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Disturb-Free Integrated Read Circuit and Constant Current Bit Driver

IP.com Disclosure Number: IPCOM000047599D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Barish, AE: AUTHOR [+2]

Abstract

The disturb-free integrated read circuit depicted in Fig. 1 provides a fast read capability for an array, integrated on a logic masterslice. In addition, power is dissipated in the read circuits for only that word being read. All unselected read circuits dissipate no power. The constant current bit driver (Fig. 2) provides a fast, switchable, constant current source to write data into a fixed voltage Harper array cell. Operation of the read circuit is as follows: Both the input and the read reference are provided by the storage cell. When the cell is unselected, the word line is at a logical "0", which keeps T5 turned off. Therefore, T6 and T7 do not draw any current. In any bit line column, only one read circuit will be active. The associated word line will be at a logical "1", which will allow T5 to conduct.

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Disturb-Free Integrated Read Circuit and Constant Current Bit Driver

The disturb-free integrated read circuit depicted in Fig. 1 provides a fast read capability for an array, integrated on a logic masterslice. In addition, power is dissipated in the read circuits for only that word being read. All unselected read circuits dissipate no power. The constant current bit driver (Fig. 2) provides a fast, switchable, constant current source to write data into a fixed voltage Harper array cell. Operation of the read circuit is as follows: Both the input and the read reference are provided by the storage cell. When the cell is unselected, the word line is at a logical "0", which keeps T5 turned off. Therefore, T6 and T7 do not draw any current. In any bit line column, only one read circuit will be active. The associated word line will be at a logical "1", which will allow T5 to conduct. Subsequently, either T6 or T7 will conduct, depending upon whether the input from the storage cell is high or low. If T6 is conducting, then the output is at a logical "0". If T7 is conducting, then the output will be at a logical "1" with T6 off and T8 on. When reading is performed, only base current is drawn by either T6 or T7. Thus, the read operation does not disturb the storage cell current. Operation of the constant current bit driver is as follows: With the write line disabled (logical "1"), transistor T9 is conducting and the voltage at the collector of T9 prevents T10 from conduct...