JPS58218094A - Drive circuit of magnetic bubble memory - Google Patents

Abstract

PURPOSE:To suppress the generation of excessive magnetic bubble produced at a generator, by providing a time constant set circuit shaping slowly only the fall waveform of a pulse current between a TTL signal input circuit and an emitter follower constant current source circuit. CONSTITUTION:When an output transistor (TR) Q1 of the emitter follower constant current source circuit 3 is turned on, a reference voltage Vref based on a reference voltage circuit 2 is impressed to the emitter, and a current determined with a current set resistor RE connected to the emitter and the emitter voltage flows to a load resistor RL located at the outside of an integrated circuit connected to the collector, so long as the output TRQ1 is not saturated. In this case, since a time constant set circuit 4 comprising a diode D3, a capacitor CT and a resistor RT is connected to the base of the output TRQ1, the base potential of the output TRQ1 is increased to a voltage charged up with the capacitor CT and the fall waveform of an output pulse current I is a mild waveform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a magnetic bubble memory drive integrated circuit that suppresses the generation of extra magnetic bubbles with a certain probability in a magnetic bubble memory drive circuit, particularly in a magnetic bubble generation circuit (generator) of a magnetic bubble memory element. It is related to circuits.

Generally, magnetic bubble memory devices require functions such as generating, erasing, or duplicating magnetic bubbles. These operations are performed by passing a pulsed current through a hairpin-shaped conductor pattern provided on the transfer path of the magnetic bubble to create a local magnetic field.For this purpose, magnetic bubble memory devices do not allow these currents to flow. The drive circuit for the magnetic bubble generation circuit (generator) that generates magnetic bubbles is designed to improve the magnetic bubble writing characteristics of the generator.

As a means of reducing omission errors and suppressing the generation of extra magnetic bubbles, the time constant of the rise time of the current waveform of the pulse current for magnetic bubble generation is made faster and the time constant of the fall time thereof is made slower. This waveform shaping is required.

FIG. 1 is a circuit diagram of a main part showing an example of a driving integrated circuit for a generator for generating magnetic bubbles proposed by the inventors. In the same figure, 1 is a transistor ROM*Q
a s Q o, diode D1 and bias resistor R1
, R2 and a current limiting resistor R3; 2 is a TTL signal input circuit 1 consisting of a current limiting resistor R4 and a diode D2, and a constant reference voltage V for the constant current source circuit described later. The reference voltage circuit that supplies f, the emitter-follower type constant current source circuit that has an output transistor Ql that supplies the pulse current 1 for generating magnetic bubbles to the generator that generates magnetic bubbles, and RL the load resistor that serves as the generator that generates magnetic bubbles. , RII is a resistance value setting resistor that sets the pulse flow I to be applied to the load resistor RL. The components constituting each of these circuits 1, 2, and 3 are integrated on, for example, a silicon chip (not shown), and the load resistor RL is connected to a magnetic bubble memory outside the chip, such as a bare hand or a top. It is located in
...': In the magnetic nibble memory drive circuit configured in this way, the TTL signal input circuit □, 1
and Emittao. Ayae......work...-pa:・
attm*fVi, v.

・1 "□・Ball and reference voltage ref are applied, ' TTL signal signal input circuit 1 output terminal 1aK When the predetermined input pulse vin shown in Figure 2 (a) is input, the emitter follower type constant current source When the output transistor Q1 of the circuit 3 is off, the base potential suddenly drops to zero potential as shown in FIG. 2(b).
As shown in FIG. 2(e), the falling waveform of the pulse current (2) was often disadvantageous in that it was steep.

Therefore, the present invention provides a time constant setting circuit that gently shapes only the falling waveform of the pulse current between the TTL signal input circuit and the emitter-follower type constant current source circuit, thereby reducing unnecessary noise that occurs in the generator. The object of the present invention is to provide a magnetic bubble memory drive circuit that suppresses the generation of magnetic bubbles.

Embodiments of the present invention will be explained in detail below using the drawings.
- Figure 3 is a partial circuit diagram showing an example of a drive integrated circuit for a generator for generating magnetic bubbles related to the magnetic bubble memory drive circuit according to the present invention, and the same symbols as in Figure 1 indicate the same elements. 9, so the explanation will be omitted. In FIG. 3, the TTL signal input circuit 1 and the reference voltage circuit 2 are electrically connected between the TTL signal input circuit 1 and the emitter follower type constant current source circuit 3 only during the fall time of the current waveform of the pulse current I. a diode D3 to be disconnected;
A time constant setting resistor R7 and a time constant setting capacitor CT are connected in parallel between the negative terminal of this diode D3 and the ground.
A time constant setting circuit 4 is connected thereto.

In this case, this time constant setting circuit 4 also applies to each circuit 1, 2 . ．． 3
The structure and components are integrated on a chip.

In the magnetic bubble memory drive circuit configured in this way, the pulse current for magnetic bubble generation is transmitted to the input terminal 1a K11E of the TTL signal input circuit 1 via the emitter follower forming constant current in response to the input pulse Via shown in FIG. By turning on the output □ transistor Ql of the source circuit 3,
A reference voltage V1, f according to the reference voltage circuit 2 is applied to the emitter, and the current determined by the emitter voltage and the current value setting resistor RM connected to the emitter V is determined by the output transistor Ql or the unsaturated I(fl D into a load resistor RL external to the integrated circuit connected to the collector, in this case diode D3 + capacitor C! and resistor R
The time constant setting circuit 4 is the output transistor Q1.
Since the output transistor Qs is connected to the base of
The base potential of increases to the voltage ν charged in the capacitor CT, and as shown in FIG.
The falling waveform of the output pulse current I becomes K when a gradual waveform is obtained as shown in FIG. 4(C).

As explained above, according to the present invention, by providing the time constant setting circuit at the input end of the emitter follower type constant current source circuit, only the falling waveform of the pulse current that generates the magnetic bubble is made to be a gentle waveform. Therefore, generation of extra magnetic bubbles can be reliably suppressed. In addition, the time constant setting capacitor that was conventionally attached to the magnetic bubble memory drive integrated circuit as an additional component is no longer required, and as a result, there is no need for connection terminals, reducing the cost of circuit configuration. It has extremely excellent effects such as being able to obtain effects at the same time.

[Brief explanation of the drawing]

Fig. 1 is a narrow circuit diagram showing an example of a driving integrated circuit for a generator for generating magnetic bubbles proposed by the inventors, Fig. 2 is a diagram showing the relationship between the output current and the input signal, and Fig. 3 4 is a main circuit diagram showing an example of a driving integrated circuit of a generator for generating magnetic bubbles related to the magnetic bubble memory driving circuit according to the present invention, and FIG. 4 is a diagram showing the relationship between the output current and the input signal. 1...TTL signal circuit, 1a...input terminal, 2...reference voltage circuit, 3...emitter follower type constant current source circuit, 4...time constant setting circuit. ,τ・,re

Claims (1)

[Scope of Claims] A magnetic bubble memory drive integrated circuit comprising at least an emitter follower type constant current source circuit for flowing a magnetic bubble generation pulse current through a magnetic bubble generation circuit of a magnetic bubble memory element, wherein the emitter follower type constant current source Diode at the input end of the circuit. A time constant setting circuit consisting of a resistor and a capacitor is provided,
A magnetic puzzle memory drive circuit characterized in that only the falling waveform of the pulse current is made gentler by the time constant of the time constant setting circuit.