JPH03231596A - Subscriber circuit control system - Google Patents

Abstract

PURPOSE:To decrease a drive current of an electronic switch when a terminal equipment is not in use by sending a periodic drive current to one electronic switch when the polarity is noninverting state and sending a continuous drive current to other electronic switch when the polarity is inverted. CONSTITUTION:When the polarity of a DC voltage is noninverting and a normal signal sent from a control section 3 is received, a periodic drive current is sent to 1st and 2nd electronic switches 1a, 1b and when a normal signal and a signal representing the hook-off state are received by the control section 3, the drive current is sent continuously to the 1st and 2nd electronic switches 1a, 1b. When the polarity of the DC voltage is inverted and a reverse signal sent from the control section 3 is received, a continuous drive current is sent to 3rd and 4th electronic switches 1c, 1d.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a control system for a subscriber circuit that uses a thyristor-type electronic switch to reverse the polarity of the line voltage of a DC voltage supplied to a terminal. In order to reduce the drive current, the line voltage of the DC voltage supplied from the power supply circuit to the terminal is reduced by driving and controlling the first to fourth thyristor-type electronic switches inserted in the communication line from the control unit. In a subscriber circuit that inverts polarity, when receiving a normal signal sent from the control unit when the polarity of the DC voltage is in a non-inverted state, the DC voltage in the polarity of the electronic switch is in a non-inverted state. normal switch pulse driving means for sending a periodic driving current to first and second electronic switches connected in a forward direction with respect to the voltage; normal switch continuous driving means for continuously sending a driving current to the first and second electronic switches when receiving a signal indicating that the DC voltage is in a reversed state; While receiving the reverse signal sent from the control unit, the third and fourth electronic switches, which are connected in the forward direction with respect to the DC voltage whose polarity is inverted among the electronic switches, are connected in a continuous manner. The device is configured to include lever switch driving means for sending out a driving current.

[Field of Industrial Application] The present invention relates to a control system for a subscriber circuit that uses a thyristor-type electronic switch (A) to invert the polarity of the line voltage of the DC voltage supplied to the terminal.

A subscriber circuit that interfaces with a terminal such as a telephone in an exchange requires a function to reverse the polarity of the DC voltage sent from the power supply circuit to the terminal when the person on the other end of the conversation responds.

In the past, this polarity reversal was performed using relay contacts, but in recent years this has been replaced by electronic switches such as thyristors to improve reliability and reduce size.

When using a thyristor-type electronic switch, it is necessary to send a voltage in a non-inverted state to the terminal in order to detect off-footer of the terminal even when the terminal is on-footer, that is, when the terminal is not in use. For this reason, drive current continues to flow through some electronic switches even when the terminal is not in use.

The drive current is a small value for one line of light, but since the number of subscriber circuits is very large and it lasts for a long time, it cannot be ignored as a factor that increases the reactive power of the exchange.

Therefore, there is a need for a subscriber circuit control scheme that can reduce the drive current of the electronic switch when the terminal is not in use.

[Conventional technology]

FIG. 4 is a block diagram of a conventional system, and FIG. 5 is a detailed circuit diagram of a thyristor switch.

In FIG. 4, 21a to 21d are thyristor-type electronic switches, among which 21a and 21b are the power supply circuit 22.
An electronic switch (referred to as a normal switch) that operates in the forward direction when the potential of the DC voltage supplied to the terminal becomes normal polarity, with a negative potential on the A line and a positive potential (earth) on the B line. and 21d are electronic switches (referred to as lever switches) that operate in the forward direction when the polarity is reversed. In addition, N1 and NZ are the normal switches 21, respectively.
Drive lines a and 21b, R4 and R2 are drive lines for lever switches 21c and 21d, respectively.

In FIG. 4, when the potential of the DC voltage supplied to the terminal from the power supply circuit 22 has a normal polarity, a normal signal is sent from the control section 23 to the normal switch drive circuit 24. While receiving the normal signal, the normal switch drive circuit 24 connects the drive lines N of the normal switches 21a and 21b.
1 and N2 as a driving potential.

