CN212751770U - Power supply protection circuit of external module of electric energy meter and electric energy meter thereof - Google Patents
Power supply protection circuit of external module of electric energy meter and electric energy meter thereof Download PDFInfo
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- CN212751770U CN212751770U CN202020453068.6U CN202020453068U CN212751770U CN 212751770 U CN212751770 U CN 212751770U CN 202020453068 U CN202020453068 U CN 202020453068U CN 212751770 U CN212751770 U CN 212751770U
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Abstract
The utility model relates to a power supply protection circuit of external module of electric energy meter, this power supply protection circuit are connected with the power supply circuit output in the electric energy meter, power supply circuit output in the electric energy meter is connected with external module's power end, its characterized in that: the control circuit comprises a control circuit, an input end of the control circuit is connected with a control end of an MCU in the electric energy meter, and an output end of the control circuit is connected with an output end of a power supply circuit in the electric energy meter; one end of the current acquisition circuit is connected with the control circuit, and the other end of the current acquisition circuit is connected with a grounding end in the power supply circuit; and the connecting wire between the control circuit and the current acquisition circuit is also connected with the acquisition end of the MCU in the electric energy meter. An electric energy meter is also disclosed. The power supply protection circuit is simple in circuit, can automatically protect the electric energy meter when the current is abnormal, and can intermittently trigger the power supply circuit to be started so as to realize power supply restart work of the external module after fault removal.
Description
Technical Field
The utility model relates to an electric energy meter field, in particular to power supply protection circuit of external module of electric energy meter and electric energy meter thereof.
Background
With the development of electric energy meter technology, the number of common electric energy meters with metering functions is less and less, and the number of intelligent electric energy meters with automatic meter reading, automatic reporting and other functions is more and more. The realization of the automatic meter reading and automatic reporting functions requires adding corresponding functional modules in the electric energy meter. In order to enable the smart meter to have stronger compatibility and realize more extensible functions, a plurality of electric energy meter manufacturers are willing to set the functional module connected with the electric energy meter into a communication interface, and the external functional module is inserted into the communication interface to meet different requirements of different markets for the electric energy meter.
At present, the electric energy meter industry adopts two more ways in the power supply circuit for external module:
1. the DC-DC module directly supplies power;
2. and the DC-DC module and the current limiting chip supply power to the external module.
The two schemes have certain limitations, the DC-DC module is used for direct output in the scheme 1, when the output of the DC-DC module is overloaded or short-circuited, the DC-DC module is heated and overheated to cause the failure of the DC-DC module, and the input power supply is heated and protected or burnt to cause the failure of the whole electric energy meter; in case of using the current limiting chip in the scheme 2, the output current can be limited within a specified range, but the scheme has many disadvantages: for example: a. the range of the current-limiting point is wide. The output current cannot be guaranteed to be limited within a specified range due to the inconsistency of each chip batch; b. the use of some modules which need to draw large current for a short time has certain limitation, and the current limiting chip is easy to trigger by mistake, so that the external module can not work normally, such as 3G and 4G modules. Further improvements are therefore desirable.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the first technical problem is to prior art's current situation, provides a power supply protection circuit of external module of electric energy meter, thereby this power supply protection circuit can protect the electric energy meter automatically when the electric current is unusual through monitoring the electric current that flows through external module, and can intermittent type trigger power supply circuit and open and restart work in order to realize restarting the power supply of external module after the troubleshooting.
The utility model discloses the second technical problem that will solve is to prior art's current situation, provides an electric energy meter that includes above-mentioned power supply protection circuit.
The utility model provides a technical scheme that above-mentioned first technical problem adopted does: the utility model provides a power supply protection circuit of external module of electric energy meter, this power supply protection circuit is connected with the power supply circuit output in the electric energy meter, the power supply circuit output in the electric energy meter is connected with external module's power end for external module power supply, its characterized in that: comprises a control circuit and a current acquisition circuit, wherein,
the input end of the control circuit is connected with the control end of the MCU in the electric energy meter, and the output end of the control circuit is connected with the output end of the power supply circuit in the electric energy meter; the control end of the MCU is used for sending a high level or a low level so as to drive the control circuit to be switched on or switched off;
one end of the current acquisition circuit is connected with the control circuit, and the other end of the current acquisition circuit is connected with a grounding end in the power supply circuit; the connecting line between the control circuit and the current acquisition circuit is also connected with the acquisition end of the MCU in the electric energy meter; the acquisition end of the MCU is used for receiving the voltage corresponding to the current acquired in the current acquisition circuit, and the MCU judges whether the current flowing through the external module is abnormal according to the acquired voltage, so that the control end of the MCU is controlled to continuously transmit a high level when the current is abnormal, and the control end of the MCU is controlled to transmit a low level when the current is abnormal, and the control end of the MCU is controlled to discontinuously transmit a high level after transmitting a low level so as to trigger the power supply circuit to restart the power supply of the external module.
As an improvement, the control circuit comprises an MOS tube, the drain electrode of the MOS tube is connected with the power output end of the power supply circuit, and the grid electrode of the MOS tube is connected with the control end of the MCU.
Furthermore, the control circuit further comprises an eighth resistor, and the eighth resistor is connected between the gate of the MOS transistor and the connection line of the control end of the MCU.
Furthermore, the current acquisition circuit comprises a ninth resistor, one end of the ninth resistor is connected with the source electrode of the MOS transistor, the acquisition end of the MCU is correspondingly connected between the ninth resistor and the connection line of the source electrode of the MOS transistor, and the other end of the ninth resistor is connected to the ground terminal of the power supply circuit. The current flowing through the external module can be converted into voltage through the ninth resistor, so that whether the current flowing through the external module is abnormal or not can be judged according to the MCU, protective measures are taken for abnormal conditions, and the external module can be effectively protected.
The current acquisition circuit further comprises an eighth capacitor, and two ends of the eighth capacitor are respectively connected between the ninth resistor and the connecting line of the acquisition end of the MCU and between the ninth resistor and the connecting line of the grounding end.
Preferably, the MOS transistor is an NMOS transistor.
In the scheme, the power supply circuit is a DC-DC power supply circuit.
Furthermore, the external module is a communication function module, a handheld terminal module or an automatic reporting module.
The utility model provides a technical scheme that above-mentioned second technical problem adopted does: the utility model provides an electric energy meter, is equipped with power supply circuit and MCU in this electric energy meter, be equipped with on the electric energy meter and supply external module to insert the external interface of establishing, power supply circuit's output is connected with external module's power end through external interface for supply power, its characterized in that for external module: the electric energy meter is characterized by also comprising a power supply protection circuit of the external module of the electric energy meter, wherein the power supply protection circuit is connected with the output end of the power supply circuit in the electric energy meter.
Specifically, the external module is a communication function module, a handheld terminal module or an automatic reporting module.
Compared with the prior art, the utility model has the advantages of: the power supply protection circuit can monitor and protect the abnormal condition of the current of the external module, and can send a high level to trigger the power supply circuit to restart the power supply of the external module after protection through intermittent sending. The method has simple circuit, and can perform discontinuous detection on the fault state so as to realize power supply restart work after fault clearing.
Drawings
Fig. 1 is a circuit connection diagram of the power supply protection circuit and the power supply circuit in the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
A power supply protection circuit of an external module of an electric energy meter is connected with the output end of a power supply circuit 1 in the electric energy meter, the output end of the power supply circuit 1 in the electric energy meter is connected with the power supply end of the external module and used for supplying power to the external module, the power supply protection circuit comprises a control circuit 2 and a current acquisition circuit 3, wherein,
the input end of the control circuit 2 is connected with the control end DRIVE of the MCU in the electric energy meter, and the output end of the control circuit is connected with the output end of the power supply circuit 1 in the electric energy meter; the control end DRIVE of the MCU is used for sending high level or low level, so as to DRIVE the control circuit 2 to be switched on or switched off;
one end of the current acquisition circuit 3 is connected with the control circuit 2, and the other end of the current acquisition circuit is connected with a ground end GND in the power supply circuit 1; the connecting line between the control circuit 2 and the current acquisition circuit 3 is also connected with the acquisition end CS of the MCU in the electric energy meter; the acquisition end CS of the MCU is used for receiving the voltage corresponding to the current acquired in the current acquisition circuit 3, and the MCU judges whether the current flowing through the external module is abnormal according to the acquired voltage, so that the control end DRIVE of the MCU is controlled to continuously transmit a high level when the current is abnormal, and when the current is abnormal, the control end of the MCU is controlled to transmit a low level and transmit the low level, and then the control end of the MCU is controlled to discontinuously transmit a high level so as to trigger the power supply circuit 1 to restart the power supply of the external module.
