JPS6146610A - Electronically designed inductance circuit - Google Patents

Abstract

PURPOSE:To improve leading characteristics by connecting a switch circuit comprising a resistor and a switch whose contact is closed at a prescribed time after a voltage of a prescribed value or over is applied across an inductance circuit in series with a capacitor in the said circuit. CONSTITUTION:When a voltage is applied between terminals 1 and 2, some current flows momentarily and then the current value increase gradually. Since the voltage drop at a resistor 5 is proportional to the said current value, the voltage is increased with time and when it reaches a prescribed value, a transistor (TR)11 is turned on. When the applied voltage is high, the voltage drop across the resistor 5 reaches a value momentarily to turn on the TR11, but since a delay circuit comprising a resitor 12 and a capacitor 13 exists inbetween, the TR11 is turned on after some electric charges are stored in the capacitor 7 after a prescribed time is elapsed. When the TR11 is turned on, the circuit constitution the same as an electronically designed inductance circuit is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic inductance circuit that achieves characteristics basically equivalent to those of an electromagnetic coil using transistors, resistors, and the like.

[Conventional technology]

2. Description of the Related Art Electromagnetic coils and electronic inductance circuits have conventionally been used as inductance circuits used in communication path devices that interface with metallic communication lines in telephone transmission devices, telephone exchanges, telephones, and the like.

Among these, the electromagnetic coil uses a wire-wound coil with a large DC current capacity as is, and this allows a high impedance circuit to be created for voice signals, which are AC current, while maintaining the DC current flowing through the communication line. It is something.

However, inductance circuits using electromagnetic coils have the disadvantage of being large in weight and volume. This is an essential property and unavoidable of making it possible to superimpose direct current, but this drawback is fatal for modern communication equipment, where small size and light weight are important conditions. Become something.

On the other hand, as mentioned above, electronic inductance circuits have basically the same characteristics as electromagnetic coils using transistors, resistors, etc., and a typical conventional electronic inductance circuit is shown in Figure 2. show.

In Figure 2, the impedance between terminals 1 and 2 is equivalent to a pure resistance and an inductance connected in series, and these values are the same as the resistances 4 and 5.6 connected to transistor 3 and the capacitor. 7.

As described above, since this electronic inductance circuit does not use a coil, it can be integrated into an IC, and has an extremely effective feature for modern communication equipment that is becoming smaller and lighter.

[Problems to be Solved by the Invention] However, the electronic inductance circuit has both the above-mentioned advantages and major drawbacks in terms of electrical characteristics. In other words, the rise of the DC current is slow.

This is because the conventional electronic inductance circuit shown in Figure 2 has close to ideal inductance, and when the equivalent inductance is increased in order to increase the impedance for AC audio signals, it remains as it is. This is because this appears as an increase in the delay of the curve characteristics.

In the case of electromagnetic coils, it was easy to reduce the inductance value in the frequency range higher than the audio frequency by utilizing the stray capacitance between the windings, but since electronic inductance circuits use capacitors, this is not possible. It is difficult to do so.

This drawback is particularly noticeable in devices that use intermittent DC current as a signal.
This is extremely inconvenient in the ffl signal system, and may even be impossible to use depending on the signal system.

The present invention has been made in view of the above-mentioned problems, and its purpose is to maintain the small size and light weight that are the characteristics of electronic inductance circuits, while also providing good current rise characteristics when voltage is applied. An object of the present invention is to provide an electronic inductance circuit.

[Means for solving problems]

To achieve this object, the electronic inductance circuit according to the present invention, as shown in FIG. 1, includes a transistor 3 as a variable resistor, a resistor 4. A switch circuit 8 is connected in series with the capacitor 7 to a conventional electronic inductance circuit configured with the above-mentioned capacitor 7. The switch circuit 8 is configured by a resistor 10 and a switch 9 connected in parallel.
has a function of closing the contacts after a certain period of time when a voltage of a predetermined value or more is applied between terminals 1 and 2.

