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Tunnel Diode Switching Circuits

IP.com Disclosure Number: IPCOM000097808D
Original Publication Date: 1961-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Stapper, CH: AUTHOR

Abstract

If a capacitor C and a signal source S are employed in a parallel circuit arrangement with a tunnel diode D as shown, the switching efficiency of D is greatly improved when compared to a circuit using a resistive element. Element C provides a two fold advantage. It shapes a switching signal to provide a better frequency match for the diode. It provides a constant current bias for D increasing its permissible tolerances.

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Tunnel Diode Switching Circuits

If a capacitor C and a signal source S are employed in a parallel circuit arrangement with a tunnel diode D as shown, the switching efficiency of D is greatly improved when compared to a circuit using a resistive element. Element C provides a two fold advantage. It shapes a switching signal to provide a better frequency match for the diode. It provides a constant current bias for D increasing its permissible tolerances.

These advantages are more evident when the circuit is applied, for example, as a memory cell. The diode D, when biased from a current source, has two stable operating points 0 and 1. When biased by current bias Ib from a source connected to a bias or bit line, capacitor C provides the load line for D, such that D can be switched from one to the other of the stable operating points. This is effected by the application of appropriate switching signals to the bit and word drive lines. In the absence of these signals, no current is drawn by D.

By coincidently applying first and second input signals of one polarity to the drive lines, the diode can be switched from the 0 state to the 1 state (line Iw). If only one of these signals is applied, D is not switched but shuttles along that portion of its volt-ampere characteristic where the 0 stable point is located (line Iw/2) until the signal is removed, at which time it returns to the 0 state. Similarly, the diode may be switched from the 1 state to the 0 state by the appli...