JPH02254698A - Polarity switching type josephson driving circuit - Google Patents

Abstract

PURPOSE:To make a circuit fine and to execute a high-speed action by specifying the superconducting critical current value of a Josephson junction. CONSTITUTION:When an input signal is inputted from an input terminal In1 in a condition in which a bias current is supplied through a bias resistance RB1 to Josephson elements J1 and J2 and the bias current is supplied through a bias resistance RB2 to Josephson elements J3 and J4 from a bias supplying terminal B, the most part of the bias current to flow through the bias resistance RB2 flows into a line to be driven. On the other hand, the most part of the bias current to flow through a bias resistance Rn2 flows through a load resistance RL2 to a grounding, and a driving current can be injected into the line to be driven in a clockwise direction. In the same way, when the input signal is inputted from an input terminal In2, the driving current can be injected into the line to be driven in a counterclockwise direction. In such a case, the superconducting critical current values of the Josephson junctions J1-J4 are made into I1-I4, and by satisfying I1=I3, I2=I4 and I1>=I2, the Josephson elements J2 and J3 or J1 and J4 are simultaneously operated by a switching once, and thereby, the high-speed action can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a superconducting integrated circuit using a Josephson element, and more specifically, to a word line of a superconducting memory integrated circuit,
The present invention relates to a polarity switching type Josephson drive circuit that can inject a current into a bit line or the like and arbitrarily reverse the direction of the current.

(Prior Art) Fig. 5 shows an equivalent circuit diagram for explaining a conventionally known polarity switching type Josephson drive circuit (Showa 6).
Spring National Conference of the Institute of Electronics, Information and Communication Engineers (3rd year). The conventional technology will be explained using FIG.

As shown in Figure 5, this drive circuit consists of four Josephson gate circuits (J, J2, J3, J4), three resistors (R1, R3), and word lines or bit lines of the memory cell array. It consists of a driven line consisting of. In this circuit, when generating an output current in the clockwise direction on the driven line, the input signals I and n1 switch the Josephson gate circuits J□ and J3 to the voltage state, and the gate current circuit g1 flows. The gate current Ig1 flowing through the driven line is the Josephson gate circuit J4.
flows into the ground through the On the other hand, when generating an output current in the counterclockwise direction on the driven line, the input signals I, n
2 switches Josephson gate circuits J2 and J4 to a voltage state and gate current Ig2 flows to the driven line. The gate current g2 flowing to the driven line flows to ground through the Josephson gate circuit J3.

As explained above, it is possible to realize a polarity switching type Josephson drive circuit that can inject a current into a driven line and arbitrarily reverse the direction of the current by using conventional techniques.

(Problem to be Solved by the Invention) In the conventional technology, in order to inject the gate current Ig1 into the driven line in the clockwise direction, input signal engineering,
After the death causes the Josephson gate circuit J1 to switch to the voltage state and the gate current I,1 flows through the resistor R1 to the Josephson gate circuit J3, it is necessary to switch the Josephson gate circuit J3 to the voltage state. Similarly, to inject the gate current Ig2 into the driven line in the counterclockwise direction, the input signal l1n2 switches the Josephson gate circuit J2 to the voltage state, and the gate current Ig2 passes through the Josephson resistor After flowing through gate circuit J3, Josephson gate circuit J4 must switch to a voltage state.

In this way, in order for this drive circuit to operate, the Josephson gate circuit J1. J3 or J2. Since J4 had to be switched twice in sequence, there was a problem in operating the circuit at high speed. Further, in the conventional technology, since a magnetically coupled interferometa gate is used as a Josephson element and a circuit, there is a problem in that the area of the gate becomes large and miniaturization is difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polarity switching Josephson drive circuit which eliminates the problems of the conventional polarity switching type Josephson drive circuit and allows circuit miniaturization and high-speed operation.

