JPS5830230A - Timing circuit - Google Patents

Abstract

PURPOSE:To obtain 3 kinds of operation modes by a small number of elements, by inputting an input signal to one input terminal of an exclusive OR circuit, directly or through a differentiating circuit, and inputting an output to one input terminal of the other exclusive OR circuit. CONSTITUTION:A square wve-like input signal applied to an input terminal IN is applied to one input terminal of the first exclusive OR circuit 5, directly by a switching circuit consisting of a switch S3 and a diode D1, or through a differentiating circuit 4 for outputting a pulse signal of constant width in response to rise of the input signal. An output of the circuit 5 is applied to one input terminal of the second exclusive OR circuit 7 through a delaying circuit 6 executing a delay operation in response to fall of a square wave-like output. The other input terminals of the circuit 5 and the circuit 7 are grounded through switches S3, S4 and diode D2, and logic of a signal applied to each input terminal is switched.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an on-delay operation in which an output signal is turned on a certain period of time after an input signal is turned on, an off-delay operation in which an output signal is turned off a certain period of time after an input signal is turned off, and an input The present invention relates to a timer circuit that can arbitrarily switch the operation mode of 3WI [with one-sided multivibrator operation that outputs a square wave signal of a constant width in response to a signal change.

Conventionally, a timer circuit for this product has been shown in FIG. As shown in the figure, three types of circuits are built-in: timer circuit 1 for on-delay operation, timer circuit 2 for off-delay operation, and timer circuit 3 for one-shot multivibrator operation. .2.
3 are selectively operated by interlocking changeover switches S1 and S2. In such a configuration, the three timer circuits 1, 2, and 3 are provided with redundant current elements such as delay circuits, waveform shaping circuits, etc., resulting in a large number of circuit elements as a whole, which is expensive. It has no choice but to become a thing.

This invention was made in view of the above-mentioned conventional problem, and its purpose is to achieve each of the above-mentioned on-delay, off-delay, and one-shot multivibrator with a minimum number of circuit elements by sharing most of the circuit elements. An object of the present invention is to provide a timer circuit that can perform operations.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

No. 2 IlI shows the first embodiment of the timer circuit according to the present invention. This timer circuit has an input terminal IN to which a square wave input signal is applied, and responds to the rising edge of the input signal applied to this input terminal IN. a differentiating circuit 4 that outputs a pulse signal of a constant width; a first exclusive OR circuit 5;
A switching circuit switches between inputting the input signal directly to one input terminal of the exclusive OR port 115 or inputting the output signal of the differentiating circuit 4, and the output signal from the exclusive OR port 115 is provided. A delay circuit 6 that performs a delay operation in response to the falling edge of a square wave signal, a second exclusive OR circuit 7 to which the output signal of this delay circuit 6 is applied to one input terminal, and a second exclusive OR circuit 7 of this circuit 7. It is equipped with an inverter 8 that inverts the output, and a switching circuit that switches the logic of the signal applied to the other input terminal of both exclusive OR circuits 5 and 7. OR circuit 7. On-delay output and off-delay output from inverter 8.

It is configured to obtain one of the output signals of the one-shot multivibrator output.

Both switching circuits include switches 83, 84 and diodes D1. It is constituted by D2. As shown in the figure, the differential circuit 4 consists of a capacitor CI, a resistor R1 and a resistor R2, and when the switch S3 is closed, the connection point side of the resistors R1 and R2 is connected to the ground line G via the diode D1 and the switch S3. It only works sometimes. When the switch S3 is open, the differentiating circuit 4 does not function and the input terminal IN is directly connected to one input terminal of the exclusive OR circuit 5 via the resistors R1 and R2.

Furthermore, when the switch S3 is closed, the other input terminal (lower input in the figure) of both exclusive OR circuits 5.7 is connected to the ground line G via the diode D2, and its input logic becomes L level.Furthermore, when switch s3 is opened and switch S4 is closed, the logic at the other input terminal of exclusive OR circuit 5.7 becomes L level via switch s4. Furthermore, if switches s3 and S4 are both open, the exclusive OR circuit 5.7
The other input terminal of is connected to the power supply line +V via the resistor R3, and its input logic becomes H level.

The delay circuit 6 includes a transistor Q1 which is turned on via a resistor R4 when the output of the exclusive OR circuit 5 reaches the L level, and a resistor connected in series with the collector of the transistor Q1 and the electron microscope line +vlI. It is composed of a resistor R5, a resistor R6, and a capacitor C2 connected in parallel with the resistor R6, and a delay operation is performed by the discharging operation of the capacitor C2. Note that the resistor R6 is a variable resistor, and the delay time can be adjusted depending on the resistance value.

Next, the on-delay operation, off-delay operation, and one-shot multivibrator operation of the timer circuit configured as described above will be explained in order according to the waveform diagram of FIG. 3.

