AN OVERVIEW OF MIXED-MODE SWITCHING CIRCUITS - Computer Methods for Analysis of Mixed-Mode Switching Circuits - page 8

ear circuits [16], Volterra series-based distortion analysis of periodically
switched nonlinear circuits [17], sampled-data simulation algorithms for
analysis of periodically switched linear and nonlinear circuits and sigma-
delta modulators [18, 19, 20], to name a few, have emerged. As compared
with time-invariant circuits and other time-varying circuits, mixed-mode
switching circuits exhibit the following distinct characteristics :
Time-varying topology - The topology of mixed-mode switching cir-
cuits varies with time. For circuits with externally clocked switches,
such as switched capacitor networks and switched current networks,
the time instants at which the topology of the circuits changes are
known a priori. For circuits with internally controlled switches, the
time instants at which the topology of the circuits varies, however, is
not known at the start of simulation and is determined by the numer-
ical value of the network variables controlling the state of switches,
such as the voltage across diodes and the effective gate-source voltage
of MOSFET switches, during simulation.
Dual-time systems - Periodically switched circuits are dual-time sys-
tems that contain rapidly varying clocks and slowly varying signals.
They have to be simulated over a large number of clock cycles with
fine steps in order to obtain their time domain characteristics accu-
rately and reliably.