Ex Parte Turkson et al

Patent Trial and Appeal Board

Oct 23, 2018

14289468 (P.T.A.B. Oct. 23, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
14/289,468 05/28/2014
23494 7590 10/25/2018
TEXAS INSTRUMENTS IN CORPORA TED
PO BOX 655474, MIS 3999
DALLAS, TX 75265
UNITED ST A TES OF AMERICA
FIRST NAMED INVENTOR
Richard Turkson
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.
TI-73746 1074
EXAMINER
LAM, TUAN THIEU
ART UNIT PAPER NUMBER
2842
NOTIFICATION DATE DELIVERY MODE
10/25/2018 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):
uspto@ti.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
ExparteRICHARD TURKSON, ALINE C. SADATE, and
PHILOMENA C. BRADY 1
Appeal2017-010895
Application 14/289,468
Technology Center 2800
Before JEFFREY T. SMITH, CHRISTOPHER L. OGDEN, and
CHRISTOPHER C. KENNEDY, Administrative Patent Judges.
KENNEDY, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) from the Examiner's
decision rejecting claims 1-20. We have jurisdiction under 35 U.S.C.
§ 6(b). We AFFIRM.
BACKGROUND
The subject matter on appeal relates to "transistor switch control, and
more particularly, control for MOSFET switch-on, such as can be used in
1 The Appellant is the Applicant, Texas Instruments Incorporated, which is
also identified as the real party in interest. See App. Br. 2.
Appeal2017-010895
Application 14/289,468
load switching applications." E.g., Spec. ,r 22; Claim 1. Claim 1 is
reproduced below from page 12 (Appendix -- Claims) of the Appeal Brief:
1. An PET switch circuit with V Gs temperature compensation,
compnsmg
an PET switch including a gate with a gate node and a source,
and with a gate source voltage V Gs with a maximum rated value
ofVGs,MAx;
switch enable circuitry to switch-on the PET switch by supplying
a switch-on signal to the PET gate;
gate control circuitry coupled to the PET gate node, including:
PT AT ~ V BE current source circuitry including a ~ V BE
resistor, to supply to the gate node a PT AT current lrTAT
corresponding to a voltage across the~ VBE resistor, including
charging the PET gate;
V Gs clamping circuitry coupled between the gate node and the
PET source, to establish a temperature compensated V Gs
clamping voltage V Gs,c1amp at the gate node, the V Gs clamping
circuitry including
a PTAT resistor RPTAT, with a temperature coefficient
substantially the same as the~ VBE resistor, coupled to the
gate node such that a PTAT voltage [VPTAT = (RPTAT *
lrTAT)] is developed across RPTAT;
at least one CT ATV BE component, with a V BE,CTAT voltage
drop with a CT AT temperature coefficient, coupled
between RPTAT and the PET source such that a CTAT
voltage [VcTAT = VBE,CTAT] is developed across the CTAT
V BE component;
such that (i) the temperature dependence of [VPTAT = (RPTAT *
lrTAT)] is compensated by the temperature dependence of
[V cTAT = VBE,CTAT], and (ii) the V Gs clamping voltage at the
2 Consistent with the Appellant's citations, citations to "Spec." in this
Decision are to "Substitute Specification (Clean)" dated October 10, 2014.
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Application 14/289,468
gate node corresponds to [Vas,c1amp = VPTAT + VcTAT = (RPTAT
* lrTAT) + VBE,CTAT].
ANALYSIS
Claims 1-20 stand rejected under 35 U.S.C. § 103 as unpatentable
over Applicant's cited prior art (Spec. Fig. 1) ( consistent with the
nomenclature of the Appellant, "ACP A") in view of Marinca
(US 2010/0244808 Al, published Sept. 30, 2010) and Kirkland
(US 6,181,121 Bl, issued Jan. 30, 2001). The Appellant argues the claims
as a group, focusing on claim 1. We select claim 1 as representative of the
rejected claims, and the remaining claims will stand or fall with claim 1.
