Browse Prior Art Database

Offset Voltage Enhancement

IP.com Disclosure Number: IPCOM000075351D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Gersbach, JE: AUTHOR [+2]

Abstract

Consider a pulse powered memory cell in the standby state. The stability of the cell is determined by the available current and load characteristic, which give rise to an offset voltage. The method of operation described below enhances the offset voltage over and above these limiting criteria, allowing for a reduced duty cycle on the standby current.

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Offset Voltage Enhancement

Consider a pulse powered memory cell in the standby state.

The stability of the cell is determined by the available current and load characteristic, which give rise to an offset voltage. The method of operation described below enhances the offset voltage over and above these limiting criteria, allowing for a reduced duty cycle on the standby current.

Consider the offset voltage of the cell shown in the figure. When the standby current is flowing and word top, WT, is up, the offset voltage will be 100mv for the resistor portion of the load and 100mv for the diode portion for a total of 200mv. To provide more would require increased power. Normally to power the cell down, the WT voltage is pulled down, turning the diodes D1 and D2 off, and turn off the standby current source (ISB) simultaneously. The offset voltage then decays from 200mv down to about 100mv or some other value dictated by the disturbs present in the environment.

This offset can be increased by pulling WT down and allowing ISB to continue flowing. During this time C1 continues to discharge at a rapid rate, while the current in C2 is a factor of Beta lower.

ISB turns off just before T1 saturates and the cell goes into the no power state with an offset voltage of approximately 600mv. This can now be allowed to decay to 100mv before pulling WT up, turning ISB on and beginning the process over again. The net result is a significantly reduced duty cycle on the standby current....