Power supply output control circuit and alarm system

Abstract

The utility model discloses a power supply output control circuit and an alarm system, the power supply output control circuit comprises an output switch module, the input end of the output switch module is connected with a power supply, and the control end is used for receiving an output control signal; the input end of the load connection module is connected with the output end of the output switch module, and the output end of the load connection module is used for being connected with the input end of a load; the anomaly detection module comprises an anti-reverse unit, a detection switch unit, a first sampling unit and a second sampling unit, the input end of the anti-reverse unit is connected with the detection power supply, the output end of the anti-reverse unit is connected with the input end of the load connection module and the input end of the detection switch unit, and the control end of the anti-reverse unit is connected with the output end of the load connection module; the first sampling unit is connected with the input end of the anti-reverse unit, and the second sampling unit is connected with the input end of the detection switch unit. The power supply output control circuit not only can detect the fault of the load line when the power supply is not output, but also can detect the fault of the load line when the power supply is output.

Description

Technical Field

[0001] The utility model relates to the technical field of line detection, in particular to a power output control circuit and an alarm system. Background Art

[0002] In fire protection project applications, in addition to the fire alarm system host and its node devices, many application requirements inevitably require the installation of some devices that do not need to communicate with the host, but need the host to control their weak power supply (hereinafter referred to as non-system communication equipment). For the two-bus communication system, such devices cannot be connected to the two-bus system. When these devices are powered on, they may affect the communication stability of the fire alarm system. In general, nodes such as input and output passive modules can be installed in the fire alarm system, and the weak power supply is connected to the normally open terminal of the passive module. When a fire occurs, the host sends a command to start the input and output passive The normally open terminal of the module becomes a normally closed terminal, and the non-system communication equipment starts working when connected to the 28V power supply. In this case, an additional 28V power supply needs to be connected, which increases the application cost. Moreover, for more important fire-fighting equipment, when the communication system is destroyed, the module cannot receive the command and the fire-fighting equipment cannot work in time, resulting in property loss caused by untimely fire extinguishing. Therefore, many host terminals have added a fire alarm 28V output power control terminal. When a fire occurs, the host controls the power output of the fire alarm terminal, and the non-system equipment connected to the control terminal is powered on and works. No communication command is required, and no additional power supply is required, so the fire is controlled in time.

[0003] However, the probability of fire is extremely low. The construction lines are in an unactivated state for a long time. As time goes by, the lines will definitely age. It is necessary to detect the line during the period when the line power is not output. Although the line detection is normal at ordinary times, when the fire alarm line circuit output occurs, due to the aging of the line, the line may fail during the line output process due to thermal expansion and other reasons. Therefore, line detection during line output is also very necessary. In the prior art, line detection can only be performed when the power is output, but it is impossible to detect the line status when the power is not output, and it is also impossible to accurately distinguish the line status when the power is output. Utility Model Content

[0004] The utility model provides a power supply output control circuit and an alarm system. The power supply output control circuit can detect load line faults when the power supply is not output, and can also detect load line faults when the power supply is output.

[0005] In order to achieve the above object, the utility model provides the following technical solutions:

[0006] A power output control circuit, comprising:

[0007] An output switch module, wherein the input end of the output switch module is connected to a power supply, and the control end of the output switch module is used to receive an output control signal to control the state of the output switch module;

[0008] A load connection module, wherein the input end of the load connection module is connected to the output end of the output switch module, the output end of the load connection module is used to be connected to the input end of the load, and the load connection module is used to output a start signal when the output switch module is turned on;

[0009] The abnormality detection module includes an anti-reverse unit, a detection switch unit, a first sampling unit and a second sampling unit, wherein the input end of the anti-reverse unit is used to be connected to a detection power supply, the detection power supply is smaller than the power supply, the output end of the anti-reverse unit is connected to the input end of the load connection module and the input end of the detection switch unit, the control end of the detection switch unit is connected to the output end of the load connection module and is used to be turned on when receiving the start signal, the first sampling unit is connected to the input end of the anti-reverse unit and is used to output a first detection signal, and the second sampling unit is connected to the input end of the detection switch unit and is used to output a second detection signal.

[0010] Optionally, the output switch module includes a first switch tube, a second switch tube, a first voltage-dividing resistor, a second voltage-dividing resistor and a first voltage-stabilizing capacitor;

[0011] The control end of the first switch tube is used to receive an output control signal, the input end of the first switch tube is connected to the power supply through the first voltage-dividing resistor, and the second end of the first switch tube is grounded through the second voltage-dividing resistor;

[0012] The control end of the second switch tube is connected to the input end of the first switch tube, the input end of the second switch tube is connected to the power supply, and the output end of the second switch tube is connected to the input end of the load connection module;

[0013] A first end of the first voltage-stabilizing capacitor is connected to an input end of the second switch tube, and a second end of the first voltage-stabilizing capacitor is grounded.

[0014] Optionally, the load connection module includes a first connection resistor, a second connection resistor, a first connection diode and a second connection diode;

[0015] The first end of the first connection resistor is connected to the output end of the output switch module, the second end of the first connection resistor is connected to the first end of the second connection resistor, and the second end of the second connection resistor is connected to the input end of the load;

[0016] The anode of the first connection diode is connected to the input end of the first connection resistor, the cathode of the first connection diode is connected to the anode of the second connection diode, and the cathode of the second connection diode is connected to the output end of the second connection resistor.

