Design of high-frequency response of negative feedback circuits

Pole-zero analysis, root-locus techniques, modeling and implementation issues

Avoiding undesired oscillations and design of the desired high-frequency response of negative feedback circuits, is a challanging topic in analog design. Commonly used phase-margin design rules do not guarantee circuit stability. For lumped systems, a design method based upon pole locations is much more solid. Unfortunately, pole-zero analysis it not very much supported in spice-like simulators. This workshop makes you familiar with high-frequency design of negative feedback circuits such as amplifiers and references. It discusses concepts, design strategies and modeling, modeling and simulation as well as implementation issues. It uses the free web application SLiCAP as simulation tool, the only tool that can make root-locus plots using an arbitrary parameter as step variable.

Please contact us for available dates and price.

Contents:

  1. Introduction linear dynamic systems
    • Modeling and analysis techniques for linear dynamic systems
    • Relation between description methods (poles and zeros, Bode plots, impulse and step response)
    • Limitations of description methods (nonlinear behavior, transmission lines)
    • Stability, instability and non-observable instability
  2. Linear dynamic networks
    • Estimation of poles and zeros from passive and active networks
    • Network analysis, Modified Nodal Analysis, Tableau Analysis and State-equation Description of networks
    • Simulation techniques and implementation of pole-zero analysis in Spice-like simulators
  3. Modeling of negative feedback systems and circuits
    • Black's model for system-level design
    • GFT for circuit analysis and measurement
    • Asymptotic-gain model for circuit synthesis and analysis
    • Maximum achievable bandwidth of a feedback circuit
    • Root locus technique and implementation in Matlab, Octave and SLiCAP
  4. High-frequency compensation of negative-feedback circuits
    • H.F. compensation strategies
    • Interaction with other performance aspects (noise performance, linearity)
    • H.F. compensation methods
      • Phantom zero compensation
      • Pole-splitting by means of local negative feedback
      • Pole-zero canceling techniques
      • Resistive broadbanding techniques
      • Bandwidth reduction techniques
  5. Implementation issues
    • Modeling of influence of interconnection parasitics and non-ideal component behavior (in ICs and on PCBs)
    • Reduction of influence of interconnection parasitics and non-ideal component behavior
  6. Design examples and exercises