Fig. 5 shows a detailed circuit of the thyristor switch. As shown in Fig. 5 (2), the thyristor switch consists of two transistors, an NPN type transistor TR and a PNP type transistor.
It is composed of an NP type transistor TRz, and is used by connecting a positive potential to the IN side and a negative potential to the OUT side.

Now, when ground, that is, a positive potential is connected to the drive line N, from the drive circuit, the collector current of the transistor TR flows, and a negative potential is applied to the base of the transistor TR2, so the transistor TRz is turned on, and the transistor T.R.
Apply a positive potential from IN to the base of 0. For this reason,
If positive and negative potentials are connected to the IN and OUT sides, both transistors TR, TR2 will continue to be on even if the drive circuit is disconnected.

In the case of FIG. 4, when the terminal is in the on-hook state, the normal switch 21a is connected to the earth (positive potential) on the IN side, but no potential is applied to the OUT side, and the normal switch 21a is 21b has a negative potential connected to its OUT side, but no potential is applied to its IN side. Therefore, the normal switch 21a does not turn on even if earth air is connected to the drive line N1, but T Rr in FIG. 5 turns on when the normal switch 21b connects earth air to the drive line N2. That is, when the normal switch drive circuit 24 sends out driving air, the power supply circuit 22 becomes . A drive current flows through the normal switch 21b due to the battery. When the terminal goes off-hook in this state, TR in the normal switch 2Ib is also turned on, and both transistors TR, TR2 are turned on, that is, the fourth transistor
The normal switch 21b in the figure becomes conductive, and the normal switch 21a also becomes conductive because a negative potential is applied through its terminal.

As described above (while the terminal is off-footer), both normal switches 21a and 21b continue to be in a conductive state even if the drive current disappears.

As described above, when the terminal is in the on-footer state, only a part of the normal switch 21b is turned on by the driving air sent from the normal switch drive circuit 24 to the drive line N2, but the drive current is While earth air is being sent out from the drive circuit 24, it flows to the negative power source of the power supply circuit. The value of this drive current is
For example, the value is about 0.5 mA, but since there are a large number of subscriber circuits and the period of non-use is much longer than the period of use, the reactive power of the exchange during this period cannot be ignored. There is.

Next, when the terminal goes off-hook, the power supply circuit 2
2 supplies current to the terminal through the normal switches 21a and 21b, and when the other terminal responds, the control unit 23
Since the lever signal is sent to the lever switch drive circuit 25, the lever switches 21c and 21d are turned on. Further, at the same time as the reverse signal is sent, the normal signal is cut off and the applied potential is also reversed, so the normal switches 21a and 21b are turned off.

In FIG. 4, for simplification of the drawing and convenience of explanation, the drive lines R1 and R2 are driven by one contact of the normal switch drive circuit 24, and the drive lines R1 and R2 are connected to the reverse switch drive circuit 25. However, each contact is driven by a separate contact, and the contact is generally an electronic contact rather than a relay contact. Furthermore, it is also possible to omit the normal switch drive circuit 24 and the reverse switch drive circuit 25 and drive directly with the normal signal and reverse signal of the control section 23.

[Problem to be solved by the invention]

As described above, in the conventional system, drive current continues to flow through the thyristor-type electronic switch when the terminal is not in use, which causes an increase in the reactive power of the exchange.

An object of the present invention is to reduce the driving current of an electronic switch when the terminal is not in use.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 18 to 1d are the first terminals inserted into the telephone line of the subscriber circuit.
to fourth thyristor-type electronic switches; 2, a power supply circuit that supplies DC voltage to the terminal; 3, a control unit that controls a subscriber circuit; 4, when the polarity of the DC voltage is in a non-inverted state, When receiving the normal signal sent from the control unit 3, the first electronic switch connected in the forward direction with respect to the DC voltage whose polarity is not inverted.
and second electronic switch (denoted as normal switch) 1
A normal switch/pulse driving means 5 for sending a periodic driving current to the terminals a and 1b, when receiving the normal signal and a signal indicating that the terminal is in an off-footer state from the control section 3, normal switch 1a,
A normal switch continuous drive means 6 continuously sends out a drive current to the electronic switch 1b when the reverse signal sent from the control unit 3 is received when the polarity of the DC voltage is inverted. Third and fourth electronic switches (hereinafter referred to as lever switches) lc, l which are connected in the forward direction with respect to the DC voltage whose polarity is inverted.
This is a lever switch driving means that continuously sends out a driving current to d.

