JPS62232252A - Telephone set circuit - Google Patents

Abstract

PURPOSE:To obtain a stable telephone set circuit without attenuation of a communication signal by connecting a constant current means, and a parallel circuit comprising a power storage circuit and a logic circuit in series after a line current is rectified and connecting the talking circuit in parallel with the series connection block. CONSTITUTION:After the line current is sbjected to full wave rectification, the power storage circuit 10 and the logic circuit including the storage means are connected in parallel, the parallel connection block comprising the power storage circuit and the logic circuit 1 is connected in series with the constant current means, and a talking circuit 14 including a transmission/reception means and a call means is connected in parallel with the series connection block comprising the constant current means and the parallel connection block. Thus, the voltage fluctuations caused between connection terminals to the subscriber line and between lines after rectification depending on the busy state and the idle state and on the line current and the length of the subscriber line are absorbed by a constant current element 13 to keep the current supplied to a control circuit 9 constant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to telephone circuits supplied with spot power from a subscriber line.

[Conventional technology]

Traditionally, telephone circuits with phone number storage, redial, and speed dialing functions have circuit configurations that require power to be supplied from an external source such as a commercial power source in addition to receiving power from the subscriber line. An example of a conventional telephone circuit of this type that receives power from an external commercial power supply is shown in FIG. 2 and will be described.

In the figure, 21 and 22 are connection terminals with the subscriber line, and 23
．． 24 is a connection terminal to the commercial power supply, 25 is this connection terminal 2
3. A power rectifying and smoothing circuit that rectifies and then smoothes the commercial power from 24; 26 is a logic circuit that includes a storage means connected to this power rectifying and smoothing circuit 25; this logic circuit 26 is connected to a button key interface circuit 27; 028, which is configured to perform telephone number registration, redial control, speed dial control, etc., is a communication circuit including a transmitting/receiving means and a calling means, and is connected to connection terminals 21 and 22. 29 is a communication circuit control line.

[Problem that the invention seeks to solve]

The conventional telephone circuit described above has a circuit configuration that requires an external power supply such as a commercial power supply, so there is a problem that the telephone cannot be used in the event of a power outage to the commercial power supply. However, there was a problem in that it was cumbersome to connect to a commercial power source.

Furthermore, it has the disadvantage of constantly consuming power from the commercial power supply even when not talking, making it uneconomical.

[Means for solving problems]

In the telephone circuit of the present invention, a power storage circuit and a logic circuit including a storage means are connected in parallel after full-wave rectification of a line current, and a parallel connection block of the power storage circuit and logic circuit is connected after the constant current means. are connected in series, and a communication circuit including a transmitting/receiving means and a transmitting means is connected in parallel to the series connection block of the constant current regulating means and the parallel connection block.

[For production]

In the present invention, a constant current element absorbs and controls voltage fluctuations that occur between connection terminals with a subscriber line and between rectified lines during a call and in an idle state, depending on the magnitude of the line current and the length of the subscriber line. Keep the current value supplied to the circuit constant.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of a telephone circuit according to the present invention.

In the figure, 1 and 2 are connection terminals with the subscriber line, 3.4,
Reference numeral 5.6 denotes a bridge-connected diode element, which is connected so as to perform full-wave rectification of the voltage applied between the connection terminals 1 and 2. 7 and 8 are these diode elements 3 to 6
These are the high potential side and low potential side of the line after full wave rectification. 9 is a control circuit, and this control circuit 9 is a power storage circuit 10.
and a logic circuit 11 including a memory means connected in parallel to the power storage circuit 10 and a pushbutton key interface circuit 12;
is configured to perform telephone number registration, redial control, speed dial control, etc. via the button/key interface circuit 12.

Reference numeral 13 denotes a constant current element constituting a constant current means, which has the function of limiting the current flowing into the control circuit 9 to a constant value (2 mA or less) at which the exchange does not detect a loop. The constant current element 13 is connected after the line current is full-wave rectified by the diode elements 3 to 6, and a parallel connection block of the power storage circuit 10 and the logic circuit 11 is connected in series to the constant current element 13. There are n. Reference numeral 14 denotes a communication circuit including a transmitting/receiving means and a transmitting means, and this communication circuit 14 is connected in parallel to the series connection block of the constant current element 13 and the parallel connection block of the power storage circuit 10 and the logic circuit 11. . 15 is a communication circuit control line.

Next, the operation of the embodiment shown in FIG. 1 will be explained. First, the function of the constant current element 13 will be explained. The telephone circuit shown in FIG. In order to receive power supply, a voltage drop occurs due to the resistance of the subscriber line itself and the line current, and the voltage applied between connection terminal 1 and connection terminal 2 with the subscriber line is fluctuate. That is, the voltage between the connection terminals 1 and 2 and the voltage between the high potential side 7 and the low potential side 8 of the line after rectification vary depending on the magnitude of the line current and the length of the subscriber line.

However, since the constant current element 13 absorbs this voltage fluctuation and maintains the current value supplied to the control circuit 9 at a constant value, the voltage applied to the control circuit 9 can be set to a constant value, resulting in a stable operating telephone circuit. can be realized. Also, when the call circuit 14 is in the middle of a call, it has a low resistance (2000 to 300
0), the voltage drop in the communication circuit 14 is higher than the voltage required for the constant current element 13 to perform its constant current function (approximately IV) and the voltage required for the logic circuit 11 to operate. The sum of the voltage (approximately 2V) is also sufficiently large, so that the control circuit 9 operates sufficiently stably.Next, by configuring the logic circuit 11 with eight CMO elements, it is possible to lower the operating voltage. Furthermore, since the current consumption can be kept extremely low (approximately 1 μA per gate), the control circuit 9 can consume extremely little power. In addition, the constant current element 13
The control circuit 9 can be made highly resistant to audio and other alternating current signals.

〔Effect of the invention〕

As explained above, according to the present invention, after rectifying the line current, the constant current means and the parallel circuit of the power storage circuit and the logic circuit are connected in series, and the communication circuit is connected in parallel to this series connection block. Even though the voltage applied to the leakage of the connection terminal with the subscriber line fluctuates significantly during a call and in an idle state, the voltage fluctuation is absorbed by the constant current means, and the AC signal is On the other hand, the control circuit can be made to have a high resistance, and a stable telephone circuit without attenuation of communication signals can be realized, so the practical effects are extremely large.

Further, it is extremely effective in that it is possible to realize a high-performance telephone circuit having a telephone number storage function, a redial function, a speed dial origination function, etc., which can be used regardless of a power outage state of the commercial power supply.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a telephone circuit according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional telephone circuit. 3-6・**a diode element, 9...-φ control circuit,
10...Power storage circuit, 11...Logic circuit, 1
3... Constant current element, 14... Call circuit.

Claims (1)

[Claims] In a telephone circuit that receives power from a subscriber line, a power storage circuit and a logic circuit including a storage means are connected in parallel after full-wave rectification of the line current, and the power storage circuit and logic circuit are connected in parallel after the constant current means. A telephone circuit characterized in that a parallel connection block is connected in series with the constant current regulating means and the parallel connection block, and a communication circuit including a transmitting/receiving means and a transmitting means is connected in parallel to the series connection block of the constant current regulating means and the parallel connection block.