Browse Prior Art Database

Bipolar Timing Pulse Generation Circuit Using a Monopolar Bias

IP.com Disclosure Number: IPCOM000050423D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Herrell, DJ: AUTHOR

Abstract

This article relates generally to pulse generating circuits and particularly to such circuits which incorporate Josephson junctions. Still more particularly, it relates to a Josephson bipolar timing pulse generator which uses a monopolar bias. In a number of applications (particularly for tester circuits), a timing pulse needs to be generated at some time in the logic cycle. The control of when this timing pulse is initiated is set by a DC bias. In known circuits, a single DC bias only allows the setting of the pulse generation time for one of the two power polarities derived from an AC source. Control of the reverse polarity pulse time has not been possible heretofore.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Bipolar Timing Pulse Generation Circuit Using a Monopolar Bias

This article relates generally to pulse generating circuits and particularly to such circuits which incorporate Josephson junctions. Still more particularly, it relates to a Josephson bipolar timing pulse generator which uses a monopolar bias. In a number of applications (particularly for tester circuits), a timing pulse needs to be generated at some time in the logic cycle.

The control of when this timing pulse is initiated is set by a DC bias. In known circuits, a single DC bias only allows the setting of the pulse generation time for one of the two power polarities derived from an AC source. Control of the reverse polarity pulse time has not been possible heretofore.

The circuit disclosed herein solves this problem by means of a basic AND function coupled to algebraic addition of control currents over each AND input device (Fig. 1). The circuit is implemented in Fig. 1 with a basic 2-input Current Injection Logic (CIL) AND gate. The circuit produces a timed pulse during both polarities of the AC power supply. Figs. 2A, 2B show the switching characteristics (Ig versus Ic) of Josephson junction devices J1, J2, respectively, of the circuit of Fig. 1. Fig. 3 shows a plurality of waveforms wherein waveform P is the AC gate current applied to devices J1, J2 of Fig. 1; waveform R is a cosine reference waveform applied to the control line 11 in Fig. 1; waveforms J1, J2 are the voltage states of devices J1,J2 of Fig. 1, and waveform i is the output waveform developed across load 12 in Fig. 1. In Fig. 1, B is a bias which adjusts the initial operating points of devices J1, J2 as indicated at points 1 in Figs. 2A,2B. The numbered points 1-10 on waveform P of Fig. 3 are related to the operating points on the threshold characteristics of Figs. 2A, 2B.

With the bias B applied to control line 13 in Fig. 1 and the cosine reference waveform R applied to control line 11 in Fig. 1, the AC waveform P of Fig. 3 is applied to devices J1, J2 of Fig. 1 When P reaches point 2 in Fig. 3, device J1 switches to its voltage state, having crossed its switching threshold at 2 as shown in Fig. 2A. J2 does not switch at this point. Waveform J1 in Fig. 3 shows the resetting of device J1 to its zero voltage state a...