Appeal No. 2000-1938
Application 08/940,467
resistor RG in component stages 102a-102n or the combination of
zener diode ZG and resistors RG and RS in driver stage 104.
Instead, Cooper explains that resistor RG and zener
diode ZG in component stages 102a-102n
are selected to prevent transistor conduction due to
leakage current during biased-off operation, to
generally protect the transistor from gate-to-source
stress during biased-on operation, and to provide the
desired gate-to-source voltage to turn the associated
transistor on when a current path to ground is
provided.
Column 5, lines 47-53. Regarding zener diode ZG and resistor RG
in driver stage 104, Cooper explains that
Zener diode ZG, connected between the gate of the
transistor and ground, is sized to limit the voltage
applied to the MOSFET gate. Resistor KG, connected
across the transistor gate and source[,] is selected to
provide sufficient gate-to-source voltage to turn the
driver transistor on when an enable signal is received.
Column 6, lines 39-44. Furthermore, Cooper's description of the
operation of the crowbar circuit (col. 6, 1. 61 to col. 9, 1. 64)
makes no mention of any of the zener diodes ZG.
Consequently, to the extent the rejection of claims 2 and 4
is based on Cooper, it is reversed.
Lebbolo's Figure 4 shows a DC power supply protection
circuit. Apparently relying on Zener diode Z2, capacitor C6, and
resistor R11, all of which are connected in parallel, the
examiner argues that Lebbolo teaches using a parallel-connected
capacitor and resistor in parallel with a zener diode in order to
"control the discharge rate" (Answer at 4) and "for the purpose
of controlling the breakover rate of discharge current when the
zener voltage is exceeded." Answer at 6. However, the only
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