Appeal No. 1999-1850
Application No. 08/870,406
transistors in the common-emitter stage are connected to emitters of transistors in the common-
base stage. Since the temperature is uniform, based on the low bias applied, current levels on the
collectors in the common-emitter stage are uniform. The collector bias in the common base stage
is substantially higher, which results in a higher junction temperature. However, even though
there are temperature variations between emitters of the common-base cells, no thermal runaway
can occur because the current of each emitter finger is limited by the collector current of the
common-emitter cells.
Representative independent claim 1 is reproduced as follows:
1. A device for controlling thermal runaway comprising:
a common-emitter cell and a common-base cell;
each cell having a first subcell and a second subcell;
said first and second subcell of the common emitter cell having at least one transistor;
said first and second subcell of the common-base cell having at least one transistor;
each transistor of the subcells in the common-emitter cell and common-base cell further
comprising an emitter, a collector and a base; and
the collectors of each subcell of the common-emitter cell being connected to the emitter
of the transistor in the equivalent subcell of the common-base cell.
The examiner relies on the following reference:
Izuhara 5,497,155 Mar. 5, 1996
2–
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