After review of the cited evidence in the appeal record and the
opposing positions of the Appellant and the Examiner, we determine that the
Appellant has not identified reversible error in the Examiner's rejection.
Accordingly, we affirm the rejection for reasons set forth below, in the Final
Action, and in the Examiner's Answer. See generally Final Act. 2-7;
Ans. 2-7.
The Examiner finds that the ACP A discloses a PET switch circuit
comprising the elements of claim 1 except that the ACP A does not show
"(1) the temperature uncompensated current source (13) as a PT AT ~ Vbe
current source including a ~ Vbe resistor and configured to supply the gate
node of the NFET with a PTAT current Iptat corresponding to a voltage
across the~ Vbe resistor," and "(2) the Vgs clamping including a PTAT
resistor Rptat and at least one CT AT VBE component." Final Act. 3.
With respect to difference ( 1 ), the Examiner finds that Marinca' s
Figure 1 discloses a reference voltage with a predetermined level dependent
upon the value of the current source 110, resistor 120, and the number of
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Application 14/289,468
diodes 130. Id. The Examiner finds that the predetermined reference
voltage has temperature variation compensation features that include a
PTAT temperature dependent current source including~ VBEresistor (110)
and is capable of being configured to supply the predetermined reference
voltage to the gate node of the NFET load switch with a PTAT current lrTAT
corresponding to a voltage across the ~ VBE resistor. Id. ( citing Marinca ,r 5
& Fig. 2).
With respect to difference (2), the Examiner finds that Marinca' s
Figure 1 "further includes PTAT resistor 120 and Vctat across diodes 130,"
and that the purpose of such an arrangement is "to compensate for
temperature variation in the predetermined reference voltage, thus, prevent
erroneous operation." Final Act. 3.
The Examiner determines that a person of ordinary skill in the art
would have been motivated to replace current source 13 and clamping circuit
15 of the ACP A with the circuit arrangement of Marinca' s Figure 1 "for the
purpose of providing a temperature compensated predetermined reference
voltage ... to prevent erroneous operation." Id. at 4.
In view of those and other findings, the Examiner concludes that the
subject matter of claim 1 would have been obvious to a person of ordinary
skill in the art. Id. at 2--4.
The Appellant first argues that "Marinca actually teaches avoiding the
use of Resistor 120, i.e. the claimed 'PTAT resistor RPTAT."' App. Br. 8, 9.
For support, the Appellant relies on ,r 6 of Marinca, which discloses that,
"[i]n some applications, for example low power applications, the resistor
120" may be large, may be expensive, may be sensitive to process
variations, and may contribute to the total noise of the resulting PT AT
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Application 14/289,468
voltage. Marinca ,r 6. Marinca goes on to disclose "resistorless PT AT
cell[s]." Id.
Prior art may teach away if it "criticize[ s ], discredit[ s ], or otherwise
discourage[s] the solution claimed." In re Fulton, 391 F.3d 1195, 1201
(Fed. Cir. 2004). "[A]ll of the relevant teachings of the cited references
must be considered in determining what they fairly teach to one having
ordinary skill in the art." In re Mercier, 515 F.2d 1161, 1165 (CCPA 1975);
Para-Ordnance Mfg., Inc. v. SGS Imps. Int'!, Inc., 73 F.3d 1085, 1090 (Fed.
Cir. 1995) ( disclosures that arguably teach away "must be weighed
alongside" disclosures that teach "the propriety of' making the proposed
modification). "[J]ust because better alternatives exist in the prior art does
not mean that an inferior combination is inapt for obviousness purposes." In
re Mouttet, 686 F.3d 1322, 1334 (Fed. Cir. 2012); see also In re Gurley, 27
F.3d 551, 553 (Fed. Cir. 1994) ("A known or obvious composition does not
become patentable simply because it has been described as somewhat
inferior to some other product for the same use."). The Federal Circuit has
explained that "a given course of action often has simultaneous advantages
and disadvantages, and this does not necessarily obviate motivation to
combine." Medichem, S.A. v. Rolabo, S.L., 437 F.3d 1157, 1165 (Fed. Cir.
