWL) function fitting is introduced to create accurate active and passive device models. We also show that in selected cases GP can enable nonconvex constraints such as bias constraints using monotonicity, which help reduce the error. Lastly, we suggest a simple method to take the modeling error into account in GP optimization, which results in a robust design over the inherent errors in GP device models. Two-stage operational amplifier and on-chip spiral inductor designs are given as examples to demonstrate the presented ideas.
The microscale obstacle-resolving meteorological model MITRAS v2.0: model theory
Abstract. This paper describes the developing theory and underlying
processes of the microscale obstacle-resolving model MITRAS version 2. MITRAS
calculates wind, temperature, humidity, and precipitation fields, as well as
transport within the obstacle layer using Reynolds averaging. It explicitly
resolves obstacles, including buildings and overhanging obstacles, to
consider their aerodynamic and thermodynamic effects. Buildings are
represented by impermeable grid cells at the building positions so that the
wind speed vanishes in these grid cells. Wall functions are used to calculate
appropriate turbulent fluxes. Most exchange processes at the obstacle
surfaces are considered in MITRAS, including turbulent and radiative
processes, in order to obtain an accurate surface temperature. MITRAS is also
able to simulate the effect of wind turbines. They are parameterized using
the actuator-disk concept to account for the reduction in wind speed. The
turbulence generation in the wake of a wind turbine is parameterized by
adding an additional part to the turbulence mechanical production term in the
turbulent kinetic energy equation. Effects of trees are considered
explicitly, including the wind speed reduction, turbulence production, and
dissipation due to drag forces from plant foliage elements, as well as the
radiation absorption and shading. The paper provides not only
documentation of the model dynamics and numerical framework but also a solid
foundation for future microscale model extensions.
