Appeal No. 1997-0288
Application No. 08/200,123
to change a constant voltage, variable current output power
system (Saito) into the opposite.”
We agree with all of appellant’s arguments. Saito
discloses a current detection circuit 7 (Figure 1) that
receives an output current that flows through current
detection resistor R6. The output from the current detection
circuit 7 is supplied via photocoupler Q5 to primary current
detection means A. According to Saito (column 6, lines 17
through 26):
If, therefore, there is no input from the
secondary current detection means B, the threshold
value for current detection is set at a level at
which a peak current can be supplied, as shown in
FIG. 2A. In contrast to this, if an input from the
secondary current detection means B is received, the
detection level of the primary current detection
means A is shifted downward to limit a current, as
shown in FIG. 2B. In this embodiment, the
transistor portion of the photocoupler Q5 serves as
a variable resistance element.
Although Saito’s circuit appears to be similar to the
circuit disclosed by appellant, Saito’s circuit is designed
and operated “to maintain the output voltage at a constant
value” (column 11, lines 17 and 18), which is the very
antithesis of the claimed invention. Accordingly, we agree
with appellant (Brief, page 5) that “[i]n Fig. 2B of Saito, it
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