2006). "The fact that the motivating benefit comes at the expense of another
benefit ... 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).
Although we agree with the Appellant that ,r 6 of Marinca discloses,
"[i]n some applications," disadvantages to the prior art's use of resistor 120,
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we are not persuaded that ,r 6 of Marinca constitutes a teaching away such
that a person of ordinary skill in the art would not have combined Marinca
with the ACP A. As an initial matter, the Appellant does not acknowledge
that ,r 6 includes the language "[i]n some applications," and the Appellant
does not explain whether ,r 6 is relevant to applications that are implicated
by the Examiner's proposed modification.
Moreover, as the Examiner finds, a person of ordinary skill would
have understood that use of the circuitry depicted in Marinca Figure 1
(including resistor 120) yields the benefit of temperature independent
voltage. See Marinca ,r,r 4--7, Fig. 1, Fig. 2. The Examiner further finds, and
the Appellant does not dispute, that temperature independent voltage reduces
"erroneous operation." Final Act. 4. Thus, a person of ordinary skill would
have understood that use of Marinca's circuitry as proposed by the Examiner
"has simultaneous advantages and disadvantages," but the existence of the
disadvantages of Marinca ,r 6 relied on by the Appellant "does not
necessarily obviate motivation to combine." Medichem, 437 F.3d at 1165.
Instead, a person of ordinary skill would have been capable of "weigh[ing]
against one another" "the benefits, both lost and gained." Winner, 202 F.3d
at 1349 n.8. In this case, a person of ordinary skill would have weighed the
advantages and disadvantages and would have been motivated to use the
temperature independent voltage circuitry of Figure 1 in situations where
temperature independence was more important than, e.g., sensitivity to
process variations or voltage noise. The Appellant does not persuasively
allege that the circuitry of Marinca Figure 1 would not function in the
combination proposed by the Examiner; the Appellant "alleges only that it
may be inferior for certain purposes." See Mouttet, 686 F.3d at 1334.
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On this record, we are not persuaded that Marinca ,r 6 teaches away
from the claimed invention.
Focusing on the Examiner's use of the words "capable of," e.g., Final
Act. 3 ("capable of being configured to supply the predetermined reference
voltage"), 5 ("capable of being used as VGS clamping circuit"), the
Appellant also argues that the Examiner does not adequately establish the
circuitry of the combined prior art would "supply to the gate node a PT AT
current hTAT corresponding to a voltage across the L1 VBE resistor, including
charging the PET gate," or that the voltage reference of Marinca is a
clamping circuit. See App. Br. 8-11. However, it appears that if the
modifications proposed by the Examiner were made to the ACP A, the
structure of the resulting circuit ( at least in relevant part) would be the same
as the structure of the circuit recited by claim 1 and depicted in the
Appellant's Figure 3. In particular, if the upper diode in box 15 of the
ACP A were replaced with a resistor, as suggested by Marinca, it appears
that the elements of box 15 would be identical to the elements of box 130 in
Figure 3, and box 130 is identified by the Specification as a Vas clamping
circuit. See Spec. ,r 26. The Appellant's do not persuasively identify a
recited element of the circuitry of claim 1 that is missing from the
Examiner's proposed combination, and, on this record, do not persuasively
show error in the Examiner's determination that the circuitry of the
combined prior art falls within the scope of claim 1.
Accordingly, we are not persuaded of reversible error in the
Examiner's rejection. See In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011)
("[I]t has long been the Board's practice to require an applicant to identify
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Application 14/289,468
the alleged error in the examiner's rejections .... "). We affirm the
Examiner's rejection of claim 1.
CONCLUSION
We AFFIRM the Examiner's rejections of claims 1-20.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
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