JPH0326675Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a waveform shaping circuit that combines two monostable multivibrators made of I ² L (Integrated Injection Logic) elements.

FIG. 1 shows a waveform shaping circuit comprising an I ² L element proposed by the present applicant in Japanese Patent Application No. 116169/1984 (Japanese Patent Application Laid-Open No. 8425/1982). In the waveform shaping circuit shown in Figure 1, a trigger pulse is input from input terminal 1 to monostable multivibrators A and B, and first the capacitor
When charging of capacitor C ₁ is started and charging of capacitor C ₁ is completed, charging of capacitor C ₂ of monostable multivibrator B is started, and a predetermined output waveform is obtained from output terminals 2 and 3.

Capacitors for monostable multivibrators A and B
When the pulse width set by the charging time of C ₁ and C ₂ is relatively short, the charges charged in the capacitors C ₁ and C ₂ are rapidly discharged via the I ² L elements 9 and 15. Therefore, there is no practical problem. However, if the pulse width set by the monostable multivibrators A, B is long, i.e. the capacitors C ₁ , C ₂
When the capacitance of I 2 is large, the accumulated charge is sufficient for I ²
If a trigger pulse is input from input terminal 1 without being discharged through the L element, it will cause malfunction.

Now, based on FIG. 2, the malfunction will be explained. FIG. 2a shows the trigger pulse applied to input terminal 1. The trigger pulse is input to monostable multivibrators A and B via I ² L elements 4, 5, and 11. First, the operation of monostable multivibrator A will be explained. I ² L element 6,
7 is a circuit system having a self-holding function (hereinafter referred to as a latch circuit); when an L level trigger pulse is input to the input terminal of the I ² L element 6, a signal is applied to the input terminal of the I ² L element 7; A potential of H level is supplied, and I ² L
The output terminal of element 7 is at L level, and the output terminal of I ² L element 6 is latched at H level. Therefore, I ² L
The output terminal of element 9 is set to H level, the injector current of I ² L element 10 flows into capacitor C ₁ , the potential of one end P ₁ of capacitor C ₁ rises to H level, and the charge is I ² It is discharged via the L element 9 (FIG. 2b). While this capacitor is in a charging state, the I ² L element 6 is at H level, and when it is in a discharging state, it is at L level (FIG. 2c).
On the other hand, a trigger pulse is also input to monostable multivibrator B via I ² L elements 4 and 11 to a latch circuit made up of I ² L elements 12 and 13, and I ² L element 1
The connection point P ₂ between the input terminal of I ² L element 13 and the output terminal of I 2 L element 13 is latched at L level. The output terminal of the I ² L element 12 becomes H level, but its output terminal a receives ^the signal from the monostable multivibrator A.
Since it is connected to the output terminal of the L element 17, it is set to the L level. Therefore, capacitor C ₂
One end _P3 is set to L level and maintains a discharged state. And monostable multivibrator A
When the charging of capacitor C ₁ is completed and the latch circuit is released and the output terminal of I ² L element 17 becomes H level, charging of capacitor C ₂ starts and the potential at point P ₃ changes from L level to H level. (Figure 2d). Then, the output terminal of the I ² L element 16 becomes L level, and the potential at point _P2 of the latch circuit becomes H level, releasing the latch. Therefore, the output terminal of the I ² L element 12 receives the trigger pulse and connects to the capacitor.
While it is charged to _C2 and becomes H level, it maintains the H level state. FIG. 2e shows the output waveform of the output terminal 3 of the I ² L element 18. On the other hand, the outputs of monostable multivibrator A and B are output from monostable multivibrator A through I ² L element 8, and output from monostable multivibrator B through I ² L elements 18 and ^19.
It is guided to the input end of the L element 20, and its output has a waveform as shown in FIG. 2f. In this way, from the output terminal 3, an output waveform obtained by combining the outputs of the monostable multivibrators A and B is obtained.