[0017] Optionally, the sampling unit further includes a current limiting unit, and the input end of the anti-reverse unit is connected to the detection power supply through the current limiting unit.

[0018] Optionally, the detection switch unit includes a third switch tube and a third connecting resistor, the input end of the third switch tube is connected to the output end of the anti-reverse unit, the output end of the third switch tube is connected to the second sampling unit, and the control end of the third switch tube is connected to the output end of the second connecting diode through the third connecting resistor.

[0019] Optionally, the first sampling unit includes a first filter resistor and a first filter capacitor, the first end of the first filter resistor is connected to the input end of the anti-reverse unit, the second end of the first filter resistor is connected to the first end of the first filter capacitor, the second end of the first filter capacitor is grounded, and the first end of the first filter capacitor outputs the first detection signal.

[0020] Optionally, the second sampling unit includes a second filter resistor, a second filter capacitor and a sampling resistor, the first end of the second filter resistor is connected to the output end of the third switch tube, the second end of the second filter resistor is connected to the first end of the second filter capacitor, the second end of the second filter capacitor is grounded, the first end of the sampling resistor is connected to the second end of the first filter resistor, the second end of the sampling resistor is grounded, and the first end of the sampling resistor outputs the second detection signal.

[0021] Optionally, a self-powered connection module is further included, which is connected to the output end of the load connection module and the control end of the output switch module, and is used to make the output switch module continuously turned on when the power supply is output.

[0022] Optionally, the self-powered connection module includes a third voltage-dividing resistor, a fourth voltage-dividing resistor and a voltage-stabilizing diode, the two ends of the third voltage-dividing resistor are respectively connected to the output end of the load connection module and the control end of the output switch module, the first end of the fourth voltage-dividing resistor is connected to the control end of the output switch module, the second end of the fourth voltage-dividing resistor is grounded, and the voltage-stabilizing diode is connected in parallel with the fourth voltage-dividing resistor.

[0023] Optionally, a protection module is also included; the load connection module is connected to the self-powered connection module and the input end of the load through the protection module, and the protection module is used to reduce the input end voltage of the load when the output switch module is turned on and the load line is short-circuited.

[0024] Optionally, the protection module includes a short-circuit protection resettable fuse, a second voltage-stabilizing capacitor and a transient voltage suppression diode, the two ends of the short-circuit protection resettable fuse are respectively connected to the output end of the load connection module and the input end of the load, the first end of the second voltage-stabilizing capacitor is connected to the output end of the load connection module, the second end of the second voltage-stabilizing capacitor is grounded, the second end of the transient voltage suppression diode is connected to the output end of the short-circuit protection resettable fuse, and the second end of the transient voltage suppression diode is grounded.

[0025] Optionally, it further comprises a control module, wherein the control module comprises an output control terminal, a first detection terminal and a second detection terminal;

[0026] The output control end is connected to the control end of the output switch module, and is used to send an output control signal to the output switch module; the first detection end is connected to the output end of the first sampling unit, and is used to receive the first detection signal; the second detection end is connected to the output end of the second sampling unit, and is used to receive the second detection signal;

[0027] The control module is used to send an output control signal to the output switch module according to a preset instruction, and is used to determine the state of the load line according to the output control signal, the first detection signal and the second detection signal.

[0028] The utility model also provides an alarm system, comprising any one of the power output control circuits provided by the above technical solution.

[0029] The embodiment of the utility model provides a power output control circuit and an alarm system. The power output control circuit includes an output switch module, a load connection module and an abnormality detection module. The state of the output switch module can be controlled by an output control signal, thereby realizing the control of the power supply state of the power supply to the load; when the power supply output is not needed, the output control signal can control the input end and the output end of the output switch module to be disconnected, and the power supply does not supply power to the load. At this time, the detection power supply in the abnormality detection module can supply power to the load through the anti-reverse unit and the load connection module. When the load line is normal and when there is an abnormality, the combination of the first detection signal and the second detection signal output by the abnormality detection module is different, and the state of the load line can be detected when the power supply is not output; and when the power supply output is needed to supply power to the load, the output control signal can control the input end and the output end of the output switch module to be connected. At this time, the power supply supplies power to the load through the load connection module, and the load connection module outputs a start signal to control the input end and the output end of the detection switch unit to be connected. When the load line is normal and when there is an abnormality, the combination of the first detection signal and the second detection signal output by the abnormality detection module is different, and the state of the load line can be detected when the power supply is output. The power supply output control circuit can detect load line faults when the power supply is not outputting, and can also detect load line faults when the power supply is outputting. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a power output control circuit provided by an embodiment of the utility model;

[0031] Figure 2 A schematic diagram of the structure of another power output control circuit provided by an embodiment of the utility model;

[0032] Figure 3 A schematic diagram of the structure of another power output control circuit provided by an embodiment of the utility model;

[0033] Figure 4 A schematic diagram of the circuit structure of a power output control circuit provided by an embodiment of the utility model;

[0034] Figure 5 A control flow chart of a power output control circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] Please refer to Figure 1 , the utility model embodiment provides a power output control circuit, including:

[0037] An output switch module 100, wherein the input end of the output switch module 100 is used to connect to the power supply V1, and the control end of the output switch module 100 is used to receive an output control signal to control the state of the output switch module 100;

