Ex Parte Hu et al

Patent Trial and Appeal Board

Aug 24, 2016

12121997 (P.T.A.B. Aug. 24, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
12/121,997 05/16/2008
28997 7590 08/26/2016
HARNESS, DICKEY, & PIERCE, PLC
7700 Bonhomme, Suite 400
ST. LOUIS, MO 63105
FIRST NAMED INVENTOR
ZongBoHu
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.
9676A-000078-US 7925
EXAMINER
GBLENDE, JEFFREY A
ART UNIT PAPER NUMBER
2838
NOTIFICATION DATE DELIVERY MODE
08/26/2016 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):
stldocket@hdp.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ZONG BO HU, YING QU, KEVIN DONALD WILD ASH,
WAI KIN CHAN, and WING LING CHENG 1
Appeal2015-001137
Application 12/121,997
Technology Center 2800
Before CHUNG K. PAK, CHRISTOPHER L. OGDEN, and LILAN REN,
Administrative Patent Judges.
OGDEN, Administrative Patent Judge.
DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner's final
decision rejecting claims 1-12, 26-38, and 101 in the above-identified
application. We have jurisdiction pursuant to 35 U.S.C. § 6(b ).
We REVERSE.
1 According to Appellants, the real party in interest is Astec International
Limited. Appeal Br. 2.
Appeal 2015-001137
Application 12/121,997
BACKGROUND
Appellants' invention relates to a control circuit for controlling
switching devices. Spec. i-f 1. Independent claim 1 is representative:
1. A control circuit for controlling a rectifier having a
first terminal, a second terminal, and a control terminal,
the control circuit comprising a first diode for coupling to
the first terminal of the rectifier, a second diode for
coupling to the second terminal of the rectifier, a first
transistor for coupling to the control terminal of the
rectifier, a second transistor coupled to the second diode,
and a third diode coupled between a first terminal of the
first transistor and a second terminal of the first
transistor to limit saturation of the first transistor, the
first transistor coupled to the first diode, the control
circuit configured to allow current flow in only one
direction between the first and second terminals of the
rectifier.
Appeal Br. 22 (emphasis added). Claim 26 is also independent, and contains
a limitation similar to the emphasized language above; however, it omits the
corresponding to the "third diode" of claim 1. See id. at 23.
An embodiment of the claimed invention is shown in Figure 16,
which is reproduced below:
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Appeal 2015-001137
Application 12/121,997
D
FIG.16
Figure 16 depicts "a control circuit 1600 coupled to a synchronous rectifier
Q for controlling the synchronous rectifier Q having a control terminal, a
drain terminal, and a source terminal." Spec. i-f 75. The rectifier, first
transistor, second transistor, first diode, and second diode correspond to Q,
Q 1, Q2, D 1, and D2, respectively. See Appeal Br. 3. The Schottky diode
D3 is the "third diode," and is coupled between the base and the collector of
transistor QI. See Spec. i-f 76. According to the Specification, diode D3
"adjusts the switching time of the synchronous rectifier Q by limiting the
saturation of transistor Q 1," and "shortens the period of time for
transitioning the transistor QI out of saturation and from ON to OFF." Id.
The Examiner maintains the following grounds of rejection:
I. Claims 1--4, 26, 27, 36-38, and 101 are rejected under
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Appeal 2015-001137
Application 12/121,997
35 U.S.C. § 103(a) as being unpatentable over U.S. Patent No.
US 6,469,564 Bl (issued Oct. 22, 2002) [hereinafter Jansen] in view of U.S.
Patent No. 4,538,075 (issued Aug. 27, 1985) [hereinafter Varadarajan].
Final Action 3-7.
II. Claim 5 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Jansen in view of Varadarajan and Philips
Semiconductors, BC847BS: NPN General Purpose Double Transistor (Apr.
28, 1999) [Philips]. Final Action 7.
III. Claims 6 and 29-33 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Jansen in view of Varadarajan, Philips, and Philips
Semiconductors, BAV23: General Purpose Double Diode (Sept. 17, 1996)
[hereinafter Philips2]. Final Action 7-9.
IV. Claims 7-9 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Jansen in view of Varadarajan and Appellants' admitted
prior art. Final Action 9-10.
V. Claim 10 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Jansen in view of Varadarajan and U.S. Patent Publication
No. US 2006/0152204 Al (published July 13, 2006) [Maksimovic]. Final
Action 10.
VI. Claims 11 and 34 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Jansen in view ofVaradarajan and U.S. Patent
Publication No. US 2008/0130321 Al (published June 5, 2008) [Artusi].
Final Action 10-12.
VII. Claims 12 and 35 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Jansen in view of Varadarajan and U.S. Patent No.
4,074,345 (issued Feb. 14, 1978) [Ackermann]. Final Action 12-14.
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Appeal 2015-001137
Application 12/121,997
VIII. Claim 28 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Jansen in view of Varadarajan and Philips2. Final Action
14.
DISCUSSION
