Power supply output circuit, power supply device and alarm system

Abstract

The utility model discloses a power supply output circuit, a power supply device and an alarm system, and the power supply output circuit comprises an output circuit, the input end of which is used for accessing a power supply voltage; the input end of the control circuit is used for accessing power supply voltage, and the control end is connected with the controlled end of the output circuit; the feedback circuit is connected with the output end of the output circuit and the controlled end of the control circuit, and the feedback circuit is used for outputting a second trigger signal to the control circuit when the output voltage of the output circuit is smaller than the preset voltage, so that the control circuit controls the output circuit to stop outputting the power supply voltage based on the second trigger signal and the power supply voltage. According to the technical scheme of the utility model, the output can be automatically turned off when the output circuit has an output short-circuit fault, and the power supply output can be restarted through the pulse signal after the short-circuit fault is eliminated.

Description

Technical Field

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

[0002] In the current automatic fire alarm system, the power line needs to provide power to external devices, such as fire alarm circuits, fan circuits, fire broadcast circuits, fire control circuits, etc., to control the startup of external devices. If the power line is short-circuited, it cannot be effectively protected in time, the device will be seriously heated or even damaged, causing the fire protection system to be paralyzed. Therefore, it is very necessary to accurately and effectively identify and protect the power supply in the alarm system from short circuits and to be able to automatically recover. Utility Model Content

[0003] The main purpose of the utility model is to provide a power supply output circuit, aiming to solve the problem that short-circuit protection cannot be performed in time when a short circuit occurs in the power supply output.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a power supply output circuit, which includes:

[0005] Output circuit, the input terminal is used to access the power supply voltage;

[0006] A control circuit, the input end of which is used to access the supply voltage, and the control end is connected to the controlled end of the output circuit; and

[0007] A feedback circuit is connected to the output end of the output circuit and the controlled end of the control circuit respectively,

[0008] The feedback circuit is used to output a first trigger signal to the control circuit when the output voltage of the output circuit is greater than a preset voltage, so that the control circuit controls the output circuit to output the connected power supply voltage based on the first trigger signal and the power supply voltage;

[0009] The feedback circuit is used to output a second trigger signal to the control circuit when the output voltage of the output circuit is less than a preset voltage, so that the control circuit controls the output circuit to stop outputting the supply voltage based on the second trigger signal and the supply voltage.

[0010] Optionally, the control circuit includes:

[0011] An output control circuit, a controlled end connected to the supply voltage, and an output end connected to the controlled end of the output circuit;

[0012] A control trigger circuit has a controlled end connected to the output end of the feedback circuit, an input end connected to the supply voltage, and an output end connected to the controlled end of the output control circuit.

[0013] Optionally, the output control circuit includes: a first transistor, a second transistor, a first resistor, a second resistor, and a first capacitor;

[0014] The controlled end and input end of the first transistor and the controlled end of the second transistor are all connected to the supply voltage, the output end of the first transistor is connected to the input end of the second transistor, the output end of the second transistor is grounded, the first resistor and the first capacitor are connected in parallel to form a first RC circuit, and the common end of the first transistor and the second transistor is connected to the controlled end of the output circuit via the first RC circuit and the second resistor in sequence.

[0015] Optionally, the power supply output circuit further includes:

[0016] A pulse width modulation circuit, wherein the input end of the pulse width modulation circuit is used to receive a pulse signal, the output end of the pulse width modulation circuit is connected to the controlled end of the control circuit, and the pulse width modulation circuit is used to trigger the control circuit to control the output circuit to output or stop outputting the connected power supply voltage according to the received pulse signal.

[0017] Optionally, the pulse width modulation circuit includes: a first diode, a third resistor, a fourth resistor, a fifth resistor, a second capacitor, and a third transistor;

[0018] The anode of the first diode is used to access the pulse signal, the cathode of the first diode is connected to the controlled end of the control circuit via the third resistor, the anode of the first diode is also connected to the controlled end of the third transistor via the fourth resistor, the second capacitor and the fifth resistor are connected in parallel to form a second RC circuit, the controlled end of the third transistor is connected to its output end via the second RC circuit, the input end of the third transistor is connected to the controlled end of the control circuit, and the output end of the third transistor is grounded.

[0019] Optionally, the feedback circuit includes a sixth resistor and a voltage regulator tube;

[0020] The cathode of the voltage regulator tube is connected to the output end of the output circuit via the sixth resistor, and the anode of the voltage regulator tube is connected to the controlled end of the control circuit.

