Rediscovery of a Voltage Gain Stage and a Darlington Emitter-Follower Section of an Amplifier
(A Human-Competitive Result Produced by Genetic Programming)
The Result
Genetic programming evolved a voltage gain stage and a recognizable Darlington emitter-follower section of a 10 dB amplifier circuit as described in Section 42.3 of Genetic Programming III: Darwinian Invention and Problem Solving (Koza, Bennett, Andre, and Keane 1999). The successful evolution of this 10 dB amplifier in this early run of genetic programming for circuit synthesis established the principle that an active circuit containing transistors can be evolved using genetic programming with the same general approach that works successfully for the filters (such as the Campbell, Zobel, and Cauer filters) and other passive RLC circuits.
Basis for Claim of Human-Competitiveness
Sidney
Darlington of the Bell Telephone Laboratories was a towering pioneer in the
field of analog circuit design. He obtained some 40 patents on numerous
fundamental circuits. In particular, he obtained U.S. patent 2,663,806 for what
is now called the Darlington emitter-follower section. Claim 1 of this patent
(Darlington 1952) covers
“A signal
translating device comprising a pair of transistors of like conductivity type
and each including a base, an emitter and a collector, means directly
connecting the collectors together, means directly connecting the emitter of
one transistor to the base of the other, and individual electrical connections
to the other emitter and base.”
In a
similar vein, claim 3 of U.S. patent 2,663,806 covers
“A signal
translating device comprising a pair of transistors of like conductivity type
and each including a base, an emitter and a collector, means directly
connecting the emitters together, means directly connecting the collector of
one transistor to the base of the other, and individual electrical connections
to the other collector and base.”
Claim 5 is
somewhat more general and covers the case where any two like electrodes of the
transistor are connected:
“A signal
translating device comprising a pair of transistors of like conductivity type
and each including a base, an emitter and a collector, means directly
connecting two like electrodes of said transistors together, means directly
connecting another electrode of one transistor to an unlike electrode, other
than one of said like electrodes of the other transistor, and individual
electrical connections to the other emitter and base.”
Claim 10
covers the case where there are three transistors in which collectors are
connected:
“A signal
translating device comprising three transistors of like conductivity type and
each including an emitter, a collector and a base, means directly connecting
the collectors together electrically, means connecting the base of one
transistor directly to the emitter of a second transistor, means connecting the
base of said second transistor to the emitter of the third transistor, and
individual electrical connections to the emitter of said one transistor and the
base of said third transistor.”
The
Darlington patent also refers to an optional external connection to the
connection between the leads of the two transistors. For example, claim 2 is a
dependent claim based on claim 1 (where the collectors are connected together)
and covers
“A signal
translating device in accordance with claim 1 comprising an additional
electrical connection to the connected emitter and base.”
Similarly,
claim 4 is based on claim 3 (where the emitters are connected together) and
covers
“A signal
translating device in accordance with claim 3 comprising an additional
electrical connection to the connected collector and base.”
The figure
below shows npn transistors Q25 and Q5 from an evolved circuit from a run of
genetic programming for the 96 dB amplifier problem (Chapter 45). This figure
shows a Darlington emitter-follower section in the canonical form, as described
in claim 1 of Darlington’s patent 2,663,806. The figure shows "means
[namely, a wire] directly connecting the collectors together." It also
shows "means directly connecting the emitter of one transistor [namely,
Q5] to the base of the other [namely, Q25]."
BBB556
Table 42.2
of Genetic
Programming III: Darwinian Invention and Problem Solving (Koza,
Bennett, Andre, and Keane 1999) shows
12 instances in which genetic programming evolved a circuit containing a
canonical Darlington section. The table identifies the particular transistors
involved and the particular claims (1, 2, 3, or 4) of U.S. patent 2,663,806
that genetic programming infringes.
Referring to the eight criteria in chapter 1 of Genetic Programming III: Darwinian Invention and Problem Solving (Koza, Bennett, Andre, and Keane 1999) for establishing that an automatically created result is competitive with a human-produced result, the automatic synthesis of a voltage gain stage for an amplifier and a Darlington emitter-follower section satisfies the following two criteria:
(A) The
result was patented as an invention in the past, is an improvement over a patented
invention, or would qualify today as a patentable new invention.
(F) The
result is equal to or better than a result that was considered an achievement
in its field at the time it was first discovered.
References
Darlington,
Sidney. 1952. Semiconductor Signal Translating Device. U.S. Patent 2,663,806.
Filed May 9, 1952. Issued December 22, 1953.
Koza, John R., Bennett III, Forrest H, Andre, David, and Keane, Martin A. 1999a. Genetic Programming III: Darwinian Invention and Problem Solving. San Francisco, CA: Morgan Kaufmann.
· The home page of Genetic Programming Inc. at www.genetic-programming.com.
· For information about the field of genetic programming and the field of genetic and evolutionary computation, visit www.genetic-programming.org
· The home page of John R. Koza at Genetic Programming Inc. (including online versions of most published papers) and the home page of John R. Koza at Stanford University
· For information about John Koza’s course on genetic algorithms and genetic programming at Stanford University
· Information about the 1992
book Genetic
Programming: On the Programming of Computers by Means of Natural Selection,
the 1994 book Genetic
Programming II: Automatic Discovery of Reusable Programs, the 1999
book Genetic
Programming III: Darwinian Invention and Problem Solving, and the
2003 book Genetic
Programming IV: Routine
Human-Competitive Machine Intelligence. Click here to read chapter 1 of Genetic
Programming IV book in PDF format.
· 3,440
published papers on genetic programming (as of November 28, 2003) in a
searchable bibliography (with many on-line versions of papers) by over 880
authors maintained by William Langdon’s and Steven M. Gustafson.
· For information on the Genetic Programming and Evolvable Machines journal published by Kluwer Academic Publishers
· For information on the Genetic Programming book series from Kluwer Academic Publishers, see the Call For Book Proposals
· For information about the annual Genetic and Evolutionary Computation (GECCO) conference (which includes the annual GP conference) to be held on June 26–30, 2004 (Saturday – Wednesday) in Seattle and its sponsoring organization, the International Society for Genetic and Evolutionary Computation (ISGEC). For information about the annual Euro-Genetic-Programming Conference to be held on April 5-7, 2004 (Monday – Wednesday) at the University of Coimbra in Coimbra Portugal. For information about the 2003 and 2004 Genetic Programming Theory and Practice (GPTP) workshops held at the University of Michigan in Ann Arbor. For information about Asia-Pacific Workshop on Genetic Programming (ASPGP03) held in Canberra, Australia on December 8, 2003. For information about the annual NASA/DoD Conference on Evolvable Hardware Conference (EH) to be held on June 24-26 (Thursday-Saturday), 2004 in Seattle.
Last updated on December 28, 2003