Ex Parte Redoute et al

Patent Trial and Appeal Board

Feb 28, 2013

11835187 (P.T.A.B. Feb. 28, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte JEAN-MICHEL VLADIMIR REDOUTE and
MICHIEL STEYAERT

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Appeal 2010-008399
Application 11/835,187
Technology Center 2800
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Before ERIC B. CHEN, MICHAEL J. STRAUSS, and JOHN G. NEW,
Administrative Patent Judges.

NEW, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-008399
Application 11/835,187

2
SUMMARY
Appellants file this appeal under 35 U.S.C. § 134(a) from the
Examiner’s Final Rejection of claims 1, 3 and 5-9. Claims 1, 3 and 6-9
stand rejected as unpatentable under 35 U.S.C. § 103(a) as being obvious
over the combination of Abdel-Hamid et al. (US 2006/0145734 A1, July 6,
2006) (“Abdel-Hamid”) and Tang et al. (US 6,700,422 B2, March 2, 2004)
(“Tang”). The Examiner also rejected claim 5 as unpatentable under 35
U.S.C. § 103(a) as being obvious over the combination of Abdel-Hamid,
Tang and Chen et al. (US 2007/0008036 A1, January 11, 2007) (“Chen”).1
We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

STATEMENT OF THE CASE
Appellants’ invention is directed to a driver circuit suitable for
outputting a signal onto an output line affected by conducted EMI
(electromagnetic interference), with a slope control circuit and an output
circuit (op-amp, Mo, M13 to M21), and which can be used for driving a
LIN network. Abstract.

1 Appellants also argue that the Examiner erred in objecting to claim 4 as
being dependent upon a rejected base claim. App. Br. 23. As we have no
jurisdiction over objections made by the Examiner, we do not address
Appellants’ argument in these respects. See M.P.E.P. § 706.01 (“[T]he
Board will not hear or decide issues pertaining to objections and formal
matters which are not properly before the Board.”)
Appeal 2010-008399
Application 11/835,187

3
GROUPING OF CLAIMS

Because Appellants either do not argue the claims separately or, with
respect to claims 5 and 9, argue that the Examiner erred for substantially the
same reasons with respect to the other claims, we select claim 1 as
representative of this group. App. Br. 25, 37, 45. Claim 1 recites:

1. A driver circuit suitable for outputting a signal onto
a line affected by conducted EMI, the driver circuit comprising:

a slope control circuit receiving an input signal and
outputting a slope controlled version of the input signal;

an operational amplifier, having two inputs and an output,
the output of the slope control circuit being connected to a first
one of said inputs of the operational amplifier; and

an output transistor, receiving at its input the output of the
operational amplifier-whereby the output transistor is arranged to
output the slope controlled version to the line;

whereby the second input of the operational amplifier is
connected over a feedback path with the output of the output
transistor

whereby the output signal of the slope control circuit and
the output of the operational amplifier are signals having a rising
edge and a falling edge, both edges being slope controlled and

whereby the feedback path contains a clipping circuit for
reducing an amount of the conducted EMI in the feedback to the
amplifier.

App. Br. 47.

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Appeal 2010-008399
Application 11/835,187

5
Appellants argue that the Examiner erred in finding that the circuits
disclosed in Fig. 3 teach or suggest that the output signal of either slope
control circuit (V1 or V2) has a slope controlled rising edge and a slope
controlled falling edge. Id. (emphasis in original).
Appellants argue that Abdel-Hamid’s Fig. 3 teaches that when input
voltage Vin transitions from high to low, the transistor MN3 opens and the
transistor MP3 closes, causing the first capacitor C1 to be charged by the
constant current source I1 and therefore, up to a certain level, voltage V1
will be sloped controlled on its rising edge. App. Br. 27. Appellants
contend, however, that when the input signal Vin transitions in the opposite
direction, from low to high, transistor MN3 will close, transistor MP3 will
open, and V1 will be coupled directly to ground. Thus, although voltage V1
was slope controlled when the input signal Vin transitioned from high to
low, the voltage V1 was not slope controlled when the input signal Vin
transitioned from low to high. Id. Appellants argue that the reverse occurs
with respect to the circuit depicted in the lower half of Fig. 3. Id. As a
result, Appellants contend, when input voltage Vin transitions from high to
low, V1 is slope controlled on its leading (rising) edge, but the leading edge
of V2 is not slope controlled, and vice versa, when Vin transitions from low
to high. Id.
The Examiner responds that the slope control circuit depicted in Fig.
3 of Abdel-Hamid provides an output signal V1 with a positive slope of l/C
when the input signal transitions from high to low, and provides the output
signal V1 with a negative slope of l/C when the input signal transitions from
low to high. Ans. 6. The Examiner finds that positive and negative slope
edges formed when the slope control circuit is in charging and discharging
Appeal 2010-008399
Application 11/835,187

6
modes have the rate of l/C, respectively. Id. Therefore, finds the Examiner,
both the rising and falling edges of the output of the slope control circuit is
slope controlled with respect to the input signal. Ans. 6.
We are not persuaded by the Examiner’s reasoning. Appellants’
Specification defines “slope control” thus:
The LIN [Local Interconnect Network] specification therefore
states that “the signal shape should be carefully selected in
order to reduce emissions on one hand and allow for bit rates up
to 20 kbit/sec on the other”: for this reason, the slope of the LIN
driver output signal must be controlled and set to a convenient
value, which emission measurements have shown to lie around
5us. This operation is commonly called slew rate control or
slope control. This slope time must furthermore be independent
of the battery voltage … and of the load….

Spec. 3. We interpret this to mean that the limitation at issue requires that
the rate of change of both the rising and falling edges (as defined by the
slope) of the output voltage of the LIN driver must fall within
predetermined limits.
Provided with that definition, we agree with Appellants’ functional
interpretation of Fig. 3 of Abdel-Hamid. Specifically, we find that when
Vin transitions from high to low, the output voltage of V1 will be slope
controlled with respect to its rising edge as capacitor C1 charges. App. Br.
27. However, when Vin transitions from low to high, C1 discharges directly
to ground via MN3, and, since the resistance along this path is negligible,
the falling edge of the voltage output of VI is not slope controlled. Id. We
further agree with the Examiner that the reverse happens with respect to the
circuit constituting the lower half of Fig. 3 producing V2. Id.
Appeal 2010-008399
Application 11/835,187

7
Moreover, because the Examiner’s finding with respect to the
operational amplifiers recited in the disputed limitation is based upon the
Examiner’s erroneous interpretation described supra (Ans. 6-7), we find the
Examiner’s findings similarly not persuasive. We consequently find that
the Examiner erred in finding claim 1 to be obvious over the combination of
Abdel-Hamid and Tang.

DECISION

The Examiner’s rejection of claims 1, 3 and 5-9 as unpatentable
under 35 U.S.C. 103(a) is reversed.
REVERSED

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