JPH07307815A - Feeder - Google Patents

Abstract

PURPOSE:To obtain a feeder capable of being integrated into a semiconductor integrated circuit in which crosstalk to adjacent subscriber lines is suppressed at polarity inversion and the size of the feeder is made small as a whole like a chip. CONSTITUTION:The flowing direction of a speech current from a current feeder circuit including transistors(TRs) Q1, Q2 to subscriber lines L1, L2 depends on the switching of PNPN switches Sl-S4. In the case of the switching (polarity inversion), after the speech current from the current feeder circuit is once transited to zero gradually, the polarity is inverted while outputs from the TRs Q1, Q2 are interrupted, and the current gradually restores to a state in the non-polarity inversion from zero. When the PNPN switches S1-S4 are adopted for the polarity inversion switches, the feeder is formed with a small chip and the entire feeder is integrated into an integrated circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for supplying power to a subscriber line corresponding to a subscriber terminal. In particular, not only can crosstalk to an adjacent subscriber line be suppressed, but the entire device is almost a semiconductor. The present invention relates to a power feeding device having a configuration suitable for being integrated.

[0002]

2. Description of the Related Art As a power supply device of this type, for example, "a power supply system for a metallic digital subscriber transmission system" (Research Practical Report, Vol. 32, No. 11, 1983).
, Which uses a field effect transistor for the reversing switch. FIG. 4 shows a schematic configuration thereof. As shown in the drawing, a constant current in a constant direction is generated from the constant current feeding circuit 41 and is supplied to the field effect transistors 451 to 454. When the subscriber lines L1 and L2 are normally fed, Under the control of the normal power feeding control circuit 42, the field effect transistors 451 and 452 are time constant circuits 441 and 4 respectively.
On the other hand, when the power is reversely fed, the field effect transistor 4 is controlled under the control of the reverse power feeding control circuit 43 while being gradually turned to the ON state via 42.
53 and 454 are gradually switched to the ON state via the time constant circuits 443 and 444. Each of the field effect transistors 451 to 454 has its gate
The time constant circuits 441 to 444 for controlling the voltage are provided between the sources.
Due to the gradual start of energization by ~ 444, the inrush current to the subscriber lines L1 and L2 and the current change rate on the subscriber lines L1 and L2 at the time of polarity reversal (polarity reversal) are alleviated. As a result of alleviating the inrush current to the main lines L1 and L2, the crosstalk to the adjacent subscriber line due to the inrush current can be suppressed.

[0003]

However, in the power feeding device according to the prior art, since the field effect transistor having high withstand voltage and low on-resistance is used as the reversing switch, it is assumed that the entire device has a small chip size. The fact is that there is still room for improvement in terms of its structure as it is integrated. A PNPN switch or the like has been known so far as a reversing switch element that can reduce the chip size when the power feeding device is integrated into a semiconductor. However, when a PNPN switch or the like is used as the reversing switch element, Generally, it is difficult to start power supply gently, and therefore crosstalk to an adjacent subscriber line cannot be suppressed.

A first object of the present invention is to provide a power supply device which can suppress crosstalk to an adjacent subscriber line at the time of repolarization and can be integrated into a semiconductor as a whole with a small chip size. A second object of the present invention is that when a subscriber line is electrically connected to a station side and is electrically disconnected from the station side, crosstalk to an adjacent subscriber line can be suppressed, and the entire device is An object of the present invention is to provide a power supply device that can be integrated into a semiconductor as a chip size is small.

[0005]

The first object is basically to provide a plurality of reversing switches (field effect transistors) for switching the call current to the subscriber line in the forward / reverse direction at the time of reversing. (Excluding the above) and an active element for generating a call current based on a call current control signal from the outside, and a call in a fixed direction to the above-mentioned reversing circuit in a fixed direction. While the current is continuously supplied, the value of the call current to the reversing circuit is gradually shifted to 0 during the reversing by switching the reversing switch.
After the pole change is performed in the state where the output cutoff control is performed on the active element, the call is made again so that the state is gradually returned from 0 in the state where the output cutoff control is released, to the non-polarized state. It is achieved by being configured with a current feeding circuit for supplying a current.

