JPS61101149A - Telephone set - Google Patents

Abstract

PURPOSE:To prevent a telephone set from ringing together in dialing a telephone number by providing a discharge circuit controlling the leading of a power supply voltage so that the impedance is low when a power supply voltage is lower than a prescribed voltage and high when the voltage is a prescribed value or over thereby placing a tone ringer to the state that the power voltage rises to a sufficient high potential. CONSTITUTION:A dial pulse is fed to a diode bridge 21. The dial pulse, however, is generated during dialing and the total energy is small, than a capacitor C1 is not charged sufficiently. That is, the impedance of power supply goes to a low impedance at trailing and since a rectified voltage does not rise to a prescribed level, transistors Q17, Q18 are not brought into ON-state. Then neither an oscillation circuit 23 nor a logic circuit 24 is not activated. No output voltage V0 is obtained and no output current of a transistor Q16 is fed to the output circuit, then no oscillation is outputted from the speaker.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a telephone equipped with a tone ringer.

[Background technology]

[Integrated Circuit Application Handbook J (June 30, 1981)
First edition published by Asakura Shoten Co., Ltd., P599-P6
00), it is stated that intensive research is being conducted on the integration of telephone circuits into semiconductor integrated circuits.

The inventors of the present application have also conducted various technical studies regarding telephones in view of the above-mentioned technical trends.

As a result, when using multiple phones in parallel, one
I noticed that when dialing on the 1110″ii handset, other phones would resonate.In particular, with phones equipped with a phone IC commonly called a tone ringer, when an incoming call comes from outside, It has been revealed that it is difficult to distinguish between emergency pressures because the sound and the resonance sound caused by dialing on one side of the phone are almost the same.The above phenomenon is noticeable in phones that use an IC, and The reason was also clarified by the inventor as shown in Q) below.

Hereinafter, the occurrence of the resonance phenomenon, etc. will be sequentially explained with reference to FIGS. 1 to 3.

The telephone exchange shown in Figure 1
ange) 1 to 2 telephones 11. 11 is T
They are connected in parallel via the ip and lin terminals 2.3. Since the two telephones 11.11 have the same circuit configuration, only the telephone 11 will be described, and the description of the other telephone 11 will be omitted by adding a dash to the same reference numeral.

It is assumed that sw, , sw are 7-way switches, and when the 7-way switch is on, in other words, when waiting for a call, the switching state is as shown in the figure, and when the handset 12 is lifted, the state is switched to the state shown by the dotted line.

On the other hand, the calling signal P from the exchange 1 is a 16H2 signal as shown in FIG.
After the remainder, a 16H2 signal is generated again for 1 second, and this is sent to the tone ringer as a calling signal P.
applied to circuit 13. Then, the tone ringer circuits 13 and 13' in the telephone set 11 and 11 operate at the same time, producing exactly the same ring tone at the same time, and when the receiver 12 is lifted, the switch SW1. SW2 changes to the switching state as shown by the dotted line, and the dialer (Pulse Dialer)
) 14. Speech Network (5peech Ne
work) 15 is operated, and a call is made.

Next, the circuit operation during transmission will be described.

When you lift the handset 12 of the telephone 11, the switch s
,,sw, are switched as shown by the dotted lines, and the switches sw,
, swt remains a solid line, and the pulse dialer (
Pulse Dialer) 14 includes a dial (which may be a rotary type or a block type), a memory that stores the dialed numbers, and a pulse generator that generates pulses according to the information stored in the mesori. It consists of When, for example, 031 is dialed by operating the dialer 14, a dial pulse PA having a waveform as shown in FIG. The tone ringer 13 is driven by the pulses generated by the pulse dialer 14, causing resonance. That is, the tone ringer circuit 13.13 integrated into an IC is T
The signal at the ip-Ring terminal is full-wave rectified and then smoothed.
While this rectified and smoothed voltage is supplied, the oscillation circuit is driven,
I am getting an oscillating tone (ringing tone). However, the quality of the oscillated sound does not differ between the calling signal shown in FIG. 2 and the dial pulse PA shown in FIG. 3. The difference between the two is the interval between two signal generation, but one is 2 s
ec is σ), while the other is, for example, 0.8 sec (
(depending on the f-earr), the difference in audibility was not clear, and the above problem was manifested.

[Purpose of the invention]

The purpose of the invention is to create a tone ringer that is integrated into a semiconductor circuit.
An object of the present invention is to provide a telephone having a circuit that can clearly receive a ringing tone from the outside and can eliminate resonance generated when dialing in parallel-connected telephones.

