KR950003472B1 - Power supply device of pbx system - Google Patents

Abstract

The device is provided for detecting the line condition and overcurrent status and for supplying uninterruptible constant voltage. The device comprises a constant current supplier controlling the current to be maintained constant value; an overcurrent/overvoltage monitoring unit for notifying the PBX main body of the line condition after detecting the supplying current state; and a circuit breaker unit for cutting off the supplying current under the PBX system command.

Description

Power Supply for Wireless PBX System

1 is a power supply of a conventional basic wireless PBX system.

2 is a circuit diagram of a power supply of a conventional advanced wireless PBX system.

3 is a schematic diagram of a power supply of a wireless PBX system according to the present invention;

4 is a detailed circuit diagram of a power supply device for a wireless PBX system according to the present invention.

5 is a flowchart of an operation in which a central processing unit of a wireless PBX system controls a power supply.

* Explanation of symbols for main parts of the drawings

1, 2, 3: Power supply of wireless PBX system 4: Constant current supply

5: over current / line state detection unit 6: circuit breaker

7 interface T: transformer

The present invention relates to a power supply device of a wireless PBX system for supplying power to a terminal side connected to a wireless PBX system. In particular, the present invention relates to a wireless device capable of supplying a certain power to a terminal side and detecting appropriate line and overcurrent conditions to take appropriate measures. A power supply for a PBX system.

The power supply of the conventional basic wireless PBX system is shown in FIG. As can be seen in the figure, the power supply 1 separates the signal from the terminal connected to the wireless PBX system main body and transmits it to the wireless PBX system main body and transmits the signal from the wireless PBX system main body to be transmitted to the terminal side. It consists of a trans focus T overlapping together, capacitors C1 and C2 for noise removal, and a varistor VA that protects the system from an external sudden electric shock. When -48V is supplied to the right side of the transformer T, current flows from the analog ground side to the terminal side through the transformer T and the line a. The terminal uses the power supplied through the line A to make the power required for the terminal, and the rest of the current flows back to the -48 V side through the line B and the transformer T. At this time, when a signal is input from the main body of the wireless PBX system on the left side of the transformer (T), the signal is changed to a DC level of -48V while passing through the transformer (T) and overlaps with the power supply, and the signal overlapping the power supply line is a It is delivered to the terminal side through A).

Since the power supply 1 as described above transmits signals and current unconditionally regardless of the state of the terminal or the state of the line, there is a problem that there is no countermeasure when an overcurrent flows to the terminal side.

As a conventional power supply device for solving the above problems, a power supply device as shown in FIG. 2 has been proposed. As can be seen from the figure, the power supply 2 has two transistors TR1 and TR2 for power protection of the system itself in the power supply 1 of FIG. If the flow rapidly increases the resistance value is greatly increased, it is configured to further comprise a poly switch (PS) and the resistor (R13 ~ R15) that serves to prevent the flow of current. This power supply device 2 supplies power to the terminal side similarly to the power supply device 1 of FIG. 1, the current input through the line B after power is supplied to the terminal side through the line A. Is passed through the transformer T and the polyswitch PS to flow to the -48V side while operating the transistors TR1 and TR2. At this time, when the current passing through the poly switch PS is increased, the resistance value of the poly switch PS is increased to cut off the circuit, thereby stopping power supply to the terminal side. Since the power supply unit 2 can automatically cut off the circuit when an overcurrent flows, the system can be stabilized to some extent, but the current cannot always be constantly supplied to the terminal side, and the central processing unit of the wireless PBX system is provided. There was a problem in that it could not be effectively dealt with when an abnormality occurred because it could not detect an abnormal state of the line or the presence of overcurrent.

The present invention has been made in view of the above-described problems. The present invention provides a constant current to the terminal side, and reports on the overcurrent supply and abnormal conditions of the line to the central processing unit of the wireless PBX system to take appropriate measures. An object is to provide a power supply for a wireless PBX system.