The second purpose is basically to connect a subscriber line to a station side at the time of connection / disconnection and to internally provide a plurality of switches (excluding field effect transistors) for disconnecting from the station side. And a cut-off circuit that includes an active element that internally generates a call current based on a call-current control signal from the outside. On the other hand, at the time of disconnection by switching the switch, the value of the call current to the cutoff circuit is gradually shifted to 0, and the output cutoff control is performed on the active element to disconnect it. When the switch is placed in the separated state and connected by switching the switch, the value of the call current to the cutoff circuit is set to the connected state after the output cutoff control is performed on the active element, Out Gradually to be brought back to the normal connection state from the 0 state cutoff control is released, it is accomplished by being composed of a current supply circuit for supplying the speech current.

[0007]

The function of reversing the subscriber line, that is, switching the speech current flowing from the current feeding circuit to the subscriber line through the reversing circuit in the forward / reverse direction is performed by the reversing switch (electric field) in the reversing circuit. (Excluding the effect transistor), but when the polarity is changed, the call current from the current feeding circuit is gradually changed to 0 and then changed to 0 again. From the above, the polarity is changed so that it can be gradually returned to the state at the time of non-polarization. However, at the time of reversing, the call current from the current feeding circuit is suppressed to almost 0, but the mirror capacitance (capacity generated by multiplying the input-output capacitance of the amplification active element) seen on the output side of the current feeding circuit. Due to the parasitic capacitance such as), an excessive inrush current to the subscriber line immediately after the inversion cannot be avoided. Therefore, in order to reduce the mirror capacitance, when the output of the active element is controlled at the time of reversal, the inrush current to the subscriber line immediately after the reversal can be prevented. Separately, when the subscriber line is connectable / disconnectable to the station side, inrush current excessively flows into the subscriber line even when the subscriber line is connected to the station side. However, this inrush current can be prevented by the same method.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. First, the configuration of an example of the power supply device according to the present invention will be described with reference to FIG. As shown in FIG. 1, the power feeding device functions as a device that bidirectionally supplies a call current to the subscriber lines L1 and L2, and is roughly composed of a reversing circuit and a current feeding circuit. ing. The inversion circuit is the normal power supply control circuit NFC, the reverse power supply control circuit RFC, and the PNPN switches S1 to S4, and the current supply circuit is the output transistors Q1 and Q2, the resistors R1 and R2, and the transconductor amplifier (for voltage-current conversion) A1. , A2,
Output cutoff circuits CUT1, CUT2, output cutoff control circuit C
C and power sources V1 and V2, respectively. As will be described later, when the subscriber lines L1 and L2 are polarized, the output cutoff circuits CUT1 and CU are controlled by the output cutoff control circuit CC.
The base of each of the output transistors Q1 and Q2 is grounded at a low impedance by T2, whereby the operation of each of the output transistors Q1 and Q2 is completely stopped.

The general operation of the power feeding apparatus configured as above is described. Generally, the call current (constant current) from the current power feeding circuit via the inversion circuit is transmitted to the subscriber lines L1 and L2. It is allowed to be supplied, but at that time, when only the PNPN switches S1 and S2 are turned on under the control of the normal power supply control circuit NFC, the call current is forward (normal power supply state), and Reverse power supply control circuit R
If only the PNPN switches S3 and S4 are turned on under the control of the FC, the call current is supplied in the reverse direction (reverse power supply state). As described above, the call current from the current feeding circuit is a constant current, but the current feeding circuit according to the present invention is based on the proportional control by the current control input (call current control signal from the outside), A constant current is generated as a call current in (non-polarization), but the value of the call current is positively controlled during polarization. When the subscriber lines L1 and L2 are poled, the call current is gradually shifted to 0, and then the poles are poled.
It is gradually returned from 0 to the constant current state at the time of non-polarization.
1 and Q2 are in the output cutoff control state so that their operations are completely stopped.

