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Browse Prior Art Database

High Performance Bipolar Logic Circuit

IP.com Disclosure Number: IPCOM000085991D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Pricer, WD: AUTHOR

Abstract

Integrated injection logic circuits, or merged transistor logic circuits, provide substantial improvements in bipolar circuit density but usually at the expense of performance. The logic circuit shown in the figure exhibits greatly improved performance, but with some loss in density.

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High Performance Bipolar Logic Circuit

Integrated injection logic circuits, or merged transistor logic circuits, provide substantial improvements in bipolar circuit density but usually at the expense of performance. The logic circuit shown in the figure exhibits greatly improved performance, but with some loss in density.

The logic is performed by emitter dotting from a normal emitter configuration such as the multiemitter emitter-followers 10, 12, 14 and 16, each having emitters a, b and c. Inversion is produced by inverter common-collector transistors 18, 20, 22 and 24 with series collector resistors 26, 28, 30 and 32 providing degenerate resistance. Since fan power is not required from these latter transistors and in view of the use of the serial degenerate resistance, this portion of the circuit performs very rapidly. The multiemitter emitter-followers, which can be operated out of saturation, determine the speed of the circuit and provide the fan power.

The circuit in the figure, which is provided with constant-current sources 34, 36, 38 and 40, has a logic input signal A of 1.3 volts applied to the base of transistor 18 producing a voltage of 1.0 volt at its emitter which, in turn, produces voltages of 0.6 volt at the emitters a, b and c of emitter-follower 10. Signal B of
0.6 volt applied to the base of transistor 20 provides a voltage of 2.0 volts at its emitter (acting collector) which, in turn, produces a voltage of 1.3 volts at the emitters a, b and c...