Browse Prior Art Database

Unipolar Mode Detector for Thin Film Memory

IP.com Disclosure Number: IPCOM000094516D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Moser, A: AUTHOR [+2]

Abstract

The unipolar detector circuit eliminates noise signals occurring during write time. It is capable of distinguishing between information signals 1 and 0 having the same polarity and low amplitude ratios. A current switch consisting of transistors T1 and T2 is used in connection with a constant current source transistor T3. This results in a strobe Level current Ir essentially independent from the strobe pulse amplitude.

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Unipolar Mode Detector for Thin Film Memory

The unipolar detector circuit eliminates noise signals occurring during write time. It is capable of distinguishing between information signals 1 and 0 having the same polarity and low amplitude ratios. A current switch consisting of transistors T1 and T2 is used in connection with a constant current source transistor T3. This results in a strobe Level current Ir essentially independent from the strobe pulse amplitude.

In the steady state, T2 and T3 are conducting while T1 is cut off. Any incoming noise signals appearing at the base of T3 therefore do not affect detector tunnel diode TD. During read time, a strobe pulse is applied to the base of T1 serving to switch the current Ir from T2 to T1 and TD. A sense signal of sufficient amplitude can now switch TD causing an output signal at the emitter of T4.

The connection from the collector of T4 to the input provides a positive feedback path increasing the switching speed of TD from the low to the high voltage state. Resistor R1 provides a path for a backward current through TD improving the switching speed from the high to the low voltage state.

The right-hand drawing indicates the tolerance limits for the sense signals 11 and 10 and for the strobe level current Ir.

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