In order to achieve the object as described above, the present invention is a power supply of the wireless PBX system for supplying current to the terminal side connected to the main body of the wireless PBX system, the constant rectification supply unit for controlling the current supplied to the terminal to flow constantly Wow ; An overcurrent / line state detection unit for sensing a current supplied to the terminal side and detecting a line state connected to the terminal side to notify the central processing unit of the main body of the wireless PBX system; And a circuit breaker to block a current supplied to the terminal by a command from a central processing unit of the main body of the wireless PBX system.

By the above-described configuration, the present invention supplies a constant current to the terminal side connected to the wireless PBX system main body, detects the overcurrent and the line state, cuts off the current supply when the overcurrent is supplied to the terminal side, and cuts off the current supply to the system operator. By alerting, it is possible to prevent damage to the terminal due to overcurrent supply and to effectively operate the wireless PBX system.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

3 is a schematic diagram of a power supply of a wireless PBX system according to the present invention, and FIG. 4 is a detailed circuit diagram of a power supply of a wireless PBX system according to the present invention. As can be seen in FIG. 3, the power supply unit 3 includes a transformer T, a constant current supply unit 4, an overcurrent / line condition detection unit 5, a circuit breaker 6 and an interface unit ( 7) is made. The constant current supply unit 4 always maintains a constant current supplied to the terminal through the transformer (T) and the line (A), and the overcurrent / line state detection unit (5) checks whether there is an abnormality in the line and whether the overcurrent is supplied. Detects and interrupts the central processing unit (not shown) of the wireless PBX system when an abnormality occurs in the line or when an overcurrent is supplied, and the central processing unit takes appropriate measures, and the circuit breaker 6 performs the central processing. When a circuit break command is input from the device, the circuit breaks. The interface unit 7 outputs a signal from the overcurrent / line state detection unit 5 to the central processing unit side of the wireless PBX system at a signal level, and outputs a signal from the central processing unit of the wireless PBX system to the circuit breaker 6. The signal level is adjusted to the

As can be seen in FIG. 4, the constant current supply unit 4 is composed of transistors Q1 to Q3, zener diodes ZD, resistors R1 to R3, and bridge circuits BD, and overcurrent / line conditions. The sensing unit 5 is composed of a poly switch PS, a transistor Q4, a photo coupler PTC2, an SCR 9, a resistor R4 to R7, a diode D, and a capacitor C4, and a circuit. The blocking unit 6 is composed of a photo coupler (PTC1) and resistors R9 and R10, and the interface unit 7 is composed of a buffer 10, three-state buffers 11 and 12 and a resistor R11. do. When -48V is supplied to the transistor Q2 and the resistor R10 of the constant current supply unit 4, current from the analog ground flows to the transformer T and the resistor R1 side. The current passing through the transformer T is supplied to the terminal side through the line A, and the remaining current supplied to the terminal flows through the line B and the transformer T to the bridge circuit BD finally. Goes. Current flowing through resistor R1 is resistor R4, polyswitch PS, resistor R6 and diode D which determine the voltage between the base and emitter of transistor Q3 via resistors R2 and R3. It flows through and operates transistor Q1 and transistor Q3 and passes through powder transistor Q2. At this time, since the voltage between the base and the emitter of the transistor Q1 is fixed by the zener diode ZD connected to the emitter of the transistor Q1, it is fixed by the C viscosity resistor R10 and the photo coupler PTC1. Applied voltage. When the current supplied from the analog ground to the terminal side through the transformer (T) and the line (A) is small, the current flowing through the resistor (R4), the polyswitch (PS), and the resistor (R6) is also small, so that the transistor (Q3) The voltage between the base and the emitter is lowered so that the transistor Q3 is turned off. As a result, the potential difference between the points C and D becomes large so that the transistor Q2 is turned ON and the current flows to the -48V side without any resistance. However, when the current flowing to the terminal side increases, the current flowing through the resistor R4, the poly switch PS, and the resistor R6 also increases, and when the current exceeds a certain amount, the voltage between the base and emitter of the transistor Q3 is increased. The transistor Q3 is turned ON because the saturation voltage of Q3 is equal to or higher. At this time, since the potential difference between points C and D is almost eliminated, transistor Q2 is turned off and transistor Q2 acts as a resistor having a large resistance value, so that the current is resistor R4, polyswitch PS, and resistor. Since almost exhausted at R6 and transistor Q2, the current flowing to the terminal side is limited. Therefore, only a constant current is always supplied to the terminal side, and even if the current supplied to the terminal side exceeds a certain amount, the circuit itself consumes a current, so that a constant current can be supplied to the terminal side. As a result, it is possible to prevent damage to the terminal due to the overcurrent supplied to the terminal.