[For production]

In FIG. 1, when the terminal is in an on-footer state, that is, in an unused state, a normal signal is sent from the control section 3. When the normal switch pulse driving means 4 receives the signal, it generates periodic pulses and sends the pulses to the driving lines N and N2 of the normal switches 1a and 1b. Among the normal switches 1a and 1b, the voltage ■ is more negative than the power supply circuit 2. The normal switch 1b to which is connected receives the pulse and is driven open, and the drive current is transferred from the earth of the normal switch/pulse driving means 4 to the battery of the power supply circuit 2 (8). flows against

When the terminal goes off-hook in the above state, the normal switch 1b is turned on at the moment earth air is sent out from the normal switch pulse drive means 4, and the negative voltage from the power supply circuit 2 is applied to the electronic switch 1a via the terminal. Therefore, the normal switch 1a is also turned on, and a loop circuit from the power supply circuit 2 to the terminal is formed. A loop monitoring circuit (not shown) detects the formation of the loop circuit and notifies the control unit 3 that the terminal is in an off-footer state,
The control unit 3 sends a terminal off-hook detection signal.

The normal switch continuous driving means 5 operates upon reception of the terminal off-footer detection signal and the previously sent normal signal, and sends continuous ground air to the drive lines N and N2 of the normal switches la and 1b. do. Therefore, the pulse drive signal sent from the normal switch pulse drive means 4 is short-circuited by the normal switch continuous drive means 5, and the normal switches 1a and 1b are in a state where no drive current flows. The reason why the drive current is turned off is to prevent the pulse drive current for the normal switch 1a from flowing to the terminal and causing noise.

When the terminal performs a connection operation in the above state and the other terminal responds, a response signal is detected in a circuit (not shown) and sent to the control section 3, and the control section 3 sends out the reverse signal and at the same time sends the normal signal. Stop. When the reverse switch driving means 6 receives the reverse signal, it sends a continuous ground signal to the drive lines R and R2 of the reverse switches 1c and 1d, so that the reverse switches 1c and 1d are turned on and the power is supplied. The polarity of the DC voltage sent from the circuit 2 to the terminal is reversed.

As a result, normal switches 1a and 1b are turned off.

As described above (in the configuration shown in FIG. 1, when the terminal is on-hook, that is, not in use, the normal switch pulse drive means 4 controls the normal switches 1a and 1).
Since periodic pulses are sent to the drive lines N1 and N2 of b, the drive current flows only while the pulses are being sent, and current consumption is significantly reduced.

In FIG. 1, for simplification of the drawing and convenience of explanation, the drive lines N1 and N2 are each driven by one contact point of the normal switch pulse drive means 4 or the normal switch continuous drive means 5, and the drive lines R, and R2 are driven by one contact of the lever switch driving means 6, but the effects of the present invention do not change even if they are driven by separate contacts and the contacts are electronic contacts instead of relay contacts. Also, normal switch pulse drive means 4, normal switch continuous drive means 5, and lever switch drive means 6.
The control unit 3 may send out the earth air from the control unit 3.
The control unit 3 in the subscriber circuit sends signals or information from
It is clear that the effect will be the same even if the signal is sent directly from the control device of the exchange (not shown) instead.

〔Example〕

FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is a time chart of the embodiment of FIG.

In Fig. 2, lla to Lid are thyristor switches, 12
13 is a power supply circuit, 13 is a control unit, 14 is a counter, 5 and 16 are logical product (AND) circuits, 17 is a logical sum (OR) circuit, 18.19 is a thyristor switch drive circuit,
Drive current is sent to the thyristor switches llb, Llc at logic '1'. Note that the thyristor switches 11a,
llb is a normal switch that is in the forward direction when the potential of the DC voltage supplied from the power supply circuit 12 to the terminal has normal polarity, with a negative potential on the A line and a positive potential (earth) on the B line;
The thyristor switches llc and lld are lever switches that operate in the forward direction when the polarity is reversed.
, and N2 are normal switches lla and ll, respectively.
The drive lines R2 and R2 of b are the drive lines of the lever switches llc and lid, respectively.

