JPH0685539B2 - Telephone - Google Patents

Description

TECHNICAL FIELD The present invention relates to a telephone including a tone ringer.

[Background Art] "Integrated Circuit Application Handbook" (published on June 30, 1981, first edition, first edition, Asakura Shoten Co., Ltd., P599-P600) is enthusiastically researched on making telephone circuits into semiconductor integrated circuits. Is described.

The inventors of the present application also made various technical studies on the telephone in view of the above-mentioned technical trends. As a result, when a plurality of telephones were used in parallel, it was found that when one telephone was dialed, the other telephone resonated. Especially, in a telephone equipped with a telephone IC generally called a tone ringer, the ringing tone when coming from the outside and the resonance sound caused by the dial operation on one side are almost the same, so they are very different. It was revealed that it was difficult to do. The above phenomenon is particularly remarkable in a telephone using an IC, and the reason thereof has been clarified by the present inventor as follows.

Hereinafter, the occurrence of the resonance phenomenon and the like will be sequentially described with reference to FIGS.

Two telephones 11 and 11 'are connected in parallel to a telephone exchange 1 shown in FIG. 5 through Tip and Ring terminals 2 and 3. Since the two telephones 11 and 11 'have the same circuit configuration, only the telephone 11 will be described below.
For 11 ', a dash signal is attached to the same reference numeral and its description is omitted.

SW ₁ and SW ₂ are hook switches, and when hook on,
In other words, the switching state shown in the figure is set when waiting for a call, and the state shown by the dotted line is switched when the handset 12 is lifted.

On the other hand, the call signal P from the exchange 1 is a 16 Hz signal as shown in FIG.
Is formed so as to continue for 1 second, and this is applied to the tone ringer circuit 13 as a calling signal P. And
Work 'tone ringer circuit 13, 13 in the' phone 11, 11 are simultaneously caused exactly the same ringing tone at the same time, lifting the receiver unit 12 switches SW _1, SW ₂ is turned such switching state of a dotted line, A dialer (Pulse Dialer) 14 and a speech network (Speech Network) 15 operate to make a call.

Next, the circuit operation during transmission will be described.

Lift the handset 12 of the telephone 11 and switch SW ₁ , SW ₂
Are switched as shown by the dotted lines, and the switches SW ₁ ′ and SW ₂ ′ remain solid.

The pulse dialer 14 is a dial (a rotary type or a bush type may be used), a memory for storing a dialed number, and a pulse generation for generating a pulse according to information stored in the memory. It consists of vessels. Then, when the dialer 14 is operated to dial 031, for example, a dial pulse P _A having a waveform as shown in FIG. 7 is transmitted to the exchange 1 and at the same time transmitted to the tone ringer 13 'of the telephone 11'. Will end up.

The tone ringer 13 'is driven by the pulse generated by the pulse dialer 14 to cause resonance. That is, the tone ringer circuits 13 and 13 'that are integrated in the IC are Tip-Ri
The signal at the ng terminal is full-wave rectified and then smoothed, and the oscillating circuit is driven while this rectified and smoothed voltage is supplied, and an oscillating sound (calling sound) is obtained. However, the sound quality of the oscillating sound is the calling signal shown in FIG. 6 and the dial pulse P shown in FIG.
It does not differ from _A. The difference between the two is the interval between signal generations, but one is 2 seconds and the other is, for example, 0.8 seconds (depending on the dialer), so the difference in hearing is not clear, and the above problem appears. It was what was there.

By the way, in a phone with a tone ringer,
As a general standard, there are conditions such as "when the pulse generated by the pulse dialer 14 is supplied, no resonance occurs at an input voltage of 60 V or less, and when the ring voltage is input from the exchange, it starts ringing at 45 V or less". Therefore, the present inventor has a time lag between the time when the pulse dialer is supplied and the time when the ring voltage is input as described above. Therefore, if the input impedance is appropriately selected, the energy detection based on the time lag, that is, the difference between the two is detected. After realizing that resonance can be prevented, the present invention has been proposed.

