WO2016127763A1

WO2016127763A1 - Remote feeding supply circuit of u interface

Info

Publication number: WO2016127763A1
Application number: PCT/CN2016/071370
Authority: WO
Inventors: 夏冠云
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-02-12
Filing date: 2016-01-19
Publication date: 2016-08-18
Also published as: CN105991295A; CN105991295B

Abstract

The present invention provides a remote feeding supply circuit of a U interface. The circuit comprises: a remote feeding power supply module outputs a first preset voltage required for feeding by a U interface; a switching module comprises two states: a connected state and a disconnected state; a sampling feedback module samples a feeding current at a feeding current output end, to obtain a current sampling signal, and converts the current sampling signal to a sampling voltage signal for output; a comparison control module is set to obtain the sampling voltage signal, compare the sampling voltage signal with a preset voltage signal, and output a control signal for controlling the switching module to be connected or disconnected; and when a difference between the sampling voltage signal and the preset voltage signal is within a preset range, the comparison control module outputs a first control signal for controlling the switching module to be continuously connected; otherwise, the comparison control module first outputs a second control signal for controlling the switching module to be disconnected, and after a preset time, outputs a third control signal for controlling the switching module to be connected, until the difference between the sampling voltage signal and the preset signal is within the preset range.

Description

A U interface is far away for the feeding circuit

Technical field

The present invention relates to the field of communications technologies, and in particular, to a U interface for a feed circuit.

Background technique

Currently, the U interface is widely used in the connection of electronic terminal equipment products. For example, an access interface of an Integrated Services Digital Network (ISDN) uses a U interface, and an ISDN network terminal device (NT side) provides This interface is connected to the ISDN office (LT side) and transmits modulated signals. The U-interface of the Integrated Services Digital Network ISDN needs to provide a 96-volt (V) feed. In the prior art, an integrated circuit (IC) chip is generally used to control the switching of the feed and the protection of the overcurrent. However, when IC control circuits are used, there are generally disadvantages of high cost and poor versatility.

Summary of the invention

The object of the present invention is to provide a U-interface for a feed circuit, which solves the problems of high cost and poor versatility when using an IC chip to control the switch and over-current protection of the feed, and reduces the U-interface for feeding. The cost of the circuit is simple, the versatility is strong, and the system is stable.

In order to achieve the above object, an embodiment of the present invention provides a U-interface remote feed circuit connected between a system power supply and a feed current output terminal. The U-interface is provided for a feed circuit including: a remote power supply module and a switch. a module, a sampling feedback module, and a comparison control module; wherein

The remote power supply module is configured to convert an output voltage of the system power supply into a first preset voltage required for feeding the U interface;

The switch module is connected to the connection circuit of the remote power supply module to the feed current output end, and includes two states of being turned on and off;

The sampling feedback module is configured to sample a feeding current at the feeding current output end, obtain a current sampling signal, and convert the current sampling signal into a sampling voltage signal output;

The comparison control module is connected to the sampling feedback module, configured to obtain the sampling voltage signal, compare the sampling voltage signal with a preset voltage signal, and output a control signal that controls whether the switching module is turned on or off. ;

When the difference between the sampling voltage signal and the preset voltage signal is within a preset range, the comparison control module outputs a first control signal that controls the switching module to be continuously turned on; otherwise, the comparison control The module first outputs a second control signal that controls the switch module to be turned off, and outputs a third control signal that controls the switch module to be turned on after a preset time until the sampled voltage signal and the preset signal are The difference is within the preset range.

The second control signal and the third control signal are superimposed as a rectangular wave signal, and the low level signal of the rectangular wave signal is a second control signal, and the high level signal of the rectangular wave signal is Three control signals.

Wherein, the U interface far away from the feeding circuit further includes:

a pulse width modulation module configured to generate a rectangular wave signal and output the signal to the comparison control module, the comparison control module outputting the second control signal according to a high level signal or a low level signal of the rectangular wave signal Three control signals.

Wherein, the U interface far away from the feeding circuit further includes:

a small power supply module connected to the output end of the remote power supply module, the small power supply module is configured to convert the first preset voltage into a second preset voltage, and the second preset voltage is used for The sampling feedback module, the comparison control module, and the pulse width modulation module supply power.

