JPS6116798Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a step motor operation display circuit, which blinks only when the step motor is operating, has a small number of parts, has a simple circuit configuration, and eliminates unnecessary current for display. An object of the present invention is to provide an operation display circuit for a step motor that does not require a power supply.

Generally, in a cumulative time meter, the cumulative time is displayed in units of hours and minutes, and there is no need to display it in units of seconds. For machines that do not have seconds display, it takes a long time to confirm that the timer and other instruments are working properly.
Conventionally, the circuit shown in FIG. 1 has been used to blink a light emitting diode to indicate its operation.

FIG. 1 shows a circuit diagram of a conventional step motor operation display circuit. In the figure, reference numerals 1 and 2 are power supply terminals to which positive and negative power supply voltages are supplied, respectively. The power supply voltage supplied to input terminals 1 and 2 passes through a protection diode D ₁ and a resistor R ₁ of the integrated circuit 3, and then is kept at a constant voltage by a Zener diode Dz. The variation is absorbed by the capacitor _C1 and supplied to the integrated circuit 3. The integrated circuit 3 includes an oscillation circuit using a crystal resonator 4, and the capacitors C ₂ and C ₃ are for adjusting the oscillation frequency. After the signal of a constant frequency generated by the oscillation circuit of the integrated circuit 3 is frequency-divided, pulses of, for example, 1 pps, which are made enough to drive the step motor 5, are supplied to the step motor 5 from terminals 3a and 3b. The step motor 5 is driven to rotate, thereby rotating the digital counter (rotation indicator).

Furthermore, one ends of resistors R 2 and R ₃ whose resistance value is sufficiently larger than the internal resistance of the step motor 5 are connected to terminals 3 a and 3 b of the integrated circuit ₃ , and the other ends of these resistors R ₂ and R ₃ are connected to transistors Tr. When a pulse _is supplied from the terminals 3a and 3b, a voltage sufficient to make the transistor _Tr1 conductive is supplied to this base. The emitter of the transistor Tr ₁ is connected to the power source 2, and the collector is a light emitting diode
D ₂ and a resistor R ₄ for protection of this light emitting diode D ₂
is connected to the cathode of diode _D1 through. Therefore, when a 1pps pulse is supplied from the terminals 3a and 3b of the integrated circuit 3 to drive the step motor 5, the transistor _Tr1 becomes conductive and current flows to the light emitting diode _D2 , causing the light emitting diode _D2 to emit light for 1 second. It flashes once to indicate the operation of the step motor 5. However, in the circuit shown in the first diagram, even if the step motor 5 is disconnected and stops rotating, the light emitting diode will blink every time a pulse is supplied from the integrated circuit 3, and this blinking will be caused by the pseudo step motor 5. It is only an operational display,
Resistor R ₂ to flashing light emitting diode D ₂ ,
R ₃ , R ₄ and the transistor Tr ₁ are required, and space is required to provide them, which increases the cost. Furthermore, in addition to the current for operating the step motor 5, the current for lighting the light emitting diode D ₂ is also required. The drawback was that extra supplies had to be provided.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described with reference to FIG. 2 and the following figures.

FIG. 2 shows a circuit diagram of one embodiment of the step motor operation display circuit according to the present invention. In the same figure, the first
The same parts as those in the figures are given the same reference numerals, and their explanations will be omitted. In Figure 2, 1 and 2 are power supply terminals,
Positive and negative power supply voltages (+B, -B) are supplied, respectively. For example, the voltage between power supply terminals 1 and 2 is
It is 24V. The power supply terminal 1 is connected to the positive power supply terminal 3 of the integrated circuit 3 via a diode D ₁ that blocks current in the reverse direction and a protective resistor R ₁ with a resistance value of, for example, 1KΩ.
c, and the power supply terminal 2 is connected to the negative power supply terminal 3d of the integrated circuit 3. In addition, the integrated circuit 3
A capacitor _C1 is connected between the positive and negative power terminals 3c and 3d to absorb sudden voltage fluctuations, and a Zener diode is connected to the power terminal 3c.
The cathode of Dz ₂ is connected to the Zener diode
The anode of Dz ₂ is connected to the cathode of a Zener diode Dz ₃ whose anode is connected to the power supply terminal 3d, and the Zener voltage Vz ₂ (for example, about 4.6V) of the Zener diodes Dz ₂ and Dz ₃ is applied between the power supply terminals 3c and 3d. Vz ₃ (e.g. around 2V) provides a constant voltage Vz ₂
+Vz ₃ (here, the Zener voltage Vz ₁ of the Zener diode Dz ₁ is Vz ₁ =Vz ₂ +Vz ₃ ) is applied. Here, the voltage Vz ₂ +Vz ₃ is a voltage lower than the voltage applied between the power supply terminals 1 and 2. At the same time, the anode of the light emitting diode D ₂ is connected to the connection point between the Zener diodes Dz ₂ and Dz ₃ , and the cathode of the light emitting diode D ₂ is connected to the power supply terminal 2. In addition, terminals 3e and 3 of the integrated circuit 3
A crystal resonator 4 is connected to f, and terminals 3e and 3f
Capacitors C ₂ and C ₃ for adjusting the oscillation frequency are connected between the terminal 3d and the terminal 3d, respectively.

