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Ground Up Low Power Bipolar Circuit

IP.com Disclosure Number: IPCOM000081470D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Gopalakrishna, YR: AUTHOR [+2]

Abstract

Large-scale integration offers high-circuit density on a logic chip. On the high-density chip, metal lands between communicating circuits are small with minimal capacitances. In such an environment, low-power internal logic circuits can effectively drive on-chip nets. For communication off-chip, where large capacitances of the package and transmission lines are involved, higher power drivers are required for reasonable performance. One such communication system is shown in the drawing having a two power supply environment with a common ground (volts VEE). This includes: a) An off-chip receiver having high-input impedance and performing inversion. b) A low voltage (VBB), low-power logic circuit (NAND). c) The totem pole off-chip driver circuit operating on a high-voltage power supply (VCC) performing NAND logic.

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Ground Up Low Power Bipolar Circuit

Large-scale integration offers high-circuit density on a logic chip. On the high-density chip, metal lands between communicating circuits are small with minimal capacitances. In such an environment, low-power internal logic circuits can effectively drive on-chip nets. For communication off-chip, where large capacitances of the package and transmission lines are involved, higher power drivers are required for reasonable performance. One such communication system is shown in the drawing having a two power supply environment with a common ground (volts VEE). This includes:
a) An off-chip receiver having high-input impedance and

performing inversion.
b) A low voltage (VBB), low-power logic circuit (NAND).
c) The totem pole off-chip driver circuit operating on a

high-voltage power supply (VCC) performing NAND logic.

In a ground up system, for an off-chip signal at the input A of the receiver, the receiver inverts and produces a signal at the collector of the transistor TX1. The signal output swings between the VBB power supply and the collector to emitter voltage (Vce) of TX1. This on-chip signal is applied to the emitter of the input transistor TX2 and produces the same signal levels, but inverted, at the output of the internal circuits. The on-chip signals appear at the cathode of the diodes D6 of the off-chip driver. The off-chip driver, which has a threshold voltage Vbe above ground, translates and inverts the on-chip signal to...