[Object of the Invention]

An object of the present invention is to provide a telephone having a semiconductor integrated circuit and a tone ringer circuit, which can clearly receive a ringing tone from the outside and can eliminate a resonance sound generated when dialing in a telephone connected in parallel. To provide.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[Outline of Invention]

A typical example of the invention disclosed in the present application will be briefly described as follows.

That is, a telephone that uses a DC power supply obtained by rectifying and smoothing a ringing signal from an exchange consisting of an intermittent signal of 16 Hz AC as an operating power supply for generating a ringing sound, and from a line terminal called a Tip terminal or Ring terminal. A power supply stabilizing circuit that changes the impedance according to the level of each signal and stabilizes the rectified output is provided in the subsequent stage of the rectifying circuit that rectifies the call signal and the pulse dialer that are supplied, and the power supply V _{CC of the} tone dialer circuit is provided. With this rectified output, the capacitor C ₂ forming a part of the power supply stabilization circuit is charged to start the power supply V _CC with a certain time constant. At the rise of the power supply V _CC , the impedance of the variable impedance discharge circuit 23 provided in the input part of the IC is kept low at the initial stage (that is, when the power supply voltage V _CC does not reach the predetermined level (first level)), The charge stored in the capacitor C ₂ is, for example, the ground potential (ground).
It is in a state where it is easily discharged. Next, despite such a state, a signal is intermittently supplied to the Tip and Ring terminals, and as a result, the charging of the capacitor C ₂ progresses and the power supply voltage V
_{When CC} reaches a predetermined level, the impedance of the variable impedance discharge circuit 23 is switched to a high state, the discharge of the electric charge stored in the capacitor C ₂ is suppressed, and the power supply voltage V _CC is rapidly raised. Eggplant Further, when V _CC becomes sufficiently high potential (second level), the variable impedance discharge circuit 23 is automatically deactivated and the oscillator circuit OSC, the logic circuit 24, etc. are operated to drive the tone ringer. Do like this. When the dial pulse from one of the phones connected in parallel to each other is input to the other phone by providing the above functions, the energy of the dial pulse is much smaller than that of the regular call pulse. Due to the function of the discharge circuit, the capacitor C ₂ is not charged and V _CC does not rise to a predetermined value, which makes it possible to deactivate the tone ringer. That is, there are intermittent call pulses from the central office.
Tone ringer works only when added to Tip, Ring.

In this way, it is possible to achieve the object of the invention of completely preventing the resonance of the other telephone when dialing one of the telephones connected in parallel.

〔Example〕

Next, an embodiment of a telephone to which the present invention is applied will be described with reference to FIGS.

It should be noted that FIG. 6 and FIG. 7 showing the cause of occurrence of resonance will also be referred to. The feature of this embodiment is to pay attention to the magnitude relation between the energy of the calling signal from the outside and the energy of the dial pulse from the inside, as described above, and the small energy of the dial pulse does not cause the power supply V _CC to rise sufficiently. To do so.

As shown in FIG. 1, the tone ringer, which is the main part of the telephone according to the present embodiment, uses a DC power supply obtained by rectifying and smoothing a ringing signal from an exchange, which is an intermittent signal of 16 Hz AC, for generating a ringing tone. Which is used as an operating power source of the DC blocking capacitor C1, the input resistance R1,
Bridge circuit 21 forming a full-wave rectifier circuit, smoothing capacitor
C2, power supply stabilization circuit 22, variable impedance discharge circuit 2
3. Has a power control circuit.

Here, the power supply stabilization circuit 22 is connected in parallel to the smoothing capacitor C2 to perform power supply stabilization operation by parallel control, and forms a predetermined parallel impedance with respect to the Tip and Ring line terminals.

The variable impedance discharge circuit 23 includes a smoothing capacitor C2.
Is connected in parallel with the terminal of the smoothing capacitor C2, and when the voltage of the terminal is below the first level, it is intervened in parallel with a predetermined low impedance, and when the voltage of the terminal exceeds the above level. Intervenes in parallel with a predetermined high impedance to control the charge / discharge speed for the capacitor C2.

