CN218958547U - Reverse connection preventing circuit, intelligent gateway and remote water meter system - Google Patents
Reverse connection preventing circuit, intelligent gateway and remote water meter system Download PDFInfo
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- CN218958547U CN218958547U CN202223062243.7U CN202223062243U CN218958547U CN 218958547 U CN218958547 U CN 218958547U CN 202223062243 U CN202223062243 U CN 202223062243U CN 218958547 U CN218958547 U CN 218958547U
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Abstract
The application relates to the technical field of control circuits, in particular to an anti-reverse connection circuit, an intelligent gateway and a remote water meter system, wherein the anti-reverse connection circuit comprises: the device comprises a detection unit, a comparison unit, a control unit, a switch unit and an interface unit; the switch unit comprises a first end, a second end and a control end, wherein the first end is connected with an external power supply, the second end is connected with the interface unit, and the control end is connected with the control unit; one end of the detection unit is connected with the first end of the switch unit, and the first end of the switch unit is detected; the first input end of the comparison unit is connected with the other end of the detection unit and is used for receiving signals output by the detection unit; the second input end of the comparison unit is grounded; the output end of the comparison unit is connected with the control unit and is used for outputting signals to the control unit; the input end of the control unit is connected with the comparison unit, the output end of the control unit is connected with the control end of the switch unit, the control unit sends a control signal to the switch unit, and the connection or disconnection of the first end and the second end of the switch unit is controlled.
Description
Technical Field
The embodiment of the application relates to the technical field of control circuits, in particular to an anti-reverse connection circuit, an intelligent gateway and a remote water meter system.
Background
At present, the remote water meter is used as a novel electronic intelligent water meter, has a full-automatic meter reading function, and greatly improves meter reading efficiency compared with the traditional mechanical water meter which needs to rely on manual meter reading. However, electronic remote water meters require proper access to a power source to function properly.
The inventor of the application finds that if the measuring instrument is connected with the power supply in a reverse way, the measuring instrument is damaged irreversibly if the measuring instrument is connected with the positive electrode and the negative electrode of the power supply in a reverse way.
Disclosure of Invention
In view of the above problems, embodiments of the present application provide an anti-reverse connection circuit, an intelligent gateway, and a remote water meter system, which avoid irreversible damage caused by reverse connection with a power supply when a measuring instrument is connected to the power supply.
According to an aspect of an embodiment of the present application, there is provided an anti-reverse connection circuit including: the device comprises a detection unit, a comparison unit, a control unit, a switch unit and an interface unit; the switch unit comprises a first end, a second end and a control end, wherein the first end of the switch unit is connected with an external power supply, the second end of the switch unit is connected with the interface unit, and the control end of the switch unit is connected with the control unit; one end of the detection unit is connected with the first end of the switch unit and is used for detecting the first end of the switch unit; the first input end of the comparison unit is connected with the other end of the detection unit and is used for receiving the detection signal output by the detection unit; the second input end of the comparison unit is grounded; the output end of the comparison unit is connected with the control unit and is used for outputting a comparison signal to the control unit; the input end of the control unit is connected with the comparison unit, the output end of the control unit is connected with the control end of the switch unit, and the control unit is used for sending a control signal to the switch unit according to the comparison signal and controlling the connection or disconnection of the first end of the switch unit and the second end of the switch unit; when the interface unit is idle or is normally connected with external electric equipment, the detection unit detects that the first end of the switch unit is in a first voltage state, and then sends a first detection signal to the comparison unit; the comparison unit compares the first detection signal with a signal of a second input end of the comparison unit, and outputs a first comparison signal to the control unit through an output end of the comparison unit; the control unit controls the first end of the switch unit to be connected with the second end of the switch unit according to the first comparison signal; when the external electric equipment is reversely connected with the interface unit, the detection unit detects that the first end of the switch unit is in a second voltage state, a second detection signal is sent to the comparison unit, the comparison unit compares the second detection signal with a signal of the second input end of the comparison unit, and a second comparison signal is output to the control unit through the output end of the comparison unit; the control unit controls the first end of the switch unit to be disconnected from the second end of the switch unit according to the second comparison signal.
In an alternative way, the switching unit comprises a relay; the first end of the contact switch of the relay is connected with one end of the detection unit, the second end of the contact switch of the relay is connected with the interface unit, and the control end of the relay is connected with the output end of the control unit; the control unit controls the contact switch of the relay to be connected or disconnected through the control signal.
In an alternative manner, the detection unit includes a first voltage dividing resistor, a second voltage dividing resistor, and a diode; one end of the first voltage dividing resistor is connected with the first end of the switch unit, and the other end of the first voltage dividing resistor is respectively connected with one end of the second voltage dividing resistor and the first input end of the comparison unit, and is used for inputting the detection signal to the comparison unit; the other end of the second voltage dividing resistor is connected with the positive electrode end of the diode.
In an alternative manner, the comparison unit comprises a voltage comparator and an N-channel field effect transistor; the voltage comparator comprises a first input end, a second input end and an output end, the second input end of the voltage comparator is grounded, and the output end of the voltage comparator is connected with the grid electrode of the N-channel field effect transistor; the source electrode of the N-channel type field effect tube is grounded, and the drain electrode of the N-channel type field effect tube is connected with the input end of the control unit; the voltage comparator generates a control comparison signal after comparing a signal of a first input end of the voltage comparator with a signal of a second input end of the voltage comparator, and the control comparison signal controls the N-channel type field effect transistor to be connected or disconnected through a grid electrode of the N-channel type field effect transistor.
In an alternative way, the comparing unit further comprises a zener diode; the zener diode is connected to the first input of the voltage comparator.
In an alternative manner, the comparison unit further includes a first pull-up resistor and a second pull-up resistor; the output end of the voltage comparator is connected with the first pull-up resistor; and the drain electrode of the N-channel field effect transistor is connected with the second pull-up resistor.
In an alternative manner, the anti-reverse connection circuit further comprises a first isolated power supply unit and a signal isolator; the detection unit and the switch unit are connected with the external power supply through the first isolation power supply unit; the control unit is respectively connected with the comparison unit and the switch unit through the signal isolator.
According to another aspect of the embodiments of the present application, there is provided an intelligent gateway, including an anti-reverse circuit as described in any one of the above.
