JPS62152221A - 'and' circuit - Google Patents

Abstract

PURPOSE:To obtain an 'and' circuit where the mutual division between inputs is separated in a direct current way by turning on and off respective transistors in accordance with a clock pulse and by extracting this with a linking means only when the first and second logical input signals are respectively and simultaneously impressed. CONSTITUTION:To an input IN, a clock pulse CK of the frequency sufficiently higher than the changing period of respective logical input signals is given, the light emitting diode of a photocoupler 1 used as the first light emitting element and light receiving element is driven by the clock pulse CK and emits the light intermittently in accordance with this. When an input terminal A1 is a positive pole, the same terminal G1 is a negative pole and as the electric power source to these, the first logical input signal is impressed, a transistor Q1 is turned on and off. To the collector of the transistor Q1, a PC2 is inserted as the second light emitting element and light receiving element, to the division between input terminals A2 and G2, the second logical input signal is impressed, a transistor Q2 at the next stage is turned on and off. In the same way, (n) stages are connected and from the optional output, an 'and' output signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an AND circuit having a fail-safe property in which the output signal is always in a special state when an interference sound occurs.

[Prior art] In traffic control devices, etc., safety as well as high stability are required, and in the event of an interference noise, a fail-safe feature is provided in which the output signal will always become a foot-like dust. Conventionally, the logic circuits shown in FIGS. 2 and 3 have been used as AND circuits.

That is, FIG. 2 shows a case where a transformer Ts having systeresis characteristics is used, and the input winding nl.

n! provides a logic input signal to the output winding n. The AND output signal is obtained from

In Fig. 3, a free-running multivibrator is constructed with resistors R1 to R4, capacitors C1 and C2, and transistors Qa1Qb, and a power supply F! :1, C2
Apply all logical human power signals to each as power supply ``I, E
The oscillation output EO from the simultaneous input port of z is taken out and used as a logical performance signal.

[Problems that the invention helps solve]

However, in the case of Fig. 2 and Fig. 3, it is difficult to increase or eliminate the number of logic inputs, and the second factor is especially expensive, while the one in Fig. It is not possible to separate the two in terms of direct current, which creates constraints on circuit design, and also causes problems such as the oscillation start 'IItEj: becoming unstable depending on logic conditions.

c Problem? + step to solve] In order to solve all the above-mentioned problems, the method of the present invention is improved.
).

That is, a first light-emitting element driven by a clock pulse having a frequency sufficiently higher than the change period of the logic input signal, a first light-receiving element that receives light emitted from this first light-emitting element, and a first light-receiving element that receives light emitted from this first light-emitting element. The first logic input signal is applied as a power source to the light receiving element of
a second light emitting element driven by a current flowing between the collector and emitter of the first transistor, and a second light emitting element that receives light emitted from the second light emitting element.
between the light-receiving element of the second light-receiving element, a second transistor whose l:9 on/off is controlled and a second logic input signal is applied as a power supply to the second light-receiving element, and the collector-emitter of the second transistor. and coupling means for transmitting changes in the current flowing through the circuit as an AND signal.

[Effect]

Therefore, for each of the first and second transistors,
Current flows between the collector and emitter of the second transistor, which turns each transistor on and off in response to a clock pulse only when the first and second logic input signals are applied simultaneously. has the same change as the clock pulse, and this can be extracted by the coupling means.
If you divide them, you will get an AND signal.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the circuit diagram of FIG. 1 showing an embodiment.

In the figure, a clock pulse CK of a sufficiently high frequency is also given to the input IN to the change periodic circuit 9 of each logic input signal, and a photocoupler (hereinafter referred to as PC) used as the first light emitting element and light receiving element ) 1 is driven by the clock pulse CK and emits light of 1 Wr continuously in response to this, the light receiving transistor of the light emitting vi-PC1 receives the light and turns on and off, and all positive terminals of the input terminal A1 , the open terminal Gl is the gold negative electrode, and if the first logic input signal is applied as a power supply to these, the light receiving transistor of the forward direction bias scan pci to the first transistor Q1 via the resistor R++' is intermittently controlled, Transistor Q turns on and off,
Accordingly, the transistor Q is connected through the resistor RI2k.
1 collector-emitter current flows.