In the circuit shown in FIG. 2, a substantially constant current I _T (for example, approximately 16 mA) flowing through the resistor R ₁ is divided into a current Ia flowing through the integrated circuit 3 and a current Ib flowing through the Zener diode Dz ₂ . Here, the integrated circuit 3 divides a signal of a constant frequency generated by an oscillation circuit including a crystal oscillator 4, amplifies it, and outputs a 1pps pulse, which has been amplified to the desired power, from terminals 3a and 3b. When supplying to the motor 5, this pulsed current flows through the step motor 5, so the current Ia
is large, for example, 16mA, and the current Ib is, for example,
The current flowing through the light emitting diode _D2 out of the current Ib is approximately less than 2 mA, which is the current value required for light emission, and the light emitting diode _D2 is turned off. In addition, in this case, the current Ia + Ib is the current I
The reason why it is larger than _T is due to the discharge current from capacitor _C1 . Next, since no pulses are supplied to the step motor 5 from the terminals 3a and 3b, the current
Ia is, for example, 1 mA, which is a very small amount that is enough to operate the integrated circuit 3, and since current I _T is approximately constant, current Ib increases to, for example, 16 mA. Here, the impedance of the light emitting diode _D2 is smaller than that of the Zener diode _Dz3 , so the current
Most of Ib flows through the light emitting diode _D2 , exceeding the current value of approximately 2mA required for light emission, and the light emitting diode _D2
lights up. In this manner, by repeating the above operation, the light emitting diode _D2 blinks once per second to indicate the operating state of the step motor 5.

Here, if the step motor 5 is disconnected, no pulse current flows through the step motor 5, so the current Ia is always a small current just enough to operate the integrated circuit 3, and the increased current flows through the light emitting diode _D2. Most of Ib flows and the light emitting diode _D2 is always on and does not blink.

Here, in order to cause the light emitting diode _D2 to emit light, it is sufficient to simply provide the Zener diode _Dz3 , and an extra current is needed to supply the current for driving the step motor 5 to the light emitting diode when the step motor 5 is stopped. do not need.

Note that the light emitting diode _D2 may be another display element such as a fluorescent display tube, and is not limited to the above embodiment.

As described above, the step motor operation display circuit according to the present invention is a step motor operation display circuit that blinks a display element in response to the operation of the step motor that is driven by being supplied with pulses generated by an integrated circuit. The integrated circuit consists of two Zener diodes connected in series between the power supply terminals of the integrated circuit to keep the voltage between the power supply terminals constant, and a display element connected in parallel to one of the Zener diodes. Assuming that the sum of the currents flowing through the circuit and each of the multiple Zener diodes is constant, when the step motor of the integrated circuit is driven, the current flowing through the multiple Zener diodes becomes small and the display element turns off, and when the step motor of the integrated circuit is not driven, the current flowing through the multiple Zener diodes becomes small. The current flowing through the Zener diode becomes large and the display element lights up, causing the display element to blink, so it blinks only when the step motor is rotating to indicate the operation of the step motor. However, other than the display element, it is extremely small with only one Zener diode, and the configuration is simple, low cost, and requires little space for circuit configuration, and there is no need to supply extra current to display the operation. It has the following features.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an example of a conventional step motor operation display circuit, and FIG. 2 is a circuit diagram of an embodiment of the step motor operation display circuit according to the present invention. 1, 2...Power terminal, 3...Integrated circuit, 4...
Crystal oscillator, 5...Step motor, _C1 to _C3 ...
...Capacitor, D ₁ ... Diode, D ₂ ... Light emitting diode, Dz ₁ to _{Dz 3} ... Zener diode, Tr ₁ ... Transistor.

Claims (1)

[Scope of utility model registration request] In a step motor operation display circuit that blinks a display element in response to the operation of a step motor driven by being supplied with pulses generated by an integrated circuit, a A plurality of Zener diodes connected in series to maintain a constant voltage, and a display element connected in parallel to any one or more of the Zener diodes, each of the integrated circuit and the Zener diodes When the step motor of the integrated circuit is driven, the current flowing through the plurality of Zener diodes becomes small and the display element goes out, and when the step motor of the integrated circuit is not driven, the current flowing through the plurality of Zener diodes becomes small. A step motor operation display circuit configured to blink a display element when the current flowing through a Zener diode becomes large and the display element lights up.