Appeal No. 95-3876
Application 08/222,009
transistor Q4 connects the voltage divider resistors R8 and R9
between constant voltage source 2 and ground, thereby creating
at the junction of the resistors a voltage sufficient to turn
on the IGBT, the turning on of Iwata's transistor 23 connects
the voltage divider resistors 24 and 25 between the output of
constant voltage generation circuit 17 and ground, thereby
creating at the junction of those resistors a voltage V
(waveform C of Fig. 4) sufficient to turn on the FET.
However, Iwata does not employ a transistor like appellants’
transistor Q3 for turning off the FET in response to a
separate flash terminating signal. Instead, the FET turns off
when the output of NAND gate 28 goes low, thereby turning off
transistors 22 and 23 and disconnecting the voltage divider
24-25 from constant voltage generation circuit 17, which
results in removal of the biasing voltage from the gate of the
FET.
The examiner reads the elements of claim 14, except
for the IGBT, on Iwata as follows: "Iwata et al[.] shows a
power source (11), a main capacitor (1), a flash firing unit
(14), the equivalent of an insulated gate bipolar transistor
(FET 15), means for receiving (29), first circuit (19), second
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Last modified: November 3, 2007