JPH08125785A - Telephone set - Google Patents

Abstract

PURPOSE: To effectively utilize the backup power supply by supplying power supply voltage, line voltage and backup voltage to the enable input of a microcomputer and controlling a switch element by these voltages. CONSTITUTION: Because a switching transistor TrQ1 is turned on when power supply voltage + VD or line voltage + VL exists, the off-hook terminal B of a hook switch 3 is grounded and the terminal becomes 'L'. An enable input port becomes 'H' at the time of the on-hook of a receiver and becomes 'L' at the time of the off-hook. Because the TrQ1 is turned off when both of the voltage + VD, + VL do not exist, the state of the input port always remains 'H' as it is. At this time, a CPU 1 does not perform the whole operation and backs up an internal memory from a backup powr source. As a result, the voltage + VL or the voltage + VB of the backup posr source back up till they become the reset voltage of an IC 2 for voltage level detection or below. Therefore, the unnecessary power consumption of the backup power source can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone, and more particularly to a telephone which effectively utilizes a backup power source.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram of an example of a conventional telephone, in which 1 is a telephone operation control microcomputer (hereinafter referred to as CPU), and an operating power supply voltage (for example, +).
9V), if any of the power supply voltage + VD, line voltage + VL, and backup power supply voltage + VB, the operating state when the enable input port HS is logic "L", logic "H"
At that time, the operation is stopped. The diodes D1, D2, D3 are connected to the enable input port HS of the CPU1.
And power supply voltage + VD, line voltage + VL via resistor R1
, While the backup power supply voltage + VB is supplied,
The common terminal C of the hook switch 3 is connected. The hook switch 3 switches to the B side when the receiver (not shown) is lifted (when off hook), and switches to the A side when the receiver is left on (on hook). The A terminal of the hook switch is open and the B terminal is grounded. The output of the voltage level detection IC 2 is supplied to the reset input port RESET of the CPU 1. The voltage level detection IC 2 is supplied with the power supply voltage + VD, the line voltage + VL, and the backup power supply voltage + VB via the diodes D1, D2 and D3, and is reset when all of these voltages fall below a predetermined voltage (for example, 2.1V). This is for outputting a voltage to reset the CPU 1 to prevent malfunction.

The conventional telephone having the above structure is in a state where the power source is not connected and the line connector is not connected for some reason, that is, the power supply voltage + VD and the line voltage + V.
When L is not available, if the hook switch 3 is on the A side with the handset held, the backup power supply voltage + V will be applied to the enable input port HS of the CPU 1.
Since B is supplied, the CPU 1 does not perform the entire operation, but its internal memory is backed up by being supplied with the backup power supply voltage + VB. Moreover, when the handset is lifted, the hook switch 3 is switched to the B side, and the CPU 1
Since the enable input port HS of 1 is grounded via the hook switch 3 and becomes a logical "L", the backup power source of the CPU 1 operates as an operating power source, and the entire CPU 1 is in an operating state. Therefore, while the off-hook state continues, the entire CPU1 remains in the operating state until the voltage + VB of the backup power source falls below the reset voltage of the CPU1.

[0004]

As described above, in the above-mentioned conventional telephone, the CPU can be operated by utilizing the line voltage even in the case of power failure, but when the telephone is forgotten to be connected to the telephone line. , The backup power supply that originally only needs to back up the internal memory of the CPU when a power failure occurs,
If the CPU as a whole is operated as described above, the power supply capacity thereof is additionally consumed, which is not preferable. The present invention
An object of the present invention is to provide a telephone that solves the above-mentioned conventional problems and can effectively utilize a backup power supply.

[0005]

A telephone according to the present invention comprises:
In a telephone having a CPU for operation control, the CPU
A power supply voltage, a line voltage, and a backup power supply voltage are supplied to the enable input of, and a hook switch is connected, and a switch element controlled by the power supply voltage and the line voltage is connected between the off-hook terminal of the hook switch and the ground. It was done. Further, in the above configuration,
A first voltage level detecting means for inputting a power supply voltage, a line voltage and a backup power supply is provided, and an output of the first voltage level detecting means is supplied to a reset input of the CPU. Further, in the above configuration,
A second voltage level detecting means having a backup power supply as an input is provided, and an output of the voltage level detecting means is applied as a control voltage of the switch element.

[0006]

When the power supply voltage and the line voltage are unavailable, the operation control CPU is prevented from operating even if the receiver is off-hook, and the backup power supply is C
Only the internal memory of the PU is supplied. Therefore, the backup time of the backup power supply is longer than in the conventional case, and it can be effectively utilized.

[0007]

1 is a circuit diagram of an embodiment of a telephone according to the present invention. The same components as those of FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted. The circuit of FIG. 1 has the following configuration added to the circuit configuration of FIG. That is, the B terminal of the hook switch 3 is grounded via the switching transistor Q1. At the base of the switching transistor Q1, diodes D4 and D5 and a resistor R are provided.
Power supply voltage + VD and line voltage + VL are supplied via 2.

In the above structure, when there is the power supply voltage + VD or the line voltage + VL, the switching transistor Q1 is turned on, and the off-hook terminal B of the hook switch 3 is grounded to "L". Therefore, the enable input port HS is "H" when the receiver is on-hook and "L" when the receiver is off-hook. Next, when there is no power supply voltage + VD and no line voltage + VL, the switching transistor Q1 is turned off, so that the state of the enable input port HS is always "H" during both on-hook and off-hook. Therefore, in this case, the CPU 1 does not perform the entire operation, but the internal memory is in a state of being backed up by the backup power supply. Line voltage + VL or backup power supply voltage + VB
However, the internal memory is backed up until the reset voltage (for example, 2.1 V) of the voltage level detecting IC 2 as the first voltage level detecting means becomes lower than the reset voltage. As described above, in the circuit shown in FIG. 1, even when the handset is lifted (off-hook) during a power failure or when the connector is not connected to the telephone line, operations other than the memory holding operation of the CPU are prohibited. Unnecessary power consumption of the backup power supply can be suppressed and memory backup time can be saved.

FIG. 2 is a circuit diagram of another embodiment of the telephone according to the present invention. This circuit has the same configuration as the circuit of FIG. 1 and further includes a power supply voltage + VD, a line voltage + VL,
A voltage level detection IC as a second voltage level detection means which receives the backup power supply voltage + VB as an input and generates an output when the input voltage becomes a predetermined value (eg, 2.7 V) or less.
4 is provided and the output of the voltage level detecting IC 4 is added to the base of the switching transistor Q1.

When the AC adapter of the telephone is plugged into an outlet and has a power source, or when the telephone is connected to the telephone line and is off-hook (there is a line voltage + VL), or the backup power source is the voltage level detecting IC4. When the voltage is equal to or higher than the reset voltage, the output of the diode D4 or D5 or the voltage level detection IC 4 becomes "H". Therefore, the switching transistor Q1 is turned on, and when the hook switch 3 is on the B side, the enable input of the CPU 1 is performed. The port HS becomes "L", and the CPU 1 is in the whole operating state. On the contrary, when there is no power source and is not connected to the telephone line and the backup power source is 2.7V or less, the diodes D4 and D5, the voltage level detection IC
Since the outputs of all 4 are "L", the switching transistor Q1 is turned off, and the enable input port HS of the CPU 1 is "H" regardless of whether it is on-hook or off-hook.

When the enable input port HS is "H", the CPU 1 is in a mode for backing up only the internal memory, and the output of the voltage level detecting IC 2 is "L".
Up to 2, 1 V, the backup power supply backs up to the internal memory. As described above, in the circuit shown in FIG. 2, when there is no external power supply, there is no line voltage + VL, and the backup power supply is lower than the reset voltage of the CPU1, the CPU1 is forcibly turned on hook and the CPU1 operates as a whole even if the handset is lifted. No, only backup the internal memory. Therefore, the backup time becomes long. That is, if the backup power supply voltage drops to the reset voltage even when the handset is lifted (off-hook) during a power failure or when the connector is not connected to the telephone line, C
Since operations other than the memory holding operation of the PU are prohibited, unnecessary power consumption of the backup power supply can be suppressed and the memory backup time can be saved.

[0012]

According to the telephone of the present invention, even if the receiver is lifted (off-hook) during a power failure or when the connector is not connected to the telephone line, operations other than the memory holding operation of the CPU are prohibited. , The unnecessary power consumption of the backup power supply can be suppressed and the memory backup time can be saved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of a telephone according to the present invention.

FIG. 2 is a circuit diagram of another embodiment of a telephone according to the present invention.

FIG. 3 is a circuit diagram of an example of a conventional telephone.

[Explanation of symbols]

 1 CPU for operation control 2 IC for voltage level detection 3 Hook switch 4 IC for voltage level detection + VD Power supply voltage + VL Line voltage + VB Backup power supply Q1 Switching transistor

Claims (3)

[Claims] 1. A telephone having an operation control microcomputer, wherein a power supply voltage, a line voltage and a backup power supply voltage are supplied to an enable input of the microcomputer and a hook switch is connected.
A telephone characterized in that a switch element controlled by a power supply voltage and a line voltage is connected between the off-hook terminal of the hook switch and the ground. 2. The telephone according to claim 1, further comprising first voltage level detecting means for inputting a power supply voltage, a line voltage and a backup power supply, and the output of the first voltage level detecting means is reset by a microcomputer. A telephone configured to feed the input. 3. The telephone according to claim 1, further comprising a second voltage level detecting means having a backup power supply as an input, and applying an output of the second voltage level detecting means as a control voltage of a switch element. Phone configured in.