JPS596616A - One-shot multivibrator circuit - Google Patents

Abstract

PURPOSE:To omit an overvoltage absorbing diode and a limiting resistor by inserting a waveform differential circuit between an inverter and a resistor and between said resistor and a fixed potential. CONSTITUTION:A signal input terminal 1 is connected to the 1st input terminal of a two-input OR gate circuit 10 and the output terminal of the circuit 10 is inputted to the input terminal of an inverter circuit 14 and also to the 1st input terminal of a two-input NOR gate circuit through a resistor 11. A capacitor 12 is connected between the input terminal of the gate circuit 13 and earth potential. The output terminal of the inverter circuit 14 is connected to the 2nd input terminal of the NOR gate circuit 13. The output terminal of the gate circuit 13 is connected to a signal output terminal 6 and also to the 2nd input terminal of the OR gate circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a one-shot multi-byte break circuit suitable for IC implementation.

(Background Art) A conventional one-shot multivibrator circuit is shown in FIG.

In Fig. 1, 1 is a signal input terminal, and 2 manual input terminals are used.
It is connected to the first input terminal of the R gate circuit 2, and the 2
The output terminal of is connected to the inverter circuit 50 via the capacitor 3.
connected to the input terminal.

A resistor 4 is inserted between the 50 input terminal and the 10 power supply voltage terminal 7. The output terminal 5 is connected to the second input terminal of the two-man power N0ft gate circuit 2 and is also connected to the signal output terminal 6.

Operation timing diagrams for explaining the operation of the circuit of FIG. 1 constructed in this manner are shown in FIGS. 2 and 3.

FIG. 2 shows the operation timing when the pulse width of the input pulse applied to the signal input terminal 1 is large, and FIG. 3 shows the operation timing when the pulse width of the input pulse applied to the signal input terminal 1 is small. In FIG. 1, the signal state of 1 is a, the signal state of output terminal 2 is b, and the signal state of the output terminal of C15, which is the signal state of 50 input terminals, that is, the signal state of 6 is d. If the signal waveform shown in FIG. 2 is given as a, then b, c and d will be as shown in FIG. 2, respectively. In other words, in C, b is at the "use" level (hereinafter simply I
When the level is reversed from the "L" level (hereinafter simply referred to as "ILI"), it becomes L", and increases exponentially by the time constants 3 and 4 below.

Now, let the capacitance value of 3 be R and the resistance value of C14 be R, and if b is inverted from P11"' to IJ1" as described above, that is the initial stage, that is, t=Q, then the potential of C' is 2. It is represented by . However, here ■DD is 10 power supply voltage, that is...H...
・Indicates voltage. At the same time as a becomes 'H', d becomes 'H'
, and then V. is the threshold level V of 5,
It operates as if it were reversed to +lLI+ when it rose at hK-1:. Therefore, it is given by the pulse width ty of the 'II' section of d, and does not depend on the pulse width of the 'II' section of a.

Next, even when the pulse width of the °'I-r' interval of a is small, <tw is determined by equation (1), regardless of the pulse width of the 'I-r' interval of a, as shown in Figure 3. .

As explained above, the circuit shown in FIG. 1 operates as a one-shot multivibrator circuit.

However, in the circuit shown in Figure 1, if the pulse width of a is large, as shown in Figure 2 (a changes from "H" to IL'''
At the point in time when the voltage is reversed, the potential becomes higher than the voltage C or °°H'' + the power supply voltage and is applied to the input terminal 5, and on the other hand,
When the pulse width of is small, d becomes ° as shown in Figure 3.
At the time when °H" is reversed to °L", C becomes a potential higher than the I-I" voltage, that is, the →-power supply voltage, and is applied to the input terminal of 5. In this way, If a high voltage is applied to the input terminal of 5, 5 will be destroyed.

Therefore, in reality, as shown in Figure 4, a diode 8 for overvoltage absorption is inserted in parallel with 4, and a limiting resistor 9 for protecting 5 is inserted in front of the input terminal of 5. . If elements 2 and 5 are to be incorporated into an integrated circuit, elements 8 and 9 in FIG. 4 cannot be incorporated into the integrated circuit, and must therefore be externally attached.

As described above, the conventional one-shot multi-byte break circuit has the drawback of requiring a diode for overvoltage absorption and a limiting resistor.

(Problems to be solved by the invention) An object of the present invention is to eliminate these drawbacks and provide a one-shot multi-vibration circuit that does not require overvoltage absorption diodes or limiting resistors. an OR circuit including an OR circuit or a NOR circuit having an input and connecting a first input to an input terminal and a second input to an output terminal; a differentiating circuit comprising a resistor and a capacitor inserted between the resistor and a predetermined potential, and the output of the differentiating circuit is used as a first input directly or through a waveform shaping circuit, and the output of the OR circuit is The one-shot multivibrator circuit has a second input of the signal directly or via an inverter, and a gate circuit that provides an output signal to the output terminal.

(Structure and operation of the invention) FIG. 5 shows a first embodiment of the present invention, in which the signal input terminal 1 is connected to the first input terminal of a two-person OR gate circuit 10, and the output terminal 10 is connected to an inverter. It is connected to the input terminal of the circuit 14 and is connected to the input terminal of the circuit 14 through the resistor 11.
It is connected to the first input terminal of the R gate circuit 13.