The comparison control circuit includes: a first resistor, a second resistor, a first comparator, and a second comparator; wherein

One end of the first resistor is connected in series with one end of the second resistor, the other end of the first resistor is connected to the second preset voltage, and the other end of the second resistor is opposite to the first preset a reverse voltage connection of the voltage, a connection point of the first resistor and the second resistor is connected to a negative input end of the first comparator, and a positive input end of the first comparator is connected to the sampling voltage signal An output of the first comparator is coupled to a positive input of the second comparator, a negative input of the second comparator is coupled to the rectangular wave signal, and a second comparator output is used to control the The control signal that the switch module is turned on or off.

The small power module includes: a third resistor, a fourth resistor, a triode, a diode, and a capacitor; wherein

One end of the third resistor and one end of the fourth resistor are connected and grounded, the other end of the third resistor is connected to the collector of the transistor, and the other end of the fourth resistor is opposite to the base of the transistor An electrode is connected, an emitter of the triode outputs the second predetermined voltage, a base electrode of the triode is further connected to a cathode of the diode, and an emitter of the triode is further connected to one end of the capacitor, The anode of the diode and the other end of the capacitor are both connected to a reverse voltage of the first predetermined voltage.

The remote power supply module is a direct current (DC) conversion circuit.

The switch module is a field effect transistor (Metal-Oxid-Semiconductor, referred to as a MOS tube).

Wherein, the pulse width modulation module is a general-purpose 555 timing circuit.

The above technical solutions of the embodiments of the present invention have at least the following beneficial effects:

The U interface of the embodiment of the invention is far away from the feeding circuit, and the feeding current is sampled by the sampling feedback module and fed back to the comparison control module for comparison, and the control signal for controlling the switching module to be turned on or off is output according to the comparison result; When the sampling voltage signal meets the design requirements, the switch module is continuously turned on, and the feed current is stably output. When the sampling voltage signal is too large, the switch module intermittently turns on and off, and the overcurrent protection is realized in the off state, and the sampling is detected in the on state. Whether the voltage signal meets the design requirements, so that the U interface is far enough for the feeding circuit to detect the normality of the line in time while implementing overcurrent protection, and The output of the stable feeding current is simple; the circuit has a simple structure, high versatility and low cost, and the use range of the circuit is improved.

DRAWINGS

1 is a schematic diagram showing the basic structure of a U-interface far-fed power feeding circuit according to an embodiment of the present invention;

2 is a schematic diagram showing an optional circuit of a small power supply module of a U interface far from a feed circuit according to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing an optional circuit of a comparison control module of a U interface far from a feed circuit according to an embodiment of the present invention.

detailed description

The technical problems, the technical solutions, and the advantages of the present invention will be more clearly described in the following description.

The embodiment of the invention is directed to the U-interface far-fetching feeding circuit in the prior art, and solves the problem of high cost and poor versatility when using the IC chip to control the feeding switch and over-current protection, and provides a U-interface remote supply. The feeding circuit samples the feeding current through the sampling feedback module and feeds back to the comparison control module for comparison, and outputs a control signal for controlling the switching module to be turned on or off according to the comparison result; when the sampling voltage signal satisfies the design requirement, the switching module Continuously conducting, the feed current is stable output; when the sampling voltage signal is too large, the switch module intermittently turns on and off, and the overcurrent protection is realized in the off state, and whether the sampling voltage signal satisfies the design requirement in the on state, so that the U The interface is far enough for the feeder circuit to detect whether the line is normal and timely output a stable feeding current while realizing overcurrent protection. The circuit has simple structure, strong versatility and low cost, which improves the use range of the circuit.

