Infineon Technologies Austria AG

Patent Trials and Appeals Board

Apr 2, 2020

14570062 - (D) (P.T.A.B. Apr. 2, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
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
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
14/570,062 12/15/2014 Armin Willmeroth 1012-1009/2011P50309
US01
2554
57579 7590 04/02/2020
MURPHY, BILAK & HOMILLER/INFINEON TECHNOLOGIES
1255 CRESCENT GREEN
SUITE 200
CARY, NC 27518
EXAMINER
RAHMAN, MOIN M
ART UNIT PAPER NUMBER
2898
NOTIFICATION DATE DELIVERY MODE
04/02/2020 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):
official@mbhiplaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ARMIN WILLMEROTH, FRANZ HIRLER, and
PETER IRSIGLER
Appeal 2019-003462
Application 14/570,062
Technology Center 2800
Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM, and
LINDA M. GAUDETTE, Administrative Patent Judges.
GAUDETTE, Administrative Patent Judge.
DECISION ON APPEAL1
The Appellant2 appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision finally rejecting claims 1, 18–23, and 25.3
We reverse.

1 This Decision includes citations to the following documents: Specification
filed December 15, 2014 (“Spec.”); Final Office Action dated January 26,
2018 (“Final”); Appeal Brief filed October 11, 2018 (“Appeal Br.”);
Examiner’s Answer dated January 31, 2019 (“Ans.”); and Reply Brief filed
March 29, 2019 (“Reply Br.”).
2 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies the real party in interest as Infineon
Technologies Austria AG. Appeal Br. 2.
3 We have jurisdiction under 35 U.S.C. § 6(b).
Appeal 2019-003462
Application 14/570,062

2
CLAIMED SUBJECT MATTER
Claim 1, reproduced below, is illustrative of the claimed subject
matter:
1. A half-bridge circuit, comprising:
a low-side transistor and a high-side transistor each
comprising a load path and a control terminal;
a high-side drive circuit comprising a level shifter with a
level shifter transistor, the high-side drive circuit
being configured to drive the high-side transistor;
and
wherein the low-side transistor and the level shifter
transistor are integrated in a common
semiconductor body,
wherein the load paths of the high-side transistor and the
low-side transistor are connected in series between
terminals for a positive supply potential and a
negative supply potential or a reference potential,
wherein a circuit node that is common to the load paths
of the high-side transistor and the low-side
transistor forms an output of the half-bridge
circuit.
Appeal Br. 11, Claims Appendix (emphasis added).
REFERENCES
The Examiner relies on the following prior art as evidence of
unpatentability:
Name Reference Date
Shimizu US 2004/0212021 Al Oct. 28, 2004
Kim US 2011/0316078 Al Dec. 29, 2011
Shimizu ’115 US 2011/0316115 Al Dec. 29, 2011

Appeal 2019-003462
Application 14/570,062

3
REJECTIONS
1. Claims 1 and 18–21 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Kim in view of Shimizu.
2. Claims 22, 23, and 25 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Kim in view of Shimizu and Shimizu ’115.
OPINION
The Examiner rejected independent claim 1 as unpatentable over Kim
in view of Shimizu. Final 2. Kim Figure 1 is reproduced below.

Kim Figure 1 is a block diagram of circuit 100 that includes high
voltage integrated circuit (IC) 102 for controlling high side transistor 106
Appeal 2019-003462
Application 14/570,062

4
and low side transistor 108. Kim ¶ 11. High side transistor 106’s source and
low side transistor 108’s drain are coupled to load 104. Id. High side
transistor 106’s drain is coupled to high voltage source 110 and low side
transistor 108’s source is coupled to ground 112. Id. High side transistor
106’s gate is coupled to high side gate driver 114 in high voltage region 116
on high voltage IC 102. Id. Low side transistor 108’s gate is coupled to low
side driver 118 in low voltage region 119 on the high voltage IC 102. Id.
High voltage region 116 includes high side gate driver 114. Id. “[O]ne or
more level-shift transistors 122 shift a voltage of a control signal from a low
voltage to a high voltage in order to control the high side gate driver 114 and
associated circuitry.” Id. ¶ 12.
The Examiner found that Kim discloses the claim 1 half-bridge circuit
with the exception that Kim’s low-side transistor 108 and level shift
transistor 122 are not “integrated in a common semiconductor body” (claim
1). Final 2–4. The Appellant does not dispute this finding. See generally
Appeal Br. 4–10. The Examiner finds that Shimizu would have suggested
modifying Kim’s half-bridge circuit to integrate low-side transistor 108 and
level shift transistor 122 in a common semiconductor body. See Final 3–4.

Appeal 2019-003462
Application 14/570,062

5
Shimizu Figure 1 is reproduced below.

Shimizu Figure 1 illustrates the configuration of high voltage integrated
circuit (HVIC) 100. Shimizu ¶ 19. As shown in Figure 1, “power devices 12
and 13 such as IGBTs (Integrated Gate Bipolar Transistors) are totem-pole-
connected between a high side (HV) power line and a low (ground potential
GND) side power line, to form a half-bridge power device.” Id. ¶ 51. “The
high side power device driving circuit HD includes a PMOS transistor 24
and an NMOS transistor 25 constituting a complementary MOS transistor
(CMOS transistor).” Id. ¶ 55. “[C]apacitor 10[,] which is a power supply of
the driving circuit HD, . . . complementarily turns on/off the PMOS
transistor 24 and NMOS transistor 25 to switch on/off the power device 12.”
Id. “A voltage at a node between the PMOS transistor 24 and NMOS
transistor 25 is called a high side output voltage or control signal HO.” Id.
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Application 14/570,062

