JPH03186053A - Semiconductor integrated circuit for telephone - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution in a telephone set by incorporating the power source switching circuit of the telephone set in the semiconductor integrated circuit of a dialer. CONSTITUTION:Analog switches 1 and 2 for power source switching are incorporated in the semiconductor integrated circuit of the dialer used for the telephone set. In the off-hook state, the analog switch 1 is ON and the analog switch 2 is OFF to receive the electric power from a telephone line 10. In the on-hook state, on the other hand, the analog switch 1 is OFF and the analog switch 2 ON to switch the power source from the telephone line 10 to the in-telephone battery 9. When the battery 9 in the telephone set is used as the power source, only a key interface circuit 3, a control circuit 4, a memory 5, and an oscillation circuit 6 are supplied with the electric power. Consequently, the circuit constitution of the telephone set is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor integrated circuit used as a telephone dialer.

[Summary of the invention]

The present invention is a telephone dialer semiconductor integrated circuit having a built-in analog switch for switching the power supply of the telephone to either the telephone line or the telephone's internal battery.

[Conventional technology]

Conventionally, the power supply of a telephone has been switched by configuring a switching circuit outside the semiconductor integrated circuit of the dialer of the telephone.

[Problem to be solved by the invention]

However, conventional switching methods use diodes and mechanical switches, which increases the size of the switching circuit.Furthermore, when mechanical switches are used, chattering occurs when switching the power supply, which can adversely affect the phone. be. When a diode is used, there are drawbacks such as a voltage drop corresponding to the threshold voltage and the power source cannot be used effectively.

SUMMARY OF THE INVENTION In order to solve these conventional drawbacks, it is an object of the present invention to provide a semiconductor integrated circuit for a dialer that can switch the power supply of a telephone without using mechanical switches or diodes.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention incorporates an analog switch for switching the power supply into a semiconductor integrated circuit of a dialer used in a telephone set.

[Effect]

By incorporating the telephone's power supply switching circuit into the dialer's semiconductor integrated circuit, it becomes easier to control the circuit inside the telephone, and it also prevents the effects of chattering and T! ! Can use # effectively.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, in the off state, analog switch 1 is on, analog switch 2 is off,
The source is taken from the telephone line 10. Further, when in the on-hook state, the analog switch 1 is set to be in the off state and the analog switch 2 is set to be in the on state. As a result, the power source is switched from the telephone line 10 to the telephone internal battery 9.

When using the telephone battery 9 as a TFI, the key interface circuit 3. Regulation? i1 circuit 4. Memo I7
5 and an oscillation circuit 6 to extend the life of a battery 9 in the telephone.

Note that 7 is an output circuit, 11 and 12 are power lines,
13 is a signal line.

In the embodiments described above, there is no need to add a power supply switching circuit to the telephone.

〔Effect of the invention〕

According to the present invention, the circuit configuration of the telephone set can be reduced by incorporating the TA switching circuit into the semiconductor integrated circuit of the dialer as described above. It also saves material costs that would have been used for an external power supply switching circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a semiconductor integrated circuit of a dialer used in a telephone according to the present invention.・Analog switch 2 Analog switch 2 ・Telephone internal battery ・Telephone line

Claims (1)

[Claims] a keyboard interface circuit, a control circuit connected to the keyboard interface circuit, a memory connected to the control circuit, an output circuit connected to the memory, an oscillation circuit connected to the control circuit, and the output. a constant voltage circuit that supplies power to the circuit, the oscillation circuit, the keyboard interface circuit, the control circuit, the memory, and an analog switch connected to the power supply of the constant voltage circuit; the keyboard interface circuit and the control circuit; A semiconductor integrated circuit for a telephone comprising the oscillation circuit and an analog switch connected to a power source of the memory.