Appeal 2007-1293
Application 10/745,124
2. The dimming control includes a dimming signal detector which
includes a zero crossing detector. The output of the zero crossing detector is
input to a Schmitt-trigger. See Figure 1.
3. The circuit of the zero crossing detector is shown in Figure 4. This
circuit includes two comparators, items 620 and 650.
4. The inverting input to each of these comparators receives a one volt
reference voltage, set by VCC and voltage divider established by two
resistors (616, 618 and 646, 648). Note, voltage divider of resistors 616 and
618 can be used to provide reference voltage to both comparators. (Col. 7,
ll. 11-20.)
5. The output of each of these comparators is connected by a resistor,
item 628 and 658, to VCC (a voltage source).
6. The resistor 628 and 658 are described as “pull-up” resistors, for
biasing the outputs of the comparators. (Col. 7, ll. 20-22.)
7. The output of the comparators is also connected to an RC filter,
resistors 630, 660 and capacitors 632, 662.
8. These RC filters filter the square wave output from the comparators to
provide a voltage (i.e. they low pass filter the output of the comparators).
(Col. 7, ll. 24-27, 45-56.)
ANALYSIS
RELATED TO ANTICIPATION BASED UPON KONOPKA
Claim 1 recites a “feedback resistor coupled between the comparator output
and one of the inputs.” One of skill in the art would recognize that a feedback path
is a path that provides a signal representative of the output to an input. We do not
find that Konopka teaches this feature.
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