JPH04312012A - Electronic inductance circuit - Google Patents

Abstract

PURPOSE:To obtain a practical electronic inductance circuit in which the delay of the rise of a current is suppressed without increasing drastically the number of parts. CONSTITUTION:The electronic inductance circuit is provided with a resistor 2 between the terminal 1 of one side of two terminals and the base of a transistor 7 and the resistor 8 between the terminal of the other side and the emitter of said transistor, and the parallel connection circuit of a capacitor 3 and the resistor 4 and the parallel connection circuit of two diodes 5,6 reversed to each other are connected in series between the other side terminal and the base of said transistor. At the time of the impression of voltage, by compensating the voltage between the base and the emitter of said transistor by the diodes until the capacitor 3 is accumulated, the current flows in said transistor immediately after the impression of the voltage.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic inductance circuit that uses capacitors, transistors, etc. to realize characteristics basically equivalent to those of electromagnetic coils.

0002

2. Description of the Related Art In wired telephone devices, direct current is often superimposed on two wires as a voice signal and a monitoring/response signal in order to reduce the number of wires in a communication circuit. In this case, the inductance circuit used as a DC pass circuit is used in electromagnetic coils and electronic inductance circuits.

[0003] Among these, the electromagnetic coil uses a wire-wound coil with a large DC current capacity as it is, and as a result, it maintains the DC current flowing in the communication circuit while providing a high impedance circuit for audio signals that are AC current. This is to realize the following.

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. It is something.

On the other hand, as mentioned above, electronic inductance circuits have basically the same characteristics as electromagnetic coils using capacitors, transistors, etc., and a typical conventional electronic inductance circuit is shown in FIG. Shown below.

In FIG. 3, when a voltage is applied to the terminal 21, the impedance of the circuit is equivalent to that of a pure resistance and an inductance connected in series, and these values are the resistances 22, 24, 26, and capacitor 23.

[0007] 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 tends to be smaller and lighter.

However, this electronic inductance circuit has both the above-mentioned advantages and major drawbacks in terms of electrical characteristics. That is, since no current flows between the base and emitter of the transistor 25 until the capacitor 23 in FIG. 3 accumulates, there is a drawback that a delay in the rise of the DC current occurs. That is, as shown in FIG. 4(c), a delay time T2 in the rise of the current occurs.

Therefore, as a method to compensate for this drawback, the above-mentioned capacitor is connected in parallel with a resistor and a switch that closes the contact after a certain period of time when a voltage of a predetermined value or more is applied to both ends of this electronic inductance circuit. An electronic inductance circuit has been proposed in which switch circuits are connected in series.
Publication No.). In this electronic inductance circuit,
When voltage is applied, the switch of this switch circuit is opened,
The resistance of this switch circuit compensates the voltage between the base and emitter of the transistor, eliminating the delay in the rise of the direct current, which is the above-mentioned drawback.

However, although the electronic inductance circuit equipped with the above-mentioned switch circuit has good current rise characteristics, it naturally requires a switch circuit, so in order to realize this switch circuit, a new ,
Transistors, resistors, capacitors, etc. are required, so
This has the drawback of increasing the number of parts, leading to a significant increase in costs.

[0011]

[Problems to be Solved by the Invention] The present invention has been made in consideration of the above-mentioned circumstances, and provides a practical electronic inductance circuit that suppresses the current rise delay without significantly increasing the number of components. This is what we provide.

0012

[Means for Solving the Problems] The electronic inductance circuit of the present invention changes the direct current resistance between two terminals by the charging voltage of a capacitor that is charged by the voltage applied between the two terminals, thereby achieving an equivalent inductance. An electronic inductance circuit constituted by circuit elements such as capacitors and transistors, which exhibits characteristics, is provided with compensation means for compensating the voltage between the base and emitter of the transistor, and as the compensation means, a diode is used. The capacitor is provided with a circuit in which circuits connected in parallel in opposite directions are connected in series with the capacitor.

Furthermore, the electronic inductance circuit of the present invention exhibits characteristics equivalent to inductance by changing the DC resistance between two terminals by the charging voltage of a capacitor that is charged by the voltage applied between these two terminals. In an electronic inductance circuit composed of circuit elements such as capacitors and transistors, a resistor is provided between one of the two terminals and the base of the transistor, and a resistor is provided between the other terminal and the emitter of the transistor. , a circuit in which a capacitor and a resistor are connected in parallel between the other terminal and the base of the transistor, a circuit in which an appropriate number of capacitors in the same direction are connected in series, and a circuit in which an appropriate number of capacitors in the opposite direction are connected in series. It is equipped with a circuit in which the two are connected in parallel, and a circuit in which the two are connected in series.

[0014]

[Operation] According to the electronic inductance circuit of the present invention,
When a voltage is applied between two terminals of the circuit, the compensation means will cause the base of the transistor to
By compensating the voltage between the emitters, a current flows between the collector and emitter of the transistor immediately upon application of the voltage.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing the structure of an embodiment of an electronic inductance circuit according to the present invention.

In the figure, a resistor 2 is connected between a terminal 1 connected to a transistor 7 and the base of the transistor 7, and a resistor 8 is connected between the other terminal (ground point) and the emitter of the transistor 7. Furthermore, a circuit in which a capacitor 3 and a resistor 4 are connected in parallel between the other terminal and the base of the transistor 7, and a circuit in which a diode 5 and a diode 6 in the opposite direction to the diode 5 are connected in parallel are connected in series.