In an alternative manner, the intelligent gateway further comprises an alarm circuit and a DC-DC circuit; the control unit is connected with the alarm circuit, and sends an alarm signal to the alarm circuit when the control unit controls the switch unit to be disconnected; the DC-DC circuit comprises a DC-DC unit and a second isolation power supply unit; the output end of the DC-DC unit is connected with the input end of the second isolation power supply unit, and the output end of the second isolation power supply is used for providing power for the reverse connection prevention circuit.
According to another aspect of the embodiments of the present application, there is provided a remote water meter system, including an intelligent gateway as described in any one of the above, a remote water meter, and a cloud internet of things platform; the intelligent gateway is connected with the cloud internet of things platform; the remote water meter is connected with the intelligent gateway; the cloud internet of things platform operates the remote water meter through the intelligent gateway.
According to the embodiment of the application, the switch unit, the detection unit, the comparison unit and the control unit are arranged, so that the access condition of external electric equipment can be monitored in real time. When the system is electrified, the detection unit detects that the external electric equipment is correctly connected to the interface unit or the interface unit is idle, a detection signal is output to the comparison unit, the comparison unit outputs a comparison signal to the control unit according to the detection signal, the control unit outputs a control signal according to the comparison signal, and the control signal controls the switch unit to be connected, so that the interface unit can be connected to an external power supply through the switch unit. When the detecting unit detects abnormal access of external electric equipment, the detecting unit outputs a detecting signal to the comparing unit, the comparing unit outputs a comparing signal to the control unit according to the detecting signal, the control unit outputs a control signal to the switch unit according to the comparing signal, and the switch unit is controlled to be disconnected, so that the power supply of the interface unit is cut off, irreversible damage caused when the external electric equipment is reversely connected with the interface unit is avoided, the structure is simple, the whole-course automatic control is realized, and damage to the circuit is avoided.
The foregoing description is only an overview of the technical solutions of the embodiments of the present application, and may be implemented according to the content of the specification, so that the technical means of the embodiments of the present application can be more clearly understood, and the following detailed description of the present application will be presented in order to make the foregoing and other objects, features and advantages of the embodiments of the present application more understandable.
Drawings
The drawings are only for purposes of illustrating embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
fig. 1 shows a block diagram of an anti-reverse connection circuit provided in an embodiment of the present application;
FIG. 2 illustrates an anti-reverse circuit diagram provided by another embodiment of the present application;
fig. 3 shows an intelligent gateway provided in an embodiment of the present application;
FIG. 4 shows a DC-DC circuit diagram provided by an embodiment of the present application;
fig. 5 shows a remote water meter system provided in an embodiment of the present application.
Detailed Description
Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein.
At present, along with development of science and technology, the intelligent measuring instrument gradually replaces the traditional mechanical measuring instrument which needs to rely on manual measurement due to the function of full-automatic measurement, so that the measuring efficiency is greatly improved, and the intelligent measuring instrument is widely applied to daily life of people. For example, it can be used for measuring the water consumption, electricity consumption, etc. of residents.
The inventor of the application notes that the intelligent measuring instrument can work normally only when the power supply is correctly connected, and if the intelligent measuring instrument is reversely connected with the positive electrode and the negative electrode of the power supply, the inside of the measuring instrument is not provided with a corresponding protection circuit, so that the measuring instrument can be irreversibly damaged. In the prior art, a diode is commonly used as an anti-reverse connection circuit, and the unidirectional conductivity of the diode is utilized to realize the anti-reverse connection protection. However, when a large current is input, the input power is relatively large, and the corresponding heat generation amount is increased, so that the diode breaks down to damage the circuit board, and therefore, the circuit board is generally suitable for a small-current circuit and is not suitable for a circuit with a large current. Meanwhile, after the circuit is damaged, the circuit needs to be replaced manually to continue to be used. In addition, the existing measuring instrument is reversely connected, and after the circuit is protected, the circuit is usually required to be reset manually, so that the operation is troublesome.
Based on the above consideration, in order to solve the problem that external electric equipment such as an intelligent measuring instrument and the like is damaged when being reversely connected with a power supply, the inventor has conducted intensive research and has proposed an anti-reverse connection protection circuit, through setting a switch unit, a detection unit, a comparison unit and a control unit, the access condition of the external electric equipment can be monitored in real time, when the detection unit detects that the external electric equipment is abnormally accessed, a detection signal is output to the comparison unit, the comparison unit outputs a comparison signal to the control unit according to the detection signal, the control unit outputs a control signal to the switch unit according to the comparison signal, the switch unit is controlled to be disconnected, thereby cutting off the power supply of the interface unit, avoiding irreversible damage caused when the external electric equipment is reversely connected with the interface unit and avoiding damage to the circuit itself. Meanwhile, when the access unit is detected to be idle or normally connected with external electric equipment, the automatic control switch unit is turned on, so that automatic control is realized, manual reset is avoided, and the workload is greatly reduced. In addition, prevent reverse circuit can also be applied to intelligent gateway in, intelligent gateway can be connected with intelligent measuring instrument to be connected with thing networking high in the clouds platform through the router, send down the break-make command to intelligent gateway connection through thing networking high in the clouds platform, and then control intelligent measuring instrument's break-make state, thereby realize saving cost, reduce the purpose of energy consumption. When the intelligent measuring instrument is required to perform measurement work, an electrifying command is issued through the cloud platform of the Internet of things, so that the intelligent measuring instrument is connected to a power supply and works; after the measurement is finished, a power-off command can be issued through the cloud platform of the Internet of things, the external power supply of the intelligent measuring instrument is cut off, and further the measurement is stopped, so that the cost can be saved, and the energy consumption can be reduced.
The reverse connection preventing circuit disclosed by the embodiment of the application can be used in an intelligent measuring instrument, but is not limited to the intelligent measuring instrument, and can also be used for external electric equipment which can normally work only by correctly connecting the anode and the cathode of a power supply. The embodiments of the present application will be described by taking a remote water meter as an example, and the present application is not limited to the remote water meter.
Fig. 1 shows a structure diagram of an anti-reverse connection circuit provided in an embodiment of the present application, and the anti-reverse connection circuit 100 includes an interface unit 1100, a switch unit 1200, a detection unit 1300, a comparison unit 1400, and a control unit 1500.
The switching unit 1200 includes a first end, a second end, and a control end, the first end of the switching unit 1200 is connected to the external power source VIN, the second end of the switching unit 1200 is connected to the interface unit 1100, and the control end of the switching unit 1200 is connected to the control unit 1500. The first terminal of the switch unit 1200 may be directly connected or indirectly connected to the external power source VIN.
