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Push Pull Preamplifier Latching Circuit

IP.com Disclosure Number: IPCOM000075339D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Platt, S: AUTHOR

Abstract

This is a latching sense amplifier circuit consisting of a current switch driving a SCR latch. The current switch consists of NPN transistors T1 and T4 with a constant current source connected in their common emitter circuit. The SCR latch consists of PNP transistor T3 and NPN transistor T2. An input is received at terminals A and B while the output is provided at the emitter of T2. If input A is high compared to B, the SCR latches up. For this condition T1 conducts. Current is pulled out of the base of PNP transistor T3; while current is supplied through resistor R2 into the base of NPN transistor T2. Thus, there is a push-pull drive for the condition when the SCR latches up. Conversely, if input B is higher than A, the SCR remains nonconducting.

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Push Pull Preamplifier Latching Circuit

This is a latching sense amplifier circuit consisting of a current switch driving a SCR latch. The current switch consists of NPN transistors T1 and T4 with a constant current source connected in their common emitter circuit. The SCR latch consists of PNP transistor T3 and NPN transistor T2. An input is received at terminals A and B while the output is provided at the emitter of T2. If input A is high compared to B, the SCR latches up. For this condition T1 conducts. Current is pulled out of the base of PNP transistor T3; while current is supplied through resistor R2 into the base of NPN transistor T2. Thus, there is a push-pull drive for the condition when the SCR latches up. Conversely, if input B is higher than A, the SCR remains nonconducting. The latch is reset by raising input B at the end of each cycle, thereby obviating the need for a separate reset transistor. This circuit is readily integrated by monolithic technology into two isolated N-type epitaxial regions.

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