[0021] Optionally, the power supply output circuit further includes:

[0022] The power output circuit is connected to the input end of the output circuit and the input end of the control circuit respectively, and the power output circuit is used to generate and output the supply voltage.

[0023] Optionally, the power supply output circuit further includes:

[0024] The anti-reverse circuit has an input end connected to the output end of the output circuit and is used to output the power supply voltage output by the output circuit after receiving the power supply voltage, and the signal flow direction of the anti-reverse circuit is from the input end to the output end.

[0025] The utility model also provides a power supply device, which includes the power supply output circuit as described above.

[0026] The utility model also provides an alarm system, which includes an external device and a power supply output circuit as described above, wherein the power supply output circuit is connected to a power supply terminal of the external device;

[0027] Alternatively, the alarm system includes an external device and a power supply device as described above, and the power supply device is connected to a power supply terminal of the external device.

[0028] The technical solution of the utility model adopts a feedback circuit to output a second trigger signal to the control circuit when the output voltage of the output circuit is less than the preset voltage, so that the control circuit controls the output circuit to stop outputting the supply voltage based on the second trigger signal and the supply voltage. That is, when the output circuit has an output short circuit, the output is immediately turned off, thereby avoiding the overheating of the back-end device caused by the output of excessive current, and the off action time is fast, the device heat is low, and the anti-interference ability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 This is a module schematic diagram of an embodiment of a power supply output circuit of the utility model;

[0031] Figure 2 This is a module schematic diagram of another embodiment of the power supply output circuit of the utility model;

[0032] Figure 3 This is a circuit diagram of another embodiment of the power supply output circuit of the utility model.

[0033] Description of Figure Numbers:

[0034]

[0035] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] 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 of 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.

[0037] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0038] The utility model provides a power supply output circuit.

[0039] Reference Figures 1 to 3 , the power supply output circuit comprises:

[0040] The output circuit 10, the input end is used to access the power supply voltage Vcc;

[0041] A control circuit 20, whose input terminal is used to access the power supply voltage Vcc, and whose control terminal is connected to the controlled terminal of the output circuit 10; and

[0042] The feedback circuit 30 is connected to the output end of the output circuit 10 and the controlled end of the control circuit 20 respectively.

[0043] The feedback circuit 30 is used to output a first trigger signal to the control circuit 20 when the output voltage of the output circuit 10 is greater than a preset voltage, so that the control circuit 20 controls the output circuit 10 to output the connected power supply voltage Vcc based on the first trigger signal and the power supply voltage Vcc;

[0044] The feedback circuit 30 is used to output a second trigger signal to the control circuit 20 when the output voltage of the output circuit 10 is less than a preset voltage, so that the control circuit 20 controls the output circuit 10 to stop outputting the supply voltage Vcc based on the second trigger signal and the supply voltage Vcc.

[0045] In this embodiment, the output control circuit 21 can be implemented by using a switch device. The output end of the output control circuit 21 can be used to connect to the external device at the back end; the output control circuit 21 can control the corresponding switch devices therein to be turned on or off, so that each switch device that is turned on can output the connected power supply voltage Vcc to the external device at the back end, thereby realizing power supply for the back end device; or, each switch device that is turned off can stop outputting the power supply voltage Vcc, thereby realizing short circuit protection.

[0046] It is understandable that when a short circuit occurs at the output end of the output control circuit 21, its output voltage will drop. Therefore, in this embodiment, the preset voltage is selected to be greater than the output voltage of the output control circuit 21, but less than the output voltage of the output control circuit 21 when no short circuit occurs (i.e., the power supply voltage Vcc). The feedback circuit 30 can determine whether a short circuit occurs at the output of the output control circuit 21 based on the relationship between the detected output voltage of the output control circuit 21 and the preset voltage, and can output a first trigger signal or a second trigger signal corresponding to the determination result. Specifically: if the output voltage of the output circuit 10 is less than the preset voltage, indicating that a short circuit occurs, then the first trigger signal is output at this time; if the output voltage of the output circuit 10 is greater than the preset voltage, indicating that no short circuit occurs, then the second trigger signal is output at this time.

[0047] The control circuit 20 can be constructed and implemented using switch devices and discrete devices. In this specification, the switch device can be one or more combinations of triodes, MOS tubes, and thyristors; the discrete device can be one or more combinations of devices such as resistors, capacitors, and diodes. When the control circuit 20 receives the first trigger signal, under the action of the first trigger signal and the power supply voltage Vcc, it can control the corresponding switch device in itself to turn on / off to control the voltage of the controlled end of the output circuit 10 to the first voltage level, so that the output circuit 10 can output the connected power supply voltage Vcc normally. When the control circuit 20 receives the second trigger signal, under the action of the second trigger signal and the power supply voltage Vcc, it can control the corresponding switch device in itself to turn on / off to control the voltage of the controlled end of the output circuit 10 to the second voltage level, so that the output circuit 10 can stop outputting the connected power supply voltage Vcc. Among them, one of the first voltage level and the second voltage level can be a high level, and the other can be a low level.