One end of the detecting unit 1300 is connected to the first end of the switching unit 1200, for detecting the first end of the switching unit 1200.
A first input end of the comparing unit 1400 is connected to the other end of the detecting unit 1300, and is used for receiving the detecting signal output by the detecting unit 1300; a second input terminal of the comparison unit 1400 is grounded; an output terminal of the comparing unit 1400 is connected to the control unit 1500, and is configured to output a comparison signal to the control unit 1500.
An input end of the control unit 1500 is connected to the comparing unit 1400, an output end of the control unit 1500 is connected to a control end of the switching unit 1200, and the control unit 1500 is configured to send a control signal to the switching unit 1200 according to the comparing signal, and control connection or disconnection of the first end of the switching unit 1200 and the second end of the switching unit 1200. The control terminal of the switch unit 1200 may be directly connected to the control unit 1500 or indirectly connected thereto.
When the interface unit 1100 is idle or normally connected to an external electric device, the detecting unit 1300 detects that the first terminal of the switching unit 1200 is in the first voltage state, and sends a first detection signal to the comparing unit 1400. The comparing unit 1400 compares the first detection signal with the signal of the second input terminal of the comparing unit 1400, and outputs the first comparison signal to the control unit 1500 through the output terminal of the comparing unit 1400. The control unit 1500 controls the first terminal of the switching unit 1200 to be connected to the second terminal of the switching unit 1200 according to the first comparison signal.
When the external electric device is reversely connected to the interface unit 1100, the detecting unit 1300 detects that the first end of the switching unit 1200 is in the second voltage state, and sends a second detection signal to the comparing unit 1400, and the comparing unit 1400 compares the second detection signal with the signal of the second input end of the comparing unit 1400 according to the second detection signal, and outputs the second comparison signal to the control unit 1500 through the output end of the comparing unit 1400. The control unit 1500 controls the first terminal of the switching unit 1200 to be disconnected from the second terminal of the switching unit 1200 according to the second comparison signal.
As shown in fig. 1, in the embodiment of the present application, the switch unit 1200 is used for connecting the interface unit 1100 and the external power source VIN, the first end of the switch unit 1200 may be directly or indirectly connected to the external power source VIN, and the second end of the switch unit 1200 is connected to the interface unit. When the first end of the switching unit 1200 is connected to the second end of the switching unit 1200, the interface unit 1100 may access the external power source VIN through the switching unit 1200; when the first end of the switching unit 1200 and the second end of the switching unit 1200 are disconnected, the interface unit 1100 cannot access the external power source VIN through the switching unit 1200. The switching unit 1200 has a control terminal, and the first terminal of the switching unit 1200 and the second terminal of the switching unit 1200 are connected or disconnected under the control of the control terminal of the switching unit 1200. The switching unit 1200 may be a variety of types of switches, such as: the digital switch, the relay control switch and the like are only required to have a control function to realize autonomous on-off under control, and the embodiment of the application is not limited.
The detecting unit 1300 is configured to obtain an access condition of the external electric device at the interface unit 1100 by detecting the first end of the switch unit 1200. One end of the detecting unit 1300 is connected to the first end of the switching unit 1200, and when the interface unit 1100 is idle or is normally connected to external electric equipment when the system is powered on, the detecting unit 1300 detects that the first end of the switching unit 1200 is in the first voltage state, and a signal at the first end of the switching unit 1200 is in the normal state, for example, a high level signal; when the external electric device is reversely connected to the interface unit 1100, the voltage signal at the first end of the switch unit 1200 will be abnormally changed due to the reverse connection of the positive electrode and the negative electrode of the external electric device, and the detecting unit 1300 detects that the first end of the switch unit is in the second voltage state, for example: at this time, the signal becomes a low level signal. The detecting unit 1300, by being connected to the first end of the switch unit 1200, can conveniently detect the access condition of the external device through the interface unit 1100, and acquire the access state of the external device in real time. The other end of the detecting unit 1300 is connected to the first input end of the comparing unit 1400, and the detected signal of the first end of the detected switching unit 1200 is sent to the comparing unit 1400 in real time for the comparing unit 1400 to determine.
The comparing unit 1400 is configured to determine according to the detection signal output by the detecting unit 1300, and output a comparison signal. As shown in fig. 1, a first input terminal of the comparing unit 1400 is connected to the detecting unit 1300, and is used for receiving the detection signal output by the detecting unit 1300, and a second input terminal of the comparing unit 1400 is grounded. When the interface unit 1100 is idle or is normally connected to an external electric device, the detecting unit 1300 outputs a first detection signal, such as a high level signal, to the comparing unit 1400 when detecting that the first end of the switch unit 1200 is in the first voltage state, and the comparing unit 1400 outputs a first comparison signal, such as a low level signal, by comparing signals of the first input end of the comparing unit 1400 and the second input end of the comparing unit 1400; when the external electric device is reversely connected to the interface unit 1100, the detecting unit 1300 outputs a second detection signal, such as a low level signal, to the comparing unit 1400 when detecting that the first end of the switching unit 1200 is in the second voltage state, and the comparing unit 1400 outputs a second comparison signal, such as a low level signal, by comparing the signals of the first input end of the comparing unit 1400 and the second input end of the comparing unit 1400. An output terminal of the comparing unit 1400 is connected to an input terminal of the control unit 1500, and a comparison signal is sent to the control unit 1500 in real time. The comparison unit 1400 may be a circuit of various forms, such as: the voltage comparator, the operational amplifier, and the like are not limited in this embodiment as long as they can output a comparison signal by comparing a signal at the first input terminal with a signal at the second input terminal.
