Ex Parte McClure

Patent Trial and Appeal Board

Apr 23, 2013

11733072 (P.T.A.B. Apr. 23, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
_____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
_____________

Ex parte DAVID MCCLURE
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Appeal 2010-009522
Application 11/733,072
Technology Center 2800
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Before, JEAN R. HOMERE, DAVID M. KOHUT, and
JOHNNY A. KUMAR, Administrative Patent Judges.

KOHUT, Administrative Patent Judge.

DECISION ON APPEAL

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This is a decision on appeal under 35 U.S.C. § 134(a) of the Final Rejection
of claims 1-22. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm the Examiner’s rejection of these claims.

INVENTION
The invention is directed to an output driver for an integrated circuit that
asserts at very low power supply voltages, such as voltages down to 0.4 volts.
Spec. 1. Claim 1 is representative of the invention and is reproduced below:
1. An output driver for an integrated circuit that asserts at very
low power supply voltages comprising:
a first input voltage node;
a first power supply voltage node;
an output voltage node;
a first internal circuit node;
a first resistive element coupled between the first power supply
voltage node and the first internal circuit node;
a first transistor having a gate coupled to first input voltage
node, a drain coupled to the first power supply voltage node, and a
source coupled to ground;
a second transistor having a gate coupled to the first internal
circuit node, a drain coupled to the output voltage node, and a source
coupled to ground;
a third transistor having a gate coupled to the first internal
circuit node, a drain coupled to the output voltage node, and a source
coupled to ground;
wherein the first and second transistors have a first Vt threshold
voltage, and the third transistor has a second Vt threshold voltage
lower than the first threshold voltage, and
wherein, during normal conditions when the first power supply
voltage at the first power supply voltage node is above a
predetermined threshold, the output voltage node is in a first data state
and wherein, during a low voltage condition when the first power
supply voltage at the first power supply voltage node is below the
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predetermined threshold voltage, the output voltage node is in a
second data state.

REFERENCES
Le US 6,597,222 B2 Jul. 22, 2003

Humphrey US 6,873,196 B2 Mar. 29, 2005

Kwon US 2005/0270077 A1 Dec. 8, 2005

Jang US 7,276,941 B2 Oct. 2, 2007
(filed Dec. 27, 2004)

REJECTIONS AT ISSUE
Claims 1-6, 8-10, and 22 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Kwon and Humphrey. Ans. 3-6 and 11-12.
Claims 1 and 7 are rejected under 35 U.S.C. § 103(a) as being unpatentable
over Jang and Humphrey. Ans. 6-7.
Claims 11-21 are rejected under 35 U.S.C. § 103(a) as being unpatentable
over Kwon, Humphrey, and Le. Ans. 7-11.

ISSUE
Did the Examiner err in finding that one of ordinary skill in the art would
have found it obvious to combine each of the primary references of Kwon and Jang
with the secondary reference of Humphrey?

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ANALYSIS1
Appellant initially contends that the Examiner relies on improper hindsight
to combine each of Kwon and Jang (“primary references”) with Humphrey
(“secondary reference”). App. Br. 8-9; Rep. Br. 7. We disagree and add the
following for emphasis.
First, as explained in In re McLaughlin:
Any judgment on obviousness is in a sense necessarily a
reconstruction based upon hindsight reasoning, but so long as it takes
into account only knowledge which was within the level of ordinary
skill at the time the claimed invention was made and does not include
knowledge gleaned only from applicant’s disclosure, such a
reconstruction is proper.
In re McLaughlin, 443 F.2d 1392, 1395 (CCPA 1971).
Our review of the record establishes that the Examiner’s case for
obviousness is only based on knowledge which was within the level of ordinary
skill at the time of Appellant’s invention and does not include knowledge gleaned
only from Appellant’s disclosure.
Second, the Examiner identifies the relevant portions of each of the
references relied on throughout the Examiner’s Answer. See Ans. 3-12. To the
extent that the Examiner relies on the knowledge of one of ordinary skill in the art
to combine the teachings of the references, this practice is consistent with current
case law. For example, the Supreme Court explains:
Often, it will be necessary for a court to look to interrelated teachings
of multiple patents; the effects of demands known to the design
community or present in the marketplace; and the background
knowledge possessed by a person having ordinary skill in the art, all
in order to determine whether there was an apparent reason to
combine the known elements in the fashion claimed by the patent at

