JPS60150364A - Telephone set - Google Patents

Abstract

PURPOSE:To attain normal talking by connecting >=2 sets of telephone sets in parallel to a subscriber remote from a telephone station and switching the power to a battery incorporated in a telephone set if a trunk line voltage is decreased due to simultaneous call to always supply a constant voltage to an amplifier. CONSTITUTION:When a handset is hooked off, a station voltage of >=3V is applied to an IC through terminals 27, 28 normally from a trunk line through a hook switch 23, and a voltage divided through resistors 38, 39, 40 is fed to a comparator circuit 41. When the station voltage is decreased by 3V due to simultaneous talking by parallel connection of telephone sets, which voltage is detected by a comparator circuit 41, a transistor (TR) 43 is turned on through a control line 42 to switch the circuit to battery drive and also, a switch 48 is turned off by the control line 44 and a constant voltage circuit 47 is disconnected to prevent that the battery is consumed by the constant voltage. Moreover, the current of the battery 24 is not supplied to the trunk line by means of anti-flow preventing diode 46. Each amplifier is operated normally to hold the talking by a voltage of 2V applied from the battery 24.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a telephone device having an integrated circuit network.

Conventional Structure and Its Problems FIG. 1 shows a telephone device in which a conventional telephone line is integrated into an integrated circuit (IC). Below is the first part about the configuration of this conventional example.
This will be explained with figures.

In FIG. 1, 1 is a telephone device, and 2 is an I
It has been converted into C. 3 is a hook switch, and when the handset is raised, the circuit network is a diode bridge 4° hook switch 3
．． It is connected to a telephone office 6 via a cable 6, and voltage and current are supplied thereto. The voltage supplied from the telephone station 6 is connected to the circuit network 2.
A constant voltage of about 2V is set by a constant voltage power source 7 inside the device, and a receiving amplifier 8 and a transmitting amplifier 9 are driven to perform a telephone conversation via a receiver 10 and a transmitter 11. Kao 12
This is a side noise prevention circuit that uses a resistor and a capacitor.

FIG. 2 is a principle diagram of the constant voltage power supply 7 shown in FIG. 1.13.
14 is a voltage input terminal, which is given high impedance characteristics in AC by a constant current source 15, and by bypassing excess current by a constant voltage circuit 16, 2V is input from the terminal 17.
This constant voltage is supplied to the valley amplifier. Note that 18 is a capacitor for ripple prevention.

Next, the operation of the above conventional example will be explained. In Fig. 1, the output voltage of the busy diode bridge 4 is normally 3V.
~1ov, the constant voltage circuit 7 operates normally,
A voltage of 2V is applied to the amplifiers 8 and 9, and the telephone operates normally.

However, in the above-mentioned conventional example, when two or more telephones are connected in parallel, such as a parent-child telephone, and two or more telephones are in a talking state at the same time, the current is shunted and the voltage applied to the telephones is halved.

At this time, if the subscriber is far from the telephone office, the voltage applied to the IC will decrease to 0.
Since the voltage drops to about 6V to 2V, the constant voltage power supply 7 becomes inoperable, and the amplifiers 8 and 9 stop operating, making it impossible to make a telephone call.

OBJECT OF THE INVENTION The present invention eliminates the drawbacks of the above-mentioned conventional examples.
"Telephone office": A remote subscriber connects two or more telephones in parallel, and even when the central office line voltage drops due to simultaneous calls, the amplifier always remains constant by switching to the built-in battery in the telephone V position. It is an object of the present invention to provide a telephone device that can normally communicate by supplying voltage (for example, 2V).

Structure of the Invention The telephone device of the present invention includes a constant voltage circuit that generates a constant voltage using a voltage supplied from a central office line, and a backup value and a value of the voltage supplied from the central office line, in an IC constituting a circuit network of the telephone. a comparison circuit that compares the value of the voltage supplied from the backup battery; a first switch circuit that disconnects the constant voltage/voltage circuit from the circuit network; and a second switch circuit that disconnects the backup battery from the circuit network. A switch circuit is built-in, and when the voltage of the station line falls below a predetermined value, the first and second switch circuits are operated to connect the backup battery to the circuit network and connect the constant voltage circuit. It is configured to be separated from the circuit network.

DESCRIPTION OF THE EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the power supply circuit inside the IC. In Fig. 3, 21 and 22 are connection input terminals for the office line, 23 is a fusokusui nochi, a 24-digit backup battery (approximately SV),
25. 49 is a capacitor for removing ripples, and 26 is a contact that is turned ON during a call. In this actual gun example, a hook switch is used, but other circuits are used to control the voltage applied during a call. A terminal may also be used. 27, 28, 29, 3
0°31.50 is the input/output pin of the IC. 32.33
is a current limiting resistor, 34 is a transistor, and 35 is a current limiter.
) A disconnection transistor is used to connect the battery 24 only during a call when the hook switch 26 is connected.