The control unit 1500 is configured to output a control signal according to the comparison signal output by the comparison unit 1400. As shown in fig. 1, an input end of the control unit 1500 is connected to an output end of the comparing unit 1400, and is used for receiving a comparison signal sent by the comparing unit 1400, an output end of the control unit 1500 is connected to a control end of the switching unit 1200, and a first end of the switching unit 1200 and a second end of the switching unit 1200 are controlled to be connected or disconnected by outputting the control signal, wherein the control unit 1500 may be directly or indirectly connected to the comparing unit 1400 and the switching unit 1200. When the interface unit 1100 is idle or is normally connected to the external electric device, the comparing unit 1400 outputs the first comparison signal to the control unit, and the control unit 1500 controls the first end of the switch unit 1200 to be connected to the second end of the switch unit 1200 through the control signal, where the control signal may be a low level signal; when the external electric device is reversely connected to the interface unit 1100, the comparing unit 1400 outputs the second comparing signal to the control unit 1500, and the control unit 1500 controls the first terminal of the switching unit 1200 and the second terminal of the switching unit 1200 to be disconnected by the control signal, and the control signal may be a high level signal. The control unit 1500 may be a variety of forms of circuitry, such as: for the control chip, etc., as long as the first terminal and the second terminal of the switching unit can be controlled to be connected or disconnected according to the control signal output by the comparison signal, in the embodiment of the present application, no limitation is made.
When the system is electrified, the detection unit detects that the external electric equipment is correctly connected to the interface unit or the interface unit is idle, a first detection signal is output to the comparison unit, the comparison unit outputs a first comparison signal to the control unit according to the first detection signal, the control unit outputs a first control signal according to the first comparison signal, the switch unit is controlled to be connected through the first control signal, and therefore the interface unit can be connected to an external power supply through the switch unit. When the detecting unit detects that the external electric equipment is abnormally connected, a second detecting signal is output to the comparing unit, the comparing unit outputs a second comparing signal to the control unit according to the second detecting signal, the control unit outputs a second control signal to the switching unit according to the second comparing signal, and the switching unit is controlled to be disconnected, so that the power supply of the interface unit is cut off, irreversible damage caused when the external electric equipment is reversely connected with the interface unit is avoided, the structure is simple, the whole-course automatic control is realized, and damage to the circuit is avoided.
According to the embodiment of the application, the switch unit, the detection unit, the comparison unit and the control unit are arranged, the detection unit can monitor the access condition of external electric equipment in real time, after the detection unit outputs the detection signal to the comparison unit, the comparison unit outputs the comparison signal to the control unit, the control unit controls the first end and the second end of the switch unit to be connected or disconnected through the control signal, and then the interface unit can be connected with the external power supply through the switch unit to provide power for the external electric equipment. When the interface unit is idle or correctly connected with external electric equipment, the switch unit is conducted, and the external electric equipment is connected with an external power supply through the interface unit, so that the external electric equipment is electrified; when external electric equipment is reversely connected with the interface unit, the first end and the second end of the control switch unit are disconnected, so that the interface unit cannot provide power for the external electric equipment, and damage to the external electric equipment due to reverse connection with the interface unit is avoided. Through this embodiment, whole control process is according to the access situation automatic control of outside consumer, and the switch unit does not receive the electric current influence in the circuit, can be applicable in the undercurrent circuit, also can be used in the undercurrent circuit, can not cause harm to circuit itself, moreover, has realized automatic control, has avoided needing manual reset, greatly reduced work load.
In order to make the circuit of the switch unit simpler and more efficient, referring to fig. 2, an embodiment of the present application proposes a switch unit 1200, where the switch unit 1200 is a relay, a first end of a contact switch of the relay is connected to one end of the detecting unit 1300, a second end of the contact switch of the relay is connected to the interface unit 1100, and a control end of the relay is connected to an output end of the control unit 1500; the control unit 1500 controls the contact switch of the relay to be connected or disconnected by a control signal. Wherein the control end of the relay may be directly or indirectly connected to the control unit 1500.
In this embodiment, one end of the contact switch of the relay, i.e. pin No. 3, can be directly or indirectly connected to the external power source VIN, and the other end of the contact switch of the relay, i.e. pin No. 4, is connected to the interface unit 1100. If the two ends of the contact switch of the relay are connected, the interface unit 1100 is connected to the external power source VIN through the contact switch of the relay; if both ends of the contact switch of the relay are opened, the interface unit 1100 cannot be connected to the external power source VIN through the contact switch of the relay. One end of the coil of the relay, namely the No. 1 pin, is connected with the working power supply VCC_33 of the relay, and the other end of the coil of the relay, namely the No. 2 pin, is used as a control end and is connected with the output end of the control unit. The control terminal of the switch unit 1200 may be directly connected to the control unit 1500 or indirectly connected thereto. The control unit 1500 directly or indirectly controls whether a current passes through a coil of the relay through the control signal pwr_en, thereby controlling connection or disconnection of both ends of a contact switch of the relay. When the interface unit is idle or normally connected with external electric equipment, the detecting unit 1300 detects that pin 3 of the contact switch of the relay is in a first voltage state, the first voltage state is in a high voltage state, the detecting unit 1300 sends a first detecting signal to the first input end of the comparing unit 1400, the first detecting signal is a high level signal, the comparing unit 1400 outputs a first comparing signal to the control unit 1500 after comparing signals of the first input end of the comparing unit 1400 and the second input end of the comparing unit 1400, the first comparing signal is a high level signal, the control unit 1500 outputs a control signal pwr_en according to the first comparing signal, the control signal is a low level signal, and the corresponding pwr_en_r signal is also a low level signal, so that a coil of the relay has current to pass through, and two ends of the contact switch of the relay are connected. Accordingly, when the external electric device is reversely connected to the interface unit 1100, the pwr_en signal output by the control unit 1500 is a high level signal, and the corresponding pwr_en_r signal is also a high level signal, so that no current passes through the coil of the relay, and thus both ends of the contact switch of the relay are opened.
Because the relay is internally provided with the contact switch and the coil, the contact switch can be controlled to be switched on or switched off in real time by controlling whether current passes through the coil. Therefore, the switching unit can directly control the connection or disconnection of the first end of the switching unit and the second end of the switching unit through the control signal only by using the relay, so that whether the interface unit can be connected to the external power supply VIN through the relay can be controlled in real time. Meanwhile, by using only the relay as a switching unit, the circuit is simple and efficient.
In order to detect the access condition of the external electric equipment more accurately in real time, referring to fig. 2, an embodiment of the present application proposes a detection unit 1300, where the detection unit 1300 includes a first voltage dividing resistor R1, a second voltage dividing resistor R2, and a diode D1. One end of the first voltage dividing resistor R1 is connected to the first end of the switch unit 1200, and the other end of the first voltage dividing resistor R1 is connected to one end of the second voltage dividing resistor R2 and the first input end of the comparison unit 1400, respectively, for inputting the detection signal to the comparison unit 1400; the other end of the second voltage dividing resistor R2 is connected to the positive terminal of the diode D1.