[0048] With such an arrangement, when an output short circuit occurs in the output circuit 10, the output can be immediately shut down, thereby preventing the over-current from overheating the back-end devices. The shut-off time is fast, the device generates low heat, and has strong anti-interference capability.

[0049] Reference Figure 2 and Figure 3, the control circuit 20 comprises:

[0050] An output control circuit 21, a controlled end of which is connected to the power supply voltage Vcc, and an output end of which is connected to the controlled end of the output circuit 10;

[0051] The control trigger circuit 22 has a controlled end connected to the output end of the feedback circuit 30 , an input end connected to the power supply voltage Vcc, and an output end connected to the controlled end of the output control circuit 21 .

[0052] In this embodiment, when receiving the first trigger signal, the control trigger circuit 22 can control the controlled end of the output control circuit 21 to be at a third voltage level under the action of the first trigger signal and the power supply voltage Vcc, so that the output control circuit 21 can control the controlled end voltage of the output circuit 10 to be at the first voltage level under the action of the third voltage level and the power supply voltage Vcc, thereby realizing the normal output of the power supply voltage Vcc.

[0053] When receiving the second trigger signal, the control trigger circuit 22 can control the controlled terminal of the output control circuit 21 to be at the fourth voltage level under the action of the second trigger signal and the power supply voltage Vcc, so that the output control circuit 21 can control the controlled terminal voltage of the output circuit 10 to be at the second voltage level under the action of the fourth voltage level and the power supply voltage Vcc, thereby realizing the output of the power supply voltage Vcc being disconnected. Among them, one of the third voltage level and the fourth voltage level can be a high level, and the other can be a low level.

[0054] Optionally, the output control circuit 21 includes: a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, and a first capacitor C1;

[0055] The controlled end and input end of the first transistor Q1 and the controlled end of the second transistor Q2 are connected to the power supply voltage Vcc, the output end of the first transistor Q1 is connected to the input end of the second transistor Q2, the output end of the second transistor Q2 is grounded, the first resistor R1 and the first capacitor C1 are connected in parallel to form an RC circuit, and the common end of the first transistor Q1 and the second transistor Q2 is connected to the controlled end of the output circuit 10 via the RC circuit and the second resistor R2 in sequence.

[0056] Optionally, the control trigger circuit 22 includes a fourth transistor Q4, and the output circuit 10 may include a fifth transistor Q5.

[0057] Here with Figure 3 Take as an example to explain the working principle of the control circuit 20 in this application. Figure 3In the illustrated embodiment, the first transistor Q1 and the fourth transistor Q4 may be NPN transistors, the second transistor Q2 may be a PNP transistor, and the fifth transistor Q5 may be a P-type MOS transistor. The fourth transistor Q4 may be turned on after receiving the first trigger signal, and pull down the voltage of the controlled terminals of the first transistor Q1 and the second transistor Q2 to the ground voltage, so as to trigger the first transistor Q1 to turn off, and trigger the second transistor Q2 and the fifth transistor Q5 to turn on, so as to output the power supply voltage Vcc to power the back-end external device. The fourth transistor Q4 may be turned off after receiving the second trigger signal, and pull up the voltage of the controlled terminals of the first transistor Q1 and the second transistor Q2 to the power supply voltage Vcc, so as to trigger the first transistor Q1 to turn on, and trigger the second transistor Q2 and the fifth transistor Q5 to turn off, so as to stop outputting the power supply voltage Vcc to power the back-end external device.

[0058] In addition, Figure 3 In the embodiment shown, the power supply output circuit further includes a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The electrical connection relationship among the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 can be referred to. Figure 3 As shown, no limitation is given here.

[0059] Reference Figure 3 , the power supply output circuit also includes:

[0060] A pulse width modulation circuit 40, wherein the input end of the pulse width modulation circuit 40 is used to receive a pulse signal, and the output end of the pulse width modulation circuit 40 is connected to the controlled end of the control circuit 20. The pulse width modulation circuit 40 is used to trigger the control circuit 20 to control the output circuit 10 to output or stop outputting the connected power supply voltage Vcc according to the received pulse signal.

[0061] In this embodiment, the pulse signal may have a cyclic signal period, and the pulse signal may be in a high level state and a low level state in each signal period. When the pulse signal is in a high level state, the pulse width modulation circuit 40 may trigger the control circuit 20 to start and control the output circuit 10 to connect and output the power supply voltage Vcc. Therefore, after the output short circuit fault of the output circuit 10 is resolved, the power supply to the external device can be restored by outputting a pulse signal to the pulse width modulation circuit 40.

[0062] It can be understood that after the output is restored, no matter whether the pulse signal is in a high level state or a low level state, since the feedback circuit 30 resumes outputting the first trigger signal at this time, the controlled terminal potential of the control circuit 20 can always maintain the normal output power supply voltage Vcc of the control output circuit 10 under the action of the first trigger signal, and the power supply output will not be disconnected again due to the pulse signal switching to a low level, thereby realizing automatic restoration of the normal output voltage.

[0063] In an optional embodiment, the signal period of the pulse signal is 5s, wherein the time in the high level state is 10us.

[0064] Optionally, the pulse width modulation circuit 40 includes: a first diode D1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2, and a third transistor Q3;

[0065] The anode of the first diode D1 is used to access the pulse signal, the cathode of the first diode D1 is connected to the controlled end of the control circuit 20 via the third resistor R3, the anode of the first diode D1 is also connected to the controlled end of the third transistor Q3 via the fourth resistor R4, the second capacitor C2 and the fifth resistor R5 are connected in parallel to form a second RC circuit, the controlled end of the third transistor Q3 is connected to its output end via the second RC circuit, the input end of the third transistor Q3 is connected to the controlled end of the control circuit 20, and the output end of the third transistor Q3 is grounded.

[0066] In this embodiment, the third transistor Q3 may also be an NPN transistor. When the pulse signal is in a high level state and the feedback circuit 30 outputs the second trigger signal, the fourth transistor Q4 is turned on. At this time, due to the existence of the second RC circuit, the Vbe of the third transistor Q3 cannot reach the turn-on voltage and is turned off, triggering the output circuit 10 to normally connect and output the power supply voltage Vcc. If the pulse signal continues to be in a high level state, the Vbe of the third transistor Q3 will reach the turn-on voltage and be turned on, pulling the controlled terminal voltage of the control circuit 20 down to the ground voltage, triggering the fourth transistor Q4 to turn off, so that the output circuit 10 stops outputting the power supply voltage Vcc.

[0067] In this way, the output control of the output circuit 10 can be achieved by setting the proportion of the high level state and the low level state in each signal cycle of the pulse signal.

[0068] Reference Figure 3 , the feedback circuit 30 includes a sixth resistor R6 and a voltage regulator tube Z1;

[0069] The cathode of the voltage regulator tube Z1 is connected to the output end of the output circuit 10 via the sixth resistor R6 , and the anode of the voltage regulator tube Z1 is connected to the controlled end of the control circuit 20 .

[0070] In this embodiment, when there is no output short circuit in the output circuit 10, the output power supply voltage Vcc is greater than the stable voltage of the voltage regulator tube Z1, so the voltage regulator tube Z1 is turned on and outputs a first trigger signal of a high level signal. When there is an output short circuit in the output circuit 10, the output power supply voltage Vcc is less than the stable voltage of the voltage regulator tube Z1, so the voltage regulator tube Z1 is turned off and outputs a second trigger signal of a low level signal. The sixth resistor R6 is a current limiting resistor to prevent excessive current from being fed back to the controlled end of the control circuit 20.

[0071] Optionally, the power supply output circuit further includes:

[0072] The power output circuit 50 is connected to the input end of the output circuit 10 and the input end of the control circuit 20 respectively, and the power output circuit 50 is used to generate and output the power supply voltage Vcc.

[0073] In this embodiment, the power output circuit 50 is used to generate and output a stable power supply voltage Vcc, such as a 24V power supply voltage Vcc, so as to ensure the power supply stability of the back-end external devices.

[0074] Optionally, the power supply output circuit further includes:

[0075] The anti-reverse circuit 60 has an input end connected to the output end of the output circuit 10 and is used to output the power supply voltage Vcc output by the output circuit 10 after receiving the power supply voltage Vcc output by the output circuit 10. The signal flow direction of the anti-reverse circuit 60 is from the input end to the output end.

[0076] In this embodiment, the anti-reverse circuit 60 may include a second diode D2 to utilize the unidirectional conduction characteristics of the diode to prevent the signal of the back-end external device from flowing back into the front end (such as the above-mentioned power supply output circuit), thereby achieving protection for the front-end devices.