[0038] A load connection module 200, wherein the input end of the load connection module 200 is connected to the output end of the output switch module 100, the output end of the load connection module 200 is used to connect to the input end of the load, and the load connection module 200 is used to output a start signal when the output switch module is turned on;

[0039] The abnormality detection module 300 includes an anti-reverse unit 301, a detection switch unit 302, a first sampling unit 303 and a second sampling unit 304. The input end of the anti-reverse unit 301 is used to connect with the detection power supply V2, and the detection power supply V2 is less than the power supply V1. The output end of the anti-reverse unit 301 is connected with the input end of the load connection module and the input end of the detection switch unit 302. The control end of the detection switch unit 302 is connected with the output end of the load connection module and is used to be turned on when receiving a start signal. The first sampling unit 303 is connected with the input end of the anti-reverse unit 301 and is used to output a first detection signal. The second sampling unit 304 is connected with the input end of the detection switch unit 302 and is used to output a second detection signal.

[0040] The power output control circuit provided by the embodiment of the utility model includes an output switch module 100, a load connection module 200 and an abnormality detection module 300. The state of the output switch module 100 can be controlled by an output control signal, thereby realizing the control of the power supply state of the power supply V1 to the load; when the power supply V1 output is not needed, the output control signal can control the input end and the output end of the output switch module 100 to be disconnected, and the power supply V1 does not supply power to the load. At this time, the detection power supply V2 in the abnormality detection module 300 can supply power to the load through the anti-reverse unit 301 and the load connection module 200. When the load line is normal and when there is an abnormal fault, the abnormality detection module 300 outputs The combination of the first detection signal and the second detection signal outputted is different, and the state of the load line can be detected when the power supply V1 is not output; and when the power supply V1 needs to be output to supply power to the load, the output control signal can control the input end and the output end of the output switch module 100 to be turned on. At this time, the power supply V1 supplies power to the load through the load connection module 200, and the load connection module 200 outputs a start signal to control the input end and the output end of the detection switch unit 302 to be turned on. When the load line is normal and when there is an abnormality, the combination of the first detection signal and the second detection signal outputted by the abnormality detection module 300 is different, and the state of the load line can be detected when the power supply V1 is output. The above-mentioned power output control circuit can realize the detection of load line faults when the power supply V1 is not output, and can also realize the detection of load line faults when the power supply V1 is output.

[0041] In the embodiment of the utility model, Figure 4 As shown, the above-mentioned output switch module 100 may include a first switch tube Q1, a second switch tube M1, a first voltage-dividing resistor R1, a second voltage-dividing resistor R2 and a first voltage-stabilizing capacitor C1; wherein, the control end of the first switch tube Q1 is used to receive an output control signal, the input end of the first switch tube Q1 is connected to the power supply V1 through the first voltage-dividing resistor R1, and the second end of the first switch tube Q1 is grounded through the second voltage-dividing resistor R2; the control end of the second switch tube M1 is connected to the input end of the first switch tube Q1, the input end of the second switch tube M1 is connected to the power supply V1, and the output end of the second switch tube M1 is connected to the input end of the load connection module 200; the first end of the first voltage-stabilizing capacitor C1 is connected to the input end of the second switch tube M1, and the second end of the first voltage-stabilizing capacitor C1 is grounded.

[0042] Specifically, the first switch tube Q1 can be a triode, the second switch tube M1 can be a PMOS tube, the first switch tube Q1 and the second switch tube M1 can also be other switch tubes, which are not limited here and depend on the actual situation. The anti-reverse unit 301 can be an anti-reverse diode D3.

[0043] In the above-mentioned output switch module 100, the control end of the first switch tube Q1 is the control end of the output switch module 100, the input end of the second switch tube M1 is the input end of the output switch module 100, and the output end of the second switch tube M1 is the output end of the output switch module 100; the control end of the first switch tube Q1 is used to receive the output control signal. When the output control signal is at a low level, the input end and the output end of the first switch tube Q1 cannot be conducted, then the voltages of the control end and the input end of the second switch tube M1 are equal, the second switch tube M1 cannot be conducted, and the power supply V1 is not output; and when the output control signal is at a high level, the input end and the output end of the first switch tube Q1 are conducted, the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series to divide the power supply V1, and the voltage difference between the control end and the input end of the second switch tube M1 reaches the conduction condition of the second switch tube M1, so that the input end and the output end of the second switch tube M1 are conducted, and the power supply V1 can supply power to the load through the load connection module 200.

[0044] In the embodiment of the utility model, Figure 4 As shown, the load connection module 200 may include a first connection resistor R3, a second connection resistor R4, a first connection diode D1 and a second connection diode D2; the first end of the first connection resistor R3 is connected to the output end of the output switch module 100, the second end of the first connection resistor R3 is connected to the first end of the second connection resistor R4, and the second end of the second connection resistor R4 is connected to the input end of the load; the positive electrode of the first connection diode D1 is connected to the input end of the first connection resistor R3, the negative electrode of the first connection diode D1 is connected to the positive electrode of the second connection diode D2, and the negative electrode of the second connection diode D2 is connected to the second end of the second connection resistor R4.

[0045] In the above-mentioned load connection module 200, the first end of the first connection resistor R3 is the input end of the load connection module 200, and the second end of the second connection resistor R4 is the output end of the load connection module 200; the first connection diode D1 and the second connection diode D2 can clamp the voltage of the first connection resistor R3 and the second connection resistor R4, and the first connection diode D1 and the second connection diode D2 can prevent the current flowing through the first connection resistor R3 and the second connection resistor R4 from being too large, causing the resistors to overheat and burn out.