In FIG. 2, a clock pulse CLK is input to the CK terminal of the counter 4. The black pulse C
LK is, for example, a pulse of 8 kHz, and the counter 14 counts this and outputs a 4-digit binary number to the Q0 to Q3 terminals.
That is, it is output in hexadecimal. The outputs of the Q and -Q terminals are input to an AND circuit 15. The AND circuit 15 is
When all outputs of Q0 to Q3 terminals become “1”,
That is, since the AND condition is satisfied during the period from when the count reaches "'15" in decimal notation starting from 0 until it returns to "'0", the output is sent. As described above, the circuit consisting of the counter 14 and the AND circuit 15 serves as a frequency dividing circuit for the clock pulse CLK, and sends out a pulse whose duty is 1/16 depending on the large clock pulse CLK.

Now, when the terminal is in an on-footer state, that is, in an unused state, a normal signal is sent out from the control section 13 and inputted to one terminal of the AND circuit 16. The pulse from the AND circuit 15 is input to the other terminal of the AND circuit 16 via the OR circuit 17, but the two inputs
The pulse from the AND circuit 15 is passed from the circuit 16 to the normal switch I via the thyristor switch drive circuit 18.
lb drive line N2. Normal switch Il
A completely similar pulse (not shown) is also sent to the drive line N1 of a, but since the terminal is in an on-hook state, the drive current flows only through the normal switch 11b to which the voltage VIIB is connected from the power supply circuit 12. The drive current flows while the terminal is in the on-footer state, but only when a logic "1" pulse is sent, it flows through the drive line N2 of the normal switch llb to the voltage of the power supply circuit 12, so in the above case. , the current consumption is 1/16 of that when flowing continuously.
becomes.

When the terminal goes off-hook in the above state, the normal switch 11b turns on at the moment the logic "1" pulse is sent to the drive line N2 of the normal switch llb, and the negative voltage from the power supply circuit 12 is applied via the terminal. [lI
Since l is applied to the normal switch lla, the normal switch lla is also turned on, and a loop circuit passing from the power supply circuit 12 to the terminal is formed.

A loop monitoring circuit (not shown) in the power supply circuit 12 detects the formation of the loop circuit and sends it to the control unit 13 as terminal off-hook information. When the control unit 13 receives the terminal off-hook information, it sends a terminal off-hook detection signal to the OR circuit 17.

The pulse is input from the AND circuit 15 to the other terminal of the OR circuit 17, but since the terminal off-hook detection signal is sent out in the form of continuous logic "1", the OR circuit 17 receives the pulse from the AND circuit 15.
Continuous logic from circuit 17 to AND circuit 6
1" is output. Since the normal signal is still input to the other terminal of the AND circuit 16, the drive line N2 of the normal switch ttb and the normal switch Ila
A drive current continuously flows through the drive line N. This prevents the pulse drive current from flowing to a terminal in an off-footer state and causing noise.

When a terminal performs a connection operation in the above state and the other terminal responds, a response signal is detected in a circuit (not shown), the normal signal sent from the control unit 13 is stopped, and at the same time a reverse signal is sent. Ru. Since the AND circuit 16 is turned off due to the stop of the normal signal, the drive current to the normal switches lla and Ilb is stopped.

On the other hand, the lever signal is in the form of continuous logic "1" and is passed through the thyristor switch drive circuit 19 to the lever switch II.
c is sent to the drive line R, and also to the lever switch Il.
It is also sent to the drive line R2 of d (details not shown). Since the earth (positive potential) and negative voltage ■■ are applied to the reverse switches llc and lid from the power supply circuit 12, both the reverse switches 11C and lid are in a conductive state, and the polarity of the supply voltage to the terminal is is reversed.

FIG. 3 is a time chart of the above-mentioned operation, and in the figure, ■ to ■ indicate each point in FIG. below,
FIG. 3 will be explained using the circuit of FIG. 2 together.

3 indicates a clock pulse CLK input to the counter 14, which is, for example, an 8 kHz pulse. The clock pulse is frequency-divided by 1/16 in a frequency dividing circuit consisting of a counter 14 and an AND circuit 15, and outputted as a pulse such as (2), which is input to an OR circuit 17. Note that ■ is the same as ■ but reduced in size.