First, the on-delay operation will be explained. in this case,
The switch S3 is turned off to disable the differentiating circuit 4, and the switch S4 is also turned off to disable the exclusive OR circuit 5.
．． An H level input signal is applied to the other input terminal of each of the input terminals 7 and 7. As a result, exclusive OR circuits 5 and 7 each function as an inverter. In this state, as shown in the on-delay part of FIG.
When a square wave signal that changes from level to H level is input,
This signal is directly input to one output terminal a of the exclusive OR circuit 5, and therefore, a signal obtained by inverting the input signal IN is generated at the output terminal of the exclusive OR circuit 5. Transistor Q1 of delay circuit 6 is conductive when signal b is at H level,
Its output signal @C is at L level. When the LQ level of the signal falls from this state, the transistor Q1 turns off and the output signal C goes to the H level. At this time, the capacitor C2 discharges, so the output signal C goes from the L level to the H level. The rising motion is delayed in an exponential curve. SL shown in FIG. 3 is the threshold level of the exclusive OR circuit 7, and the output signal of the delay circuit 6 @C
is the threshold level S in the exclusive OR circuit 7.
The signal is binarized and inverted by L, and the signal is further inverted by inverter 8 and appears at output terminal OUT. As a result, as shown in the figure, the output signal OUT turns on with a delay of a certain period T1 after the input signal IN turns on. This is an on-delay operation.

Next, off-delay operation will be explained. In this case, the switch S3 is turned off in the same way as above, the switch S4 is turned on and an L level input signal is applied to the other input terminal of the exclusive OR circuit 5.7, and the exclusive OR circuit 5. 7 functions as a non-inverter. And the third
As shown in the figure, λ power goes from L level to H level @
When INd is applied, a square wave signal having the same polarity as the input signal IN appears from the exclusive OR circuit 5. Therefore, the delay circuit 6 performs a delay operation in response to the falling of the input signal IN, and the signal 0LIT obtained by binarizing the output signal C of the delay circuit 6 at the threshold level SL is as shown in the figure. It will be turned off after a certain period of time T1 after the input IN is turned off. This is off-delay operation.

The one-shot multivibrator operation will be explained. In this case, the switch S3 is turned on to effectively operate the differentiating circuit 4. As a result, the exclusive switch S4 may be either on or off. As shown in FIG. 3, when a square wave input signal jJIN that changes from L level to H level is applied, the rising edge of this input signal IN is differentiated by the differentiating circuit 4, and a constant A pulse signal of the same width is applied to one input terminal a of the exclusive OR circuit 5. At this time, since the exclusive OR circuit 5 functions as a non-inverter, the differentiated pulse from the differentiator circuit 4 appears as it is at its output terminal. The delay circuit 6 performs a delay operation in response to the falling of the signal S, and as shown in FIG. 2, the output signal C thereof gradually becomes the H level after the signal S returns to the L level. This signal @C is binarized at the threshold level SL and the inverted output signal OUT becomes a pulse signal with a constant width T2 in response to the rise of the input signal IN, as shown in FIG. This is one-shot multivibrator operation.

FIG. 4 shows another embodiment of the timer circuit according to the present invention, which is basically the same as the embodiment shown in FIG. is reversed. Regarding this timer circuit, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and a description thereof will be omitted.

As described in detail above, the timer circuit according to the present invention includes an input terminal to which a square wave input signal is applied, and a differentiator circuit that outputs a pulse signal of a constant width in response to the first change point of the input signal. and a switch for switching between directly inputting the input signal to one input terminal of the first exclusive OR circuit and inputting the output signal of the differentiating circuit. a delay circuit that performs a delay operation in response to a change point of one of the square wave signals output from the first exclusive OR circuit; and an output signal of the delay circuit that is applied to one input terminal. A second exclusive OR circuit, and a switching circuit that switches the logic of the signal applied to the other input terminal of the first and second exclusive OR circuits, Depending on the switching state of the circuit, the second exclusive OR circuit outputs an on-delay output, an off-delay output,
It is characterized by being configured to obtain an output signal from one of the one-shot multivibrator outputs, and since two exclusive OR circuits, delay circuits, etc. are shared, the overall circuit element is It is extremely small in number and can therefore be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional timer circuit, FIG. 2 is a circuit diagram showing an embodiment of the timer circuit according to the present invention, FIG. 3 is a waveform diagram showing the operation of the timer circuit shown in FIG. FIG. 4 is a circuit diagram showing another embodiment of the timer circuit according to the present invention. 4...Differentiating circuit 5...First exclusive OR circuit 6...
Delay circuit 7...Second exclusive OR circuit 83,84...
...Switch that constitutes a switching circuit Patent applicant: Tateishi Den Co., Ltd.

Claims (1)

[Claims] (1) An input terminal to which a square wave input signal is applied;
a differentiation circuit that outputs a pulse signal of a constant width in response to the first change point of the input signal; a first exclusive OR circuit; A switching circuit that switches between inputting the signal directly or inputting the output signal of the differentiating circuit, and a delay operation in response to a change point of one of the square wave signals output from the first exclusive OR circuit. a second exclusive OR circuit to which the output signal of the delay circuit is applied to one input terminal; and a second exclusive OR circuit to which the output signal of the delay circuit is applied to one input terminal of the first and second exclusive OR circuits Switch the logic of the signal to OFF! circuit, and configured to obtain any one of an on-delay output, an off-delay output, and a one-shot multivibrator output signal from the second exclusive OR circuit according to the switching layer of each of the switching circuits. A timer circuit characterized by: