WO2013013555A1 - An access control device for communication power supply storage battery - Google Patents

Abstract

An access control device for communication power supply storage battery is applied to the communication technology field. The device comprises an Alternating Current (AC)/battery voltage detection circuit, sequential control circuit, a relay and the first MOS transistor. The AC/DC voltage detection circuit is set for detecting the on-off of the system AC and the residual electricity of a storage battery, and inputting a detection result to the sequential control circuit. The two output ends of the sequential control circuit are respectively connected with the gate electrode of the first MOS transistor, and the input end of the relay, the sequential control circuit is used for controlling the first MOS transistor to switch on and the relay contact to switch off when the system AC is powered off and the battery voltage is lower than the threshold value; and controlling the relay to be switched on when the system AC is powered on, so as to realize the normal access of a system. The source electrode and the drain electrode of the first MOS transistor are respectively connected with the two ends of the relay contact. By adopting the device, the requirements of miniaturization and embedded installation of power supply systems can be satisfied.

Description

 Communication power battery access control device

Technical field

 The utility model relates to the technical field of communication, in particular to a communication power battery access control device.

Background technique

 At present, the communication power supply system is generally composed of an AC input unit, a rectifier unit, a monitoring unit, a DC power distribution unit, and a battery pack, and realizes a conversion process from AC to DC. In order to achieve uninterrupted power supply, batteries must be configured to ensure that the power supply system can still supply power to the load in the event of AC power failure. However, due to the limited capacity of the battery, the load cannot be supplied to the load without limitation. To the extent that the battery and load need to be disconnected, the battery is prevented from being over-discharged. Therefore, when the battery is connected to the power supply system, the battery is connected to the busbar of the power supply through a circuit breaker. The system block diagram of the communication power supply is shown in Figure 1. When the system is energized, the rectifier output DC voltage supplies power to the load device, and at the same time completes the charging function of the battery. At this time, the circuit breaker is in the closed state. When the system AC power is cut off, the rectifier has no output, and the battery supplies power to the load to maintain normal operation of the system.

 Due to the limited discharge time and capacity of the battery, and excessive discharge will greatly shorten the life of the battery. When the battery voltage drops to a certain value, the circuit breaker operates, disconnects the battery from the load, and stops discharging to protect the battery. When the system exchanges the incoming call again, the rectifier has output to supply power to the load. At the same time, it is necessary to control the circuit breaker to close and charge the battery to achieve repeated use. At this time, because the battery voltage is low, the circuit breaker will be larger when it is closed. The current surge has an effect on battery life. At the same time, since the circuit breaker is a mechanical contact, when the circuit is opened or closed, the arc is generated due to the change of the current, and the capacity of the circuit breaker is high. Generally, the circuit breaker has a large volume and a strong flow capacity.

In addition, in the embedded communication power system, since the space is small and the height is limited, for example, when the height is 1U (44.5 mm), it is difficult to install the circuit breaker in the communication power supply system. Even if it can be installed, there is a problem that the wiring space is narrow and the operation is difficult. Solder the circuit breaker to the PCB In the realization of the automated production of circuits is more difficult.

Utility model content

 The purpose of the embodiment of the present invention is to provide a communication power source battery access control device, which is used for solving the related art embedded communication power supply system, and it is difficult to realize the circuit breaker in the space of small space and limited height. Problems installed in the communication power system.

 In order to solve the above technical problem, the following technical solutions are used in the embodiment of the present invention:

 A communication power source battery access control device, wherein when the battery is charged and discharged, the battery is connected to the busbar of the power source through the device, wherein:

 The device includes an AC voltage/battery voltage detection circuit, a timing control circuit, a relay, and a first

MOS tube, where:

 The AC voltage/battery voltage detecting circuit is configured to: detect whether the system AC is powered off and the remaining amount of the battery, and input the detection result to the timing control circuit;

 The two output ends of the timing control circuit are respectively connected to the gate of the first MOS transistor and the input end of the relay, and are configured to: when the detection result is that the system is AC-powered and the battery voltage is lower than the threshold Controlling the first MOS transistor to be turned on, and controlling the relay contact to be turned off; after the relay contact is disconnected, issuing a control signal for turning off the first MOS tube; After that, the relay is controlled to be turned on to achieve normal access of the system;

 The source and the drain of the first MOS transistor are respectively connected to both ends of the contact of the relay.

 Optionally, the device further includes a third MOS transistor, a gate of the third MOS transistor is connected to an output end of the timing control circuit, and a source and a drain are respectively connected at two ends of the contact of the relay.

 Optionally, the first MOS transistor and the third MOS transistor are respectively connected with a parasitic diode, and two ends of each parasitic diode are respectively connected to the source and the drain of the corresponding MOS transistor. Optionally, the timing control circuit includes a first resistor, a second resistor, a first capacitor, a Zener, and a triode, where:

One end of the first resistor is connected to the output end of the AC voltage/battery voltage detecting circuit, and the other end is connected to the second resistor, and the first resistor is connected in series with the second resistor; The other end of the second resistor is grounded, and the first capacitor is connected in parallel at both ends of the second resistor;

 One end of the Zener tube is connected between the first resistor and the second resistor, and the other end is connected to a base of the transistor;

 The collector of the triode is connected to the gate of the first MOS transistor, and the emitter is grounded.

 Optionally, the timing control circuit further includes a third resistor connected between the output end of the AC voltage/battery voltage detecting circuit and the collector of the transistor.

 Optionally, the device further includes a second capacitor connected in parallel across the contacts of the relay.

 Optionally, the device further includes a fourth resistor, and the fourth resistor is connected in series with the second capacitor. Optionally, the apparatus further includes a first diode, the first diode being coupled in parallel across the contacts of the relay.

 Optionally, the relay is a relay of a normally closed contact.

 Optionally, when the contact of the relay is disconnected, an on time of the first MOS transistor is greater than an operation time of the relay.

The device provided by the embodiment of the utility model realizes the control of the reverse current on and off by using the single-controllable active switch and the normally closed contact of the relay in parallel, and the relay is not suitable for the forward current. Control to achieve fast access to the device. The volume of the communication power system is reduced, and the miniaturization and embedded installation of the communication power system are realized.

BRIEF abstract

 1 is a schematic diagram of connection of a communication power system in the related art;

2 is a schematic diagram of a communication power source battery access control device according to an embodiment of the present invention; FIG. 3 is a schematic structural diagram of a communication power source battery access control device according to another embodiment of the present invention. Preferred embodiment of the present invention

 The embodiment of the present invention provides a communication power source battery access control device, which can reduce the demand for the circuit breaker capacity, realize the miniaturization of the communication power supply system, and reduce the large current impact when the AC call is charged to the battery.

 As shown in FIG. 2, a communication power source battery access control device according to an embodiment of the present invention, when the battery is charged and discharged, the battery is connected to the bus bar of the power source through the device. And the apparatus includes an AC voltage/battery voltage detecting circuit 201, a timing control circuit 202, a relay 203, and a first MOS transistor VT1, wherein:

 The AC voltage/battery voltage detecting circuit 201 is configured to: detect whether the system AC is powered off and the remaining capacity of the battery, and input the detection result to the timing control circuit 202;

 The two output ends of the timing control circuit 202 are respectively connected to the gate of the first MOS transistor VT1 and the input end of the relay 203, and are set to: when the system is powered off and the battery voltage is lower than the threshold, the control station The first MOS transistor VT1 is turned on, and the contact of the control relay 203 is turned off; after the contact of the relay 203 is turned off, the control signal for turning off the first MOS transistor VT1 is issued; when the system is in an incoming call, the control relay is turned on. 203 is turned on to achieve normal access of the system;

 In the embodiment of the present invention, the relay 203 is a relay of a normally closed contact.

 The source and the drain of the first MOS transistor VT1 are respectively connected across the contacts of the relay 203. As shown in FIG. 3, the first MOS transistor used in another embodiment of the present invention is an NMOS transistor having a large forward-reverse current-passing capability, and of course, a PMOS transistor can also be used; wherein, the MOS transistor specific model The choice is based on the system's load condition and the battery charging current size to consider its flow capacity.

 In addition, when the contact of the relay 203 is turned off, the on-time of the MOS transistor is guaranteed to be greater than the operation time of the relay. In a specific application, the on-time of the MOS transistor can be twice as long as the operation time of the relay 203.

 As shown in Figure 3, to confirm the allowable current of the internal parasitic diode of the MOS transistor VT1, the heat generation of the MOS transistor should also be considered. If necessary, a heat sink or a MOSFET can be added in parallel to the device. The flow capacity of the MOS tube.

The specific implementation of the parallel connection of the two MOS transistors is: adding a third MOS transistor VT3, the gate of the third MOS transistor VT3 is connected to an output terminal of the timing control circuit 202, and the source and the drain are respectively connected Connected to both ends of the relay 203, the gate is also connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded.

 In addition, in order to prevent an AC incoming call, the charging current flowing through the MOS transistor is too large, and a parasitic diode is connected to the inside of the first MOS transistor and the third MOS transistor, and the two ends of the parasitic diode are respectively connected to the source and the drain of the MOS transistor. pole.

 As shown in FIG. 3, the timing control circuit 202 of another embodiment of the present invention includes a first resistor R1, a second resistor R2, a first capacitor Cl, a Zener diode D2, and a transistor VT2, wherein:

 One end of the first resistor R1 is connected to the output end of the AC voltage/battery voltage detecting circuit 201 and one end of the third resistor R3; the other end of the first resistor R1 is connected to the second resistor R2, and the first resistor R1 is connected in series with the second resistor R2. ;

 The other end of the second resistor R2 is grounded, and the first capacitor C1 is connected in parallel at both ends of the second resistor R2;

 One end of the Zener diode D2 is connected between the first resistor R1 and the second resistor R2, and the other end is connected to the base of the transistor VT2;

 The collector of the transistor VT2 is connected to the gate of the first MOS transistor VT1, and the emitter is grounded. The control signal is divided by the first resistor R1 and the second R2 to determine the magnitude of the final charging voltage across the first capacitor C1. The magnitude of the first resistor R1 and the first capacitor C1 determines the length of the charging time. Zener diode D2 determines the minimum turn-on voltage of transistor VT2.

 The timing control circuit 202 further includes a third resistor R3 coupled between the output of the AC voltage/battery voltage detecting circuit 201 and the collector of the transistor VT2. When the transistor VT2 is turned on, in order to limit the maximum current flowing through the transistor VT2, the protection VT2 will not burn out.

 In order to avoid arcing and overvoltage that may occur when the relay K1 contact is opened, double protection of the contacts is achieved. The device also includes a second capacitor C2 that is coupled in parallel across the contacts of the relay 203. In addition, in order to protect the capacitor C2 from being burned out and limiting the amount of current in the second capacitor C2, the apparatus provided by the embodiment of the present invention further includes a fourth resistor R4, the fourth resistor R4 and the second capacitor C2. In series.

Among them, in order to protect the MOS tube VT1 and VT3 from being burnt by a large current when the system exchanges incoming calls Bad, a high-power first diode is shunted in parallel at both ends of the MOS transistor, and the first diode D1 is juxtaposed at both ends of the contact of the relay 203.

 The device for controlling the entire access control of the battery according to the embodiment of the present invention is divided into two parts: one is the battery power-off process; the other is the battery access process. The following two parts are explained:

 1. The embodiment of the utility model realizes the power-off control of the battery by the following methods:

1) When the system is energized, the rectifier supplies power to the load and charges the battery. The current is constantly closed by the negative terminal of the battery through the relay, *, the negative flow to the system, and the current is positive flow. At this time, the relay contacts are closed, and the MOS transistors VT1, VT3 and the first diode D1 are short-circuited by the contacts of the relay K1, and no current flows.

 2) When the system AC power is disconnected, the rectifier group has no DC output, and the battery starts to discharge, which supplies power to the system load. The current flows from the negative discharge through the normally closed contact of the relay to the negative terminal of the battery. The current flows in the opposite direction.

 After a period of discharge of the battery, the stored electrical energy is reduced and the voltage is continuously reduced. In order to protect the battery from loss or over-discharge, it is necessary to disconnect the battery from the load when the battery voltage drops to a certain value, that is, disconnect the contact of relay K1. Since the current through the relay contact is large at this time, and there is no arc extinguishing device inside the relay, the arcing discharge phenomenon occurs when the contact of the relay is disconnected, causing the contact to burn out. In severe cases, the contacts may stick together and cannot be disconnected. Therefore, in the embodiment of the present invention, two MOS tubes VT1 and VT3 having a large current-carrying capability are connected to both ends of the contact of the relay to realize shunt and arc-extinguishing protection of the contacts and complete the disconnection function of the circuit.

 3) After the battery disconnection control command is issued, first control the MOS transistors VT1 and VT3 to be turned on, and start charging the capacitor C1 through the resistor R1. The operation time of MOS tube VT1 and VT3 is very different from the operation time of relay. The opening time of MOS tube VT1 and VT3 is microsecond, and the operating time of relay is millisecond, usually several milliseconds. Since the internal resistance of the MOS transistor VT1 is small, it is equivalent to a short circuit to the relay contact after the conduction. At the same time, a portion of the current flows through the MOS transistors VT1, VT3, reducing the amount of current in the relay contacts.

4) After the MOS transistors VT1 and VT3 are turned on for a few milliseconds, the relay starts to operate and its contacts are disconnected. Current flows through the MOS tubes VT1, VT3 to the load. At this point, the contact of the relay is disconnected, Arcing discharge will occur. At the same time, the current in the circuit flows from the MOS tubes VT1 and VT3, which reduces the difficulty in disconnecting the relay contacts. The capacitor C2 connected in parallel across the contact of the relay K1 can eliminate the arc and overvoltage that may occur when the contact of the relay K1 is disconnected, so as to double protect the contact. The resistor R4 connected in series with the capacitor C2 mainly acts as a current limiting, and the protection capacitor C2 is not burned out.

 5) After the relay contact is completely disconnected, as the voltage across the capacitor C1 rises continuously, after several tens of milliseconds, after reaching the voltage regulator value of the Zener diode D2, the Zener diode D2 is turned on, and the transistor VT2 With this turned on, the gate pin VGS of the MOS transistors VT1 and VT3 is pulled to the zero level, the control voltage disappears, the MOS transistors VT1 and VT3 are turned off, and the current flowing through the MOS transistors VT1 and VT3 is cut off to realize the battery and the load. Electrical disconnection. In this way, the MOS tubes VT1 and VT3 are only turned on in a short period of the relay operation, the power consumption is low, the control circuit is simple, the function of the circuit breaker is realized, and the reliable disconnection of the battery is ensured.

 Second, the embodiment of the utility model realizes the access control of the battery by the following methods:

1) When the system exchanges the incoming call again, the rectifier outputs the DC voltage again. The contact of relay K1 is now open. When the voltage difference between the negative row and the negative terminal of the battery is greater than 0.7V, the parasitic diodes inside the MOS transistors VT1 and VT3 are conducting, and the current flows from the rectifier to the battery through the MOS tube. MOS tube When VT1 has no turn-on voltage, its reverse current capability is low, only about half of the forward conduction current. In order to protect the MOS transistors VT1 and VT3 from being burned by short-time large currents, a power diode is connected in parallel at both ends thereof for shunting, as shown by D1 in Fig. 3.

 2) When the AC voltage/battery voltage detection circuit of the system works normally, the AC recovery information will be detected, and then the timing control circuit will issue a command to control the relay K1 contact to close. Since the first diode D1 connected in parallel at both ends of the relay contact is in an on state at this time, the voltage across the two ends of the relay does not exceed 0.7V, and can be safely and reliably sucked. After the contact of the relay K1 is sucked, the current will flow back to the battery through the relay K1. The parasitic diode inside the MOS tube VT1 and VT3 and the diode D1 are short-circuited by the relay contacts, and the voltage difference is lost and the disconnection state is resumed. The battery is reconnected to the communication power system and recharged to provide power during the next AC power outage. Here capacitor C2 will again eliminate the overvoltage.

单The control of the reverse current on and off is realized by the way that the single-controllable active switch and the relay normally closed contact are connected in parallel, and the relay can be used to quickly access the forward current by the uncontrollable forward current. In the embodiment of the present invention, a small relay with a normally closed contact and two MOS tubes with two ends connected in parallel are used to replace the circuit breaker in the prior art, and the power-off control function of the system is completed. Since the relay itself does not have an arc extinguishing device, the MOS tube can also perform arc extinguishing and protection functions for the relay contacts. In order to prevent the AC incoming call, the charging current flowing through the MOS tube is too large, and a shunted high-power diode is connected in parallel between the source and the drain of the MOS transistor.

 The device described in the present invention is not limited to the embodiment described in the specific embodiment, and other embodiments are obtained by those skilled in the art according to the technical solution of the present invention, which also belong to the technical innovation scope of the present invention.

Industrial and practical

 The device provided by the above technical solution realizes the control of the reverse current on and off by using the one-way controllable active switch and the relay normally closed contact in parallel, and realizes the uncontrollable forward current by the relay. Fast access to the device. The volume of the communication power system is reduced, and the miniaturization and embedded installation of the communication power system are realized. Therefore, the utility model has strong industrial applicability.

Claims

Claim  1. A communication power supply battery access control device, wherein when the battery is charged and discharged, the battery is connected to the power supply bus through the device, wherein:  The device comprises an AC voltage/battery voltage detecting circuit (201), a timing control circuit (202), a relay (203) and a first MOS transistor (VT1), wherein:  The AC voltage/battery voltage detecting circuit (201) is configured to: detect whether the system AC is powered off and the remaining capacity of the battery, and input the detection result to the timing control circuit (202); the timing control circuit (202) The two output terminals are respectively connected to the gate of the first MOS transistor (VT1) and the input end of the relay (203), and are set to: when the detection result is that the system is AC-powered and the battery voltage is lower than the threshold When the value is controlled, the first MOS transistor (VT1) is controlled to be turned on, and the relay (203) is controlled to be disconnected; after the relay (203) is disconnected, the first is turned off. The control signal of the MOS tube (VT1); after the system exchanges an incoming call, the relay (203) is controlled to be turned on to achieve normal access of the system;  The source and the drain of the first MOS transistor (VT1) are respectively connected to both ends of the contact of the relay (203).  2. The communication power source battery access control device according to claim 1, further comprising a third MOS transistor (VT3), a gate of said third MOS transistor (VT3) being connected to said timing control circuit (202) The output terminal, the source and the drain, are respectively connected across the contacts of the relay (203).  The communication power source battery access control device according to claim 2, wherein the first MOS transistor (VT1) and the third MOS transistor (VT3) are respectively connected with a parasitic diode, two of each parasitic diode The terminals are respectively connected to the source and the drain of the corresponding MOS transistors.  4. The communication power source battery access control device according to claim 1, wherein said timing control circuit (202) comprises a first resistor (R1), a second resistor (R2), a first capacitor (Cl), and a stable Pressure tube (D2) and triode (VT2), where:  One end of the first resistor (R1) is connected to the output end of the AC voltage/battery voltage detecting circuit (201), and the other end is connected to the second resistor (R2), the first resistor (R1) is The second resistor (R2) is connected in series; The other end of the second resistor (R2) is grounded, and the first capacitor (C1) is connected in parallel Both ends of the second resistor (R2);  One end of the Zener diode (D2) is connected between the first resistor (R1) and the second resistor (R2), and the other end is connected to the base of the transistor (VT2);  The collector of the transistor (VT2) is connected to the gate of the first MOS transistor (VT1), and the emitter is grounded.  The communication power source battery access control device according to claim 4, wherein said timing control circuit (202) further comprises a third resistor (R3), said third resistor (R3) being connected to said alternating current voltage / The output of the battery voltage detecting circuit (201) and the collector of the transistor (VT2).  A communication power source battery access control device according to claim 1, further comprising a second capacitor (C2) connected in parallel across the contacts of said relay (203).  A communication power source battery access control device according to claim 6, further comprising a fourth resistor (R4), said fourth resistor (R4) being in series with said second capacitor (C2).  The communication power source battery access control device according to any one of claims 5 to 7, further comprising a first diode (D1), wherein the first diode (D1) is connected in parallel Relay (203) at both ends of the contact.  The communication power source battery access control device according to any one of claims 1 to 7, wherein the relay (203) is a relay of a normally closed contact.  10. The communication power source battery access control device according to claim 1, wherein when the contact of the relay (203) is turned off, an on time of the first MOS transistor (VT1) is greater than the relay ( 203) action time.