Ex parte HUNLEY

Board of Patent Appeals and Interferences

Feb 19, 1998

08052213 (B.P.A.I. Feb. 19, 1998)

THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today
(1) was not written for publication in a law journal and
(2) is not binding precedent of the Board.
Paper No. 22
UNITED STATES PATENT AND TRADEMARK OFFICE
_______________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________
Ex parte STEVEN A. HUNLEY
_______________
Appeal No. 95-0020
Application 08/052,2131
_______________
ON BRIEF
_______________
Before HAIRSTON, KRASS, and BARRETT, Administrative Patent
Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 42 through 44 and 46. Claims 45, 47 and 48 have been
indicated by the examiner as being directed to allowable subject
matter but stand objected to as relying on a rejected base claim.
Claims 8, 10 through 19, 22, 24 through 29 and 31 through 41 have
been allowed.

1 Application for patent filed April 23, 1993. According to
appellant, this application is a continuation of Application
07/776,141, filed October 15, 1991.
Appeal No. 95-0020
Application No. 08/052,213
2
The invention is directed to a CMOS buffer with a controlled
slew rate. By optimally controlling the rate of transition from
a high/low state to a low/high state at the output, reduction of
signal line reflection and ringing at the output and in the cable
or connectors coupled to the output is said to be enabled.
Independent claim 42 is reproduced as follows:
42. A method of controlling slew rate on an output terminal,
comprising the steps of:
activating an output transistor;
comparing a voltage on the output terminal to an internal
node voltage during output transistor activation; and
modulating the rate of a voltage transition at the output
terminal in response to the comparison of the output terminal to
the internal node voltage.
The examiner relies on the following reference:
Bianchi 5,122,690 Jun. 16, 1992
(filed Oct. 16, 1990)
Claims 42 through 44 and 46 stand rejected under 35 U.S.C.
' 102(e) as anticipated by Bianchi.
Reference is made to the brief and answer for the respective
positions of appellant and the examiner.
OPINION
In accordance with appellant’s statement at page 3 of the
brief, claims 42 through 44 and 46 stand or fall together.
Accordingly, we will base our decision on an analysis of
independent claim 42.
Appeal No. 95-0020
Application No. 08/052,213
3
The examiner applies Figure 2 of Bianchi against instant
claim 42 as follows:
The output transistor being activated is identified as
transistor NS. Voltage on output terminal 50 is said to be
compared to an internal node voltage (at the output of inverter
44) during activation of output transistor NS with the comparison
effected by NOR gate 46, the result of such comparison either
enabling or disabling transistor NL. The examiner then points to
column 6, line 38, to column 7, line 8 of Bianchi for a teaching
of modulating the rate of voltage transition at the output
terminal in response to the comparison of the output terminal to
the internal node voltage.
Appellant takes the position that Bianchi does not teach any
“modulating” but that if it did, it certainly does not teach
“modulating the rate of a voltage transition” and, even if one
considered that Bianchi did teach such, Bianchi clearly does not
teach this modulation step “in response to the comparison of the
output terminal to the internal node voltage” as set forth in
claim 42.
We agree with the examiner that claim 42 sets forth rather
broad language. We also agree with the examiner that the term,
“modulating,” per se, is broad enough to cover an on/off
situation as in Bianchi where transistor NL is disabled if a
current condition exceeds some value.
Appeal No. 95-0020
Application No. 08/052,213
4
However, instant claim 42 does not call for “modulating,”
per se, but rather for “modulating the rate of a voltage
transition at the output terminal…” Notwithstanding the
examiner’s valiant, and commendable, effort to interpret the
broad language of claim 42 in such a manner as to make Bianchi’s
disclosure applicable to such language, it is our view that
Bianchi simply does not disclose or suggest the modulation of
“the rate of a voltage transition.” At best, perhaps one could
say that an output voltage level in Bianchi is “modulated” by
switching transistors on or off, based on current magnitude, but
even this interpretation is one that views as a modulation the
switching of an output voltage between two levels. Quite
clearly, there is no modulation of a “rate of a voltage
transition at the output terminal” [emphasis ours], as claimed,
in the digital circuitry of Bianchi. We simply cannot agree with
the examiner, at page 4 of the answer, that Bianchi’s disabling
of pulldown transistor NL “inherently ‘modulates the rate of
voltage transition’ in that the disabling of the large transistor
will slow down the transition of the output terminal from the
previous logic high to a logical low.”
Since we find that Bianchi’s digital circuitry does not
teach or suggest the claimed “modulating the rate of a voltage
transition at the output terminal…,” Bianchi cannot anticipate
Appeal No. 95-0020
Application No. 08/052,213
5
the instant claimed invention. Accordingly, the examiner’s
decision rejecting claims 42 through 44 and 46 under 35 U.S.C.
' 102(e) is reversed.
REVERSED
Kenneth W. Hairston )
Administrative Patent Judge )
)
)
)
Errol A. Krass ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
Lee E. Barrett )
Administrative Patent Judge )
Appeal No. 95-0020
Application No. 08/052,213
6
Thomas G. Eschweiler
Texas Instruments Incorporated
P.O. Box 655474 M/S 219
Dallas, Texas 75265