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Pinch Resistor Tracking Constant Current Source

IP.com Disclosure Number: IPCOM000053070D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Houghton, RJ: AUTHOR [+2]

Abstract

A standby offset voltage for a static pinch resistor random access memory cell 10, connected to word top line WT1 and word bottom line WB1, is maintained by a circuit 12 which maintains the cell current I proportional to the reciprocal of the value of the pinch resistor R(P1) or R(P2) The circuit 12 includes a reference pinch resistor R(P3) wherein the same or a similar voltage is developed as that developed across either pinch resistor R(P1) or R(P2) to provide desired tracking, resulting in lower nominal standby power. By making the cell current I a function of the reciprocal of the value or magnitude of the pinch resistor R(P1) or R(P2), the offset voltage between the bases of the multi-emitter flip-flop transistors T1 and T2 becomes substantially constant.

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Pinch Resistor Tracking Constant Current Source

A standby offset voltage for a static pinch resistor random access memory cell 10, connected to word top line WT1 and word bottom line WB1, is maintained by a circuit 12 which maintains the cell current I proportional to the reciprocal of the value of the pinch resistor R(P1) or R(P2) The circuit 12 includes a reference pinch resistor R(P3) wherein the same or a similar voltage is developed as that developed across either pinch resistor R(P1) or R(P2) to provide desired tracking, resulting in lower nominal standby power. By making the cell current I a function of the reciprocal of the value or magnitude of the pinch resistor R(P1) or R(P2), the offset voltage between the bases of the multi-emitter flip-flop transistors T1 and T2 becomes substantially constant.

The circuit 12 in the figure further includes a standard differential amplifier 14 which includes transistors T3, T4, T5 and T6, resistors R1 and R2, and current sources CS1 and CS2 with input nodes N1 and N2. A current mirror 16 formed by diode D1 and transistor T7 has the same current passing through T7 as is passed through D1, with the current through D1 being determined by the voltage at node N3, or the emitter of transistor T9, which is a function of the reciprocal of the pinch resistor R(P3), as described hereinbelow.

The voltage at node N4 at the emitter of transistor T8, which is substantially independent of V(be) and temperature variations, is determi...