On the other hand, when the terminal is in the on-footer state, the control unit 13 sends out a normal signal as shown in ■ and is input to the AND circuit 16. Therefore, the pulse of said ■ is sent as a normal switch drive signal from the AND circuit 16 as shown in ■. is output,
The normal switch llb is driven through the thyristor switch drive circuit 18, and the normal switch lla is similarly driven (details are omitted).

In this state, when the terminal goes off-hook as shown in (2), the off-hook is detected in the power supply circuit 13 (details omitted) when the pulse (2) is sent, and the terminal off-hook information is transmitted to the control unit 13. Based on the information, the control unit 13 sends the terminal off-hook detection signal (3) to the OR circuit 17, and the OR circuit 17 sends the information to the drive line N2 of the normal switch llb via the AND circuit 16 and the thyristor switch drive circuit 1B. .

For this reason, the drive signal of the normal switch Ilb changes from a pulse to a continuous one as shown in (2) to prevent pulse noise from being sent to the terminal. Note that the same applies to the normal switch lla.

When the connection operation at the terminal and the exchange (not shown) is completed and the partner terminal responds, the normal signal (2) sent from the control unit is stopped, and the reverse signal (2) is sent out. As a result, the driving of the normal switches lla and llb is stopped as shown in (■), and the thyristor switch drive circuit 1
The drive current (3) flows to the lever switch llc via the switch 9. Note that the same applies to the lever switch lid.

When the communication ends and the terminal goes on-hook, the control unit 13
Since the reverse signal of ■ and the terminal off-hook detection signal of ■ are stopped, and the normal signal of ■ is sent out, the drive current of reverse switches llc and lid of ■ is stopped, and the drive current of normal switches lla and llb becomes as shown in ■. It flows with the same pulse as in the initial state.

As described above, in the circuit of FIG. 2, when the terminal is in the on-footer state, that is, in the unused state, the normal switches lla and llb are driven by pulses, so that the current consumption is significantly reduced.

In addition, in FIGS. 2 and 3, 8k is displayed on the counter 14.
Although a Hz clock pulse is input and the frequency is divided by 1/16, the frequency and division ratio of the clock pulse can be set arbitrarily. In addition, although various signals and information are received from the control unit 13 in FIG. 2, the control unit 13 is not limited to the control unit in the subscriber circuit, and receives signals directly from the control device of the exchange. It is clear that there is no difference in effectiveness. The present invention does not exclude these variations.

〔Effect of the invention〕

As explained above, according to the present invention, in a subscriber circuit that uses a thyristor-type electronic switch to reverse the polarity of the line voltage of a DC voltage supplied to a terminal, the driving current of the electronic switch when the terminal is not in use is This greatly contributes to reducing the reactive power of exchanges that use a large number of such subscriber circuits.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a circuit diagram of an embodiment of the invention, Fig. 3 is a time chart diagram of an embodiment of the invention, Fig. 4 is a configuration diagram of a conventional system, and Fig. 5 is a diagram of an embodiment of the invention. It is a detailed circuit diagram of a thyristor switch. In the figure, 1a to 1d are electronic switch power supply circuit control unit normal switch pulse drive means normal switch continuous drive means lever switch drive means. Fig. Embodiment of the present invention Time chart diagram

Claims (1)

[Claims] By driving and controlling the first to fourth thyristor-type electronic switches (1a, 1b, 1c, 1d) inserted into the communication line by the control unit (3), the power supply circuit (2) In a subscriber circuit that inverts the polarity of a line voltage of a DC voltage supplied to a terminal, when the polarity of the DC voltage is in a non-inverted state, the controller (
3) When receiving the normal signal sent from the electronic switch, the first and second electronic switches (1a, 1a, 1b) when receiving the normal signal and a signal indicating that the terminal is in an off-hook state from the control section (3); a normal switch continuous drive means (5) that continuously sends a drive current to the first and second electronic switches (1a, 1b); 3
) while receiving the reverse signal sent from
Reverse switch driving means (for sending a continuous driving current to third and fourth electronic switches (1c, 1d) among the electronic switches that are connected in a forward direction with respect to the DC voltage in a polarity inverted state; 5) A subscriber circuit control system comprising: