JPH02288756A - Multi-function telephone set - Google Patents

Abstract

PURPOSE:To surely prevent occurrence of an event of current flowing from a backup power supply of a microcomputer by raising a line voltage by a prescribed voltage with a voltage increase means at the speaker reception mode and constituting so that the level is nearly equal to the line voltage at the handset mode. CONSTITUTION:When a speaker reception button is depressed, an L level signal appears at an output 81 of a speaker reception control circuit 8 and the reception amplifier 7 is in the operating mode. In this case, since a diode D2 is energized, a diode D1 connects to a telephone line 21 and the line voltage is increased by a forward voltage Vf of the diode D1. Thus, the voltage applied to a power terminal 111 of the microcomputer 11 from a supply circuit 10 is not lowered but kept to a sufficient voltage, then no current flows from a backup power supply 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multifunctional telephone device that includes a microcomputer equipped with a bank amplifier power supply and a speaker that operates only with line voltage.

(Prior art) Due to recent advances in science and technology, telephone devices that used to be focused solely on exchanging calls with the other party's terminal are now equipped with a variety of functions. . For example, the answering function, answering function, one-touch dialing function, redialing function, etc. are included, and the microcomputer to control these functions and the backup power supply to power up the microcomputer are located within the main body of the device. has been implemented.

In a conventional multifunction telephone device that includes such a microcomputer and a speaker that operates only on line voltage, the line voltage is lower in the speaker listening mode than in the handset mode. This is because the receiver amplifier consumes a large amount of current in the speaker receiver mode.

However, despite the fact that the line voltage is different between the handset mode and the speaker listening mode, conventional multifunction telephone devices do not have a means to switch the telephone line to support both modes. Ta.

(Problem that the invention aims to solve) For this reason, since the line voltage decreases when the speaker is in listening mode, the power supply voltage supplied to the microcomputer's power supply terminal also decreases, and as a result, current flows from the bank-up power supply of the microcomputer. There was a problem with the leakage.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent current from flowing out from the bank-up power supply by increasing the line voltage by a predetermined voltage using a voltage increasing means during the speaker receiving mode. The purpose of the present invention is to provide a multifunctional telephone device.

(Means for Solving the Problems) In order to solve the above problems, the multifunctional telephone device of the present invention, which includes a microcomputer equipped with a back amplifier power supply and a speaker that operates only by line voltage, is provided with , voltage increasing means is provided for increasing the line voltage by a predetermined voltage from that in the handset mode.

(Function) In the speaker receiving mode, the voltage increasing means increases the line voltage of the telephone line by a predetermined voltage.

Ideally, the line voltage is increased to approximately the same level as the line voltage in handset mode. This can prevent current from flowing out from the backup power supply added to the microcomputer.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The drawing is a block diagram showing the electrical configuration of the multifunctional telephone device of the present invention.

In the same figure, the output of the rectifier circuit 1 to which the telephone line 21 is led is led to the power supply terminal 111 of the microcomputer 11 via the power supply circuit 10, and the output of the diode D whose cathode is connected to the power supply circuit 6. connected to the anode.

Further, the output of the power supply circuit 6 is guided to a receiver amplifier 7, and the output of the receiver amplifier 7 is guided to a speaker 9.

On the other hand, the cathode of a diode D is connected to the power supply terminal 111 of the microcomputer 11, and the positive terminal of a backup power supply 12 whose negative terminal is grounded is connected to the anode of the diode D. There is.

Further, the emitter of the switching transistor Q is connected to the anode of the diode D, and the collector of the switching transistor Q is connected to the anode of the diode D.
1 cathode. Further, a resistor R is connected between the base and the emitter. The base of this switching transistor Q1 is connected via a resistor R3 to the collector of a switching transistor Q2 whose emitter is grounded.
The base of the switching transistor Qt is connected to a resistor R4.
, R1 to the output of the power supply circuit 6. Further, a resistor R is connected between the base and emitter of the switching transistor Q2. One end of the resistor R4 (one end on the resistor R9 side) is connected to the anode of a diode D2 whose cathode is connected to the C8 terminal of the receiver amplifier 7, and the C8 terminal of the receiver amplifier 7 is connected to the speaker receiver. Output 81 of control circuit 8
is connected.

Next, the operation of the multifunction telephone device having the above configuration will be explained.

In handset mode, switching transistor Q2
A voltage is applied to the base from the power supply circuit 6 via resistors Ra and R+. Therefore, since the switching transistor Q is turned on, the switching transistor Ql is also turned on, and the diode D is short-circuited from the telephone line.

Next, by pressing the speaker receiver button (not shown), an rLJ level signal appears at the output 81 of the speaker receiver control circuit 8, and is applied to the C8 terminal of the receiver amplifier 7, so that the receiver amplifier 7 enters the operating mode. Become. At this time,
Since the diode D2 becomes conductive, the base potential of the switching transistor Q2 is pulled to the ground potential,
The switching transistor Qffi is switched from an on state to an off state. Therefore, since the switching transistor Q1 is also switched from the on state to the off state, the diode D is connected to the telephone line 21, and the line voltage at this time is the forward voltage (Vf) of the diode D1. It will rise by that amount. As a result, the voltage applied from the power supply circuit 10 to the power supply terminal 111 of the microcomputer 11 is maintained at a sufficient voltage without decreasing, so that no current flows out from the bank-up power supply 12.

(Effects of the Invention) The multifunctional telephone device of the present invention increases the line voltage by a predetermined voltage using the voltage increasing means during the speaker receiving mode, so that the line voltage reaches almost the same voltage level as the line voltage during the handset mode. With this configuration, even in speaker listening mode, a voltage with almost the same potential as in handset mode is applied to the microcomputer's power supply terminal, so it is possible to ensure that a situation such as current flowing out from the microcomputer's bank-up power supply does not occur. can be prevented.

[Brief explanation of the drawing]

The drawing is a block diagram showing the electrical configuration of the multifunctional telephone device of the present invention. 1... Rectifier circuit 6... Power supply circuit 7... Receiving amplifier 8... Speaker receiving control circuit 9... Speaker 11... Microcomputer 12... Backup power supply Q,,Q,...・Switching transistor +DID3
···diode

Claims (1)

[Scope of Claims] 1) In a multi-function telephone device equipped with a microcomputer equipped with a backup power source and a speaker that operates only on line voltage, when the speaker is in listening mode, the line voltage is lowered by a predetermined voltage compared to when in handset mode. A multifunctional telephone device characterized by being provided with voltage raising means for raising the voltage.