[0046] In the embodiment of the utility model, the above-mentioned abnormality detection module 300 may also include a current limiting unit, and the input end of the anti-reverse unit 301 is connected to the detection power supply V2 through the current limiting unit. When the abnormality detection module 300 is working and the detection power supply V2 supplies power to the load, the current limiting unit can pass through the branch line to prevent the current from being too large and burning. Specifically, this current limiting unit may include a current limiting resistor R6, which can limit the size of the current in the branch to prevent the current from being too large and burning the components connected in series.

[0047] In the embodiment of the utility model, Figure 4 As shown, the detection switch unit 302 may include a third switch tube Q2 and a third connection resistor R5, the input end of the third switch tube Q2 is connected to the output end of the anti-reverse unit 301, the output end of the third switch tube Q2 is connected to the second sampling unit 304, and the control end of the third switch tube Q2 is connected to the output end of the second connection diode D2 through the third connection resistor R5. Specifically, the third switch tube Q2 may be a triode. When the output switch module 100 is turned on, the current at the control end of the third switch tube Q2 may satisfy the condition that the input end and the output end of the third switch tube Q2 are turned on, that is, the load connection module 200 outputs a start signal, so that the third switch tube Q2 is turned on, and the corresponding detection switch unit 302 is turned on, and the third connection resistor R5 may make the third switch tube Q2 work in the saturation region.

[0048] In the embodiment of the utility model, Figure 4 As shown, the first sampling unit 303 may include a first filter resistor R7 and a first filter capacitor C2, the first end of the first filter resistor R7 is connected to the input end of the anti-reverse unit 301, the second end of the first filter resistor R7 is connected to the first end of the first filter capacitor C2, the second end of the first filter capacitor C2 is grounded, and the first end of the first filter capacitor C2 outputs the first detection signal. The first sampling signal collects the voltage signal of the output end of the current limiting resistor R6, and the first filter resistor R7 and the first filter capacitor C2 play a sampling and filtering role, so that the output end of the first sampling signal outputs the first detection signal.

[0049] In the embodiment of the utility model, the second sampling unit 304 may include a second filter resistor R8, a second filter capacitor C3 and a sampling resistor R9, the first end of the second filter resistor R8 is connected to the output end of the third switch tube Q2, the second end of the second filter resistor R8 is connected to the first end of the second filter capacitor C3, the second end of the second filter capacitor C3 is grounded, the first end of the sampling resistor R9 is connected to the second end of the first filter resistor R7, the second end of the sampling resistor R9 is grounded, and the first end of the sampling resistor R9 outputs the second detection signal. In the second sampling unit 304, the second filter resistor R8 and the second filter capacitor C3 play the role of sampling and filtering, the sampling resistor R9 plays the role of voltage division with the second filter resistor R8, and the second detection signal output by the second sampling unit 304 is a voltage signal at both ends of the sampling resistor R9.

[0050] like Figure 4As shown, in the above power output control circuit, when the output switch module 100 is not turned on, the abnormality detection module 300 can detect the state of the load line. Wherein, when the load line is normal, the detection power supply V2, the anti-reverse diode D3, the load connection module 200 and the circuit where the load is located are turned on. Since the voltage of the detection power supply V2 is less than the power supply V1, the current generated in this circuit is small, so the voltage across the first connection resistor R3 and the second connection resistor R4 can be small, which cannot satisfy the conditions for the first connection diode D1 and the second connection diode D2 to be turned on. The circuit at the control end of the third switch tube Q2 cannot satisfy the conditions for making the third switch tube Q2 turned on. The third switch tube Q2 is not turned on, and the first sampling unit 303 and the second sampling unit 304 output a set of first detection signals and second detection signals respectively; if the load line is broken, it will cause the detection There is no current in the detection power supply V2, the anti-reverse diode D3, the load connection module 200 and the circuit where the load is located, the third switch tube Q2 is not turned on, and the first sampling unit 303 and the second sampling unit 304 output a set of first detection signals and second detection signals accordingly; if the load circuit is disconnected, the current of the detection power supply V2, the anti-reverse diode D3, the load connection module 200 and the circuit where the load is located will increase, and at this time, the voltage across the first connection resistor R3 and the second connection resistor R4 still does not meet the condition that the first connection diode D1 and the second connection diode D2 are turned on, the third switch tube Q2 is not turned on, and the first sampling unit 303 and the second sampling unit 304 output a set of first detection signals and second detection signals accordingly. In the above-mentioned utility model embodiment, when the output switch module 100 is not turned on, the data of the three sets of first detection signals and second detection signals obtained by the abnormality detection module 300 in the three conditions of normal, disconnected and short-circuited load circuits are different, and the abnormality detection module 300 can detect disconnection and short-circuit faults of the load circuit.

[0051] like Figure 4As shown, in the above power output control circuit, when the output switch module 100 is turned on, the abnormality detection module 300 can detect the state of the load line. Wherein, when the load line is normal, the voltage of the power supply V1 is greater than the voltage of the detection voltage, the anti-reverse unit 301 is turned off, and the loop where the power supply V1, the output switch module 100 and the load connection module 200 are located is turned on. At this time, the current in the loop is greatly increased, the first connection diode D1 and the second connection diode D2 are turned on, the total voltage across the first connection resistor R3 and the second connection resistor R4 is clamped, and the current flowing through the first connection resistor R3 and the second connection resistor R4 is small. The excess current flows through the first connection diode D1 and the second connection diode D2, and the condition that the third switch tube Q2 is turned on is met. The first sampling unit 303 and the second sampling unit 304 output a set of first detection signals and second detection signals accordingly; if the load line is disconnected, it will cause no current in the loop, and the third switch tube Q2 is not turned on. At this time, the first sampling unit 303 and the second sampling unit 304 output a set of first detection signals and second detection signals accordingly. In the above utility model embodiment, when the output switch module 100 is turned on, the data of the first detection signal and the second detection signal obtained by the abnormality detection module 300 when the load line is normal and short-circuited are different, and the abnormality detection module 300 can detect the fault of the load line being broken.

[0052] In the embodiment of the utility model, Figure 2 As shown, the power output control circuit may further include a self-powered connection module, which is connected to the output end of the load connection module 200 and the control end of the output switch module 100, and is used to keep the output switch module 100 turned on when the power supply V1 is output. After the output switch module 100 is turned on, when there is voltage at the output end of the load connection module 200, the self-powered connection module may realize self-power supply through the power supply V1, thereby ensuring that the power output control circuit supplies power to the load stably.

[0053] Specifically, Figure 4 As shown, the above-mentioned self-powered connection module 500 may include a third voltage-dividing resistor R10, a fourth voltage-dividing resistor R11 and a voltage-stabilizing diode D5, the two ends of the third voltage-dividing resistor R10 are respectively connected to the output end of the load connection module 200 and the control end of the output switch module, the first end of the fourth voltage-dividing resistor R11 is connected to the control end of the output switch module, the second end of the fourth voltage-dividing resistor R11 is grounded, and the voltage-stabilizing diode D5 is connected in parallel with the fourth voltage-dividing resistor R11.

[0054] In the above power output control circuit, when the output control signal is at a low level, the input and output ends of the output switch module 100 are not conducting, and the power supply V1 is not output; when the output control signal is at a high level, the input and output ends of the output switch module 100 are conducting, and the power supply V1 supplies power to the load through the load connection module 200. When there is voltage at the output end of the load connection module 200, the output control signal can be switched to a high impedance value, and the voltage at the output node of the load connection module 200 forms a path to the ground through the third voltage-dividing resistor R10 and the fourth voltage-dividing resistor R11. At this time, the voltage at the control end of the first switch tube Q1 is the voltage at both ends of the fourth voltage-dividing resistor R11, and this voltage can continuously maintain the first switch tube Q1 conducting, thereby maintaining the power supply V1 continuously outputting. The voltage-stabilizing diode D5D5 can protect the device connected to the control end of the output switch module 100 from being broken down by high voltage.

[0055] In the embodiment of the utility model, Figure 3 As shown, the above power output control circuit may also include a protection module 400; the load connection module 200 is connected to the self-power connection module and the input end of the load through the protection module 400, and the protection module 400 is used to reduce the voltage at the input end of the load when the output switch module 100 is turned on and the load line is short-circuited. When the output switch module 100 is turned on, the power supply V1 supplies power to the load. If the load line is short-circuited, there is a large current in the loop. At this time, the protection module 400 can make the voltage at the input end of the load sharp, so that the voltage at both ends of the fourth voltage-dividing resistor is too low to maintain the conduction of the first switch tube Q1, the first switch tube Q1 is turned off, and then the second switch tube M1 is turned off, and the power supply V1 does not output. Through this voltage feedback, the components in the circuit can be quickly protected from damage.

[0056] Specifically, Figure 4As shown, the protection module 400 may include a short-circuit protection self-recovery fuse RT, a second voltage-stabilizing capacitor C4, and a transient voltage suppression diode D4. The two ends of the short-circuit protection self-recovery fuse RT are respectively connected to the output end of the load connection module and the input end of the load. The first end of the second voltage-stabilizing capacitor C4 is connected to the output end of the load connection module, the second end of the second voltage-stabilizing capacitor C4 is grounded, the second end of the transient voltage suppression diode D4 is connected to the output end of the short-circuit protection self-recovery fuse RT, and the second end of the transient voltage suppression diode D4 is grounded. When the power supply V1 supplies power to the load and the load line is short-circuited, the action resistance of the short-circuit protection self-recovery fuse RT is greatly increased. At this time, the voltage at the input end of the load drops sharply, which can make the voltage at both ends of the fourth voltage-dividing resistor cross, and the first switch tube Q1 cannot be maintained on. The first switch tube Q1 is turned off, the second switch tube M1 is turned off, and the power supply V1 cannot be output, thereby quickly protecting the components in the circuit from being damaged. The transient voltage suppression diode D4 (TVS tube) can play a role in lightning surge protection.

[0057] In the above-mentioned power output control circuit, when the power supply V1 supplies power to the load and the load line is short-circuited, the protection module 400 is activated, causing the voltage at the input end of the load to drop sharply, and the output switch module 100 is turned off, shutting down the output of the power supply V1. This situation is the same as the state when the load line is short-circuited when the power supply V1 has no output. The detection power supply V2 is used to supply power to the load line. At this time, the voltage across the first connection resistor R3 and the second connection resistor R4 still cannot satisfy the first connection diode D1 and the second connection diode D2 to be turned on. At this time, the first sampling unit 303303 and the second sampling unit 304304 of the abnormality detection module 300 correspondingly output a set of first detection signals and second detection signals. In this way, the abnormality detection module 300 can also detect the state of the load line short circuit when the output switch module 100 is turned on.

[0058] In the embodiment of the utility model, the power supply output control circuit may further include a control module, the control module including an output control terminal, a first detection terminal and a second detection terminal; the output control terminal is connected to the control terminal of the output switch module 100, and is used to send an output control signal to the output switch module 100; the first detection terminal is connected to the output terminal of the first sampling unit 303, and is used to receive a first detection signal; the second detection terminal is connected to the output terminal of the second sampling unit 304, and is used to receive a second detection signal; the control module is used to send an output control signal to the output switch module 100 according to a preset instruction, and is used to judge the state of the load line according to the output control signal, the first detection signal and the second detection signal. Through the control module, the load line can be judged to be normal, short-circuited and open-circuited according to the data of the output control signal, the first detection signal and the second detection signal, and the abnormal situation can be reported when there is a fault in the load line, so as to ensure that the abnormal situation is synchronized to the observer in time, and the faulty line can be repaired in time. The control module may be a single-chip microcomputer.

[0059] In a possible implementation, the power output control circuit can be applied to an alarm system, for example, a fire alarm system, where the load is a non-system communication device in the fire alarm system. Figure 5 As shown, when the on-site environment is normal, there is no fire alarm reported on the controller end of the fire alarm system, and the non-system communication equipment in the fire alarm does not need to be enabled, then the output switch module 100 in the power output control circuit can be controlled not to be turned on, and the power supply V1 output can be turned off, and the load line status can be continuously detected through the abnormal detection module 300. When a short circuit or open circuit is detected in the load line, the control module can report it, and the line fault prompt information can be displayed on the controller screen of the fire alarm system to the fire control room personnel; and when there is a fire alarm in the on-site environment, the controller of the fire alarm receives the fire alarm signal to meet the linkage output conditions, controls the output switch module 100 to be turned on, and the power supply V1 powers on the non-system communication equipment. When a short circuit or open circuit fault is detected during the output of the power supply V1, the line fault prompt information can be displayed on the screen of the fire alarm controller to the fire control room personnel, and the fire control personnel make further processing measures.

[0060] The following is a detailed description of the embodiment of the utility model in conjunction with the overall circuit diagram. Figure 4 The figure shows a complete circuit diagram of a control circuit provided by an embodiment of the utility model. The power supply V1 can be +28V, and the voltage of the detection power supply V2 can be +3.3V.

[0061] CTR is the control terminal of the output switch module 100. Normally, CTR is configured to output a low level. When the power supply V1 needs to output, CTR is configured to output a high level. When the power supply V1 is output, CTR is configured to input a high impedance state. At this time, the power supply V1 automatically maintains the output state. When the output needs to be turned off, the CTR state is changed to output a low level.

[0062] Specifically, when CTR is configured to output a low level, the first switch tube Q1 cannot be turned on, then the G pole and S pole voltages of the second switch tube M1 are equal, the second switch tube M1 is not turned on, and the power supply V1 is not output to the outside; the first voltage stabilizing capacitor C1 and the second voltage stabilizing capacitor C4 play a voltage stabilizing role; when CTR is configured to output a high level, the first switch tube Q1 is turned on, the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are connected in series to divide the power supply V1 and turn it on, the G pole voltage of the second switch tube M1 is the voltage across the second voltage dividing resistor R2 plus the voltage drop of the first switch tube Q1, and the second switch tube M1 The S pole voltage is 28V, and the voltage difference between the G pole and the S pole of the second switch tube M1 reaches the conduction condition of the second switch tube M1. The D pole and the S pole of the second switch tube M1 are turned on, and the voltage at the power output terminal P of the power output control circuit is +28V minus the voltage drop of the second switch tube M1 minus the voltage drop of the parallel circuit of the first connection diode D1, the second connection diode D2, the first connection resistor R3, and the second connection resistor R4; the first connection diode D1 and the second connection diode D2 will clamp the voltage of the first connection resistor R3 and the second connection resistor R4 at 1.4V, and the excess current will flow through this branch of the diode. The two diodes prevent the current flowing through the first connection resistor R3 and the second connection resistor R4 from being too large, causing the resistors to overheat and burn out. P is the positive electrode of the power output control circuit, the negative electrode of the power supply is connected to the ground, and the power output terminal P of the power output control circuit is directly connected to the third voltage-dividing resistor R10. When there is voltage at the power output node P of the power output control circuit, the control terminal CTR of the output switch module 100 is switched to an input high-impedance state, and the voltage at the P node forms a path to the ground through the third voltage-dividing resistor R10 and the fourth voltage-dividing resistor R11. At this time, the control terminal voltage of the first switch tube Q1 is the voltage across the fourth voltage-dividing resistor R11. This voltage can continuously maintain the conduction of the first switch tube Q1, thereby maintaining the continuous output of the +28V power supply of the power supply V1; when the fourth voltage-dividing voltage is greater than 3.3V, the voltage-stabilizing diode D5 can stabilize the control terminal voltage of the first switch tube Q1 at 3.3V, protecting the microcontroller port from being broken down by high voltage.

