Appeal No. 96-2722
Application 08/281,168
which constitute all of the pending claims in the application before us.
BACKGROUND
The subject matter on appeal is directed to a start-up circuit for starting a bias supply circuit,
and more specifically, to the integration of such a start-up circuit in a semiconductor integrated circuit
(see specification, page 1). Appellants admit in the specification that the use of start-up circuits, such as
shown in Figures 10 to 12, is a conventional way of starting a bias supply circuit (see specification,
pages 1 to 6). Appellants recognized that a known problem in the prior art was that large resistances
are needed in the start-up circuit, requiring a very large layout area (see specification, page 6).
Appellants also admit that the production of high resistances for R1 creates the need for more masking
steps and increases fabrication costs. (see specification, page 6). Most significantly, appellants admit
that in the preferred embodiments, "MOS transistors are used to form the start-up circuit and the circuit
to be started," and that "the start-up circuit and the circuit to be started may include other insulated gate
transistors which provide effects similar to those of the preferred embodiments." (Specification, pages
40 to 41).
Representative claim 1 is reproduced below:
1. A start-up circuit formed in a semiconductor integrated circuit including an insulated
gate transistor of a first conductivity type and an insulated gate transistor of a second conductivity type,
and connected to first and second power-supply potentials and to a circuit-to-be-started conducting a
current between said first and second power-supply potentials when started for starting said circuit-to-
be-started, said start-up circuit comprising:
2
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Last modified: November 3, 2007