“The advanced processors that emerged from Carver Mead’s
Caltech laboratory mimic the analog response of natural
systems. Cameron Laird and guest columnist David Cuthbert look
at further developments that could lead to more portable and
power-thrifty devices.”
“…time to market is not the critical factor in every design.
Power consumption is becoming the limiting factor in more systems,
especially in portable electronics. In this domain, analog holds a
significant advantage. The smaller component count means fewer
components require power. Also, swinging an output from one rail to
the other requires a significant amount of power. Reducing the
range of the swing helps somewhat. (This motivated the gradual drop
in digital logic’s operating voltage from 5 volts to today’s 1.8
volts.) Still, an analog design utilizing the full range of
output voltages will always have better power efficiency than its
digital counterpart.”
“This has led to a renaissance of sorts in analog design.
Interest is on the rise in both industry (where the demand for
analog design tools far surpasses their availability) and in
university research laboratories, such as the Physics of
Computation (Physcmp) group at Caltech, headed by Carver Mead until
recently. As an undergraduate there, David Cuthbert (coauthor of
this article) observed the group’s efforts to bring neurally
inspired computing to the silicon realm. The remainder of this
article is a brief summary of ideas picked up there. For more
detail, see the homepages of former Physcmp students. … Brad
Minch, in particular, offers the presentation “Analog Signal
Processing: Why Bother?”