(Means for Solving the Problems) According to the present invention, a first bias resistor connected between a bias supply terminal and a first terminal;
a first Josephson element connected between the terminals of the first Josephson element, a second Josephson element connected between the second terminal and ground, and a first Josephson element connected between the first terminal and ground. a load resistance, a first input resistance connected between the second terminal and the first input terminal, and a second input resistance connected between the first terminal and the second input terminal; a second bias resistor connected between the bias supply terminal and a third terminal;
a third Josephson element connected between the third terminal and the fourth terminal; a fourth Josephson element connected between the fourth terminal and ground; and the third Josephson element and ground. a second load resistor connected between the fourth terminal and the second input terminal; a third input resistor connected between the fourth terminal and the second input terminal;
a fourth input resistor connected between the terminal of the input terminal and the first input terminal; a driven line connected between the second terminal and the fourth terminal; and a fourth input resistor inserted into the driven line. a first polarity switching type Josephson drive circuit, characterized in that the first polarity switching type Josephson drive circuit is characterized in that the first terminal and the second polarity switching type Josephson drive circuit are provided with a third load resistance; a fifth Josephson element inserted between the input resistors; a first input/output separation resistor with one end connected between the second input resistor and the fifth Josephson element and the other end grounded; a sixth Josephson element inserted between the second terminal and the first input resistor, one end of which is connected between the first input resistor and the sixth Josephson element, and the other end of which is grounded; a second input/output isolation resistor; a seventh Josephson element inserted between the third terminal and the fourth input resistor; and a seventh Josephson element inserted between the fourth input resistor and the seventh Josephson element. a third input/output isolation resistor having one end connected to the terminal and the other end grounded; an eighth Josephson element inserted between the fourth terminal and the third input resistor; A second polarity-switchable Josephson drive circuit comprising a resistor and a fourth input/output separation resistor having one end connected between the eighth Josephson element and the other end grounded; In the first and second polarity switching type Josephson drive circuits, in place of the second Josephson element, the fourth Josephson element, the sixth Josephson element, and the eighth Josephson element, A third device characterized in that each of the plurality of connected Josephson elements is provided.
A polarity switching type Josephson drive circuit is obtained.

(Example) FIG. 1 is an equivalent circuit diagram for explaining in detail the invention of claim 1.

The first embodiment is a Josephson element (J1+J21
J3J J4), a bias resistor ("81' RB□), an input resistor (R,1,R,□T"131R14), a load resistor (RLl'RL2' RL3), and a driven line consisting of a memory cell array. Ru.

The operating principle of the polarity switching type Josephson drive circuit of the first embodiment is as follows.

Bias current flows from bias supply terminal B to bias resistor R
When an input signal is input from the input terminal Inu, the Josephson elements J2 and J3 switch to a voltage state while being supplied to the Josephson elements J1 and J2 through B1 and to the Josephson elements J3 and J4 through the bias resistor -2. However, most of the bias current flowing through the bias resistor RB1 flows into the driven line consisting of the memory cells A1/A. On the other hand, most of the bias current flowing through the bias resistor R132 flows to ground through the load resistor RL2. Therefore, even if the bias current flowing into the driven line flows into the Josephson element J through the load resistance, the Josephson element J is already in an unbiased state, so it does not switch to the voltage state, and the Josephson The current flowing into element J4 flows to ground. Through the above operation, driving current can be injected clockwise into the driven line consisting of memory cells. Similarly, input terminal I
When an input signal is input from n2, Josephson element J1
and J4 can be switched to a voltage state to inject drive current into the driven line in a counterclockwise direction.

Here, Josephson junction J1. J2. J3. J
4(7) Superconducting critical current value 11. I2. I3.
If I4 is used, the following conditions must be satisfied.

11: I3. I2: I4.11≧I2 As explained above, the circuit of this example has Josephson elements J2 and J
3 or Jl and J4 operate simultaneously with one switch, high-speed operation is possible. Furthermore, since one Josephson element performs the function of a gate consisting of a magnetically coupled interferometer used in the conventional technology, it is possible to miniaturize the circuit.

FIG. 2 is an equivalent circuit diagram for explaining in detail the invention of claim 2.