The voltage dividing circuit is composed of a first voltage dividing resistor R1, a second voltage dividing resistor R2 and a diode D1, one end of the first voltage dividing resistor R1 is connected with the first end of the switch unit 120, the other end of the first voltage dividing resistor R1 is connected with one end of the second voltage dividing resistor R2, the other end of the second voltage dividing resistor R2 is connected with the positive end of the diode D1, and the negative end of the diode D1 is grounded. When the system is powered on, i.e. connected to the external power supply VIN, when the interface unit is idle or is normally connected to the external electric device, the first voltage dividing resistor R1, the second voltage dividing resistor R2 and the diode D1 form a closed loop, and after the first voltage dividing resistor R1 divides the voltage of the connected external power supply VIN, a first detection signal is generated and is input to the first input end of the comparison unit 1400, and at this time, the first detection signal is a high level signal. When the external electric device is reversely connected to the interface unit 1100, the voltage at the first end of the switch unit 1200 is greatly and rapidly reduced due to the influence of the second end, and the first voltage dividing resistor R1, the second voltage dividing resistor R2 and the diode D1 cannot form a closed loop due to the unidirectional conductivity of the diode D1, so that the first voltage dividing resistor R1 cannot divide the connected power supply, and therefore a second detection signal is generated and input to the first input end of the comparison unit, and at this time, the second detection signal is a low level signal.
When the system is powered on, namely the external power supply VIN is connected, if the external electric equipment is reversely connected with the interface unit, namely the external electric equipment is reversely connected with the positive electrode and the negative electrode of the power supply provided by the interface unit, the voltage of the second end of the switch unit is rapidly reduced due to the fact that the second end of the switch unit is connected with the interface unit, and therefore the voltage of the first end of the switch unit connected with the second end of the switch unit is also rapidly reduced, and therefore whether the external electric equipment is reversely connected with the interface unit or not can be judged through detecting the voltage state of the first end of the switch unit. According to the embodiment of the application, one end of the first voltage dividing resistor is connected with the first end of the switch unit, when external electric equipment is reversely connected with the interface unit, the voltage of the first end of the switch unit is affected by the second end to be rapidly reduced, the voltage change state of the first end of the switch unit can be monitored in real time through the voltage dividing circuit, and the detection signal is timely output to the comparison unit.
In order to determine the access condition of the external electric device more accurately in real time, referring to fig. 2, the embodiment of the application proposes a comparison unit 1400, where the comparison unit 1400 includes a voltage comparator U1 and an N-channel field effect transistor Q1. The voltage comparator U1 comprises a first input end, a second input end and an output end, the second input end of the voltage comparator U1 is grounded, and the output end of the voltage comparator U1 is connected with the grid electrode of the N-channel field effect transistor Q1. The source of the N-channel field effect transistor Q1 is grounded, and the drain of the N-channel field effect transistor Q1 is connected to the input terminal of the control unit 150. The voltage comparator U1 generates a control comparison signal after comparing a signal of a first input end of the voltage comparator U1 with a signal of a second input end of the voltage comparator U1, and the control comparison signal controls the on or off of the N-channel type field effect transistor Q1 through a grid electrode of the N-channel type field effect transistor Q1. The drain of the N-channel fet Q1 may be directly or indirectly connected to the input terminal of the control unit 1500.
In this embodiment, the positive phase input end of the voltage comparator U1, i.e. pin No. 1, is the first input end, the negative phase input end of the voltage comparator U1, i.e. pin No. 2, is the second input end, the first input end of the voltage comparator U1 is connected with the detection unit, the second input end of the voltage comparator U1 is grounded, the power input end of the voltage comparator U1, i.e. pin No. 3, is connected with the working power source vcc_33, and pin No. 4 of the voltage comparator U1 is grounded. The output end of the voltage comparator U1, namely a pin 5, is connected with the grid electrode of the N-channel field effect transistor Q1. The drain electrode of the N-channel field effect transistor Q1 is connected to the input end of the control unit 1500, and is connected to the operating power vcc_33, and the source electrode of the N-channel field effect transistor Q1 is grounded. When the interface unit 1100 is idle or normally connected to an external electric device, the first detection signal output by the detection unit through the first voltage dividing resistor R1 is a high level signal, at this time, the voltage of the first input end of the voltage comparator U1 is higher than the voltage of the second input end of the voltage comparator U1, so that the control comparison signal output by the voltage comparator U1 to the gate of the N-channel field effect transistor is a high level signal, and the voltage between the gate and the source of the N-channel field effect transistor Q1 is greater than the turn-on voltage of the N-channel field effect transistor Q1, so that the N-channel field effect transistor Q1 is turned on, at this time, the drain voltage of the N-channel field effect transistor Q1 is at a low level, i.e., the mcu_con_r signal is a low level signal, and the comparison signal mcu_con obtained by the corresponding control unit is also a low level signal.
When the external electric equipment is abnormally connected to the interface unit, the second detection signal output by the detection unit through the first voltage dividing resistor R1 is a low-level signal, and the condition that the voltage of the first input end of the voltage comparator is higher than that of the second input end of the voltage comparator is not met, so that the control comparison signal output by the voltage comparator U1 to the grid electrode of the N-channel type field effect transistor Q1 is a low-level signal, the voltage between the grid electrode and the source electrode of the N-channel type field effect transistor Q1 is smaller than the on voltage of the N-channel type field effect transistor Q1, the N-channel type field effect transistor is in an off state, the drain voltage of the N-channel type field effect transistor Q1 is at a high level at the moment, namely the MCU_CON_R signal is a high-level signal, and the comparison signal MCU_CON obtained by the corresponding control unit 1500 is also a high-level signal.
In this embodiment of the present application, the first input end of the voltage comparator is connected to the detection unit, and is configured to receive the detection signal, and the second input end of the voltage comparator is fixedly grounded, so that the voltage of the second input end is fixed. The output end of the voltage comparator outputs a control comparison signal by comparing the signal of the first input end of the voltage comparator with the signal of the second input end of the voltage comparator, and when external electric equipment is correctly connected or reversely connected with the interface unit, the signals input to the first input end of the voltage comparator by the detection unit are correspondingly different, so that the voltage comparator correspondingly outputs different control comparison signals, and whether the N-channel field effect transistor is conducted or not is further controlled. Because the external electric equipment is only correctly accessed and reversely accessed to the interface unit, the comparison unit needs to generate corresponding stable comparison signals to the control unit respectively corresponding to the two access states, and the control unit further controls the switch unit through the control signals according to the comparison signals. The comparison unit utilizes the characteristics of the N-channel field effect transistor, namely, when the field effect transistor is turned on and turned off, the corresponding drain voltage is different and only has two voltage states, so that a stable level signal can be correspondingly output according to the connection state of external electric equipment and the interface unit to reflect whether the current external electric equipment is reversely connected with the interface unit.
In order to improve the stability of the comparing unit and avoid damage to the comparing unit when the voltage is relatively large, referring to fig. 2, in the embodiment of the present application, the comparing unit 1400 further includes a zener diode D2. The zener diode D2 is connected to the first input of the voltage comparator U1.
In this embodiment, the positive terminal of the zener diode D2 is connected to the first input terminal of the voltage comparator U1, and the negative terminal of the zener diode D2 is connected to the connection terminal of the first voltage dividing resistor R1 and the switching unit 1200. When the first input terminal of the voltage comparator U1 obtains a partial voltage of the connected external power source VIN through the first voltage dividing resistor R1, the zener diode D2 makes the voltage input from the first input terminal of the voltage comparator U1 within a certain range, thereby protecting the voltage comparator and increasing the stability of the circuit. By adding the zener diode, damage caused by the larger voltage input by the first input end of the voltage comparator can be avoided.
In order to increase the stability of the circuit, the voltage comparator and the N-channel field effect transistor can output stable signals, referring to fig. 2, in the embodiment of the present application, the comparing unit 1400 further includes a first pull-up resistor R3 and a second pull-up resistor R4. The output end of the voltage comparator U1 is connected with a first pull-up resistor R3, and the drain electrode of the N-channel field effect transistor Q1 is connected with a second pull-up resistor R4.
One end of the first pull-up resistor R3 is connected with the output end of the voltage comparator, and the other end of the first pull-up resistor R3 is connected with the working power supply VCC_33, so that when the voltage input by the first input end of the voltage comparator U1 is higher than the voltage input by the second input end of the voltage comparator U1, the voltage comparator U1 can output a stable control comparison signal, and the control comparison signal is a high-level signal at the moment; when the voltage input by the first input terminal of the voltage comparator U1 is lower than the voltage input by the second input terminal of the voltage comparator U1, the voltage comparator U1 outputs a stable control comparison signal, and the control comparison signal is a low level signal. One end of the second pull-up resistor R4 is connected with the drain electrode of the N-channel field effect transistor, and the other end of the second pull-up resistor R4 is connected to the working power supply vcc_33, so that when the control comparison signal output by the voltage comparator U1 controls the on-off state of the N-channel field effect transistor Q1, the control unit 1500 can obtain a stable comparison signal through the drain electrode of the N-channel field effect transistor Q1, and the comparison signal has two states of high level and low level.
If the voltage difference between the first input end voltage of the voltage comparator and the second input end voltage of the voltage comparator is very low, the voltage comparator can be unstable and output an unknown level signal, so that the on-off state of the N-channel field effect transistor is affected. The output end of the voltage comparator is connected with a high level through the first pull-up resistor, so that the output signal of the voltage comparator is prevented from being unstable due to the internal instability, and after the first pull-up resistor is added, the output end of the voltage comparator can stably output a high level signal or a low level signal, and then the N-channel type field effect transistor is controlled to be conducted or disconnected. Similarly, the drain electrode of the N-channel type field effect transistor is connected to a working power supply through a second pull-up resistor, so that the stability of the circuit can be enhanced, when the N-channel type field effect transistor is conducted, the drain electrode is in a low-level stable state, and when the N-channel type field effect transistor is disconnected, the drain electrode is in a high-level stable state.
In order to further increase the stability of the anti-reverse circuit, referring to fig. 2, in the embodiment of the present application, the anti-reverse circuit 100 further includes a first isolated power unit 1600 and a signal isolator 1700. The detection unit 1300 and the switching unit 1200 are connected to the external power source VIN through the first isolated power source unit 1600, and the control unit 1500 is connected to the comparison unit 1400 and the switching unit 1200 through the signal isolator 1700, respectively.
The first isolation power supply unit 1600 can output the power input through the power input end by the power output end, the power voltage cannot change after the input power is output through the first isolation power supply unit 1600, and only the input power supply and the output power supply are isolated, so that the mutual influence of a circuit directly connected to the input power supply end and a circuit directly connected to the output power supply end is avoided. In this embodiment, the power input end of the first isolated power unit 1600 is connected to the external power source VIN, and the output end of the first isolated power unit 1600 outputs the power PVIN, where the voltages of the power source VIN and the power PVIN are the same. The output end of the first isolated power supply unit 1600 is connected to the first ends of the detection unit 1300 and the switch unit 1200, respectively, and the detection unit 1300 and the switch unit 1200 are connected to the power supply PVIN. When the first end of the switch unit 1200 is connected to the second end of the switch unit 1200, the interface unit 1100 obtains the power PVIN output by the first isolated power unit 1600 through the switch unit 1200, thereby providing the power PVIN for the external electric device. Through using first isolation power supply unit, keep apart the power VIN of the power input end of first isolation power supply unit with the power PVIN of power output end, the power PVIN of power output end provides the power for external consumer through switch unit and interface unit, when external consumer, detecting element or comparison unit appear unusual, can not lead to the fact the influence to the power VIN of the power input end of first isolation power supply unit, and then can not influence the circuit of switch-in power VIN end.
The signal isolator 1700 is used for connecting the control unit 1500 with the comparing unit 1400 and the switching unit 1200 respectively, the signal isolator 1700 can output the signal input through the signal input end from the signal output end, the input signal is output through the signal isolator 1700, the signal will not change, only the input signal and the output signal are isolated, the circuits connected through the two ends of the signal isolator 1700 are isolated, and the circuit at the two ends of the signal isolator is prevented from being affected mutually. In this embodiment, the control unit 1500 is connected to the comparing unit 1400 and the switching unit 1200 through the signal isolator 1700, and the signals mcu_con_r and mcu_con passing through the signal isolator 1700 are not changed before and after, but only the mcu_con_r signal and the mcu_con signal are isolated, so that the control unit is prevented from being affected when the external electric equipment or the comparing unit is abnormal. Similarly, the signals pwr_en and pwr_en_r passing through the signal isolator will not change before and after, but only the pwr_en signal and the pwr_en_r signal are isolated, thereby avoiding the control unit from being affected when the external electric equipment or the comparison unit is abnormal.
