Browse Prior Art Database

Josephson Memory Cell

IP.com Disclosure Number: IPCOM000079115D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Hamel, HC: AUTHOR

Abstract

This memory is capable of selecting and reading only one cell in a cell array. This function is possible due to a double-control device in the cell, as shown in Fig. 1. The actual schematic of the cell arrangement is shown in Fig. 2, where the device of interest is labelled J3. The cell works like the Anacker cell except in the readout of the information.

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Josephson Memory Cell

This memory is capable of selecting and reading only one cell in a cell array. This function is possible due to a double-control device in the cell, as shown in Fig. 1. The actual schematic of the cell arrangement is shown in Fig. 2, where the device of interest is labelled J3. The cell works like the Anacker cell except in the readout of the information.

The cell is designed so that the sensed circuit Is, word current Iw, and the read bit current IB' must be present simultaneously, to have the sense device J3 switch out of the Josephson state. More precisely the operating region of J3 is designed as shown in Fig. 3.

In Fig. 3, four cases are summarized. Is is assumed the 5 units of current. Iw/2 is assumed to be 2 units of current. IB' is assumed to be 2 units of current. When Is is present, J3 can only switch if the accumulation control current is 5 units or greater. Iw plus IB' equals 6 units; this is thy only case that will switch J3. The other combinations of accumulation control current are: Iw/2 + IB = 4 units

Iw/2 + 0 = 2

-Iw/2 + IB' = 0

-Iw/2 + 0 = -2. When J3 is 0, not even Iw + IB' = 6 units can switch J3.

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