The second embodiment is a Josephson device (Jll J21
J3+ J4yJ5. J6. J7. J8), bias resistance (fan 7, l RB2) and input resistance (horse 0. martyr 2)
'R13) RT4) and load resistance (RLll RL2)
1 RL3) and input/output separation resistor (Rdi) Rd2'
The operating principle of the polarity switching type Josephson drive circuit of the second embodiment, which is composed of Rd3T Rd4) and a driven line consisting of a memory cell array, is as follows.

Bias current flows from bias supply terminal B to bias resistor R
When an input signal is input from input terminal In1 with the input signal being supplied to Josephson elements J1 and J2 through Bl and to Josephson elements J3 and J4 through bias resistor RB2, Josephson elements J2, J3, J5, J6, and J7 switches to a voltage state, and most of the bias current flowing through the bias resistor RB□ flows into the driven line consisting of the storage cell array. On the other hand, most of the bias current flowing through the bias resistor R8□ is
Flows to ground through L□. Therefore, even if the bias current flowing into the driven line flows into the Josephson element J through the load resistor R3, the Josephson element J is already in an unbiased state, so it does not switch to the voltage state, and the Josephson element The current flowing into J flows to ground. On the other hand, the input signal input from input terminal I is connected to ground through input/output isolation resistors Rdi and Rd4, respectively, after Josephson elements J6 and J7 switch to the voltage state. Therefore, the input signal can be completely separated from the output signal.

With the above operation, a drive current can be injected clockwise into the driven line made up of memory cells with input and output separated. Similarly, when an input signal is input from the input terminal In2, the Josephson elements J1, J4, J5, J7, and J8 switch to the voltage state, and the counterclockwise direction is applied to the driven line with the input and output separated. A driving current can be injected in the direction of .

Here, as in the first embodiment, Josephson junction J1.
J2. J3. The superconducting critical current value of J4 is I7. I2. I
3. If I4 is used, the following conditions must be satisfied.

I, = I3. I2: I4.11≧I2 As explained above, the second embodiment realizes a polarity switching type Josephson drive circuit that has the same effect as the first embodiment and also has an input/output separation function. be able to.

FIG. 3 is an equivalent circuit diagram for explaining in detail the invention of claim 3.

The third embodiment is a Josephson element (Jll J21t
J2□.

J31 J41) J4゜) and bias resistor (RBl,
RB2), an input resistor (R11+R1□, 锇3.锇.), a load resistor (RLl RL21 RL3), and a driven line consisting of a memory cell array.

The third embodiment is the same as the first embodiment except that the Josephson elements J2 and J4 are replaced with two series-connected Josephson elements J2□ and J2□ and J41 and J4□. The operating principle of the circuit is similar to that of the first embodiment. The operating time of the circuit is determined by changing the inductance of the driven line consisting of the memory cell array to
, where the drive current (output current) is i, it can be evaluated as Li/V. The drive voltage V is determined by the voltage generated when the Josephson element switches to a voltage state.

Therefore, in this embodiment, by connecting two Josephson elements in series, it is possible to generate twice as much driving voltage as in the first embodiment, thereby shortening the operating time.

In this embodiment, two Josephson elements are connected in series, but by using three or more Josephson elements connected in series, the drive voltage can be further increased and high-speed operation can be achieved.

As explained above, according to the third embodiment, it is possible to realize a polarity switching type Josephson drive circuit which has the same effects as the first embodiment and can operate at higher speed.

FIG. 4 is an equivalent circuit diagram for explaining in detail the invention of claim 3.

The fourth embodiment is a Josephson element (Jl) J211
J221J3. J4□, J4□t J51 J611
J6□, J7. J80. J8□) and bias resistor (R
131) RB2) and input resistance (R11, RI2.R1
3, RI4) and load resistance (RLit RL21 RL3
) and input isolation resistor (Rdll Rd21 Rd31 R
d4) and a driven line consisting of a memory cell array.

The fourth embodiment is a combination of Josephson elements (J211 J2□) and (J4
, and J4□) and (J6□, J6□) and (J81 and J8□
) is the same as the circuit replaced with The working principle of the circuit is
This is similar to the second embodiment.