As shown in FIG. 1 , an embodiment of the present invention provides a U-interface remote feed circuit connected between a system power supply and a feed current output terminal, and the U-interface remote feed circuit includes: a remote power supply module 1 , the switch module 2, the sample feedback module 3, and the comparison control module 4; wherein

The remote power supply module 1 is configured to convert an output voltage of the system power supply into a first preset voltage required for feeding the U interface;

The switch module 2 is connected to the connection circuit of the power supply module 1 to the feed current output end, and includes two states of being turned on and off;

The sampling feedback module 3 is configured to sample the feeding current at the feeding current output end, obtain a current sampling signal, and convert the current sampling signal into a sampling voltage signal output;

The comparison control module 4 is connected to the sampling feedback module 3, configured to obtain the sampling voltage signal, compare the sampling voltage signal with a preset voltage signal, and output to control the switching module 2 to be turned on or off. Control signal

In the above embodiment of the present invention, the remote power supply module 1 mainly converts the output voltage of the system power supply into a first preset voltage required for the U interface feeding; and is applied to the U interface feeding of the integrated service digital network ISDN. Take the 96V voltage as an example, that is, the first preset voltage is 96V. In an alternative embodiment of the present invention, the remote power supply module 1 can employ a universal DC conversion circuit to output a regulated voltage source that meets the standard requirements.

The switch module 2 is arranged to control the output of the feed current. A general-purpose MOS tube design can be used in design, and other circuits capable of implementing the control function are applicable in the embodiments of the present invention. Optionally, when the switch module 2 is turned on, the sampling feedback module 3 outputs a feed current; when the switch module 2 is turned off, the sample feedback module 3 does not output a feedback current. Optionally, the on or off state of the switch module 2 is determined by the control signal output by the comparison control module 4, and the control signal output by the comparison control module 4 has the sampled voltage signal fed back by the sample feedback module 3 and the preset voltage signal. determine.

Two cases of determining the optional control signal: Case 1, when the difference between the sampled voltage signal and the preset voltage signal is within a preset range, the comparison control module outputs controlling the switch module to continue a first control signal that is turned on; in the implementation process, the first control signal is a high level signal, that is, a high level signal controls the switching module 2 to be turned on; and in the case 2, when the sampling voltage signal is When the difference between the preset voltage signals is not within the preset range (generally, the feedback current is too large), in order to prevent the excessive current from damaging the terminal or the load, the comparison control module 4 first outputs the control switch module 2 The second control signal is turned on, and the step realizes the function of overcurrent protection; however, in order to know in time whether the feed current is restored to a reasonable range, the comparison control module 4 outputs the control switch module 2 after a predetermined time. The third control signal, the switch module 2 is turned on, immediately generates the feed current, and then the comparison control module 4 immediately acquires the sampled voltage signal, and continues to be based on the sampled voltage signal and the preset power The difference of the signal determines the control signal, and is repeated until the difference between the sampled voltage signal and the preset signal is within the preset range, and the comparison control module outputs a control that the switch module is continuously turned on. A control signal that stabilizes the output of the feed current.

Under normal circumstances, the situation that the feed current is too large will not be solved in a short time, so the second control signal and the third control signal are repeatedly outputted repeatedly, in order to better output the second control signal and the third. a control signal, superimposing the second control signal and the third control signal into a rectangular wave signal; wherein, the low-level signal of the rectangular wave signal is a second control signal, and the high-voltage of the rectangular wave signal The flat signal is the third control signal.

Optionally, in order to obtain the rectangular wave signal, the embodiment of the present invention further provides a pulse width modulation module 5 configured to generate a rectangular wave signal and output to the comparison control module 4, wherein the comparison control module 4 is configured according to the rectangle The high level signal or the low level signal of the wave signal outputs the second control signal or the third control signal. The pulse width modulation module 5 is generally implemented by a general-purpose 555 timing circuit, but is not limited thereto, and other circuits capable of generating a rectangular wave signal of a specific period and a pulse width ratio are applicable in the embodiments of the present invention. Since the sampling feedback module 3, the comparison control module 4 and the pulse width modulation module 5 all need a supply voltage, and generally, the supply voltage of the module is small, and the output voltage of the remote power supply module 1 cannot be directly used. The power supply may be powered by an external power supply, or by using a small power supply module 6 connected to the output end of the remote power supply module 1, the small power supply module 6 being configured to convert the first preset voltage into a first The second preset voltage is used to supply power to the sampling feedback module 3, the comparison control module 4, and the pulse width modulation module 5.