Next, operating waveforms when such a waveform shaping circuit malfunctions will be explained. In order to make the pulse width of the output waveform of monostable multivibrator B relatively long, if the capacitance of capacitor _C2 is increased, the capacitor will close while the trigger pulse is input.
This is a condition in which the charge of C ₂ is not sufficiently discharged.
Even if a trigger pulse is input to point _P2 in this state, capacitor _C2 is still not sufficiently discharged and remains at H level, and the output terminal of ^I2L element 16 remains latched at L level. . That is, the potential at point _P2 remains at H level. When a trigger pulse Y is input to this waveform shaping circuit as shown in Figure 2a, the capacitor
_C1 performs charging and discharging operations. _Y1 in FIG. 2b is the waveform due to charging and discharging. Therefore, the output of the I ² L element 6 has the waveform shown at Y ₂ in FIG. 2C. However, in monostable multivibrator B, capacitor C ₂ remains charged, and at point P ₂ , capacitor C ₂ remains charged at H level, as shown by the dotted line in Figure 2 d. . Therefore, the potential at the output terminal of the I ² L element 18 is kept at the H level as shown by the dotted line in FIG. 2d. In other words, monostable multivibrator B becomes inoperable, and of course,
A composite waveform cannot be obtained from the output terminal 3. Further, no output can be obtained from the output terminal 2. In this way, if the trigger pulse Y is input before the capacitor _C2 is sufficiently discharged, the above condition will occur, and no matter how many trigger pulses Y3 and Y4 are applied afterwards, this waveform shaping circuit will not operate. It was hot.

The present invention improves the above-mentioned problems and provides an I ² circuit that is easy to integrate into a semiconductor integrated circuit and operates at high speed.
The present invention provides a waveform shaping circuit including L elements.

Another object of the present invention is to provide a waveform shaping circuit including an I ² L element that can set a pulse width with higher reliability.

Hereinafter, the waveform shaping circuit of the present invention will be explained based on the drawings.

FIG. 3 shows an embodiment of a waveform shaping circuit comprising an I ² L element according to the present invention. FIG. 3 shows a waveform shaping circuit formed from two monostable multivibrators A and B each consisting of an I ² L element, 1 being an input terminal for trigger pulses, and 2 and 3 being output terminals.

In the embodiment shown in FIG. 3, the basic structure of the monostable multivibrators A and B is the same as that of the conventional example shown in FIG. The difference between the embodiment shown in FIG. 3 and the waveform shaping circuit shown in FIG. 1 is that the waveform shaping circuit shown in FIG. The trigger pulse is supplied only to monostable multivibrator A, and the output of monostable multivibrator A is connected to I 2 through I ² L element ⁶ .
The output terminal of the I ² L element 17 forms the latch circuit of the monostable multivibrator B. The input terminal of the I ² L element 12 and the I ² L element 1
3 and the output terminal of the I ² L element 12, respectively.

The waveform shaping circuit of the present invention will be explained based on FIG.

A trigger pulse X as shown in FIG. 4a is input from an input terminal 1 to a monostable multivibrator A via I ² L elements 4 and 5. The latch circuit consisting of I ² L elements 6 and 7 is activated, and the output terminal of I ² L element 6 is inverted from L level to H level as shown in FIG. 4C. The injector current of the I ² L element 10 flows into the capacitor _C1 , and the point _P1 at one end of the capacitor _C1 changes from the L level to the H level by charging (FIG. 4b). The output terminal of the I ² L element 6 is connected to the I ² included in the monostable multivibrator B via the I ² L element 17.
I ² of the latch circuit formed from L elements 12 and 13
It is connected to the input/output terminal of the L element 12. That is, when the monostable multivibrator A is activated by the trigger pulse X, the I ² L element 1 is forcibly activated.
Set the output terminal of 2 to L level. This results in
The charge in the capacitor C ₂ is sufficiently discharged through the I ² L element 15, and the P ₃ point is set to the L level. I ²
The output of the L element 12 is H as shown in FIG.
The output terminal of the I ² L element 18 is inverted to the L level (FIG. 4f). Then, when the capacitor C ₁ of the monostable multivibrator A becomes H level, the output terminal of I ² L element 10 becomes L level, and the output terminal of I ² L element 7 becomes H level, and the latch is ^released . The output terminal of element 6 becomes L level (FIG. 4c). Therefore, the latch circuit consisting of I ² L elements 12 and 13 of monostable multivibrator B is released, ensuring that I ² L element 16 is connected to capacitor C ₂ .
Charging starts via And the capacitor
When point _P3 of _C2 becomes H level, the output terminal of ^I2L element 12 is inverted to L level (Fig. 4e). Then
The output terminal of the I ² L element 18 is inverted to H level (the fourth
Figure f), an output waveform as shown in Figure 4g is obtained from the output terminal 2.