[0063] The abnormality detection module 300 outputs a first detection signal through the first sampling terminal DE_N and a second detection signal through the second sampling terminal DE_O. The AD sampling value signals of the first sampling terminal DE_N and the second sampling terminal DE_O can be used to determine the load line state. When CTR is in the output low state, the +28V output of the power supply V1 is turned off. Assuming that the load resistance is R 负载 When the line is normal, the current loop is the detection power supply V2, the current limiting resistor R6, the anti-reverse diode D3, the first connection resistor R3, the second connection resistor R4, the short-circuit protection self-recovery fuse RT, R 负载 , GND. Because the voltage of the detection power supply V2 is 3.3V, the voltage is relatively small, so the current is relatively small when the loop is normal, that is, the voltage across the first connection resistor R3 and the second connection resistor R4 is relatively small, which does not meet the requirements of the first connection diode D1 and the second connection diode D2 being turned on. The voltage difference between the input terminal and the control terminal of the third switch tube Q2 is very small, and the third switch tube Q2 is not turned on. At this time, the sampling voltage of the second sampling terminal DE_O is close to U O正常1 =0; the sampling voltage of the first sampling terminal DE_N is U N正常1 =3.3V*(R3+R4+RT+R 负载 ) / (R6+R3+R4+RT+R 负载 ); When the line is broken, there is no current in the circuit. At this time, the sampling voltage of the first sampling terminal DE_N is U N断1 =3.3V, the sampling voltage of the second sampling terminal DE_O is U O断1 =0V; when the loop line is short-circuited, the current in the loop increases, and at this time, the voltage across the first connection resistor R3 and the second connection resistor R4 still does not meet the first connection diode D1 and the second connection diode D2 are turned on, and the third switch tube Q2 is not turned on. At this time, the sampling voltage U of the first sampling terminal DE_N N短1 =3.3V*(R3+R4+RT) / (R6+R3+R4+RT), the sampling voltage U of the second sampling terminal DE_O O短1 = 0 V. The state of the load line can be determined by the data of each group of the first sampling terminal DE_N and the second sampling terminal DE_O.

[0064] When CTR is in input high impedance state, when the load line is normal, V1 is output externally, the second switch tube M1 is turned on, the negative terminal voltage of the anti-reverse diode D3 is 27.3V=28V-0.7V (M1 voltage drop), the anti-reverse diode D3 is turned off, and the sampling voltage of the first sampling terminal DE_N is U N正常2=3.3V, at this time, the current in the loop increases greatly, the first connection diode D1 and the second connection diode D2 are turned on, the total voltage across the first connection resistor R3 and the second connection resistor R4 is clamped at 1.4V, and the current flowing through the branch of the first connection resistor R3 and the second connection resistor R4 is 1.4V / (R80+R81), and the excess current flows through the branch of the first connection diode D1 and the second connection diode D2, then the cathode voltage of the second connection diode D2 is 25.9V=28V-0.7V(M1 voltage drop)-1.4V(D1 and D2 voltage drops), the third switch tube Q2 is turned on, and the output terminal voltage of the third switch tube Q2 is 26.6V=28V-0.7(M1 voltage drop)-0.7(Q2 voltage drop), then the second sampling terminal DE_O sampling voltage U O正常2 =26.6V*R9 / (R8+R9); when the load line is disconnected, there is no current in the circuit, and the third switch tube Q2 is not turned on. At this time, the sampling voltage of the first sampling terminal DE_N is U N断2 =3.3V, the second sampling terminal sampling voltage U O断2 =0V; when the load line is short-circuited to the ground, the short-circuit protection resettable fuse RT is activated, the resistance of RT is greatly increased, most of the voltage is at both ends of RT, and the voltage at P drops sharply. At this time, the resistance voltage at both ends of the fourth voltage-dividing resistor R11 is too low to maintain the first switch tube Q1 on, the first switch tube Q1 is turned off, the second switch tube M1 is turned off, and the V1 output is turned off. It is the same as the short-circuit state when the power supply V1 has no output. The current loop is V2, R6, D3, R3, R4, RT, GND, and the loop becomes V1 power supply. At this time, the voltage at both ends of R3 and R4 still does not meet the requirements of D36 and D37 being on, and Q2 is not on. At this time, the sampling voltage U of the first sampling terminal DE_N N短2 =3.3V*(R3+R4+RT) / (R6+R3+R4+RT), the sampling voltage U of the second sampling terminal DE_O O短2 =0V. Therefore, the sampling voltage state of the first sampling terminal DE_N and the second sampling terminal DE_O can be used to detect and distinguish the load line state when the power supply V1 has no output and outputs, and timely feedback to the host, so as to ensure that the abnormal situation is synchronized to the fire control room personnel in time, and the CTR state can be controlled, the power supply V1 output can be controlled, and the power output can be automatically cut off when short-circuited.

[0065] An embodiment of the utility model further provides an alarm system, comprising any one of the power output control circuits provided by the above technical solutions.