In this embodiment, by using the isolation power supply unit 1700, the power PVIN connected to the anti-reverse circuit is isolated from the external power VIN, so as to avoid the circuit directly connected to the external power VIN from being affected when the anti-reverse circuit is abnormal. The control unit is indirectly connected with the switch unit and the comparison unit through the signal isolator, so that signal transmission between the control unit and the switch unit and between the control unit and the comparison unit is not affected, the control unit is prevented from being affected when an external electric device or the comparison unit is abnormal, and the stability of the circuit is further improved.
Referring to fig. 3, an embodiment of the present application further provides an intelligent gateway 10, where the intelligent gateway 10 includes an anti-reverse circuit 100. The intelligent gateway 10 is used for controlling the accessed intelligent measuring instrument, when the intelligent measuring instrument is reversely connected, the intelligent measuring instrument can be protected through the intelligent gateway 10, and when the intelligent measuring instrument is correctly accessed, the power supply can be automatically recovered. The anti-reverse connection circuit 100 is identical to the structure and function of the anti-reverse connection circuit 100 in the above embodiment, and the structure and function of the anti-reverse connection circuit 100 can be referred to the above embodiment, and will not be described in detail here.
The intelligent gateway 10 includes a control unit 1600, and the control unit 1600 is connected to the anti-reverse connection circuit 100, and is configured to receive and transmit control signals. The control unit 1600 in the intelligent gateway 10 and the control unit 1500 in the anti-reverse connection circuit 100 may be the same control unit, or may be control units that are mutually interactive and independent, which is not limited in this embodiment of the present application.
Referring to fig. 3, in order to prompt a user in time when an external electric device is reversely connected to the interface unit, the intelligent gateway 10 in the embodiment of the present application includes an alarm circuit 200. The control unit 1600 is connected to the alarm circuit 200, and transmits an alarm signal to the alarm circuit 200 when the control unit 1500 controls the switching unit 1200 to be turned off.
The alarm circuit 200 comprises a resistor and an LED lamp, one end of the resistor is connected with one end of the control unit, the other end of the resistor is connected with the positive end of the LED lamp, and the negative end of the LED lamp is grounded. When the control unit controls the switch unit to be disconnected, the sent alarm signal is a high-level signal, and accordingly, the LED lamp is lightened to prompt a user that external electric equipment is reversely connected with the interface unit. Through using the warning circuit, when external electric equipment and interface unit are connected reversely, can in time remind the user to deal with in time, avoid unable normal use external electric equipment because of the user is unknowing.
In order to provide operating power for the electronic components in the intelligent gateway 10, referring to fig. 3, in the embodiment of the present application, the intelligent gateway 10 further includes a DC-DC circuit 300. Referring to the DC-DC circuit diagram of fig. 4, the DC-DC circuit 300 includes a DC-DC unit 3100 and a second isolated power unit 3200, wherein an output terminal of the DC-DC unit 3100 is connected to an input terminal of the second isolated power unit 3200, and an output terminal of the second isolated power unit 3200 is used for providing power to the anti-reverse connection circuit 100.
The DC-DC unit 3100 may convert a direct current voltage input from a power input terminal of the DC-DC unit 3100 into a 3.3V voltage, thereby providing an operating power for the electronic components in the intelligent gateway 10. In this embodiment, the power input end of the DC-DC unit 3100 is connected to the external power VIN, the power output end of the DC-DC unit 3100 is connected to the power input end of the second isolation power unit 3200, the power output end of the DC-DC unit 3100 outputs 3.3V, so as to provide working power for the control unit 1500 and the first side of the signal isolator 1700, and the power output end of the second isolation power unit 3200 outputs vcc_33, so as to provide working power for the second side of the signal isolator 1700, the comparison unit 1400 and the switch unit 1200. By using a DC-DC unit, a direct current power supply can be converted into an operating power supply for each unit in the circuit, and the operating power supply can be provided for each unit. By using the second isolation power supply unit, the power supply output from the power supply output end of the DC-DC unit can be isolated from the power supply output end of the second isolation power supply unit. In the embodiment of the application, the DC-DC unit and the second isolation power supply unit respectively provide working power for different components in the intelligent gateway, so that the influence on other components when a certain component in the intelligent gateway is short-circuited or abnormal is avoided, and the stability of the system is enhanced.
In order to enable the intelligent gateway to be conveniently connected to an external device, referring to fig. 3, in this embodiment of the present application, the intelligent gateway further includes an RS485 interface circuit 400 for providing a signal interface of the remote water meter. The RS485 interface circuit 400 includes a digital isolator, an RS-485 transceiver, and an RS485 interface.
The digital isolator is connected to the working power supply through the DC-DC circuit 300, and the control unit 1600 is connected with the RS-485 transceiver through the digital isolator, so that electric isolation is realized, and external loop noise is avoided. The digital isolator is connected with the RS485 interface through an RS-485 transceiver, the RS-485 transceiver converts TTL level signals output by the control unit 1600 into RS-485 signals, and the RS-485 transceiver inputs the RS-485 signals to the RS485 interface, so that the remote water meter can be accessed into the system through the RS485 interface.
Referring to fig. 5, the embodiment of the present application further provides a remote water meter system, where the remote water meter system includes an intelligent gateway 10, a remote water meter, a router, a power adapter, and a cloud internet of things platform. The structure and function of the intelligent gateway 10 are identical to those of the intelligent gateway 10 in the above embodiment, and the structure and function of the intelligent gateway 10 can be referred to the above embodiment, and will not be described in detail here. The remote water meter is connected with the interface circuit 400 and the reverse connection preventing circuit 100, the router is connected with the network port in the intelligent gateway 10, and the cloud Internet of things platform is connected with the router, so that the cloud Internet of things platform can send an on-off instruction for the connection of the remote water meter to the intelligent gateway, and further the on-off state of the remote water meter is controlled, and the purposes of saving cost and reducing energy consumption are achieved. The power input end of the power adapter is connected with 220V commercial power, and the output end of the power adapter outputs power VIN to provide power for the intelligent gateway 10.