As shown in fig. 1, the control circuit 2 includes a MOS transistor M1 and an eighth resistor R8, a drain of the MOS transistor M1 is connected to the power output terminal of the power supply circuit 1, a gate of the MOS transistor M1 is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is connected to the control terminal DRIVE of the MCU.
The current collecting circuit 3 comprises a ninth resistor R9 and an eighth capacitor C8, one end of the ninth resistor R9 is connected with the source electrode of the MOS transistor M1, the collecting terminal CS of the MCU is correspondingly connected between the connecting lines of the ninth resistor R9 and the source electrode of the MOS transistor M1, the other end of the ninth resistor R9 is connected with the ground terminal GND of the power supply circuit 1, and two ends of the eighth capacitor C8 are respectively connected between the connecting lines of the ninth resistor R9 and the collecting terminal CS of the MCU and between the connecting lines of the ninth resistor R9 and the ground terminal GND.
In the present embodiment, the MOS transistor M1 is an NMOS transistor; the power supply circuit 1 is a DC-DC power supply circuit, the power supply circuit 1 in fig. 1 is a specific DC-DC power supply circuit, wherein an output end of the power supply circuit includes an anode output end V _ MODU and a relative ground end V _ GND, a voltage difference between the V _ MODU and the V _ GND is a voltage corresponding to the output end of the power supply circuit, the ground end GND in the power supply circuit 1 and the ground end GND at the lower end of the ninth resistor R9 in the current collection circuit 3 are the same ground end, and equivalently, the lower end of the ninth resistor R9 is connected to the ground end in the power supply circuit 1. Of course, other DC-DC power supply circuits are also possible; the external module is a communication function module, a hand-held terminal module or an automatic reporting module.
The working principle of the power supply protection circuit is as follows: sending a high level through a control end DRIVE of the MCU to enable an MOS tube M1 to be conducted, so that when the external module is inserted, the current of the power supply circuit 1 sequentially passes through an output end V _ MODU, the external module, V _ GND, an MOS tube M1 and a ninth resistor R9 in the power supply protection circuit to the grounding end GND of the power supply circuit 1, and forms a loop, so that the power supply circuit 1 can be controlled to supply power to the external module, after the current of the external module passes through the MOS tube M1 and the ninth resistor R9, the current flowing through the ninth resistor R9 can be converted into a voltage signal through the resistor, the voltage signal is collected by a collecting end CS of the MCU, and the MCU judges whether the current of the current external module is normal or not according to the collected voltage; when the voltage collected by the collecting end CS of the MCU is within a set range, the MCU judges the current of the external module at the moment, and the control end DRIVE of the MCU continuously sends a high level to ensure that the power supply circuit 1 normally supplies power to the external module; when the voltage collected by the collecting end CS of the MCU exceeds the set range, the MCU judges that an interface of the external module is attacked maliciously so as to enable the power supply circuit to work in an overload or short-circuit state, and controls a control end DRIVE of the MCU to send a low level so as to control the MOS tube M1 to be switched off, so that the output end V _ MODU, the external module, V _ GND of the power supply circuit 1, the MOS tube M1 in the power supply protection circuit, the ninth resistor R9 and the grounding end GND of the power supply circuit 1 do not form a loop, and therefore the power supply circuit cannot provide current for the external module at the moment, the connection between the power supply circuit and the external module is disconnected, and the meter is protected; and after the MOS transistor M1 is turned off, the DRIVE of the control terminal of the MCU intermittently transmits a high level to intermittently turn on the MOS transistor M1, and when the MOS transistor M1 is turned on, it is determined again whether the voltage collected by the CS terminal of the MCU is normal to determine whether the fault of the external module has been withdrawn, so that the circuit can automatically trigger the power supply circuit 1 to restart the external module for power supply after the fault is removed.
The utility model provides an electric energy meter with above-mentioned power supply protection circuit, is equipped with power supply circuit 1 and MCU in this electric energy meter, is equipped with on the electric energy meter and supplies external module to insert the external interface of establishing, and power supply circuit 1's output provides the power for external module through external interface for external module supplies power, and power supply protection circuit is connected with the power supply circuit 1 output in the electric energy meter.