The energization control circuit includes transistors Q14 to Q21 and the like, and the terminal voltage of the smoothing capacitor C2 is the first voltage mentioned above.
When the second level higher than the level is reached, the terminal of the smoothing capacitor C2 is connected to the power supply line for generating the ringing sound, and the impedance variable discharge circuit 23 is opened to the smoothing capacitor C2. It becomes a non-differential state.

The input impedance seen from the Tip and Ring terminals can be adjusted by the capacitor C ₁ and the resistor R ₁ , but there are standard values for these values. Therefore, it is better to adjust the tone ringer impedance in other circuits. However, resistance
This is not the case when R ₁ is formed in the IC.

The impedance of the tone ringer circuit viewed from the rectifier circuit 21 can be set by the resistance component of the capacitor C ₂ and the constant voltage circuit 22, but if the capacitor C ₂ has a large capacity, the cost is high,
Since the volume at the time of mounting becomes large, the capacity value has its own limit, and in this embodiment, it is set to about 10 μF.

On the other hand, the resistance value of the resistance component _RA consisting of the resistances R ₄ and R ₅ is determined in association with the resistance R ₂₀ of the discharge circuit 23, which will be described later, and the tone ringer circuit is integrated into an IC, so high resistance is preferable. Absent.

By the way, in this embodiment, the resistance R ₂₀ was set to about 30 KΩ, and the resistance component _RA , which is a series combined resistance, was set to various resistance values. As a result, the resistance component _RA is 500Ω to 600Ω
When set in between, the optimum impedance that prevents resonance at the time of inputting the pulse dialer and produces a ringing state at the time of inputting the calling signal is obtained.

Next, a change in input impedance will be described prior to the description of the tone ringer circuit.

By setting the resistors R _A and R ₂₀ as described above, the input impedance of the tone ringer circuit viewed from the output side of the rectifier circuit 21 changes as shown in FIG. 2 when supplying the calling signal and the third impedance when supplying the pulse dial. It changes as shown in the figure.

First, when the call signal is input, in this case, it must ring at 45V or less. It was found that the ringable input impedance was obtained when the resistance _RA was set to approximately 500Ω or more as shown in FIG.

On the other hand, when supplying a pulse dialer, resonance must be prohibited at an input voltage of 60 V or less. And when the resistance R _A set approximately 560Ω or less, to obtain an impedance which satisfies the above conditions, as shown in Figure 3.

Referring to FIG. 2 and FIG. 3 above, the resistance R _A is 500Ω.
If it is set to about 560Ω, ringing and resonance can be prevented by the change in the impedance.

Incidentally, since the resistor R _A is a series combined resistance of the resistors R _4, R _5, resistors R _4, the resistance value of R ₅ is good as the resistance value of each 1/2 · Ra.

When the input impedance of the tone ringer circuit changes according to the ringing signal and the pulse dialer as described above, the rising change of the rectified output becomes different between them.

In other words, when the call signal is input and when the pulse dialer is supplied, the tone ringer circuit operates as follows in correspondence with these.

First, the time of receiving a call signal supplied from the outside will be described.

At the time of reception, a received signal as shown in FIG. 6 is supplied to the Pip, Ring terminals shown in FIG. Then, it is rectified by the bridge circuit 21 composed of the transistors Q _{1 to} Q ₄ .

Transistors Q _{5 to} Q ₈ , Zener diodes ZD _{1 to} ZD ₆ , resistors
The R _{2 to} R ₅ and the capacitor C ₂ operate as the power supply stabilizing circuit 22 and perform the overvoltage protection operation while changing the impedance as described above.

Next, the operation of the discharge circuit 23 that plays an important role in the present invention will be described. When a calling signal is supplied to the Tip and Ring terminals, and as a result, the capacitor C ₂ is charged and V _CC rises gradually, first, the transistor Q ₁₄ , the transistor Q ₁₅ ,
An initial current I ₁ flows to the base of the transistor Q ₁₂ via Q ₁₆ and resistors R _{7 to} R ₁₂ . Then, the transistor Q ₁₂ operates in the ON state, and the transistor forming the current mirror circuit
The initial current I ₂ flows through Q ₉ , and this current becomes the base current of the transistor Q ₃₁ via the transistor Q ₁₂ and the resistors R ₂₀ and R ₂₁ .