As mentioned above, in the waveform shaping circuit of the present invention, when the monostable multivibrator A operates, the waveform-shaped pulse is transmitted to the I ² L element 1 via the I ² L element 17.
The capacitor _C2 of the monostable multivibrator B is forcibly discharged. This eliminates malfunctions seen in conventional waveform shaping circuits, and
The pulse width of the output waveform obtained from the output terminal 3 is a composite waveform of the pulse widths T ₁ and T ₂ obtained from the monostable multivibrators A and B with extremely high accuracy. Further, the output waveform obtained from the output terminal 2 is also extremely accurate. Furthermore, the waveform shaping circuit of the present invention has the advantage of being able to easily create a waveform with a relatively large pulse width.

FIG. 5 shows another embodiment of the invention, in which trigger pulses are supplied to monostable multivibrators A and B simultaneously, but other circuit parts are similar to the embodiment of FIG. 3. In the embodiment shown in FIG. 3, the trigger pulse is supplied only to monostable multivibrator A, whereas in the embodiment shown in ^FIG . ² L
It is supplied via elements 5 and 11. This enables higher precision and faster operation.

In addition, throughout the embodiments shown in FIGS. 3 and 5, the I ² L elements 8, 9 or 14, 15, etc. are elements added to increase the current amplification degree, and the amplification degree of the I ² L element In some cases, it may be increased or decreased.

Further, FIG. 6 shows the symbol mark of the I ² L element, and FIG. 7 shows its equivalent circuit.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a conventional waveform shaping circuit, FIG. 2 is a diagram for explaining its operation, FIG. 3 is a diagram of a waveform shaping circuit according to the present invention, and FIG. 4 is a diagram for explaining its operation. FIG. 5 is a circuit diagram showing another embodiment of the waveform shaping circuit according to the present invention, FIG. 6 is a diagram showing the symbol mark of the I ² L element, and FIG. 7 is an equivalent circuit diagram of the I ² L element. . A, B... Monostable multivibrator.

Claims (1)

[Scope of utility model registration request] A second I ² L element is connected to the first output terminal of the first I ² L element.
a first latch circuit to which the input terminal of the element is connected, and the output terminal of the second I ² L element is connected to the input terminal of the first I ² L element, and a first capacitor;
a third I ² L element whose input terminal is connected to one end of the first capacitor; and a fourth I ² L element whose output terminal is connected to one end of the first capacitor; Based on the output of the first latch circuit, the third latch circuit
charging the first capacitor via an I ² L element;
Based on the inverted output of the third I ² L element due to the increase in the charging voltage of the first capacitor, the latch state of the first latch circuit is released and the charge of the first capacitor is transferred to the fourth capacitor. The second I ² L element of the first I ² L element is
a first monostable multivibrator which obtains an output from an output terminal of the fifth I ² L element; the input terminal of the sixth I 2 L element is connected to the first output terminal of the fifth I ² L element;
a second latch circuit in which the output terminal of the sixth I ² L element is connected to the input terminal of the sixth I ² L element, a second capacitor, and a second latch circuit whose input terminal is connected to the second capacitor. 7 I ² L elements and an eighth I ² L element whose output terminal is connected to the second capacitor, and the seventh I 2 L element is connected to the ^seventh I 2 L element based on the output of the second latch circuit.
The second capacitor is charged via the L element, and the seventh capacitor is charged due to the increase in the charging voltage of the second capacitor.
The latch state of the second latch circuit is released based on the inverted output of the I ² L element, and the charge in the second capacitor is discharged via the eighth I ² L element. a second monostable multivibrator configured to obtain an output from a second output terminal of the fifth I ² L ^element ; Connect the output terminal of No. 3 to the input terminal of the ninth I ² L element, and
One of the output terminals of the I ² L element is connected to the input terminal of the fifth I ² L element of the second monostable multivibrator, and the other output terminal is connected to the third input terminal of the fifth I ² L element. A waveform shaping circuit characterized in that each output terminal is connected to the other.