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Pulse Powered Current Driver Circuit

IP.com Disclosure Number: IPCOM000077913D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Cassidy, BM: AUTHOR [+3]

Abstract

This is a low-power high-speed current driver for driving current sources in true-complement generators that gives a surge of current at the initial part of the cycle, and then switches to zero current after the true-complement generators are powered up and latched in their proper state. A power saving on the chip is thus realized. At the same time, the driver is kept on long enough to allow the address, data-in, and read/write pulses to be read into the true-complement generators.

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Pulse Powered Current Driver Circuit

This is a low-power high-speed current driver for driving current sources in true-complement generators that gives a surge of current at the initial part of the cycle, and then switches to zero current after the true-complement generators are powered up and latched in their proper state. A power saving on the chip is thus realized. At the same time, the driver is kept on long enough to allow the address, data-in, and read/write pulses to be read into the true-complement generators.

In standby the node Y which is being controlled by a power supply, not shown, sits at a voltage of -1.4 V and thus keeps transistor T2 off. With the coincidence of both the column and row select pulses, node Y rises towards, but does not reach, +1.25 V, allowing T2 to turn on. however, as soon as input A line reaches -1.2 V, T1 turns on and the Y node goes to -0.7 V and is again referenced to the -3.0 V supply. When the node Y is at -0.7 V, the base of the load transistor T5 is at -2.0 V. thus defining 1 milliamp of current through it.

The true and complement outputs of a true-complement generator (W4 and W4) are used to turn on transistors T3 and T4. Transistor T3 being on pulls the Y node to -2.2 V, which in turn turns off transistor T2. At the same time, transistor T4 actively discharges the base of transistor T5 and reduces its voltage to -2.7 V. At the end of the cycle, the output of a true-complement generator (either W4 or W4) goes down and t...