Browse Prior Art Database

Current Biased Array Sense Circuit

IP.com Disclosure Number: IPCOM000052530D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Montegari, FA: AUTHOR [+3]

Abstract

Providing for the supply of a bleeding current path in an array sense circuit prevents sense nodes from assuming floating potentials. As a result, a higher sensitivity, as well as a reduced delay (access) time, is obtainable when addressing array cells.

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Current Biased Array Sense Circuit

Providing for the supply of a bleeding current path in an array sense circuit prevents sense nodes from assuming floating potentials. As a result, a higher sensitivity, as well as a reduced delay (access) time, is obtainable when addressing array cells.

For illustration, the drawing depicts a portion of a read-only memory arrangement indicating row drivers T1-T3, array diodes D1-D3, column drivers T4-T6 and output stage transistors T9-T11 connected conventionally as clamp, inverter and emitter follower (driver) circuits. The emitter of sense amplifier T7 connects to, e.g., 144 Schottky diodes D4, D5, D6, etc., to allow for sensing the state of any one of corresponding 16 array columns. A relatively high metallurgy capacitance CM appears at the T7 emitter node as a result of these emitter-diode interconnections.

Prior array designs using similar sense circuits allowed the T7 emitter node to float to a positive potential limited only by the cathode potential of diodes D4-D6. In those designs, when the array code was such that no diode D4-D6 was conducting, the T7 emitter node would float to a relatively high DC potential. Then, metallurgy capacitance CM would retain this potential and cause a very slow negative transition when an array code with a conducting diode was addressed.

The proposed sense circuit avoids the above problem through the addition of a biasing current source consisting of T8 and R1. A small current of 100 MuA i...