In addition, the current I ₃ flows through the transistor Q ₁₀ and the current I ₂ ,
The sum current of I ₃ flows to the ground via the transistor Q ₃₁ and the resistor R ₂₂ . That is, in the initial stage of the rise of V _CC, the currents I ₁ , I ₂ , and I ₃ initially flow, so that the charging of the capacitor C ₂ is difficult to proceed.

Next, the capacitor C ₂ is further charged, and V _CC rises (I ₁ + I ₂ ) (R ₂₁ + R ₂₂ ) + V _BE Q ₃₁ voltage required to turn on the transistor Q ₃₀ 3V _F + V _BE Q It becomes ₃₀ or more, (V _F is the forward voltage of the diode _{D 2, D 3, D 4} ) current
The current of the sum of I ₁ and I ₂ is now the resistor R 21 and the transistor Q
_Comes through ₃₀ . That is, the discharge circuit 23 changes to the high impedance state. As a result, the charging of the capacitor C ₂ is promoted and V _CC becomes higher in potential. (Finally rises to 36V.) V _CC is the forward voltage of diode D ₁ , and ZD ₅ , ZD ₆ , ZD ₇ , and ZD
₁₀ , total voltage level of V _F of transistor Q ₁₉ (about 31.6
V) or more, this current path current I ₅ flows, and this current I ₅ causes the transistors Q ₁₇ and Q _{18 to} be turned on. Then, the currents I ₃ and I ₁ both flow through the transistor Q ₁₈ , which turns off Q ₁₂ and Q ₃₀ ,
The variable impedance discharge circuit 23 is the smoothing capacitor.
It is open to C2. While the output current of the transistor Q ₁₅ is supplied to the emitter of the transistor Q _20, supplied by connection illustrated in the transistor Q _25, Q _26, Q ₂₈ or the like the output current of the transistor Q ₁₆ constitute the output circuit.

Since the base current is supplied to the transistor Q ₂₀ by the current I ₅ , the transistors Q ₂₀ and Q ₂₁ are sequentially turned on, and the power supply voltage V _B appears on the line l ₁ . Then, power is supplied to the oscillator circuit OSC via the transistors Q ₂₂ and Q _23, and the frequency signal fo that follows the time constant of the resistor R ₂₁ and the capacitor C ₂₁
Are supplied to the logic circuit 24. Further, power is supplied to the logic circuit 24 via a constant current circuit composed of a Zener diode ZD ₈ , a transistor Q ₂₄ , and resistors R ₁₅ and R ₁₆ . The logic circuit 24 is for changing the timbre. The output signal Vo drives the transistor Q ₂₅ , and the output circuit composed of the transistors Q ₂₆ , Q ₂₇ , Q ₂₈ , and Q ₂₉ operates to output the output signal. Voot is obtained.

A piezoelectric speaker, a magnetic speaker, or the like is connected to the output capacitor C ₀ and continues to ring in accordance with the time width of the calling signal.

Next, the circuit operation when a dial pulse is supplied from one of the phones in parallel to each other to the other phone will be described.

In this case, the diode bridge 21 is supplied with the dial pulse described with reference to FIG. However dial pulse is generated only when the dial is around, the total energy can not sufficiently charge the capacitor C ₁ is smaller, the power supply voltage as indicated by the dotted line in FIG. 4 is a transistor Q _17, Q ₁₈ Base-emitter voltage V
The forward voltage of _BE , diode D ₁ , and the total voltage level up to diode ZD ₇ are not increased. In other words,
If the impedance of the power source becomes low at the time of rising and the power source voltage does not reach a high level, a high energy output voltage cannot be obtained. Then, the transistors Q ₁₇ described above because the rectified voltage does not rise to a predetermined level, Q ₁₈
Cannot be driven to the on state. Therefore, the transistors Q ₂₀ and Q ₂₁ are not driven by the output current of the transistor Q ₁₅ , and the power supply voltage does not appear on the line l ₁ .
The oscillator circuit OSC and the logic circuit 24 do not operate, the output voltage Vo is not obtained, and the output current of the transistor Q ₁₆ is not supplied to the output circuit, so that the speaker does not oscillate.