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

[Summary of the invention]

A typical example of the invention disclosed in this application is briefly described below.

That is, 'rip' charges the capacitor C1 with the rectified output of the signal supplied from the Ring terminal and supplies the power supply V. C is started up with a certain time constant. This power supply ■
. At the rise of C, initially (that is, the power supply voltage V
(When cc does not reach a predetermined level), the impedance of the discharge circuit provided at the input section of the IC is kept low, so that the charge stored in the capacitor C7 is easily discharged to, for example, the ground potential (ground).

Next, despite being in this state, Tip.

A signal is intermittently supplied to the Ring terminal, and as a result, charging of the capacitor progresses, and when the power supply voltage VCC reaches a predetermined level, the impedance of the discharge circuit is switched to a high state, and the charge stored in the capacitor CI is discharged. is suppressed, and the power supply voltage V. , to start up rapidly. Furthermore, V. When C reaches a sufficiently high potential, the discharge circuit is automatically rendered inactive and the oscillation circuit 23. By operating the logic circuit 24 etc. to drive the tone ringer, K is provided with a function such as 6 or more. When a dial pulse from one of the telephones connected in parallel is input to the other telephone, the dial pulse Since the energy possessed by the capacitor is extremely small compared to the regular calling pulse, the capacitor 〇 is not charged due to the action of the discharge circuit, and the vcC does not stop to the required value.
Therefore, the tone ringer can be made inactive.

That is, intermittent call pulses from the central office are Tip +
Tone ringer only works when Ringic is added.

In this way, it is possible to achieve the object of the present invention, which is to completely prevent one telephone from resonating when dialing one telephone in parallel-connected telephones.

〔Example〕

Next, an embodiment of a telephone to which the present invention is applied will be described with reference to FIGS. 1 and 2.

Furthermore, reference should also be made to FIGS. 4 and 5, which illustrate the causes of resonance. The feature of this embodiment is that, as mentioned above, attention is paid to the magnitude relationship between the energy of the external calling signal and the internal dial pulse. The purpose is to prevent 0 from rising sufficiently.

First, a description will be given of the time when a call signal is received from the outside.

During reception, a received signal as shown in FIG. 4 is supplied to terminals 1 and 2 shown in FIG. 1, and is rectified by a bridge circuit 21 comprised of transistors Q and Q4. In this case, the rectified output is capacitor C2
With the time constant of , it rises with a rise characteristic as shown by the solid line in FIG. And transistors Q, ~Q6. The Zener diodes ZD, -ZDa and the resistors R8 to R3 operate as a power supply stabilizing circuit 22, and also perform an overvoltage protection operation.

Next, the operation of the discharge circuit 23, which plays an important role in the present invention, will be explained. A calling signal is supplied to the Tip+Ring terminal, and as a result, the capacitor 〇! is charged and vcC gradually rises, first transistor Q+4
．． ) Ransistor QI5+Q+^.

An initial current I, flows through the resistor R, %R, , into the pace of the transistor Q +t. Then transistor Ql!
operates in the on state, and an initial current flows through the transistor Q, which constitutes the current mirror circuit, and this current flows through the transistor Q12. This becomes the base current of the transistor Qs+ via the resistors R, o, R, .

Also, a current flows through the transistor Q+b, and the sum of the currents I, , I is the transistor Qs+resistor R.
Flows to ground via □. That is, at the initial rise of vcC, the current is 11°1, . 1. is flowing, making it difficult for capacitor C2 to charge.

Next, charging of capacitor 〇 progresses, and VCC power rises') (L +L) (Rt+ +R22) +VBE
Q31 Voltage 3■, +vBEQ, required for chisel pressure to turn on transistors Q and o. If it becomes more than (v,
+sp-i, t-dos Dt, Ds, D4 forward direction voltage), the current sum of current 11 and diode D
t-D4゜transistor Q,. It becomes K as if flowing through it. In other words, the discharge circuit 23 goes into a high impedance state and changes by ρ. As a result, charging of the capacitor CI is promoted, and vcC becomes even higher. (Finally 3
It rises to 6V. ) vcc is the forward voltage of diode D, and further ZDs +
ZDa, ZDt, Zoo, 'p
;y 7') S IQ le ') VF ') fig'
When the KJ voltage exceeds the N level (approx. 1.6 V), this current path current flows, and this current error causes the transistor Q l? IQ+s operates in the on state. Then, currents I, , I, both flow through transistor Q+i, and as a result, Q□ and Qaa are turned off. On the other hand, the output current of transistor Q+s is transistor Q,. is supplied to the emitter of transistor Q+
The output current of a constitutes the output circuit of the transistor Qzs
+ O26+ Qta etc. are supplied by the shown connection, transistor Q! . Since the base current is supplied by the current generator, the transistor Q2G+O21 and the transistor Q2G+O21 are sequentially turned on, and the power supply voltage 2 appears on the line 1. Then, power is supplied to the oscillation circuit (O8C section) 23 via the transistor Qu+Qhs, and a frequency signal fO according to the time constant of the resistor R21 and the capacitor Cwt is supplied to the logic circuit 24.