[0077] The utility model also proposes a power supply device, which includes a power supply output circuit. The specific structure of the power supply output circuit refers to the above-mentioned embodiment. Since the power supply device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0078] The utility model also proposes an alarm system, which includes an external device and a power supply output circuit, or includes an external device and a power supply device. The specific structure of the power supply device and the power supply output circuit refers to the above embodiment. Since the power supply device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here. Among them, the external device can be a fire alarm circuit, a fan circuit, a fire broadcast circuit, a fire control circuit 20, etc., which is not limited in this embodiment.

[0079] The above description is only an optional embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A power supply output circuit, characterized in that: The power supply output circuit comprises: Output circuit, the input terminal is used to access the power supply voltage; A control circuit, the input end of which is used to access the supply voltage, and the control end is connected to the controlled end of the output circuit; and A feedback circuit is connected to the output end of the output circuit and the controlled end of the control circuit respectively, The feedback circuit is used to output a first trigger signal to the control circuit when the output voltage of the output circuit is greater than a preset voltage, so that the control circuit controls the output circuit to output the connected power supply voltage based on the first trigger signal and the power supply voltage; The feedback circuit is used to output a second trigger signal to the control circuit when the output voltage of the output circuit is less than a preset voltage, so that the control circuit controls the output circuit to stop outputting the supply voltage based on the second trigger signal and the supply voltage.

2. The power supply output circuit according to claim 1, characterized in that: The control circuit comprises: An output control circuit, a controlled end connected to the supply voltage, and an output end connected to the controlled end of the output circuit; A control trigger circuit has a controlled end connected to the output end of the feedback circuit, an input end connected to the supply voltage, and an output end connected to the controlled end of the output control circuit.

3. The power supply output circuit according to claim 2, characterized in that: The output control circuit includes: a first transistor, a second transistor, a first resistor, a second resistor, and a first capacitor; The controlled end and input end of the first transistor and the controlled end of the second transistor are both connected to the supply voltage, the output end of the first transistor is connected to the input end of the second transistor, the output end of the second transistor is grounded, the first resistor and the first capacitor are connected in parallel to form a first RC circuit, and the common end of the first transistor and the second transistor is connected to the controlled end of the output circuit via the first RC circuit and the second resistor in sequence.

4. The power supply output circuit according to any one of claims 1 to 3, characterized in that: The power supply output circuit also includes: A pulse width modulation circuit, wherein the input end of the pulse width modulation circuit is used to receive a pulse signal, the output end of the pulse width modulation circuit is connected to the controlled end of the control circuit, and the pulse width modulation circuit is used to trigger the control circuit to control the output circuit to output or stop outputting the connected power supply voltage according to the received pulse signal.

5. The power supply output circuit according to claim 4, characterized in that: The pulse width modulation circuit includes: a first diode, a third resistor, a fourth resistor, a fifth resistor, a second capacitor, and a third transistor; The anode of the first diode is used to access the pulse signal, the cathode of the first diode is connected to the controlled end of the control circuit via the third resistor, the anode of the first diode is also connected to the controlled end of the third transistor via the fourth resistor, the second capacitor and the fifth resistor are connected in parallel to form a second RC circuit, the controlled end of the third transistor is connected to its output end via the second RC circuit, the input end of the third transistor is connected to the controlled end of the control circuit, and the output end of the third transistor is grounded.

6. The power supply output circuit according to claim 1, characterized in that: The feedback circuit includes a sixth resistor and a voltage regulator tube; The cathode of the voltage regulator tube is connected to the output end of the output circuit via the sixth resistor, and the anode of the voltage regulator tube is connected to the controlled end of the control circuit.

7. The power supply output circuit according to claim 1, characterized in that: The power supply output circuit also includes: The power output circuit is connected to the input end of the output circuit and the input end of the control circuit respectively, and the power output circuit is used to generate and output the supply voltage.

8. The power supply output circuit according to claim 1, characterized in that: The power supply output circuit also includes: The anti-reverse circuit has an input end connected to the output end of the output circuit and is used to output the power supply voltage output by the output circuit after receiving the power supply voltage, and the signal flow direction of the anti-reverse circuit is from the input end to the output end.

9. A power supply device, characterized in that: The power supply device comprises a power supply output circuit as described in any one of claims 1-8.

10. An alarm system, characterized in that: The alarm system comprises an external device and a power supply output circuit as claimed in any one of claims 1 to 8, wherein the power supply output circuit is connected to a power supply terminal of the external device; Alternatively, the alarm system includes an external device and the power supply device as claimed in claim 9, and the power supply device is connected to a power supply terminal of the external device.

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