[0066] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power output control circuit, characterized in that: include: An output switch module, wherein the input end of the output switch module is connected to a power supply, and the control end of the output switch module is used to receive an output control signal to control the state of the output switch module; A load connection module, wherein the input end of the load connection module is connected to the output end of the output switch module, the output end of the load connection module is used to be connected to the input end of the load, and the load connection module is used to output a start signal when the output switch module is turned on; The abnormality detection module includes an anti-reverse unit, a detection switch unit, a first sampling unit and a second sampling unit, wherein the input end of the anti-reverse unit is used to be connected to a detection power supply, the detection power supply is smaller than the power supply, the output end of the anti-reverse unit is connected to the input end of the load connection module and the input end of the detection switch unit, the control end of the detection switch unit is connected to the output end of the load connection module and is used to be turned on when receiving the start signal, the first sampling unit is connected to the input end of the anti-reverse unit and is used to output a first detection signal, and the second sampling unit is connected to the input end of the detection switch unit and is used to output a second detection signal.

2. The power output control circuit according to claim 1, characterized in that: The output switch module includes a first switch tube, a second switch tube, a first voltage-dividing resistor, a second voltage-dividing resistor and a first voltage-stabilizing capacitor; The control end of the first switch tube is used to receive an output control signal, the input end of the first switch tube is connected to the power supply through the first voltage-dividing resistor, and the second end of the first switch tube is grounded through the second voltage-dividing resistor; The control end of the second switch tube is connected to the input end of the first switch tube, the input end of the second switch tube is connected to the power supply, and the output end of the second switch tube is connected to the input end of the load connection module; A first end of the first voltage-stabilizing capacitor is connected to an input end of the second switch tube, and a second end of the first voltage-stabilizing capacitor is grounded.

3. The power output control circuit according to claim 2, characterized in that: The load connection module includes a first connection resistor, a second connection resistor, a first connection diode and a second connection diode; The first end of the first connection resistor is connected to the output end of the output switch module, the second end of the first connection resistor is connected to the first end of the second connection resistor, and the second end of the second connection resistor is connected to the input end of the load; The anode of the first connection diode is connected to the input end of the first connection resistor, the cathode of the first connection diode is connected to the anode of the second connection diode, and the cathode of the second connection diode is connected to the output end of the second connection resistor.

4. The power output control circuit according to claim 3, characterized in that: The sampling unit further comprises a current limiting unit, and the input end of the anti-reverse unit is connected to the detection power supply through the current limiting unit.

5. The power output control circuit according to claim 4, characterized in that: The detection switch unit includes a third switch tube and a third connection resistor, the input end of the third switch tube is connected to the output end of the anti-reverse unit, the output end of the third switch tube is connected to the second sampling unit, and the control end of the third switch tube is connected to the output end of the second connection diode through the third connection resistor.

6. The power output control circuit according to claim 5, characterized in that: The first sampling unit includes a first filter resistor and a first filter capacitor, the first end of the first filter resistor is connected to the input end of the anti-reverse unit, the second end of the first filter resistor is connected to the first end of the first filter capacitor, the second end of the first filter capacitor is grounded, and the first end of the first filter capacitor outputs the first detection signal.

7. The power output control circuit according to claim 6, characterized in that: The second sampling unit includes a second filter resistor, a second filter capacitor and a sampling resistor, wherein a first end of the second filter resistor is connected to the output end of the third switch tube, a second end of the second filter resistor is connected to the first end of the second filter capacitor, a second end of the second filter capacitor is grounded, a first end of the sampling resistor is connected to the second end of the first filter resistor, a second end of the sampling resistor is grounded, and a first end of the sampling resistor outputs the second detection signal.

8. The power output control circuit according to claim 2, characterized in that: It also includes a self-powered connection module, which is connected to the output end of the load connection module and the control end of the output switch module. The self-powered connection module is used to keep the output switch module turned on when the power supply is output.

9. The power output control circuit according to claim 8, characterized in that: The self-powered connection module includes a third voltage-dividing resistor, a fourth voltage-dividing resistor and a voltage-stabilizing diode. The two ends of the third voltage-dividing resistor are respectively connected to the output end of the load connection module and the control end of the output switch module. The first end of the fourth voltage-dividing resistor is connected to the control end of the output switch module. The second end of the fourth voltage-dividing resistor is grounded. The voltage-stabilizing diode is connected in parallel with the fourth voltage-dividing resistor.

10. The power output control circuit according to claim 9, characterized in that: It also includes a protection module; the load connection module is connected to the self-powered connection module and the input end of the load through the protection module, and the protection module is used to reduce the input end voltage of the load when the output switch module is turned on and the load line is short-circuited.

11. The power output control circuit according to claim 10, characterized in that: The protection module includes a short-circuit protection resettable fuse, a second voltage-stabilizing capacitor and a transient voltage suppression diode. The two ends of the short-circuit protection resettable fuse are respectively connected to the output end of the load connection module and the input end of the load, the first end of the second voltage-stabilizing capacitor is connected to the output end of the load connection module, the second end of the second voltage-stabilizing capacitor is grounded, the second end of the transient voltage suppression diode is connected to the output end of the short-circuit protection resettable fuse, and the second end of the transient voltage suppression diode is grounded.

12. The power output control circuit according to any one of claims 1 to 11, characterized in that: It also includes a control module, which includes an output control terminal, a first detection terminal and a second detection terminal; The output control end is connected to the control end of the output switch module, and is used to send an output control signal to the output switch module; the first detection end is connected to the output end of the first sampling unit, and is used to receive the first detection signal; the second detection end is connected to the output end of the second sampling unit, and is used to receive the second detection signal.

13. An alarm system, characterized in that: Comprising the power output control circuit as described in any one of claims 1-12.

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