JPS58187025A - Not device used in alternating current - Google Patents

Abstract

PURPOSE:To hold an oscillation circuit to a specific state for the fail-safe at a failure of components, by controlling a power supply voltage applied to the oscillating circuit with a DC voltage obtained from a rectified input signal. CONSTITUTION:The input signal is rectified into DC with rectifying diodes D1, D2 of an input signal processing circuit 7 and the voltage drop is produced across a resistor R3. The generated voltage is set to overcome a voltage of a power supply 5 in the absolute value in advance, the algebraic sum of the power supply 5 and the voltage drop of the resistor R3 is applied to the power supply voltage of the oscillating circuit 4, and since the supplied voltage is reduced to zero or a negative potential, the oscillation circuit 4 does not oscillate. When the supply of the input signal is interrupted, since the voltage drop across the resistor R3 is zero, the power supply voltage of the power supply 5 is applied to the oscillating circuit 4, and the oscillator 4 continues the oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for stopping oscillation in an oscillation circuit when a bipolar pulse input signal arrives, and causing the oscillation circuit to oscillate when the input signal is interrupted. It relates to NOT devices and is suitable for use in 7-fail safe designs of logic such as safety devices.

Conventionally, the device shown in Figure 1 has been used to provide this food.

In the figure, (1) is a transformer in which a bipolar pulse input signal (hereinafter referred to as input signal) is input to the primary winding; (2)
is an input signal processing circuit that is provided on the secondary side of the transformer (1) and is controlled on/off by the output of the secondary side, consisting of a transistor Tr and a capacitor C, (8) is a resistor, and (4) is a power supply voltage. It oscillates when supplied with . An oscillation circuit consisting of gate G□* G@* Gjl, resistor R, R8 and capacitor C3, (5) indicates a power supply, and the operation of the conventional example with these configurations is shown in the operating waveform diagram shown in Fig. 2. The following is an explanation based on this.

That is, in the configuration of FIG. 1, when the input signal shown in FIG. 2A is input to the primary winding of the transformer (1).

The transistor T of the input signal processing circuit (2) whose pace is connected to the secondary winding of the transformer (1) is controlled in operation by the base current (see FIG. 2B) flowing based on the input signal. It also performs switching operations.

A capacitor C□ connected in parallel between the collector and the capacitor of the transistor Tr and charged by the voltage supplied from the power supply (6) is charged and discharged with a charging voltage as shown in FIG. 2C by the switching operation of the transistor Tr. As a result, the voltage supplied to the gate (C) of the oscillation circuit (4) is set to a predetermined operating voltage (8) or lower. That is, the input signal processing circuit (2) stops the oscillation (see the second diagram) by the oscillation circuit (4) when the input signal arrives.

On the other hand, at 9 o'clock when the input signal is cut off at the time shown in Figure 2 (see Figure 2A), K is the transistor of the input signal processing circuit (2), and Tr is the base current (see Figure 2B). The supply voltage to G□ (A) is cut off and it becomes OFF state, and the conditioner C is charged to the specified power supply voltage. From this nK, the oscillation circuit (4) oscillates as shown in the second diagram.

However, since conventional AC NOT devices are configured in the manner described above, if a component fails, the output may be based on incorrect logic, making it impossible to create a satisfactory design. Oscillation circuit (4) caused by short-circuit accident of capacitor C, C1 or disconnection of resistor (8) in input signal processing circuit (2) and oscillation circuit (4).
), or the oscillation circuit (4) continues to oscillate regardless of the input signal in the event of a breakage accident in the collector of the transformer (x) or transistor TH. There were no drawbacks.

Therefore, the present invention was devised to eliminate the above-mentioned drawbacks of the conventional system, and it rectifies the input signal t to direct current to generate a direct current voltage.

By controlling the power supply voltage supplied to the oscillation circuit using this generated voltage, if a failure occurs in a component,
It is an object of the present invention to provide an AC NOT device which eliminates the drawbacks of the conventional example by holding an oscillation circuit in a specific state, and which makes it easy to implement a 7-eliminate-7 design.

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 3, in which the same parts as in FIG. 1 of the conventional example are denoted by the same reference numerals. In the figure (6)
is a transformer in which a neutral point is provided in the secondary winding and an input signal is input to the primary winding, and (γ) is an input signal processing circuit of the present invention consisting of a rectifier diode D, D, and a resistor R5. The input signal processing circuit generates a predetermined voltage at 9 o'clock when a bipolar pulse is input, and the above-mentioned oscillation circuit (
4) The zero potential on the supply voltage to the input terminal of 1 is assumed to be a negative potential.
There is no way to control the oscillation of the oscillation circuit (4).

