Ex parte Canter

Board of Patent Appeals and Interferences

Feb 16, 2001

08654763 (B.P.A.I. Feb. 16, 2001)

-1-
The opinion in support of the decision being entered
today was not written for publication and is not binding
precedent of the Board.
Paper No. 28
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte STANLEY CANTER
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Appeal No. 1998-2460
Application No. 08/654,763
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ON BRIEF
________________
Before KRASS, BARRETT, and BARRY, Administrative Patent
Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 1-4, 6 and 8-10, all of the pending claims.
Appeal No. 1998-2460
Application No. 08/654,763
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The invention is directed to a battery charger power
regulator that operates from a solar array and uses a Peak
Power Tracker (PPT). Unlike the prior art, which tracked and
determined the peak power point of the solar array, the
invention seeks to maximize the charge current of the battery
and not to operate at a particular point on the power curve of
the solar array. In particular, a PPT control loop is
utilized. This control loop employs an oscillator which, in
combination with other elements, causes an increase in the
duty cycle of a pulse width modulated buck regulator by
incrementally increasing the potential across a capacitor that
has no discharge path. The total output current from the buck
regulator is sensed and a decrease in current causes a
reduction in the duty cycle while the decreased duty cycle, in
turn, results in a sensed increase in total current. Thus,
the circuit will eventually oscillate about a maximum battery
charging current value that corresponds to the peak power
point of the solar array, analogous to the functioning of a
PPT.
Appeal No. 1998-2460
Application No. 08/654,763
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Representative independent claim 1 is reproduced as
follows:
1. A method for operating a pulse width modulated
switching power converter having an input coupled to an output
of a solar array and an output providing an output current,
the output current being coupled to a battery for supplying a
current I to the battery and also coupled to a load forCHARGE
supplying a load current I comprising the steps of:LOAD,
sensing a first magnitude of the output current, the output
current comprising both I and I ;CHARGE LOAD
storing the sensed magnitude;
incrementally increasing a duty cycle of the pulse width
modulated switching power converter to attempt to
incrementally increase a magnitude of the output current of
the switching power converter;
sensing a second magnitude of the output current; and
comparing the stored first magnitude to the sensed second
magnitude;
if the stored first magnitude is less than the sensed second
magnitude, maintaining the duty cycle at a current duty cycle
increment, else
if the stored first magnitude is greater than the sensed
second magnitude, decreasing the duty cycle;
wherein the method does not directly sense the output of the
solar array while operating to maximize the charging current
to the battery, and wherein the duty cycle of the pulse width
modulated switching power converter is controlled only in
accordance with the sensed output current.
Appeal No. 1998-2460
Application No. 08/654,763
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The examiner relies on the following references:
Rogers 4,314,198 Feb. 02, 1982
Chetty 4,604,567 Aug. 05, 1986
Black et al. (Black) 4,731,870 Mar. 15, 1988