Through setting up foretell power supply protection circuit in the electric energy meter, can effectively protect with the electric energy meter, thereby prevent to cause this electric energy meter to break down because of external module work is transshipped or the short circuit, the circuit of this method is simple, the circuit accuracy is high and the commonality is strong, can be applicable to the electric energy meter of multiple different models.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the technical principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The utility model provides a power supply protection circuit of external module of electric energy meter, this power supply protection circuit is connected with power supply circuit (1) output in the electric energy meter, power supply circuit (1) output in the electric energy meter is connected with the power end of external module for external module power supply, its characterized in that: comprises a control circuit (2) and a current acquisition circuit (3), wherein,
the input end of the control circuit (2) is connected with the control end (DRIVE) of the MCU in the electric energy meter, and the output end of the control circuit is connected with the output end of the power supply circuit (1) in the electric energy meter; the control end (DRIVE) of the MCU is used for sending high level or low level so as to DRIVE the control circuit (2) to be switched on or switched off;
one end of the current acquisition circuit (3) is connected with the control circuit (2), and the other end of the current acquisition circuit is connected with a ground terminal (GND) in the power supply circuit (1); the connecting line between the control circuit (2) and the current acquisition circuit (3) is also connected with an acquisition end (CS) of an MCU in the electric energy meter; and the acquisition end (CS) of the MCU is used for receiving the voltage corresponding to the current acquired in the current acquisition circuit (3).
2. The power supply protection circuit of the external module of the electric energy meter according to claim 1, characterized in that: the control circuit (2) comprises an MOS (metal oxide semiconductor) tube (M1), the drain electrode of the MOS tube (M1) is connected with the power output end of the power supply circuit (1), and the grid electrode of the MOS tube (M1) is connected with the control end (DRIVE) of the MCU.
3. The power supply protection circuit of the external module of the electric energy meter according to claim 2, characterized in that: the control circuit (2) further comprises an eighth resistor (R8), and the eighth resistor (R8) is connected between the grid of the MOS transistor (M1) and a connecting line of a control end (DRIVE) of the MCU.
4. The power supply protection circuit of the external module of the electric energy meter according to claim 3, characterized in that: the current acquisition circuit (3) comprises a ninth resistor (R9), one end of the ninth resistor (R9) is connected with the source electrode of the MOS transistor (M1), the acquisition end (CS) of the MCU is correspondingly connected between the connecting wire of the ninth resistor (R9) and the source electrode of the MOS transistor (M1), and the other end of the ninth resistor (R9) is connected with the ground end (GND) in the power supply circuit (1).
5. The power supply protection circuit of the external module of the electric energy meter according to claim 4, characterized in that: the current acquisition circuit (3) further comprises an eighth capacitor (C8), and two ends of the eighth capacitor (C8) are respectively connected between the ninth resistor (R9) and the connecting line of the acquisition end (CS) of the MCU and between the ninth resistor (R9) and the connecting line of the ground end (GND).
6. The power supply protection circuit of the external module of the electric energy meter according to any one of claims 2 to 5, characterized in that: the MOS tube (M1) is an NMOS tube.
7. The power supply protection circuit of the external module of the electric energy meter according to any one of claims 1 to 5, characterized in that: the power supply circuit (1) is a DC-DC power supply circuit.
8. The power supply protection circuit of the external module of the electric energy meter according to any one of claims 1 to 5, characterized in that: the external module is a communication function module, a handheld terminal module or an automatic reporting module.
9. The utility model provides an electric energy meter, is equipped with power supply circuit (1) and MCU in this electric energy meter, be equipped with on the electric energy meter and supply external module to insert the external interface of establishing, the output of power supply circuit (1) is connected with external module's power end through external interface for external module power supply, its characterized in that: the electric energy meter is characterized in that a power supply protection circuit of the external module of the electric energy meter according to any one of claims 1-5 is further included in the electric energy meter, and the power supply protection circuit is connected with the output end of the power supply circuit (1) in the electric energy meter.
10. The electrical energy meter of claim 9, wherein: the external module is a communication function module, a handheld terminal module or an automatic reporting module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020453068.6U CN212751770U (en) | 2020-03-31 | 2020-03-31 | Power supply protection circuit of external module of electric energy meter and electric energy meter thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020453068.6U CN212751770U (en) | 2020-03-31 | 2020-03-31 | Power supply protection circuit of external module of electric energy meter and electric energy meter thereof |
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| Publication Number | Publication Date |
|---|---|
| CN212751770U true CN212751770U (en) | 2021-03-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020453068.6U Active CN212751770U (en) | 2020-03-31 | 2020-03-31 | Power supply protection circuit of external module of electric energy meter and electric energy meter thereof |
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| Country | Link |
|---|---|
| CN (1) | CN212751770U (en) |
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2020
- 2020-03-31 CN CN202020453068.6U patent/CN212751770U/en active Active
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