SAMPLED-DATA SIMULATION OF CIRCUITS WITH INTERNALLY CONTROLLED SWITCHES - Computer Methods for Analysis of Mixed-Mode Switching Circuits - page 175

Chapter 8
SAMPLED-DATA SIMULATION OF
CIRCUITS WITH INTERNALLY
CONTROLLED SWITCHES
Internally controlled switches are switches whose state (ON or OFF) is
controlled by the internal network variables associated with the switches.
The switching time at which internally controlled switches change their
state is not known at the start of simulation. This differs fundamen-
tally from circuits with externally clocked switches where the state of
switches in these circuits is solely determined by the state of external
clocks and is known a priori. More importantly, the topology of circuits
with internally controlled switches may change at any time, depending
upon the value of the switching variable of internally controlled switches
that controls the state of these switches. Moreover, the switching of
one internally controlled switch may trigger other internally controlled
switches in the circuits, subsequently further altering the topology of
the circuits. As compared with the analysis of circuits with externally
clocked switches, the evaluation of the switching variable of internally
controlled switches must be carried out in each time step of simulation
and at each time instant at which an internally controlled switch changes
its state in order to detect any change in the topology of the circuits.
This significantly complicates the analysis.
This chapter is concerned with the analysis of circuits with internally
controlled switches. In Section 1, the switching variable of internally
controlled switches typically encountered in mixed-mode switching cir-
cuits is defined. We show that the switching variable of each internally