Now, as an example of the reversing operation, the reversing operation from the normal feeding state to the reverse feeding state will be described with reference to FIG. 2 showing a reversing sequence at that time. It seems That is, in the normal power supply state, the PNPN switches S1 and S are set by the normal power supply control circuit NFC.
2 are both in the ON state, and the reverse power supply control circuit R
Both PNPN switches S3 and S4 are turned off by FC
The output transistors Q1 and Q
2 The output cutoff control by the output cutoff control circuit CC for each of them is canceled. Since an appropriate value is set in advance as the value of the current control input for the normal power supply state, a constant current corresponding to the set value is used as the call current from the subscriber line L1 to the subscriber line L2. It is what is supplied. Here, assuming a case where the necessity of reversal occurs in this normal power feeding state, as shown in FIG. 2, first, the value of the current control input gradually increases from time t ₁ to time t _2. The value of the call current is gradually changed to 0 along with the change to 0. As a result, the rate of change in current on the subscriber lines L1 and L2 can be suppressed to a low level, and crosstalk to other subscriber lines can be suppressed. Eventually, at time t ₂ when the call current reaches 0,
Output cut-off control circuit CC allows output transistors Q1, Q
2 Each is placed in the output cutoff control state, and at the same time, the PNPN switches S1 and S are set by the normal power feeding control circuit NFC.
Both 2 are set to the OFF state. At the subsequent time t ₃ , both the PNPN switches S3 and S4 are turned on by the reverse power feeding control circuit RFC, and at the time t ₄ after the PNPN switches S3 and S4 are turned on. First time output transistor Q1,
The output cutoff control for each Q2 is released and at time t
_By updating the value of the current control input from ₄ to time t ₅ , the value of the call current is gradually returned from 0 to the constant current state at the time of non-polarization, and the polarization is completed at time t ₅ . It is a thing. This means that if the output transistors Q1 and Q2 are not in the output cutoff control and the PNPN switches S3 and S4 are turned on, the subscriber line L
2, L1 through the parasitic capacitance (output transistors Q1, Q2
This is because a large inrush current flows between C1 and C2, which is a mirror capacitance by the transconductor amplifiers A1 and A2, and the capacitance between the input and output of the amplification element is equivalently multiplied. As a result of suppressing the bases of the output transistors Q1 and Q2 and reducing the parasitic capacitances C1 and C2, the inflow of inrush current onto the subscriber lines L1 and L2 is suppressed. Regarding the reversing operation from the reverse power feeding state to the normal power feeding state, the PNPN switch S1 is used.
The ON / OFF control order for each of S4 to S4 is simply reversed, and no further explanation is necessary.

Next, the configuration of another example of the power feeding device according to the present invention will be described with reference to FIG. In the simpler metallic subscriber line transmission system, the reversing function is not required, and only the connection / disconnection function between the subscriber line and the power supply device is needed (line test, disconnection of inoperable subscriber circuit). Etc.), but it is intended to provide a power supply device for such a simpler metallic subscriber line transmission system. Although the configuration of the power feeding device is shown in FIG. 3, as can be seen from this, the configuration of the current feeding circuit is the same as that shown in FIG. 1, but is substantially different from that shown in FIG. Is a cut-off circuit (PNPN switch S
1, S2 and a cutoff control circuit COC).
Under the control by, both the PNPN switches S1 and S2 are simply placed in the ON state and the OFF state, whereby the subscriber lines L1 and L2 are electrically connected to the current feeding circuit,
It can be separated. PNPN switch S
When both 1 and S2 are constantly in the ON state, that is,
In the normal connection state, the cutoff circuit is continuously supplied with the call current from the current feeding circuit, but when the subscriber lines L1 and L2 are disconnected, the above cutoff is performed. The value of the call current to the off circuit gradually becomes 0
After that, the output transistor Q1,
Output cutoff control is performed for Q2, and PNPN
Since the switches S1 and S2 are both in the OFF state, the subscriber lines L1 and L2 are in a disconnected state from the current feeding circuit. In this disconnected state, in order to connect the subscriber lines L1 and L2 to the current feeding circuit, the value of the call current to the cutoff circuit is the output transistor Q.
Assuming that the output cutoff control is being performed for 1 and Q2, the output cutoff control for the output transistors Q1 and Q2 is gradually released from 0 after the PNPN switches S1 and S2 are both turned on. The call current is supplied from the current feeding circuit so as to restore the normal connection state. This is because if the PNPN switches S1 and S2 are placed in the ON state while the output transistors Q1 and Q2 are not in the output cutoff control, for the same reason as in the case of the above-mentioned pole change, the subscriber line is used. This is because a large inrush current flows between the parasitic capacitances C1 and C2 via L1 and L2.