[Effect]

Next, 1. The operation of the electronic inductance circuit according to the present invention will be explained using the rise characteristic diagram when voltage is applied shown in FIG. 3(A) is a rise characteristic diagram of the electronic inductance circuit according to the present invention, and FIG. 3(B) is a rise characteristic diagram of the conventional electronic inductance circuit, where the horizontal axis t represents both terminals 1. 2 represents the time since voltage was applied, and the vertical axis i represents the current flowing from one terminal of the circuit to the other.

When voltage is applied, the contacts of switch 9 are open and capacitor 7 is discharged, so terminal 1
．． When a predetermined voltage is applied between terminals 2 and 2, the voltage drop that appears across resistor 10 causes a forward bias between the heath and emitter of transistor 3, and an instantaneous current flows between terminals 1 and 2, as shown in Figure 3 (A). flows.

Thereafter, as time passes, the capacitor 7 is gradually charged, the voltage between the transistor 3 and the emitter rises, and the current flowing between the terminals 1 and 2 gradually increases.

Further time passes, and at time t1, after T time has elapsed since the voltage application, the contact of the switch 9 is closed. When the switch 9 is closed, the circuit configuration becomes the same as the conventional electronic inductance circuit shown in FIG. 2, and exhibits the same characteristics as the characteristic diagram shown in FIG. 3(B), that is, the required characteristics.

〔Example〕

Next, one embodiment of the present invention will be explained using the circuit diagram of FIG. 4.

In this embodiment, the switch 9 in the present invention is replaced with the l/ungister 11. This is realized using a resistor 12 and a capacitor 13.

Transistor 11 functions as a contact point of switch 9, and on/off control of transistor 11 is performed based on the voltage drop value across resistor 5.

Note that the resistor 12 and capacitor 13 constitute a delay circuit, which provides a certain time delay to the above-mentioned on/off control.

Now, when voltage is applied between terminals 1 and 2, the above [effect]
As mentioned in the section above, a certain amount of current flows instantaneously, and then the current value gradually increases. Since the voltage drop value across the resistor 5 is proportional to this current value, it increases over time, and when it reaches a predetermined value, the transistor 11 is turned on.

Note that when the applied voltage is high, the voltage drop across the resistor 5 is just enough to instantly turn on the transistor 11, but between the resistor 5 and the transistor 11 there is a resistor 12 and a capacitor 13. Since a delay circuit consisting of the following steps is involved, the transistor 11 is turned on after a certain amount of time has elapsed and a certain amount of charge has been accumulated in the capacitor 7.

When the transistor 11 is turned on, as described above, the circuit configuration becomes equivalent to the conventional electronic inductance circuit, that is, the circuit configuration exhibits the desired characteristics.

〔Effect of the invention〕

As explained above, according to the present invention, when a voltage of a predetermined value or more is applied to the capacitor of an electronic inductance circuit in which the value of inductance is controlled by a capacitor, a voltage of a predetermined value or more is applied to the capacitor of the electronic inductance circuit for a certain period of time. Since the switch/two-channel circuit, which is composed of a switch that later closes the contact and a resistor connected in parallel, is connected in series, it maintains the small size and lightness that are the characteristics of electronic inductance circuits, while still allowing voltage application. It is possible to improve the rise and fall characteristics of the current during the time.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram for explaining the present invention in detail, Fig. 2 is a circuit diagram showing a conventional electronic inductance circuit, and Fig. 3 is a circuit diagram showing a conventional electronic inductance circuit.
The figure is a rise characteristic diagram of an electronic inductance circuit, and FIG. 4 is a circuit diagram showing an embodiment of the present invention. 1.2...terminal, 3...transistor, 7...capacitor, 8...switch circuit, 9...switch,
IO...Resistance.

Claims (1)

[Claims] The resistance value between the two terminals is changed by the charging voltage of the capacitor that is charged by the voltage applied between the two terminals,
In an electronic inductance circuit configured to exhibit characteristics equivalent to an inductance, the capacitor is connected to a switch and a resistor that close the contact after a certain period of time when a voltage of a predetermined value or more is applied across the electronic inductance circuit. An electronic inductance circuit characterized in that a switch circuit constituted by a parallel connection with a switch circuit is connected in series.