As described above, the tone ringer circuit to which the present invention is applied generates a sound with respect to a calling signal from the outside and does not detect a dial pulse signal from the inside.

Furthermore, a diode that converts changes in power supply voltage into changes in current
D ₂ to D ₄ are not limited to three, it may be set to any number.

[Field of application]

In the above description, the invention made by the present inventor has been mainly described with respect to a tone ringer which is a field of application which is the background of the invention, but the invention is not limited thereto.

For example, it can be used for a composite IC for a telephone, an intercom, and the like.

〔effect〕

(1) A power supply voltage obtained by rectifying a ringing signal and a dial pulse signal from inside is converted into a binary voltage level by a power supply stabilization circuit having a desired input impedance and a discharge circuit, and Since the oscillating circuit that obtains the ringing tone signal when the rectified output is below a predetermined level is in the non-operating state, no sound is generated by the dial operation except when receiving the reception signal that is the ringing tone, The effect that the dial pulse from the inside can be clearly distinguished is obtained.

(2) Since the input impedance can be integrally set to a desired value in connection with the setting of the resistance value of the discharge circuit when the tone ringer circuit is integrated into an IC, it is not necessary to adjust it by an external component, The effect that the workability at the time is improved is obtained.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. Nor.

For example, the input impedance of the tone ringer circuit can be set to a desired value also by the capacitor C ₁ and the resistor R ₁ shown in FIG.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a tone ringer circuit to which the present invention is applied, FIG. 2 is an input impedance characteristic diagram of the tone ringer circuit when a ringing tone is input, and FIG. 3 is a pulse dialer supplied. Fig. 4 shows the input impedance characteristic diagram of the tone ringer circuit of Fig. 4, and Fig. 4 shows the characteristic diagram of the power supply voltage when the call signal from the outside and the dial pulse signal from the inside are rectified. Fig. 5 shows the resonance. FIG. 6 shows a telephone connection diagram for explaining the occurrence of the phenomenon, FIG. 6 shows a waveform diagram of a ringing signal from the outside, and FIG. 7 shows a waveform diagram of a dial pulse signal generated from the inside to the outside. . 1 ... Switch, 11,11 '... Telephone, 12,12' ... Receiver, 13,13 '... Tone ringer circuit, 14,14' ... Dialer, 15,15 '... Speech network, 21 ... … Rectifier circuit, 22 …… Power supply stabilization circuit, 24 …… Logic circuit, D ₁
~ D ₄ ... diode, Q ₁ ~ Q ₂₉ ... transistor, I ₁ ,
_{I 2, I 3, I 5} ...... current, C ₂ ...... capacitor, _{R A} ...... resistance.

Claims (1)

[Claims] 1. A telephone for generating a ringing tone using a ringing signal input from a line terminal, comprising: (1) a DC blocking capacitor interposed in series with the line terminal; and (2) the line. By interposing in series with the terminal, an input resistance that forms a predetermined series input impedance with the line terminal together with the DC blocking capacitor, and (3) is input via the DC blocking capacitor. A rectifying circuit for rectifying a signal, (4) a smoothing capacitor that generates a power supply voltage by being charged by the rectified output of the rectifying circuit, and (5) connected in parallel to the terminals of the smoothing capacitor,
An impedance variable discharge circuit that forms a low-impedance discharge circuit when the terminal voltage of the smoothing capacitor is below a first level, and forms a high-impedance discharge circuit when the terminal voltage exceeds the first level. (6) A level determination is made as to whether or not the terminal voltage of the smoothing capacitor has reached a second level higher than the first level, and when the terminal voltage reaches the second level, the smoothing is performed. A telephone comprising: an energization control circuit that connects a terminal of a capacitor to a power supply line of a ringing tone generation circuit and deactivates the variable impedance discharge circuit.