Ex Parte Karp

Patent Trial and Appeal Board

Apr 27, 2016

13401439 (P.T.A.B. Apr. 27, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/401,439 02/21/2012
24309 7590 04/29/2016
XILINX, INC
ATTN: LEGAL DEPARTMENT
2100 LOGIC DR
SAN JOSE, CA 95124
FIRST NAMED INVENTOR
James Karp
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
X-3834 US 2724
EXAMINER
HOANG, ANN THI
ART UNIT PAPER NUMBER
2836
NOTIFICATION DATE DELIVERY MODE
04/29/2016 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
xilinxipl @xilinx.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JAMES KARP
Appeal2014-008917
Application 13/401,439
Technology Center 2800
Before TERRY J. OWENS, WESLEY B. DERRICK, and
JULIA HEANEY, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
The Appellant appeals under 35 U.S.C. § 134(a) from the Examiner's
rejection of claims 1-17. We have jurisdiction under 35 U.S.C. § 6(b).
The Invention
The Appellant claims an electrostatic discharge protection circuit and
method. Claim 1 is illustrative:
1. An electrostatic discharge (ESD) protection circuit,
compnsmg:
an RC-triggered clamp comprising:
an RC-circuit having a resistor coupled between a
first node and a second node, and a capacitor
coupled between the second node and a third
node;
Appeal2014-008917
Application 13/401,439
a transistor with a first source/ drain, a gate, and a
second source/ drain, wherein the first
source/ drain is coupled to the first node, and
the second source/ drain is coupled to the
third node; and
an inverter, wherein an input of the inverter is
coupled to the second node, and an output of
the inverter is coupled to the gate of the
transistor; and
one or more forward-biased diodes coupled in series
between a supply node and the first node;
wherein the RC-triggered clamp is configured to support
a maximum voltage;
wherein the maximum voltage supported by the
RC-triggered clamp is less than a voltage provided by the
supply node; and
wherein the one or more forward-biased diodes are
configured to reduce a voltage seen at the first node to a level
that is equal to or less than the maximum voltage supported by
the RC-triggered clamp.
Roy
Pequignot
The References
us 5,159,518
US 6,262,873 B 1
The Rejections
Oct. 27, 1992
July 17, 2001
The claims stand rejected under 35 U.S.C. § 103 as follows: claims 1-
4 and 8-15 over Pequignot, and claims 5-7, 16, and 17 over Pequignot in
view of Roy.
OPINION
We reverse the rejections. We need address only the independent
claims (1 and 11 ). 1 Those claims require that the maximum voltage
1 The Examiner does not rely upon Roy for any disclosure that remedies the
deficiency in Pequignot as to the independent claims (Ans. 6-7).
2
Appeal2014-008917
Application 13/401,439
supported by an RC-triggered clamp is less than a voltage provided by that
clamp's supply node.
Pequignot discloses electrostatic discharge (ESD) protection circuitry
for electronic circuits having multiple power supply rails (col. 6, 11. 16-25).
Each of multiple single-rail ESD circuits (e.g., 203a; Fig. 1) comprises an
RC discriminator (e.g., 207) connected to a clamp (e.g., 211) via inverter
logic (e.g., 209) to provide a low impedance path between that circuit's
power rail (e.g., V DDI) and a reference rail (e.g., V ss) to dissipate (e.g., to
ground) an ESD impulse's energy (col. 6, 11. 27-39, 44--49; Fig. 1).
The Examiner asserts that "it would have been obvious to one of
ordinary skill in the art at the time of the invention to determine the
preferred maximum voltage supported by the RC-triggered clamp in the
design [of] the ESD protection circuit, since it has been held that, where the
general conditions of a claim are disclosed in the prior art, discovering the
optimum or workable ranges involves only routine skill in the art" (Ans. 3-
4).
The Examiner has not established that the general conditions known
in prior art and, therefore, achievable by determining optimum or workable
ranges, included a maximum voltage supported by an RC-triggered clamp
which is less than a voltage supplied by that clamp's supply node.
The Examiner asserts that "one of ordinary skill would know that
designing for a maximum voltage supported by the RC-triggered clamp less
than the voltage provided at the supply node would be possible because the
voltage provided by the supply node would be dropped by the one or more
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Appeal2014-008917
Application 13/401,439
forward-b[i]ased diodes to a voltage lower than the voltage of the supply
node" (Ans. 4).
The Examiner has not established that dropping Pequignot's supply
node voltage causes the maximum voltage supported by the RC-triggered
clamp to be less than the reduced supply node voltage.
The Examiner asserts that "it would appear that the claim limitation
that is the subject of this appeal ('wherein the maximum voltage supported
by the RC-triggered clamp is less than a voltage provided by the supply
node') describes a problem that is commonly encountered when an ESD
circuit has a high voltage power rail, and Appellant's solution to that
problem is to include forward-biased diodes, which Pequignot teaches (see
diodes 323a-b[] in Fig. 3), to reduce the high power supply voltage"
(Ans. 10).
As explained by the Appellant (Reply Br. 3-5), the Examiner's
assertion that the Appellant's Specification indicates that an RC-triggered
clamp's maximum voltage being less than its supply node's voltage is a
commonly encountered problem is based upon a misinterpretation of the
Specification. As for the Examiner's assertion regarding the solution to the
alleged commonly encountered problem, the Examiner has not established
that Pequignot's disclosure of forward-biased diodes (325, 327) for
powering power rails (V DDI, V nn2) up and down (col. 9, 1. 35 - col. 10, 1. 3:
Fig. 3) would have provided one of ordinary skill in the art with an apparent
reason to make the maximum voltage supported by the RC-triggered clamp
less than its supply node's voltage. See KSR Int 'l Co. v. Teleflex Inc., 550
U.S. 398, 418 (2007).
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Appeal2014-008917
Application 13/401,439
The Examiner asserts that "one of ordinary skill in the art at the time
of the invention would have found it obvious to design an ESD protection
circuit as disclosed by Pequignot to have a (relatively high) voltage supply,
but a maximum supported voltage of the RC-triggered clamp of a lesser
value based on availability and cost of circuit components, while taking into
account performance and feasibility" (Ans. 10).
That assertion is based purely upon speculation, and such speculation
is not a sufficient basis for a prima facie case of obviousness. See In re
Warner, 379 F.2d 1011, 1017 (CCPA 1967); In re Sporck, 301F.2d686,
690 (CCPA 1962).
Thus, the Examiner has not established a prima facie case of
obviousness of the Appellants' claimed invention.
DECISION/ORDER
The rejections under 35 U.S.C. § 103 of claims 1--4 and 8-15 over
Pequignot, and claims 5-7, 16 and 17 over Pequignot in view of Roy are
reversed.
It is ordered that the Examiner's decision is reversed.
REVERSED
5