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Low Power Current Switch Circuitry with Higher Power External Drive Circuitry

IP.com Disclosure Number: IPCOM000076929D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Spadavecchia, RI: AUTHOR [+2]

Abstract

With the ever-increasing density of microminiaturized chips, heat dissipation within the chip becomes a significant problem. One approach towards the mitigation of this problem involves reducing current levels within the circuitry. The current switch family of circuits is very adaptable to such low-power operation, since the transistors do not operate at saturation currents. However, when operated at such low levels, current-switch logic circuits require circuitry such as emitter-followers to reduce output impedance in order for the low-power current-switch circuitry to drive external circuitry, including large fanouts or transmission lines.

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Low Power Current Switch Circuitry with Higher Power External Drive Circuitry

With the ever-increasing density of microminiaturized chips, heat dissipation within the chip becomes a significant problem. One approach towards the mitigation of this problem involves reducing current levels within the circuitry. The current switch family of circuits is very adaptable to such low-power operation, since the transistors do not operate at saturation currents. However, when operated at such low levels, current-switch logic circuits require circuitry such as emitter-followers to reduce output impedance in order for the low-power current-switch circuitry to drive external circuitry, including large fanouts or transmission lines.

In the circuitry shown, emitter-follower outputs are used for driving other circuits external to the integrated circuit chip containing the current-switch logic circuits. With the approach shown, it is possible to satisfy the low-power requirements of the current-switch circuitry and still provide sufficiently high- power levels to operate the emitter-follower circuitry from a single-voltage source.

The voltage source is provided from +V to -V. The current-switch circuitry, as typified by circuitry 10, is connected to +V through voltage level shifter 11 which suitably reduces the voltage level applied across circuit 10. On the other hand, emitter-follower circuitry 12 is connected directly to +V through line 13 and, consequently, has the full voltag...