A capacitor 12 is connected between the input terminal 13 and the ground potential. The output terminal of the inverter circuit 14 is 1
3 is connected to the second input terminal of No. 3. The 13 output terminals are connected to the signal output terminal 6 and are also connected to the 10 second input terminals.

Operation timing charts for explaining the operation of FIG. 5 configured as above are shown in FIGS. 6 and 7.

FIG. 6 shows the timing of the operation when the input cable width applied to the signal input terminal 1 is large.
On the other hand, FIG. 7 shows the operation timing when the pulse width of the input pulse applied to the signal input terminal 1 is small.

In FIG. 5, the signal state of 1 is a, the signal state of the 10 output terminal is 1), and the signal state of the 13 first input terminal is C.
The signal state of the output terminal of 113, that is, the signal state of 6 d
If the pulse width of the input pulse applied to 1 is large, each signal state will be obtained as shown in Fig. 6, and on the other hand, each signal state will be obtained when the pulse width of the input pulse applied to 1 is small. The signal states are obtained as shown in FIG. 7, respectively.

(Then, d becomes C after a is reversed from 'L'' to H''
It becomes an 'H' pulse that becomes II HII until the potential rises and reaches the threshold level of 13. The pulse width of 'H'H' of d is not related to the pulse width of a (( 1) can be determined by formula.

In this way, the circuit shown in FIG. 5 operates as a one-shot multi-byte break circuit, but does not cause the overvoltage shown in FIGS. 6 and 7. In other words, no overvoltage is applied to the input terminal 13.

The reason why C does not become overvoltage in FIG. 5 is because 12 is directly connected to the ground potential.

As explained above, in the first embodiment, an overvoltage greater than 10 power supply voltages does not occur, so there is no need for overvoltage absorbing diodes or limiting resistors.

In the first embodiment, a multi-chip break circuit was explained in which the capacitor 1 was connected to the ground potential, but the same could be said of the circuit configuration in which the capacitor 11 was connected to the power supply voltage terminal as shown in FIG. The circuit section formed by 11 to 14 in FIG. 5 is equivalent to the circuit section formed by 1, 1, 12, and 15 to 7 in FIG. After ``H'' changes from Ll+ to ``H'', the ``Y'' remains at ``H'' only for the time determined by the CR time constants 11 and 12. It is a waveform differentiator circuit that operates every time a pulse is generated.

In Figures 5 and 8, a two-man OR gate circuit was used as the gate circuit for receiving and receiving signal input, but the
It is obvious that the diagrams are equivalent to FIG. 9, and that FIG. 8 is equivalent to FIG. 10. In other words, the gate circuit that receives and receives signal input does not necessarily have to be an OR gate circuit.
An OR gate circuit can also be used. In addition, in Figures 5, 8, 9, and 10, the resistors connected in series and the capacitors whose one end is connected to the power supply voltage terminal or the ground potential terminal form a delay circuit. However, since the potential at the connection point between the resistor and the capacitor changes slowly, once the waveform is reproduced by the waveform shaping circuit 17 such as a Schmitt trigger circuit, the circuit operation becomes more reliable. This embodiment is shown in FIG.

(Effects of the Invention) The one-shot multivibrator circuit of the present invention does not require an overvoltage absorbing diode or a limiting resistor, and an IC
In this case, fewer external parts are required, so it can be used in a wide range of applications.

[Brief explanation of the drawing]

Figure 1 is a conventional one-shot multivibrator circuit, Figures 2 and 3 are operational diagrams of the circuit in Figure 1, Figure 4 is another conventional one-shot multivibrator circuit, and Figure 5 is the main circuit. 6 and 7 are operational diagrams of the circuit of FIG. 5, and FIGS. 8, 9, 10, and 11 are circuit diagrams of another embodiment of the invention. It is a circuit diagram. 1... Signal input terminal, 2... 2-person powered NOR gate circuit, 3... Capacitor, 4... Resistor, 5...
- Inverter circuit, 6... Signal output terminal, 7... Power supply voltage terminal, 8... Diode, 9... Resistor,
1()...Two-man OR gate circuit, 11...
Resistor, 12... Capacitor, 13...2
Human powered NOR gate circuit, 14...inverter circuit. Patent Applicant Oki Electric Industry Co., Ltd. Patent Attorney Megumi Yamamoto - Figure 1 Figure 2 1 1 Figure 3 b ゛d ” “ Figure 4 Figure 6 Figure 7 Figure 8 Figure 9

Claims (2)

[Claims] (1) An OR circuit using an OR circuit or a NOR circuit that has at least two inputs and connects the first input to the input terminal and the second input to the output terminal, and the output of the OR circuit directly or A differentiating circuit consisting of a resistor connected via an inverter and a capacitor inserted between the resistor and a predetermined potential, and the output of the differentiating circuit being used as a first input either directly or through a waveform shaping circuit. A one-shot multivibrator circuit comprising: a gate circuit which uses the output of the OR circuit as a second input directly or via an inverter and provides an output signal to the output terminal. (2) The one-shot multivibrator circuit according to claim 1, wherein the inverter is inserted into only one input of the gate circuit.