36.37 is a voltage dividing resistor for reference voltage, 38° 39.40 is a voltage dividing resistor for local voltage, 41 is a comparison circuit between local voltage and battery voltage, and transistor 4 is used to apply battery power when the local voltage drops.
It controls a control line 42 for turning on the switch 3, and an irises-to-bow line 44 for controlling a switch 48 for disconnecting the constant voltage circuit. 45 is a constant current source, 46 is a reverse current prevention diode, 4
7 is a constant voltage circuit.

Next, the operation of the above embodiment will be explained. In Fig. 3, when the handset is raised, a station voltage of usually 3V or more is applied from the station line through the hook switch 23 to the terminal 27 and 28.
applied to C. This voltage is divided and applied to the comparison circuit 41 through resistors 3B' and 39.40. At the same time, the hook switch 26 is turned ON, and since the battery voltage is applied to the transistor 34 through the terminal 30° resistor 32, the transistor 34 is ONL, and the transistor 35 is also ONL through the resistor 33, so that the voltage from the battery 24 is applied to the transistor 35. It is applied as a reference voltage to the comparator circuit 41 through resistors 36 and 37. Comparison circuit 41 compares the reference voltage and local normal pressure, and if the local voltage is 3V or more, control line 42
turns the transistor 43 off (orF)L, and the control line 4
4, the system note 48 is turned on and a constant voltage of 2V is supplied to each amplifier from the station power supply to enable a telephone conversation.

At this time, when the telephones are connected in parallel and simultaneous calls are made, the local voltage increases to 3.
Since the voltage applied by the resistors 38, 39, and 40 drops below v, the comparison circuit u41 detects this voltage and turns on the transistor 43 through the control line 42 to switch to battery drive. Switch 4 by Ii control unit 44
8 is turned off to disconnect the constant voltage circuit 47 and prevent the battery from being consumed by the constant voltage circuit. At this time,
The voltage of the battery 24 is dropped by the transistor 36.43 to a voltage of about 2V. Furthermore, the current from the battery 24 cannot be supplied to the office line due to the backflow prevention diode 46. Due to the 2V voltage supplied by the battery 24, each amplifier operates normally and maintains a call.

Note that the comparison circuit 41 is connected to the hook switches 23 and 26 when the handset is disconnected when the central office line is not connected or during transportation, etc.
In order to avoid consuming the battery even if the voltage is 0.6V or less, transistor 4
It is necessary to have a function to turn off the transistor 3, but this can be easily detected because the transistor cannot turn on when the snow pressure is less than 0.6V.

Further, the battery disconnection circuit composed of the transistor 35 is
This is necessary to prevent current from flowing through the resistors 36 and 37 and draining the battery 24 when the telephone is not in use. However, this circuit is unnecessary if a mechanical contact 51 similar to a hook switch can be used, as shown in FIG.

Effects of the Invention The present invention has the above-described configuration, and provides the following effects. In other words, in an IC-based telephone circuit network, when the voltage applied to telephones far from the central office is low, or when two or more telephones are connected in parallel, the power is limited by the IC process. Even when the operating voltage is lowered, calls can be made by using a backup battery to maintain the operating voltage of the IC.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a telephone communication circuit section of a conventional telephone device in which the circuit network is integrated into an IC, Fig. 2 is a principle diagram of a constant voltage power supply of the circuit of Fig. 1, and Fig. 3 is an example of an embodiment of the present invention. FIG. 4 is a circuit diagram of a power supply circuit of a telephone device, and is a circuit diagram of a main part of another embodiment of the present invention. 23,'26...-hook switch, 24...
・Backup battery, 32, 33, 36, 37, 3
8゜39.40・-cart'1゛, 34, 35, 4
3... Transistor, 41... Comparison circuit, 4
6... Constant current source, 46... Backflow prevention diode,
47... Constant voltage circuit, 48... Switch. Agent's name Benf! JJ player Toshio Nakao 11 or 1 person Figure 1 Figure 3 Figure 4 Figure 1

Claims (1)

[Claims] The circuit network of the telephone is composed of integrated circuits, and also includes a constant voltage circuit that generates a constant voltage from the voltage supplied from the office line to the integrated circuit, and a constant voltage circuit that generates a constant voltage from the voltage supplied from the office line, and A comparison circuit that compares the value of the voltage supplied from the battery, a first Swiss-Sochi circuit that disconnects the constant voltage circuit from the circuit network, and a second switch circuit that disconnects the backup battery from the circuit network. is built in, and when the voltage of the station line falls below a predetermined value, the first and second switch circuits are operated to connect the Ba Noqua Knob battery to the circuit network and to adjust the constant voltage. A telephone device configured so that the circuit is separated from the circuit network.