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Low Power Monolithic Storage

IP.com Disclosure Number: IPCOM000089968D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Ho, IT: AUTHOR [+4]

Abstract

This storage circuit uses PNPN diodes as storage elements. A method of making the storage elements is also described. The T-network in drawing 1 comprises a grounded PNPN diode connected by resistive paths to a word line and a bit-sense line. This is one storage cell, a plurality of the cells being required to form an array. Drawing 2 shows the current-voltage curve of the PNPN diode.

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Low Power Monolithic Storage

This storage circuit uses PNPN diodes as storage elements.

A method of making the storage elements is also described. The T-network in drawing 1 comprises a grounded PNPN diode connected by resistive paths to a word line and a bit-sense line. This is one storage cell, a plurality of the cells being required to form an array. Drawing 2 shows the current-voltage curve of the PNPN diode.

To place the diode in one of its two stable states, a positive pulse is applied to the diode causing it to break down. The switching voltage is determined largely by the avalanche breakdown of the middle junction. In this first state, the diode operates on the loadline at point A, drawing 2, requiring a holding current Ih. In order to sense the state of the diode, a small voltage pulse is applied and the resultant current drawn is measured. When operating near point A, a relatively small voltage pulse results in a relatively large current swing. This is nondestructive readout. In order to bring the diode into its other stable state, a large negative voltage pulse is applied. This results in operation along the loadline at point B. This second stable state of the diode is sensed in the identical manner as the first, by applying a small voltage pulse. When operating near point B, the application of the small voltage pulse results in practically no current flow.

This circuit also operates without the application of a holding current Ih. In that case, it is ne...