Appeal No. 95-3592
Application 08/109,203
On page 7 of the specification, Appellants disclose that the
N-well isolation resistor 10 increases in resistance with an
increase in voltage to limit the amount of current supplied to
the protected circuit structure 21.
Independent claim 1 is reproduced as follows:
1. An isolation stage device for protecting a
circuit structure against over-voltage conditions, comprising:
a lightly doped region having a first conductivity
type formed in a lightly doped substrate having a second
conductivity type;
a first heavily doped region formed at least par-
tially in said lightly doped region having said first conduc-
tivity type, said first heavily doped region being electri-
cally connected to a first input node;
a second heavily doped region formed at least par-
tially in said lightly doped region having said first conduc-
tivity type, said second heavily doped region being electri-
cally connected to said circuit structure; and
a resistive means being electrically connected
between said first heavily doped region and said second
heavily doped region having a resistance responsive to the
voltage between said first heavily doped region and said
second heavily doped region.
The reference relied on by the Examiner is as
follows:
Shirato et al. (Shirato) 4,710,791 Dec. 1,
1987
3
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