In this embodiment of the application, through using high in the clouds thing networking platform, when needs teletransmission water gauge during operation, only need down the circular telegram instruction to teletransmission water gauge connection through high in the clouds thing networking platform before the teletransmission water gauge checks meter for teletransmission water gauge work, and at other time that do not need the teletransmission water gauge work, down send the outage command to teletransmission water gauge connection through high in the clouds thing networking platform, let the teletransmission water gauge stop working, thereby can reduce the power consumption by a wide margin, practice thrift the cost. Meanwhile, as the intelligent gateway 10 can directly provide the working power supply for the remote water meter, compared with the remote water meter which can be accessed into the working power supply through the external power supply adapter in the prior art, the cost of the external power supply adapter is saved, and the circuit is simple.
In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the present application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the above description of exemplary embodiments of the application, various features of embodiments of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the application and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed application requires more features than are expressly recited in each claim.
Those skilled in the art will appreciate that the modules in the apparatus of the embodiments may be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components of the embodiments may be combined into one module or unit or component, and they may be divided into a plurality of sub-modules or sub-units or sub-components. Any combination of all features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or units of any method or apparatus so disclosed, may be used in combination, except insofar as at least some of such features and/or processes or units are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names. The steps in the above embodiments should not be construed as limiting the order of execution unless specifically stated.
Claims (10)
1. The reverse connection preventing circuit is characterized by comprising a detection unit, a comparison unit, a control unit, a switch unit and an interface unit;
the switch unit comprises a first end, a second end and a control end, wherein the first end of the switch unit is connected with an external power supply, the second end of the switch unit is connected with the interface unit, and the control end of the switch unit is connected with the control unit;
one end of the detection unit is connected with the first end of the switch unit and is used for detecting the first end of the switch unit;
the first input end of the comparison unit is connected with the other end of the detection unit and is used for receiving the detection signal output by the detection unit; the second input end of the comparison unit is grounded; the output end of the comparison unit is connected with the control unit and is used for outputting a comparison signal to the control unit;
the input end of the control unit is connected with the comparison unit, the output end of the control unit is connected with the control end of the switch unit, and the control unit is used for sending a control signal to the switch unit according to the comparison signal and controlling the connection or disconnection of the first end of the switch unit and the second end of the switch unit;
When the interface unit is idle or is normally connected with external electric equipment, the detection unit detects that the first end of the switch unit is in a first voltage state, and then sends a first detection signal to the comparison unit; the comparison unit compares the first detection signal with a signal of a second input end of the comparison unit, and outputs a first comparison signal to the control unit through an output end of the comparison unit; the control unit controls the first end of the switch unit to be connected with the second end of the switch unit according to the first comparison signal;
when the external electric equipment is reversely connected with the interface unit, the detection unit detects that the first end of the switch unit is in a second voltage state, a second detection signal is sent to the comparison unit, the comparison unit compares the second detection signal with a signal of the second input end of the comparison unit, and a second comparison signal is output to the control unit through the output end of the comparison unit; the control unit controls the first end of the switch unit to be disconnected from the second end of the switch unit according to the second comparison signal.
2. The reverse connection prevention circuit according to claim 1, wherein the switching unit includes a relay;
the first end of the contact switch of the relay is connected with one end of the detection unit, the second end of the contact switch of the relay is connected with the interface unit, and the control end of the relay is connected with the output end of the control unit;
the control unit controls the contact switch of the relay to be connected or disconnected through the control signal.
3. The reverse connection prevention circuit according to claim 1, wherein the detection unit includes a first voltage dividing resistor, a second voltage dividing resistor, and a diode;
one end of the first voltage dividing resistor is connected with the first end of the switch unit, and the other end of the first voltage dividing resistor is respectively connected with one end of the second voltage dividing resistor and the first input end of the comparison unit, and is used for inputting the detection signal to the comparison unit;
the other end of the second voltage dividing resistor is connected with the positive electrode end of the diode.
4. The anti-reverse circuit of claim 3, wherein the comparison unit comprises a voltage comparator and an N-channel field effect transistor;
The voltage comparator comprises a first input end, a second input end and an output end, the second input end of the voltage comparator is grounded, and the output end of the voltage comparator is connected with the grid electrode of the N-channel field effect transistor;
the source electrode of the N-channel type field effect tube is grounded, and the drain electrode of the N-channel type field effect tube is connected with the input end of the control unit;
the voltage comparator generates a control comparison signal after comparing a signal of a first input end of the voltage comparator with a signal of a second input end of the voltage comparator, and the control comparison signal controls the N-channel type field effect transistor to be connected or disconnected through a grid electrode of the N-channel type field effect transistor.
5. The anti-reverse circuit of claim 4, wherein the comparison unit further comprises a zener diode;
the zener diode is connected to the first input of the voltage comparator.
6. The anti-reverse circuit of claim 4, wherein the comparison unit further comprises a first pull-up resistor and a second pull-up resistor;
the output end of the voltage comparator is connected with the first pull-up resistor;
and the drain electrode of the N-channel field effect transistor is connected with the second pull-up resistor.
7. The anti-reverse circuit of claim 1, further comprising a first isolated power supply unit and a signal isolator;
the detection unit and the switch unit are connected with the external power supply through the first isolation power supply unit;
the control unit is respectively connected with the comparison unit and the switch unit through the signal isolator.
8. An intelligent gateway comprising the anti-reverse circuit of any of claims 1-7.
9. The intelligent gateway of claim 8, comprising an alarm circuit and a DC-DC circuit;
the control unit is connected with the alarm circuit, and sends an alarm signal to the alarm circuit when the control unit controls the switch unit to be disconnected;
the DC-DC circuit comprises a DC-DC unit and a second isolation power supply unit; the output end of the DC-DC unit is connected with the input end of the second isolation power supply unit, and the output end of the second isolation power supply is used for providing power for the reverse connection prevention circuit.
10. A remote water meter system, comprising the intelligent gateway according to claim 8 or 9, a remote water meter and a cloud internet of things platform;
The intelligent gateway is connected with the cloud internet of things platform;
the remote water meter is connected with the intelligent gateway;
the cloud internet of things platform operates the remote water meter through the intelligent gateway.
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| CN202223062243.7U CN218958547U (en) | 2022-11-17 | 2022-11-17 | Reverse connection preventing circuit, intelligent gateway and remote water meter system |
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| CN202223062243.7U CN218958547U (en) | 2022-11-17 | 2022-11-17 | Reverse connection preventing circuit, intelligent gateway and remote water meter system |
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