That is, the operation of the above configuration will be explained based on the waveform diagram shown in FIG. 4. First, when the input signal (see FIG. 2 C) is input to the primary winding of the transformer (6), 6) Input signal processing circuit (γ
), the input signal is rectified into direct current by the rectifier diodes D□, D8, which causes a voltage drop across the resistor R1. in this case.

The generated voltage (Fig. 4 E) is set in advance so that its absolute value is higher than the voltage of the power supply (5), and the algebraic sum of the voltage drops of the power supply (5) and the resistor R5 is the voltage of the oscillation circuit (4). ) is supplied as a power supply voltage (FIG. 4F), which becomes a negative potential after zero, so that the oscillation (B) path (4) does not oscillate from this nK (FIG. 4D). In other words, as long as the input signal is supplied, the AC signal will not be output, so the NOT logic %H
Corresponds to logical %Ll output for I input.

On the other hand, the input signal supply is interrupted at time t shown in FIG.
, fC, the voltage drop across resistor R5 is zero (Fig. 4 Z
), the 1 oscillation circuit (4) has the power supply (6)'
1 pressure is supplied (FIG. 4F), and in this state, the oscillation circuit (4) continues to oscillate (FIG. 4D). That is, as long as the input signal is uninterrupted, an AC signal is output, which corresponds to the logical %lI# output for the logical %LI input of NOT.

In the above embodiment, the entire input signal processing circuit was constructed so as to compare the voltage drop across the resistor Ra caused by the power supply (5) and the input signal in series. However, in the structure shown in FIG. To is used in the opposite direction to the one in Figure 6, a rectifier circuit is constructed with the neutral point grounded on the secondary side of the transformer (6), and a resistor R4 is added, and the above resistor R3 is connected to the output side of the rectifier circuit. The resistor R4 is connected in series with the power supply (5), and the power supply voltage is supplied to the oscillation circuit (4) at the connection point of both resistors. Even if the input signal processing circuit (8) is configured to supply the voltages compared in parallel using R, the same effect as in the above embodiment can be obtained.

As described above, the present invention has a feature that when a bipolar pulse is input, the power supply voltage supplied from the direct current to the oscillation circuit is lower than the operating voltage to stop the oscillation caused by the oscillation circuit V, and the bipolar pulse is input to the oscillation circuit. An input signal processing circuit that causes the oscillation circuit to oscillate by supplying a predetermined operating voltage from the DC power supply to the oscillation circuit at 9 o'clock when the sexual power is cut off? a rectifier diode connected to the secondary side of the one-person quadrant; and a rectifier diode provided in the path of the current flowing through the rectifier diode, and interposed in the supply path of the power supply voltage supplied from the DC power supply to the oscillation circuit;
Since it is constructed with a resistor that generates a predetermined voltage when the above-mentioned bipolar pulse is input, and the generated voltage changes the voltage supplied to the input terminal of the oscillation circuit from zero potential to negative potential, the failure rate is reduced. This has the effect of providing a highly reliable AC NOT device that uses components with a low cost and that has a simple circuit structure.

[Brief explanation of the drawing]

Figure 1 shows the conventional AC NO? A circuit diagram showing the device, FIG. 2 is its operation diagram, and FIG. 5 is an AC NO according to an embodiment of the present invention.
FIG. 4 is a circuit diagram showing the T device, FIG. 4 is an operating waveform diagram thereof, and FIG. 5 is a circuit diagram showing an AC NOT device according to another embodiment of the present invention. (131 (6): ) Lance (2) # (7) # (8) : Input signal processing circuit (8): Resistor (4): Oscillator circuit (6): In the power supply diagram, the same symbols indicate the same parts. indicates a considerable portion. Daiouin Shin Kuzuno - Brush 1 Figure 3 Figure 2 ■ I Figure 4; Chikan/Xt 1

Claims (1)

[Claims] An oscillation circuit that oscillates when supplied with a power supply voltage from a DC power source, and a transformer that is provided on the secondary side of a transformer to which bipolar pulses are input, The power supply voltage supplied from the DC power supply to the oscillation circuit is set to be lower than the operating voltage to stop the oscillation circuit, and when the bipolar pulse is cut off, the oscillation circuit is supplied with the full predetermined operating voltage from the DC power supply. In an AC NOT device, an input signal processing circuit that generates oscillation is used. The input signal processing circuit is connected to the secondary side of the transformer and connected to a rectifier diode, which is provided in a path for current flowing through the rectifier diode, and has a power supply voltage supplied from the DC power supply to the oscillation circuit. a resistor interposed in the supply path of the oscillator circuit, which generates a predetermined voltage when the bipolar pulse is input, and uses the generated voltage to reduce the voltage supplied to the input terminal of the oscillation circuit from zero potential to a negative potential; An AC NOT device that consists of a body and a friend.