1 We note at the outset that Appellant does not dispute the Examiner’s findings
regarding the references, but rather merely argues that the combination would not
have been obvious to one of ordinary skill in the art. App. Br. 5-12; Reply Br. 5-7.
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issue. To facilitate review, this analysis should be made explicit. See
In re Kahn, 441 F.3d 977, 988 (C.A.Fed.2006) (“[R]ejections on
obviousness grounds cannot be sustained by mere conclusory
statements; instead, there must be some articulated reasoning with
some rational underpinning to support the legal conclusion of
obviousness”). As our precedents make clear, however, the analysis
need not seek out precise teachings directed to the specific subject
matter of the challenged claim, for a court can take account of the
inferences and creative steps that a person of ordinary skill in the art
would employ.
KSR Int’l Co, v. Teleflex, Inc., 550 U.S. 398, 418 (2007).
In this case, the Examiner’s conclusions of obviousness are clearly articulated and
are based on detailed factual findings that are supported by the references of
record. See Ans. 3-12. Thus, we agree with the Examiner’s findings and
conclusions.
Appellant additionally contends that the combination of the primary
references with Humphrey is harmful to one of the stated purposes of the primary
references. App. Br. 10. Appellant specifically argues that each of the primary
references’ circuits including delay features are negatively impacted in their ability
to quickly generate a “true” POR signal when Humphrey’s lower threshold voltage
transistor is combined within the primary references’ circuits because instead of
helping in the prevention of “false” POR signals from being generated, the addition
of Humphrey only limits the slew rate which is in no way applicable to “false”
POR signals. App. Br. 10. We disagree, as Appellant has not provided sufficient
evidence or explanation to prove the argument that the combination would be
harmful.
Additionally, the Examiner finds that combining each of the primary
references with the second reference will help prevent the generation of a false
POR signal because inputting Humphrey’s third transistor into each of the circuits
of the primary references will serve to increase the signal’s frequency (e.g. pulse
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width) and further that this will make it more likely that the transistor will have a
chance to change the output, instead of creating a false POR signal if the transistor
is unable to act on an otherwise narrower-width input pulse. Ans. 13-14. We
agree with the Examiner.
The Federal Circuit has set forth that if the proposed modification would
render the primary references being modified unsatisfactory for its intended
purpose, there is no suggestion or motivation to make the proposed modification.
In re Gordon, 733 F.2d 900, 902 (1984). However, the secondary reference
presented by the Examiner does not impair the intended purposes of either of the
primary references. There is no indication in either of the primary references or
the secondary reference that placing a third transistor having a low voltage
threshold in the circuit, as claimed, would make the primary references
unsatisfactory for their intended purpose. The Examiner found (Ans. 13-14) and
we agree that the combination would prevent “false” POR signals from being
generated and that therefore this intended purpose of the primary references will
not be impaired.
Appellant further contends that a skilled artisan would not combine the
additional transistor of Humphrey with the circuits of the primary references
because this combination would only add circuit area and cost with no additional
functionality. App. Br. 10; Rep. Br. 6-7. We disagree. The Federal Circuit held
that “[t]he fact that the motivating benefit comes at the expense of another benefit,
however, should not nullify its use as a basis to modify the disclosure of one
reference with the teachings of another. Instead, the benefits, both lost and gained,
should be weighed against one another.” Winner Int’l Royalty Corp. v. Wang, 202
F.3d 1340, 1349 n.8 (Fed. Cir. 2000). Here, the benefit gained by using a third
transistor as taught by Humphrey may come at the expense of additional cost,
circuit area, and effort but should not nullify its use as the basis to modify the
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Kwon or Jang. One of ordinary skill in the art could see a benefit in adding the
additional transistor in order to reduce the slew rate in the power on signal (Ans. 4)
and to prevent “false” POR signals (Ans. 13) as mentioned above.
In KSR International Co. v. Teleflex Inc., the Supreme Court emphasized
“the need for caution in granting a patent based on the combination of elements
found in the prior art,” and discussed circumstances in which a patent might be
determined to be obvious. 550 U.S. 398, 415 (2007). Importantly, the Supreme
Court reaffirmed principles based on its precedent that “[t]he combination of
familiar elements according to known methods is likely to be obvious when it does
no more than yield predictable results.” Id. at 416. Here, the Examiner finds (Ans.
3-4 and 6-8) and we agree that each element of claim 1 is taught by the
combination of references. The Examiner finds that Humphrey teaches connecting
a third transistor to a circuit that has a lower threshold voltage than other
transistors in the circuit. Ans. 4. Additionally, the Examiner finds that Kwon and
Jang each teaches connecting two transistors together each having a threshold
voltage. Ans. 4. Therefore, we agree with the Examiner (Ans. 3-4 and 6-7) and
we consider substituting Humphrey’s third transistor with a lower threshold
voltage with Kwon’s or Jang’s transistors as nothing more than using known
devices to perform their known function of lowering output voltage. As such, we
agree with the Examiner (Ans. 3-4 and 6-7) and we find that the combination
yields the predictable result of limiting the slew rate.
Thus, for the reasons mentioned supra, we sustain the Examiner’s rejections
of claims 1-22.

CONCLUSION
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The Examiner did not err in finding that one of ordinary skill in the art
would have combined each of the primary references of Kwon and Jang with the
secondary reference of Humphrey.

SUMMARY
The Examiner’s decision to reject claims 1-22 is affirmed.
No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).
AFFIRMED

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