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“The low side power device driving circuit LD includes a PMOS transistor
27 and an NMOS transistor 28 connected in series between the two
electrodes of a capacitor 11 . . . .” Id. ¶ 63. Capacitor 11 “is a power supply
for the driving circuit LD, and complementarily turns on/off the PMOS
transistor 27 and NMOS transistor 28 to switch on/off the power device 13.
A voltage at a node between the PMOS transistor 27 and NMOS transistor
28 is called a low side output voltage or control signal LO.” Id. Interface
circuit 1 and pulse generator 3 are a low side logic circuit. Id. ¶ 56. Pulse
generator 3 has two outputs respectively connected to the gate electrodes of
high voltage N-channel field effect transistors (HNMOS transistors) 4 and 5,
which are level shift transistors. Id. ¶ 57.
The Examiner found that Shimizu’s NMOS transistor 28 is a low-side
transistor that is integrated with level shift transistor 5 in a common
semiconductor body (HVIC 100). Final 3. The Examiner found that one of
ordinary skill in the art would have modified Kim to integrate Kim’s low-
side transistor 108 and level shift transistor 122 in a common semiconductor
body “to reduce complexity of having multiple semiconductor substrates for
the components and having miniaturized efficient device by having a
common semiconductor substrate or semiconductor wafer for the device.”
Id. at 3–4. The Appellant contends that the Examiner erred reversibly as to
these findings.
The Appellant argues that Shimizu’s low-side transistor is power
device 13. Appeal Br. 7. The Appellant argues that Shimizu’s power device
13 is not integrated with level shift transistor 5 in a common semiconductor
body. Id. The Appellant contends that NMOS transistor 28 forms part of a
low side power device driving circuit LD that switches power device 13 on
Appeal 2019-003462
Application 14/570,062

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and off, but is not a low-side transistor as claimed. Id. The Appellant argues
that the Examiner has conflated the circuit concepts of a half-bridge and a
driver for a half-bridge. Id. The Appellant’s arguments are persuasive of
reversible error in the Examiner’s obviousness determination as to
independent claim 1 and its dependent claims 18–23 and 25.
The Specification discloses that “[i]n a half-bridge circuit the
transistor connected between output and a terminal for a negative supply
potential is referred to as low-side transistor (low side switch), while the
transistor connected between a terminal for the positive supply potential and
the output is referred to as high-side transistor (high-side switch).” Spec. ¶ 2.
Kim discloses a half-bridge circuit: “low side transistor 108” is connected
between load 104 and ground 112, and “high-side transistor 106” is
connected between load 104 and high voltage source 110. Kim ¶ 11.
Shimizu also discloses a half-bridge circuit: “power device 12” (a transistor)
is connected between a load (at node N1) and ground, and “power device
13” (a transistor) is connected between a load (at node N1) and a high side
(HV) power line. Shimizu ¶ 51, Figure 1. Kim discloses that control
components 120 generate control signals that are sent to high and low side
gate drivers 114, 118 to control the voltage at the gates of high-side and low-
side transistors 106, 108, thereby controlling the voltage and current
supplied to load 104. Kim ¶ 13. Similarly, Shimizu discloses that transistors
24, 25 of high side power device driving circuit HD and transistors 27, 28 of
low side power device driving circuit LD receive control signals and provide
high and low side output voltages or control signals HO, LO for controlling
power devices 12, 13. Shimizu ¶¶ 55, 56, 63, 64. Kim discloses level-shift
transistor 122 for controlling high side gate driver 114 (Kim ¶ 12), and
Appeal 2019-003462
Application 14/570,062

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Shimizu discloses level-shift transistor 5 is connected to the input of logic
filter 8, which is in the high side power device driving circuit HD (Shimizu
¶¶ 73, 90).
The above disclosures in the Specification, Kim, and Shimizu support
the Appellant’s contention that the ordinary artisan at the time of the
invention would have understood that “[a] driver for a half-bridge . . . is not
the same as the half-bridge itself.” Reply Br. 2 (emphasis omitted); see
Appeal Br. 7. Based on the description in the Specification (see, e.g., Spec.
¶ 2), we are persuaded that the ordinary artisan would have understood that
the claimed half-bridge circuit low-side transistor reads on Shimizu’s power
device 13. See Appeal Br. 8; Reply Br. 2–3. We are also persuaded that the
ordinary artisan would have understood that Shimizu’s transistors 27, 28,
like Kim’s gate driver 118, are part of drive circuits that are configured to
drive Shimizu’s low-side transistor (power device 13) and Kim’s low-side
transistor 108. See Appeal Br. 8; Reply Br. 2–3.
The Examiner has not articulated clearly why the Appellant’s
arguments, which we find are supported by the record evidence, are not
persuasive of error in the Examiner’s obviousness determination. See, e.g.,
Ans. 5 (failing to explain why Shimizu’s transistor 28 is properly
characterized as a low-side transistor as this term is used in the Appellant’s
Specification and claims (see Spec. ¶ 2)). We additionally note that the
Examiner has not identified evidentiary support for the alleged reason why
the ordinary artisan would have modified Kim. See Final 3–4; Ans. 7.
Because the Examiner’s obviousness determination is not supported by a
preponderance of the record evidence, we do not sustain the rejections of
claims 1, 18–23, and 25.
Appeal 2019-003462
Application 14/570,062

9
DECISION SUMMARY
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1, 18–21 103(a) Kim, Shimizu 1, 18–21
22, 23, 25 103(a) Kim, Shimizu, Shimizu
’115
22, 23, 25
Overall
Outcome:
1, 18–23,
25

REVERSED