In this embodiment, by connecting two Josephson elements in series, twice the driving voltage as in the second embodiment is generated.
For the reasons described in the third embodiment, the operating time can be shortened.

In this example, two Josephson elements are connected in series as in the third example, but by using three or more Josephson elements connected in series, the driving voltage can be further increased and high-speed operation can be achieved. becomes.

As described above, the embodiment of Suihiro 4 can realize a polarity switching type Josephson drive circuit which has the same effects as the second embodiment and can operate at higher speed.

(Effects of the Invention) As described above, according to the present invention, it is possible to realize a polarity switching type Josephson drive circuit that is capable of miniaturizing the circuit and operating at high speed.

[Brief explanation of drawings]

FIG. 1 is an equivalent circuit diagram for explaining an embodiment of a polarity switching type Josephson drive circuit according to the first aspect of the invention. FIG. 2 is an equivalent circuit diagram for explaining an embodiment of the polarity switching type Josephson drive circuit according to the second aspect of the invention. FIG. 3 is an equivalent circuit diagram for explaining an embodiment of the polarity switching type Josephson drive circuit according to the third aspect of the invention. FIG. 4 is an equivalent circuit diagram for explaining an embodiment of the polarity switching type Josephson drive circuit according to the third aspect of the invention. FIG. 5 is an equivalent circuit diagram for explaining a conventional polarity switching Josephson drive circuit. In FIGS. 1 to 4, Jl) J2. J31 J
4J J5T J61 J7TJ8. J2□, J2□l
J411 J4゜l J611 J6□l J811
J8゜...Josephson element, RLll "L21
RL3...Load resistance, RIll"I□l R131
RI4・, 1 input resistance, Rd□+ Rd22 Rd3T
Rd4...Input/output separation resistor. In FIG. 5, Jl, J2. J3. J4...Josephson gate circuit, R1, R2, R3...Load resistance.

Claims (1)

[Claims] 1. A first terminal connected between a bias supply terminal and a first terminal.
a bias resistor; a first Josephson element connected between the first terminal and the second terminal; a second Josephson element connected between the second terminal and ground; a first load resistor connected between the first terminal and ground; a first input resistor connected between the second terminal and the first input terminal; and a first input resistor connected between the first terminal and the second input terminal. a second input resistor connected between the terminals; a second bias resistor connected between the bias supply terminal and the third terminal; and a second input resistor connected between the third terminal and the fourth terminal. a fourth Josephson element connected between the fourth terminal and ground, a second load resistor connected between the third terminal and ground, and a fourth Josephson element connected between the third terminal and ground; a third input resistor connected between the terminal and the second input terminal; a fourth input resistor connected between the third terminal and the first input terminal; A polarity switching type Josephson drive circuit comprising: a driven line connected between the fourth terminals; and a third load resistor inserted into the driven line. 2. The polarity switching type Josephson drive circuit according to claim 1, wherein a fifth Josephson element is inserted between the first terminal and the second input resistor, and the second input resistor and the fifth a first input/output isolation resistor with one end connected between the Josephson elements and the other end grounded; a sixth Josephson element inserted between the second terminal and the first input resistor; a second input/output isolation resistor having one end connected between the first input resistor and the sixth Josephson element and the other end grounded; and a second input/output isolation resistor inserted between the third terminal and the fourth input resistor. a seventh Josephson element, a third input/output isolation resistor having one end connected between the fourth input resistor and the seventh Josephson element and the other end grounded; and the fourth terminal. and an eighth Josephson element inserted between the third input resistor and the eighth Josephson element, and a fourth input whose one end is connected between the third input resistor and the eighth Josephson element and whose other end is grounded. A polarity switching type Josephson drive circuit characterized by comprising an output separation resistor. 3. In the polarity switching type Josephson drive circuit according to claim 1 or 2, the second Josephson element, the fourth Josephson element, the sixth Josephson element, and the eighth Josephson element Instead, a polarity-switchable Josephson drive circuit is characterized in that it each includes a plurality of Josephson elements connected in series.