Low Temperature SLAVE Circuit
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
A SLAVE circuit in the Josephson latch is used to detect if current is stored in a superconducting storage loop during the transition time of the AC power supply. Previous SLAVE circuits used a single junction to sense the stored current; this design has poor operating margins and is relatively slow. This SLAVE circuit, shown in Fig. 1, substantially improves the operating margins by: (1) Using a double-turn low-inductance interferometer as one of the sensing gates to improve the circuit's ability to discriminate between a "1" and a "0" stored in the loop. Note that the low inductance device (Gate A) has a much lower "floor" to the threshold curve and therefore switches when current Ic is far from its threshold curve.