In addition, when an overcurrent flows through the resistor R4, the polyswitch PS, and the resistor R6, the resistance of the polyswitch PS increases rapidly, so that most of the current flows through the resistor R5 and the transistor Q4. ) Will be turned on. When the transistor Q4 is turned ON, the SCR 9 is operated and a high state signal is output to the cathode K side of the SCR 9. The high state signal from the cathode K of the SCR 9 is supplied as an interrupt signal to the central processing unit side of the wireless PBX system via the buffer 10 of the interface unit 7. At this time, the leveling device of the wireless PBX system recognizes that an overcurrent has flowed, stops other work for a while, and performs appropriate emergency measures. At this time, the central processing unit of the wireless PBX system is the input stage (S1) and write stage ( When the high state signal and the light signal are output to each side, the current through the resistor R9 of the circuit breaker 6 does not pass through the photo coupler PTC1, so the circuit is blocked. Therefore, when the overcurrent is supplied to the terminal side, the polyswitch PS may operate to cut off the circuit, or the central processing unit of the wireless PBX system may arbitrarily cut off the circuit.

In the normal state, the current passing through the poly switch PS flows not only to the resistor R6 but also to the photo coupler PTC2 through the resistor R7. At this time, since the photo coupler (PTC2) is operated, a low state signal is output through the tri-state buffer 11 of the interface unit 7, and the central processing unit of the wireless PBX system controls the side of the tri-state buffer 11. In lead ( When the signal is output and read, the low signal is input. When the line connected to the terminal side is disconnected, the current passing through the poly switch PS is rapidly reduced, so that the photo coupler PTC2 is turned off. At this time, since + 5V supplied to the resistor R8 is output to the output terminal S side of the tri-state buffer 11, the central processing unit of the wireless PBX system transmits a read signal to the control terminal of the tri-state buffer 11. ) Outputs and reads the high signal. Accordingly, the central processing unit of the wireless PBX system can also detect the line condition.

5 is a flow chart of the operation of the central processing unit of the wireless PBX system to control the power supply (3). The central processing unit performs other work when the power supply 3 is normal, and an overcurrent is generated to interrupt the high state from the overcurrent / line state detection unit 5 through the buffer 10 of the interface unit 7. When a signal is input, a high state signal is output to the circuit breaker 6 through the buffer 12 of the interface unit 7 to stop the light emitting means provided in the photo coupler PTC1, thereby shutting off the circuit and alarming at the same time. Emergency measures for the occurrence of overcurrent, such as informing the system operator of the occurrence of overcurrent. In addition, if the track status is not normal due to the disconnection of the track, an alarm is triggered to notify the system operator of the track error so that emergency measures can be taken.

Claims (2)

A power supply apparatus for a wireless PBX system for supplying current to a terminal side connected to a wireless PBX system main body, the power supply apparatus comprising: a constant current supply unit for controlling a current to be supplied to the terminal side to flow constantly; An overcurrent / line state detection unit for sensing a current supplied to the terminal side and detecting a line state connected to the terminal side to notify the central processing unit of the main body of the wireless PBX system; And a circuit breaker for interrupting current supplied to the terminal by a command from a central processing unit of the main body of the wireless PBX system. The power supply apparatus of claim 1, further comprising an interface unit for connecting the overcurrent / line state detection unit and the circuit breaker to a central processing unit of the main body of the wireless PBX system.