In addition, Zener diodes ZD, h transistor Q24.
Power is supplied to the logic circuit 24 through a foot current circuit composed of resistors R, , , R, . logic circuit 24
is for changing the tone, and its output signal ■. The transistor Q1m is driven by
The output circuit composed of 26 + Qty + Qhs + Q2G operates to obtain an output signal Voot.

Note that a piezoelectric speaker, a magnetic speaker, or the like is connected to the output capacitor C0, and continues to sound in accordance with the time width of the calling signal.

Next, the operation of the circuit will be described when a dial pulse is supplied from one of the telephones in a parallel relationship to the other telephone.

In this case, diode bridge 21 is supplied with the dial pulse described in connection with FIG. However, the dial pulse occurs only when the dial is rotating, and its total energy is small, so it cannot sufficiently charge the capacitor C0, and as shown by the dotted line in FIG. Base-emitter voltage V,8, forward voltage of diode D,
Further, the voltage does not rise to the voltage level of the sum up to the diode ZD. In other words, if the impedance of the source becomes low at startup, and the supply voltage does not reach a high level, a high-energy output voltage will not be obtained. Then, since the rectified voltage does not rise to a predetermined level, the above-mentioned transistor Q I? IQ+s cannot be driven to the on state. Therefore, the output current of transistor Q +s causes transistor Qzo+ Q! I is not driven (no power supply voltage appears on line 11, oscillation circuit 23 and logic circuit 24 do not operate,
Output voltage ■.

Also, since the output current of transistor Q+6 is not supplied to the output circuit, oscillation does not appear from the speaker.

As described above, the tone ringer circuit to which the present invention is applied generates sound in response to a ringing signal from the outside, and does not sense a dial pulse signal from within.

〔effect〕

fi+ Rectifies the received signal that becomes the ringing tone and the dial pulse signal from the inside, and the rectified output reaches a predetermined level μ
Since the oscillation circuit that obtains the audio signal is inactive when the dial is turned on, no sound is generated by dial operation except when receiving a reception signal that becomes a ring tone, and the ring tone from the outside and the dial from the inside are not activated. This has the effect that it can be clearly distinguished from pulses.

The invention made by the present inventor was specifically explained based on the working examples, or the present invention is not limited to the working examples and can be modified in various ways without departing from the gist thereof. Needless to say.

For example, the number of diodes D2 to D that convert changes in power supply voltage to changes in current is not limited to three, and may be set to any number.

[Application field]

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

For example, it can be used in composite ICs for telephones, intercoms, and the like.

[Brief explanation of the drawing]

Fig. 1 shows a circuit diagram showing an embodiment of the tone ringer circuit to which the present invention is applied, and Fig. 2 shows the characteristics of the power supply voltage when an external calling signal and an internal dial pulse signal are rectified. Fig. 3 shows a telephone connection diagram to explain the occurrence of resonance phenomenon, Fig. 4 shows a waveform diagram of a calling signal from the outside, and Fig. 5 shows a signal directed from the inside to the outside. This figure shows a waveform diagram of the dial pulse signal generated. 1...Switchboard, 11.11'...Telephone, 12.1
2'...Handset, 13.13...Tone ringer circuit, 14°14...Dialer-115, 15...Speech network, 21...Rectifier circuit, 22...
Power supply stabilization circuit, 23... Oscillation circuit, 24... Logic circuit, D, ~D. ...Diode, Ql ~ Qu...Transistor, I
, II2, 1. , I... Current, C2... Capacitor, Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. When the power supply voltage is lower than a predetermined voltage, it becomes a low impedance state and when the power supply voltage exceeds the predetermined voltage, it switches to a high impedance state.Equipped with a discharge circuit that controls the rise of the power supply voltage, and the power supply voltage is at a sufficiently high potential. A telephone characterized in that a tone ringer is driven in a standing state.