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Sensitive Single Input Voltage Detector

IP.com Disclosure Number: IPCOM000082587D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Craig, WJ: AUTHOR

Abstract

This sense amplifier circuit provides a simple, effective, single input, memory array voltage detector that does not require multiple clocks or threshold voltage tracking. Since it is a simple all field-effect transistor (FET) circuit, it can be designed on the same chip as the memory array, thus eliminating the need for an external sense amplifier. It is particularly useful where a detector is needed on every bit sense line and sense amplifier pitch is a critical parameter.

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Sensitive Single Input Voltage Detector

This sense amplifier circuit provides a simple, effective, single input, memory array voltage detector that does not require multiple clocks or threshold voltage tracking. Since it is a simple all field-effect transistor (FET) circuit, it can be designed on the same chip as the memory array, thus eliminating the need for an external sense amplifier. It is particularly useful where a detector is needed on every bit sense line and sense amplifier pitch is a critical parameter.

Assuming that clock phi 1 is up, metal-oxide semiconductor (MOS)FET devices T2 and T3 can be considered as electrical shorts, leaving T5 connected as an FET diode for the current supplied by T1 and T4. The voltage at node A, the gate of T5, will adjust itself so that it is one threshold voltage plus the overdrive necessary to sink the current from T1 and T4. If the voltage at node A is greater than the quiescent point, there will be a net current flow out of node A reducing the voltage at that node. Conversely if the voltage is below the quiescent point, there will be a net current flow into node A increasing the voltage.

When clock phi 1 drops to zero volts, both T2 and T3 now can be considered open circuits. The voltage at node A will remain at the quiescent point, since that node is essentially a charged capacitor without any current sources or sinks. Since the voltage at node A remains the same, T5 will try to sink the same amount of current as prev...