The Examiner finds that Jansen teaches the limitations of independent
claims 1 and 26, except that "Jansen does not disclose a diode coupled
between the first terminal of the first transistor and the second terminal of
the first transistor to limit saturation of the first transistor." Final Action 5
(citing Jansen Fig. 10); see also id. at 3. Figure 10 of Jansen is reproduced
below:
~-----------------,
Vee I I
86
A
c1
87
b2
b1
91
90
88Jl
85
-- -----
e1 I I
FIG. 10
I
~82
1
!
I
I
i
1
I
I
I
J sg
K
According to the Examiner: Figure 10 depicts a control circuit
for controlling a rectifier (10) having a first terminal (A),
a second terminal (K), and a control terminal (control
terminal of 10), the control circuit comprising a first
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Appeal 2015-001137
Application 12/121,997
diode (91) for coupling to the first terminal (A) of the
rectifier (10), a second diode (89) for coupling to the
second terminal (K) of the rectifier (10), a first transistor
(90) for coupling to the control terminal of the rectifier
(10), a second transistor (86) coupled to the second diode
(89), the first transistor (90) coupled to the first diode
(connection of 90 and 91 ), the control circuit configured
to allow current flow in only one direction between the
first and second terminals of the rectifier.
Final Action 3.
For a disclosure of the "third diode" required by claim 1 and the
"diode" required by claim 26, the Examiner cites Varadarajan, Figure 3,
which is reproduced below:
Figure 3 depicts a NOR logic gate including transistor Qs and diode D1. See
V aradaraj an 3: 3 3-3 5. V aradaraj an discloses that
[t]he first Schottky diode D1 ... starves the base of Qs so that Qs
does not saturate heavily. This has the effect of inhibiting ringing
at node 1 as the voltage at node 1 moves from high to low. Thus,
soft saturation, implemented through the use of the Schottky
diode D1, enhances speed and limits undesired oscillation.
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Appeal 2015-001137
Application 12/121,997
Id. at 4:28-33. The Examiner concludes that "it would have been obvious to
one having ordinary skill in the art at the time of the invention [to] modify
the control circuit of Jansen to include a third diode from Varadarajan
because the third diode is used as a protection means for the switching
device." Final Action 3--4; see also id. at 5.
Appellants argue that the circuit of Jansen as modified by
incorporating a diode D1 according to the teaching of Varadarajan would
result in a modified Jansen circuit as follows:
FlG, 10 Of JANSEN Moownm
WITH THE DIODE 01 OF VARADA.RAJAN
Appeal Br. 7. The modified Jansen circuit includes a diode D1 connecting
the base b2 of transistor 90 to the collector c2, corresponding to how diode
D1 of Varadarajan Figure 3 connects the base to the collector of transistor
Qs. Appellants cite a declaration of inventor Wing Ling Cheng, dated Dec.
3, 2012, testifying that as connected in modified Figure 10 above, diode D1
would never conduct any current, because the voltage of the base b2 of
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Appeal 2015-001137
Application 12/121,997
transistor 90 will always be lower than that the collector c2. See Cheng
Deel. i-fi-f 11-14. Thus, according to Appellants, diode D 1 does not limit the
saturation of transistor 90 of Jansen, and serves no functional purpose. See
Appeal Br. 7-9. Therefore, Appellants argue that the prior art teaches away
from the combination of Jansen and Varadarajan.
The Examiner does not dispute the argument regarding Appellants'
modified Figure 10 of Jansen, but concludes that the modified figure
illustrates only one possible combination of the teachings of Jansen and
Varadarajan. Answer 4--5. The Examiner notes that obviousness does not
depend on "whether the features of the secondary reference may be bodily
incorporated into the structure of the primary reference." Id. at 5. However,
the Examiner does not suggest any alternate way than that proposed by
Appellants in which a person of ordinary skill in the art would have
incorporated the teaching of Varadarajan into the circuit described by
Jansen.
On this record, we find Appellants' arguments persuasive of
reversible error. To establish a prima facie case of obviousness, the
Examiner must set forth a rational underpinning on which the rejection is
based, and "this analysis should be made explicit." KSR Int 'l Co. v. Teleflex
Inc., 550 U.S. 398, 418 (2007). The Examiner has not explicitly explained
how a person of ordinary skill in the art would have combined the teachings
of Varadarajan and Jansen to produce a device within the scope of claims 1
or 26. Therefore, the Examiner has not established a prima facie case for
rejecting independent claims 1 and 26. Because the Examiner's additional
findings regarding the dependent claims do not cure this error, we also
determine that the Examiner reversibly erred in rejecting dependent claims
2-12, 27-38, and 101.
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Appeal 2015-001137
Application 12/121,997
DECISION
The Examiner's decision is reversed.
REVERSED
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