Abstract.
The application of optimization methods for determining parameters of analog
integrated circuits is considered. The different types of optimization problem
definition and methods of solving the optimization problems are given for the
fast operational amplifiers and linear voltage regulators circuit classes. In
design of CMOS Op-Amp circuits the conflicting design requirements must be met,
including constraints on gain, power consumption, noise, phase margin etc., that
makes difficult the problem of circuit parameters determination. For system on
chip applications the solution of the important problem of reduction of power
consumption while increasing the circuit performance is required. The CMOS
Op-Amp with dual-input stage architecture is the promising class for these
applications due to the fact that it can provide high values of slew rate. To
avoid the degradation of stability of a circuit the frequency compensation
technique is applied. In this paper the parameter optimization problem of
high-speed CMOS folded cascode Op-Amp with dual-input stage and current mirror
based push-pull parallel channels is considered. The problem formulation to
obtain minimum power consumption under given constraints on slew rate, gain,
unity gain frequency and phase margin is presented. Linear voltage regulators
are the most popular circuits widely used in power management systems. The
integration of linear regulators in a system-on-chip requires the output
capacitor value reduced to a level that can be realized on chip. The frequency
compensation scheme is used to provide the stability of a circuit. Transient
response characteristics of a voltage regulator strongly depend on the
combination of compensation capacitors and load capacitor. The main design
problem is to find a trade-off between stability, precision, and fast-transient
characteristics. The formulation of the optimization problem involves the
minimization of the sum of capacitances under constraints on transient response
characteristics and transistors sizes. The optimization subsystem with
simulation-based optimization technique is described. Examples of circuit
parameters optimization are given.
Key words: operational amplifier, linear voltage regulator, system on chip, circuit
simulation, parameter optimization, optimization methods.
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