i*,ru/Jista Q! A PC20 light emitting diode used as a second light emitting element and a light receiving element is inserted into the collector of the transistor Q.
+ The collector ta receives light and turns on and off.If the second logic input signal is applied between the input terminals At and G2 in the same way as described above, the first The forward bias to transistor Q1 of 2 is PC
The transistor Q2 is intermittently controlled by the light-receiving transistor No. 2, and the transistor Q2 turns on and off, and a collector-emitter current flows through the collector through the resistor Rtxk. The JPC30 light emitting diode is driven by a light receiving transistor on the PCB and a transistor Qs via a resistor Rsl.

Forward bias is controlled, transistor Qs is also turned on,
When the transistor Q3 is completely turned off and the third logic input signal is applied between the input picture elements A3 and Gs in the same manner as described above, a current flows between the collector and emitter of the transistor Q3.

Similarly, the n-th transistor Qnf is configured below, and the input terminals An, GnK'! Under the condition that each logic input signal is applied simultaneously, a current flows between the collector and emitter of the transistor Qn, so this change is extracted from the collector of the transistor Qn via the resistor Rn2 by the capacitor Co serving as a coupling means. , output OU, this becomes the AND signal of each logical input (i).

1. When further cascading similar circuits, etc., insert it into the collector of the transistor Q and use it as a PC/mkta combining means, and output the output OU2 from the light-receiving transistor.
It is designed to send intermittent output to.

Therefore, by rectifying the output OUI signal, a DC AND signal can be obtained, and the input signal from the input IN to the output OU+-
If a fault occurs in either f or OU2, the signal at output OU will always be /P! ! At the same time, the output OU,
is in a non-intermittent state of on or off, and the state of the output signal does not become unspecified when a fault occurs, ensuring reliable failsafe control.
) sex is realized.

-17j, PCI and transistor Q1 are all basic configurations, and by cascading the required number of stages, an AND circuit with an arbitrary number of inputs can be obtained, and each input terminal AI, GI~AyIXGn can be separated in terms of direct current. This increases the degree of freedom in circuit design.

In addition, in the case of Fig. 1, one stage is alternately turned on and off, and all rows are not turned on at the same time, so even if in-phase noise is applied to each input terminal AIXGI to Afi, GH, the output Not only is the signal not sent out to OU, , OU2, but also the possibility of unnecessary oscillations being generated is completely eliminated.

fC, instead of PCI~m, a combination of other emitter 7 IC elements and a light receiving element may be used, and the insertion site of the light receiving element can be installed at a location where the on/off of the transistor can be controlled. , as the emitter side of all the transistors at the insertion site of the light emitting element [Ruri Tsukasa, it is optional to use a transformer etc. as a coupling means, and as a minimum configuration, PCI, 2, transistor Q+ , Qz, and the construction of the coupling means, etc., may be modified to a certain degree.

〔Effect of the invention〕

As is clear from the above description, if the present invention is implemented, it will be possible to have a simple and inexpensive configuration, complete fail-safe performance and high reliability, obtain an arbitrary number of inputs, and have mutual input interaction. The present invention realizes an AND circuit in which the circuits are separated in terms of direct current, and can be easily integrated into an integrated circuit, providing remarkable effects in various applications requiring high reliability and fail-safe performance.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are circuit diagrams of a conventional example. 1-3. m+1=Pc (photocoupler), CK...
Clock pulse, Q1~Qn...Transistor, A, -Afi, G, ~Gn...Fist input terminal, Co
...Capacitor.

Claims (1)

[Claims] A first light emitting element driven by a clock pulse having a frequency sufficiently higher than a change period of a logic input signal, a first light receiving element that receives light emission from the first light emitting element, and the first light receiving element. a first transistor whose ON/OFF state is controlled by a transistor and to which a first logic input signal is applied as a power supply; a second light emitting element driven by a current flowing between the collector and emitter of the first transistor; a second light-receiving element that receives light emitted from the second light-emitting element; a second transistor that is turned on and off by the second light-receiving element and to which a second logic input signal is applied as a power source; , and coupling means for transmitting a change in the current flowing between the collector and emitter of the second transistor as an AND signal.