In the figure, when a voltage is applied to terminal 1, a voltage divided by resistors 2, 4 and diode 5 is applied to the base of transistor 7. At this time, capacitor 3
Since is in a discharge state, the resistor 4 is in a short-circuit state. However, due to the action of diode 5, a certain potential (this potential is set to V
F) is maintained. Furthermore, since a resistor 8 is connected to the emitter end of the transistor 7, a current flows through the transistor 7 from the moment a voltage is applied to the circuit. That is, as shown in FIG. 4(a), there is no delay in the rise of the current.

Thereafter, as time passes, the capacitor 3 is gradually charged, the voltage between the base and emitter of the transistor 7 rises, and the current flowing between the terminals of the circuit gradually increases. At this time, the capacitor 3 is charged to the same potential as the resistor 8. In the circuit of the present invention, transistor 7
Since the current increase rate is set large, the current flowing through the circuit is determined by the voltage division ratio of the resistors 2 and 4. Furthermore, in the alternating current component of the current, the time constant of the resistor and capacitor 3 is equivalent to the time constant of the electromagnetic coil. Further, the diode 6 forms a discharge path for the capacitor 3.

FIG. 2 shows the circuit configuration of another embodiment of the electronic inductance circuit of the present invention, in which two transistors are used to increase the current amplification factor of the transistor in the circuit shown in FIG. Since a transistor with characteristics equivalent to Darlington connection is used,
Two diodes are connected in series to increase the threshold of the diode.

In the same circuit, the resistors 12 and 14 are several tens of kilohms, the resistor 18 is several ohms, and the capacitor 13 is 10 μF.
diodes 15, 16, 9, and 10 have a threshold value of 0.
A silicon diode of about 5 is used.

The current rise characteristics of this circuit are as shown in FIG. 4(a), similar to the first embodiment circuit described above. Also, for comparison, the four diodes 15 and 16 of the same circuit
, 9, and 10, two diodes 9 and 10 are omitted (two diodes 15 and 16 in opposite directions are connected in parallel), and the current rise characteristic is shown in FIG.

Below, the operation of the electronic inductance circuit of the present invention will be explained in detail based on the characteristic diagram of FIG.

In the conventional circuit, when a voltage is applied to the terminal 21, the capacitor 23 is in a discharged state as described above, so the resistor 24 is in a shorted state. Therefore, until the capacitor 23 is accumulated, the period T shown in FIG.
2 (in this example T2 is 60
(about msec).

On the other hand, in the circuit of the present invention, 2 in FIG.
If the diodes 9 and 10 are omitted, when a voltage is applied to the terminal 11, the voltage divided by the resistors 12 and 14 and the diode 15 is applied to the base of the transistor 17. At this time, the capacitor 13 is in a discharged state, so the resistor 1
4 is in a shorted state. However, the diode 15 works to maintain a specific voltage. Also, since the resistor 18 is connected to the emitter end of the transistor 17,
As shown in FIG. 4(b), the current rise delay is over a period T
1 (in this example, T1 is about 30 msec).

Furthermore, as shown in FIG. 2, when two series-connected diodes 15 and 9 in the same direction and two diodes 16 and 10 in the opposite direction are connected in parallel, the transistor 7 As the voltage applied to the base increases, the current rise delay is further improved and almost disappears as shown in Figure 4(a).By connecting in this way, a circuit equivalent to an inductance with a DC resistance of 600Ω or more is obtained. .

Furthermore, as in the same circuit, if the number of connected diodes is increased, the current rise angle becomes steeper, and an electronic inductance with even better current rise characteristics can be realized. However, due to the number of components and cost issues, it is preferable to connect an appropriate number of diodes.

[0027]

[Effects of the Invention] As explained above, according to the present invention,
By providing means for compensating the voltage between the base and emitter of a transistor when a voltage is applied, an electronic inductance circuit with good current rise characteristics when a voltage is applied can be obtained.

[Brief explanation of drawings]

[Figure 1] Circuit diagram of the electronic inductance of the present invention (1)

[Figure 2] Circuit diagram of the electronic inductance of the present invention (2)

[Figure 3] Circuit diagram of conventional electronic inductance

[Figure 4]
Rising characteristic diagram of electronic inductance circuit

[Explanation of symbols]

1 Terminal 2 Resistance 3 Capacitor 4 Resistance 5 Diode 6 Diode 7 Transistor 8 Resistance

Claims (2)

[Claims] [Claim 1] A circuit of a capacitor, a transistor, etc., in which the direct current resistance between two terminals is changed by the charging voltage of a capacitor that is charged by the voltage applied between the two terminals, so that it exhibits characteristics equivalent to inductance. An electronic inductance circuit configured by an element, comprising compensation means for compensating the voltage between the base and emitter of the transistor, and the compensation means includes a circuit in which a circuit in which diodes are connected in parallel in opposite directions is connected in series with the capacitor. Equipped with an electronic inductance circuit. [Claim 2] A circuit such as a capacitor, a transistor, etc., in which the direct current resistance between two terminals is changed by the charging voltage of a capacitor that is charged by the voltage applied between the two terminals, so that it exhibits characteristics equivalent to inductance. In the electronic inductance circuit composed of elements, the above two
A parallel connection circuit including a resistor between one of the terminals and the base of the transistor, a resistor between the other terminal and the emitter of the transistor, and a capacitor and a resistor between the other terminal and the base of the transistor, An electronic inductance circuit characterized in that a series connection circuit of an appropriate number of diodes in the direction and a parallel connection circuit of the series connection circuit of an appropriate number of diodes in the opposite direction are connected in series.