Bavaro et al. (Bavaro) 4,794,272 Dec. 27, 1988
Frederick et al. (Frederick) 5,327,071 Jul. 05, 1994
Claims 1-4, 6 and 8-10 stand rejected under 35 U.S.C.
103. As evidence of obviousness, the examiner cites Bavaro,
Chetty, Rogers and Frederick with regard to claims 1-4 and 6,
adding Black to the combination with regard to claims 8-10.
Reference is made to the briefs and answer for the
respective positions of appellant and the examiner.
OPINION
We reverse.
Appeal No. 1998-2460
Application No. 08/654,763
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The examiner employs Chetty for the teaching of a sample
and hold circuit. Rogers is employed for the teaching of not
sensing the output of the solar array; Frederick is employed
for its teaching of providing “the sensing of the output
current delivered to load that is used as a signal sent to a
pulse width modulator to control the switching power
converter” [answer-page 5] and Black is employed for its
teaching of a low earth orbit satellite that employs a solar
array.
However, it is the primary reference to Bavaro on which
the examiner relies for a disclosure of much of the subject
matter of the independent claims. Each of the independent
claims requires, inter alia, the sensing of both the current
to the battery and the load current in operating the claimed
pulse width modulated switching power converter. Since none
of the other references is alleged by the examiner to disclose
or suggest the sensing of both the battery current and the
load current, this claimed feature must be disclosed or
suggested by Bavaro if the rejection is to succeed.
Appeal No. 1998-2460
Application No. 08/654,763
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However, reference to Figures 3 and 4, and column 5,
lines 47-49 indicates that, in Bavaro, the operating point
adjustments and load regulation is a “function of readings
from only the battery current sensor” [emphasis ours]. Thus,
Bavaro specifically teaches that both the battery current and
the load are not employed in operating the pulse width
modulated regulator. We note that column 5, lines 52-53,
recites that “Battery current was chosen for simplicity” which
might leave open the possibility that other current measures
could be employed. However, such a suggestion is still a few
steps away from suggesting that perhaps both battery current
and load current should be sensed. As far as we can tell from
the record, including the examiner’s allegations, the only
suggestion for sensing both the battery current and the load
current comes from appellant’s disclosure alone.
Even in the rationale explaining the rejection, at page 4
of the answer, the examiner states that Bavaro discloses
“...the sensing of the output current delivered to load that
is used as a signal sent to a pulse width modulator to control
the switching power converter...” However, the examiner does
Appeal No. 1998-2460
Application No. 08/654,763
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not appear to be alleging that both the battery current and
the load current are to be used by Bavaro to control the power
converter. Moreover, while the examiner alleges that output
current “delivered to load” is used to control the power
converter, the examiner never indicates any particular section
of Bavaro that suggests this sensing of load current.
In response to appellant’s argument on this point, the
examiner responds with what he believes to be the “crux” of
appellant’s invention. Analyses under 35 U.S.C. 103 must be
made with regard to the claimed subject matter which recites
what an applicant regards as his invention and may not be made
on a general concept or “crux of the invention" criteria.
Further, the examiner explains, at pages 7-8 of the
answer, that Bavaro teaches an output current measuring means
“within the different embodiments that measure the two
different components of the output current, the load current
and the battery current.” However, the examiner fails to
specifically point to the portion of Bavaro on which he relies
for the conclusion that both the battery current and the load
current are measured. Both Figures 3 and 4 of Bavaro, show a
sensor 355 V/T only at the battery and a battery current
Appeal No. 1998-2460
Application No. 08/654,763
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sensor I but we find absolutely no suggestion in Bavaro thatBC
more than the battery current is sensed for determining the
operating point. It also does not appear that any of the
other applied references can cure this deficiency of Bavaro,
except, possibly, Frederick. Frederick does disclose a
control signal derived from a current sensor which senses the
output current which comprises a battery current and a load
current (See Figure 2 of Frederick). However, independent
claim 1 requires that the duty cycle of the pulse width
modulated switching power converter is controlled only in
accordance with the sensed output current. Frederick’s duty
cycle is controlled in accordance with the control signal 36
and the output voltage of the solar array. Since there is no
suggestion of doing away with the solar array output voltage
as a controlling factor, Frederick does not appear to aid in
providing for the deficiency of the other references regarding
the subject matter of instant claim 1. Thus, we will not
sustain the rejection of independent claim 1 under 35 U.S.C.
103.
Appeal No. 1998-2460
Application No. 08/654,763
-9-
With regard to independent claim 3, appellant argues
[page 15-principal brief] that this claim distinguishes over
the applied references by its recitation of the means for
controlling the duty cycle in accordance with the sensed
current having an input coupled to an output of the current
sensing means and to an output of said means for incrementally
increasing. Since the examiner has not addressed the
limitation of the means for “incrementally increasing a duty
cycle...”, and we are unaware of any reason to modify the
applied references to provide for this claimed recitation, we
will not sustain the rejection of claim 3 under 35 U.S.C. 103.
With regard to independent claim 6, appellant argues
[principal brief-page 15] that the distinguishing feature is
the recitation of a combination of a capacitance and an
oscillator for providing a signal for periodically applying a
charge to the capacitance. Since this is the means by which a
corresponding increase in the duty cycle is produced and we
have held that the recitation of the “incrementally
increasing” limitation distinguished over the applied
Appeal No. 1998-2460
Application No. 08/654,763
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references with regard to claim 3, we will also not sustain
the rejection of claim 6 under 35 U.S.C. 103.
The final independent claim, claim 8, recites subject
matter similar to the other claims but includes the limitation
that the solar array is part of an “earth satellite.” The
examiner relies on the additional reference to Black for the
teaching of employing solar cells in an earth satellite.
However, Black does not provide for the deficiencies of the
other references, noted supra, relative to the current sensor
coupled only to an output of the switching device and not to
an output of the solar array.
Accordingly, the examiner’s decision rejecting claims 1-
4, 6 and 8-10 under 35 U.S.C. 103 is reversed.
REVERSED
Appeal No. 1998-2460
Application No. 08/654,763
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ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
)
LEE E. BARRETT ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
LANCE LEONARD BARRY )
Administrative Patent Judge )
EK/RWK
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