Optionally, the optional circuit of the small power module 6 is as shown in FIG. 2, and includes: a third resistor R3, a fourth resistor R4, a triode BJT, a diode D, and a capacitor C; wherein

One end of the third resistor R3 and one end of the fourth resistor R4 are connected to the ground GND, the other end of the third resistor R3 is connected to the collector of the transistor R3, and the other end of the fourth resistor R4 Connected to the base electrode of the transistor BJT, the emitter of the transistor BJT outputs the second predetermined voltage, the base electrode of the transistor BJT is also connected to the negative electrode of the diode D, and the emitter of the transistor BJT Also connected to one end of the capacitor C, the anode of the diode D and the other end of the capacitor C are connected to a reverse voltage of the first predetermined voltage.

Optionally, the optional circuit of the comparison control module 4 is as shown in FIG. 3, and includes a first resistor R1, a second resistor R2, a first comparator M1, and a second comparator M2.

One end of the first resistor R1 is connected in series with one end of the second resistor R2, and the other end of the first resistor R1 is connected to the second preset voltage (ie, the output voltage of the small power module 6). The other end of the second resistor R2 is connected to a reverse voltage of the first predetermined voltage, a connection point of the first resistor R1 and the second resistor R2 and a negative input of the first comparator M1 End connection, the positive input end of the first comparator M1 is connected to the sampling voltage signal (ie, the sampling voltage signal output by the sampling feedback module 3); the output of the first comparator M1 is compared with the second The positive input terminal of the M2 is connected, the negative input terminal of the second comparator M2 is connected to the rectangular wave signal (ie, the output signal of the pulse width modulation module), and the output of the second comparator M2 is used for controlling the The control signal that the switch module is turned on or off.

The U-interface provided by the above-mentioned embodiments of the present invention is generally applied to the ISDN system. The following describes the workflow of the embodiment of the present invention by taking an ISDN system as an example:

1. When the NT terminal in the ISDN system is not connected or the local power supply is used, the line has no feeding current, and the output signal of the comparison control circuit 4 makes the switch module 2 in the on state, and the line output is far from the stable voltage converted by the power module, that is, First preset voltage, 96V;

2. When the NT terminal in the ISDN system adopts the far-fed feed, the sampling feedback module 3 outputs an over-current signal due to the large NT starting current, and the comparison control module 4 uses the rectangle output by the pulse width modulation module 5. The wave signal intermittently controls the on and off of the switch module 2, so that the remote power supply module 1 intermittently supplies the sample feedback module 3 tentatively; when the output signal of the pulse width modulation module 5 is low, the line There is no feed current output; when the output signal of the pulse width modulation module 5 is high level, the feed circuit is turned on, and the NT terminal is charged. As the NT supply current is gradually reduced and tends to be stable, the sampling feedback circuit output is normal, and the comparison is performed. The control circuit 4 is turned to output a stable high level control signal (ie, the first control signal), and the line feed current is stably outputted;

3. When the line is short-circuited due to external faults and other large current scenarios, the U-interface is far from the feeding circuit in accordance with the above-mentioned excessive current processing method. Simply speaking, it is maintained by the sampling feedback module 3 and the comparison control module 4. The line performs continuous tentative power supply to protect the remote power supply module 1 and realize normal recovery of the feed immediately when the line returns to normal, ensuring stable and normal output of the feed current for the first time.

The U-interface of the ISDN provided by the embodiment of the invention with low cost, high stability and versatility is far enough for the feeding circuit to well control the switching of the feeding current and the protection of the overcurrent.

Industrial Applicability: As can be seen from the above description, the present invention is directed to the U-interface far-fetching feeding circuit in the prior art, and solves the problems of high cost and poor versatility when using an IC chip to control the feeding switch and over-current protection. Provide a U connection The mouth is supplied to the feeding circuit, and the feeding current is sampled by the sampling feedback module and fed back to the comparison control module for comparison, and the control signal for controlling the switching module to be turned on or off is output according to the comparison result; when the sampling voltage signal satisfies the design requirement The switch module is continuously turned on, and the feed current is stably outputted; when the sampling voltage signal is too large, the switch module intermittently turns on and off, and the overcurrent protection is realized in the off state, and whether the sampled voltage signal meets the design requirement in the on state. The U interface is far enough for the feeding circuit to detect whether the line is normal and timely output a stable feeding current while realizing overcurrent protection; the circuit has simple structure, strong versatility and low cost, and improves the use range of the circuit. .