The power supply device according to the present invention has been described above, but the structure is not limited to the above examples, and various modifications are possible. For example, the transistors Q1 and Q2 may be replaced by field effect transistors, and the constant current source does not include the transconductor amplifiers A1 and A2, or a constant resistance power supply device of another power supply type (however, Even when the technical idea according to the present invention is applied to (including at least an active element), the same effect can be obtained. Further, in the above two examples, the PNPN switch is used as a switching element for reversing the polarity and for disconnecting the subscriber line, but the existing electromagnetic relay (it cannot be integrated into the semiconductor itself) or control. Optical PNPN switch capable of achieving isolation between the system and the subscriber line system, and further, a new semiconductor device which has recently been in the limelight as having both high-speed switching characteristics of power MOS FET and high power characteristics of bipolar transistor. IGBT element (Insulated Gate)
Abbreviation for Bipolar Transistor, whose function is COM
FET (Conduction Mode FET) and ICT (Insulated)
The same) can be used for the Gate Transistor).

[0013]

As described above, according to the first aspect, the crosstalk to the adjacent subscriber line can be suppressed at the time of repolarization, and the entire device can be integrated into a semiconductor with a small chip size. In the power supply device according to claim 2, when the subscriber line is electrically connected to the station side and is electrically disconnected from the station side, crosstalk to the adjacent subscriber line can be suppressed, Moreover, it is possible to obtain the power supply devices which can be integrated into the semiconductor, respectively, as the entire device has a small chip size.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an example of a power supply device according to the present invention.

FIG. 2 is a diagram showing a reversing sequence in an example of the power feeding device.

FIG. 3 is a diagram showing a configuration of another example of the power supply device according to the present invention.

FIG. 4 is a diagram showing a configuration of a power supply device according to a conventional technique.

[Explanation of symbols]

L1, L2 ... subscriber line, S1, S2, S3, S4 ... PN
PN switch, Q1, Q2 ... (Output) transistor, R
1, R2 ... Resistance, A1, A2 ... Transconductor amplifier, V1, V2 ... Power supply, C1, C2 ... Parasitic capacitance, CC ...
Output cutoff control circuit, CUT1, CUT2 ... Output cutoff circuit, NFC ... Normal power supply control circuit, RFC ... Reverse power supply control circuit, COC ... Cutoff control circuit

Front Page Continuation (72) Inventor Seiichi Yamano 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A power supply device in which, when a subscriber line corresponding to a subscriber terminal is polarized on the station side, the subscriber line is slowly polarized with the rate of change in call current being relaxed. hand,
A reversing circuit including a plurality of reversing switches (excluding field effect transistors) for switching the call current to the subscriber line in the forward / reverse direction at the time of reversing and a call current control from the outside inside. An active element for generating a call current based on a signal is included, while a call current in a fixed direction is continuously supplied to the reversing circuit during non-polarization, while the polarity is changed by switching the reversing switch. The value of the call current to the inversion circuit is gradually shifted to 0, and after the inversion control is performed in a state where the output cutoff control for the active element is performed, the output cutoff control is released. In this state, a current supply circuit for supplying a call current so that the state can be gradually returned from 0 to the state in the non-polarized state. 2. A subscriber line corresponding to a subscriber terminal is connected to the station side at the station side, and when the station line is disconnected from the station side, the subscriber line is loosely connected with the rate of change in call current being eased / A power supply device that is designed to be disconnected, and a cut that includes a plurality of switches (excluding field effect transistors) inside for connecting the subscriber line to the station side at the time of connection / disconnection and disconnecting from the station side An off circuit and an active element for internally generating a call current based on a call current control signal from the outside are included, and a call current in a fixed direction is continuously supplied to the cutoff circuit in a normal connection state. At the time of disconnection by switching the switch, the value of the call current to the cutoff circuit is gradually shifted to 0, and output disconnection control is performed on the active element to bring it into the disconnected state. Turn off the above switch At the time of connection by replacement, the value of the call current to the cutoff circuit is set in the connected state after the output cutoff control is performed on the active element, and then in the state where the output cutoff control is released. A current supply circuit for supplying a call current so that the normal connection state can be gradually returned from 0.