The above is an alternative embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present invention. Retouching should also be considered as the scope of protection of the present invention.

Claims

The U interface is far away from the feeding circuit and is connected between the system power supply and the feeding current output end, and the U interface is far away from the feeding circuit, comprising: a remote power supply module, a switch module, a sampling feedback module and a comparison control module; among them,

The remote power supply module is configured to convert an output voltage of the system power supply into a first preset voltage required for feeding the U interface;

The switch module is connected to the connection circuit of the remote power supply module to the feed current output end, and includes two states of being turned on and off;

The sampling feedback module is configured to sample a feeding current at the feeding current output end, obtain a current sampling signal, and convert the current sampling signal into a sampling voltage signal output;

The comparison control module is connected to the sampling feedback module, configured to obtain the sampling voltage signal, compare the sampling voltage signal with a preset voltage signal, and output a control signal that controls whether the switching module is turned on or off. ;

When the difference between the sampling voltage signal and the preset voltage signal is within a preset range, the comparison control module outputs a first control signal that controls the switching module to be continuously turned on; otherwise, the comparison control The module first outputs a second control signal that controls the switch module to be turned off, and outputs a third control signal that controls the switch module to be turned on after a preset time until the sampled voltage signal and the preset signal are The difference is within the preset range.
The U interface far-reaching feeding circuit according to claim 1, wherein the second control signal and the third control signal are superimposed as a rectangular wave signal, and the low-level signal of the rectangular wave signal is a second The control signal, the high level signal of the rectangular wave signal is a third control signal.
The U interface is further provided by the feed circuit of claim 2, wherein the U interface is further provided by the feed circuit further comprising:

a pulse width modulation module configured to generate a rectangular wave signal and output the signal to the comparison control module, the comparison control module outputting the second control signal according to a high level signal or a low level signal of the rectangular wave signal Three control signals.
The U-interface is further provided by the feeder circuit according to claim 3, wherein the U-interface is further provided by the feeder circuit further comprising:

a small power supply module connected to the output end of the remote power supply module, the small power supply module is configured to convert the first preset voltage into a second preset voltage, and the second preset voltage is used for The sampling feedback module, the comparison control module, and the pulse width modulation module supply power.
The U interface far-reaching feed circuit of claim 4, wherein the comparison control circuit comprises: a first resistor, a second resistor, a first comparator, and a second comparator; wherein

One end of the first resistor is connected in series with one end of the second resistor, the other end of the first resistor is connected to the second preset voltage, and the other end of the second resistor is opposite to the first preset a reverse voltage connection of the voltage, a connection point of the first resistor and the second resistor is connected to a negative input end of the first comparator, and a positive input end of the first comparator is connected to the sampling voltage signal The output of the first comparator and the positive input of the second comparator Connected, the negative input of the second comparator is connected to the rectangular wave signal, and the second comparator outputs a control signal for controlling the switching module to be turned on or off.
The U-interface is further provided by the power feeding circuit according to claim 4, wherein the small power supply module comprises: a third resistor, a fourth resistor, a triode, a diode, and a capacitor; wherein

One end of the third resistor and one end of the fourth resistor are connected and grounded, the other end of the third resistor is connected to the collector of the transistor, and the other end of the fourth resistor is opposite to the base of the transistor An electrode is connected, an emitter of the triode outputs the second predetermined voltage, a base electrode of the triode is further connected to a cathode of the diode, and an emitter of the triode is further connected to one end of the capacitor, The anode of the diode and the other end of the capacitor are both connected to a reverse voltage of the first predetermined voltage.
The U interface far-reaching feeding circuit according to claim 1, wherein the remote power supply module is a universal DC power conversion circuit.
The U interface according to claim 1 is provided for a feed circuit, wherein the switch module is a field effect transistor MOS transistor.
The U-interface remote feed circuit of claim 2 wherein said pulse width modulation module is a general purpose 555 timing circuit.