Electric energy meter power supply circuit and electric energy meter

Abstract

The present invention proposes an electric energy meter power supply circuit and an electric energy meter. The circuit includes a main power supply module and a backup power supply module. The first output end of the main power supply module is connected to the power supply end of the processing module of the electric energy meter, the second output end of the main power supply module is connected to the charging end of the backup power supply module, and the output end of the backup power supply module is connected to the power supply end of the processing module of the electric energy meter. The main power supply module is used to supply power to the processing module and charge the backup power supply module; the backup power supply module supplies power to the processing module when the main power supply module is powered off. By adopting a rechargeable backup power supply module, when there is an external power supply, the backup power supply module is powered by the external power supply, and when there is no external power supply, the processing module is powered by the backup power supply module. This allows the electric energy meter to communicate with the terminal device during a power outage. At the same time, the backup power supply module does not need to be replaced due to exhaustion of power, which greatly extends the service life of the backup power supply and reduces the cost of power replacement.

Description

Technical Field

[0001] The present invention relates to the field of equipment power supply, and in particular to an electric energy meter power supply circuit and an electric energy meter. Background Art

[0002] Most existing electricity meters draw power from the mains grid, then go through a series of rectification and step-down steps to generate the required DC voltage to power the meter's MCU and peripheral circuits. To prevent mains power outages, the meter uses a lithium-ion battery as a backup power source. When the meter loses power, the power supply switches to the lithium-ion battery, ensuring that the meter's data and clock are maintained during a power outage and preventing electricity theft. However, lithium-ion batteries have limited load capacity and cannot support the operation of higher-power modules, such as wireless modules and communication circuits. This results in the meter being unable to communicate with terminal devices when the mains power fails. Furthermore, the lifespan of lithium-ion batteries is generally around three years. When the battery is depleted, the lithium-ion battery needs to be replaced, increasing material and labor costs. Summary of the Invention

[0003] The main purpose of the present invention is to provide an electric energy meter power supply circuit and an electric energy meter, aiming to solve the problem that the backup power supply of the electric energy meter in the prior art has low load capacity and needs to be replaced when the power is exhausted.

[0004] To achieve the above-mentioned object, the present invention provides a power supply circuit for an electric energy meter, the circuit comprising a main power supply module and a backup power supply module, wherein a first output end of the main power supply module is connected to a power supply end of a processing module of the electric energy meter, a second output end of the main power supply module is connected to a charging end of the backup power supply module, and an output end of the backup power supply module is connected to a power supply end of the processing module of the electric energy meter, wherein:

[0005] The main power supply module is used to supply power to the processing module and the backup power supply module;

[0006] The backup power supply module is used to supply power to the processing module when the main power supply module is powered off.

[0007] Optionally, the circuit further includes a step-down unit, wherein the input end of the step-down unit is connected to the output end of the main power supply module and the output end of the backup power supply module respectively, and the output end of the step-down unit is connected to the power supply end of the processing module, wherein:

[0008] The main power supply module is used to convert the voltage of the mains electricity into the operating voltage of the electric energy meter and output it to the step-down unit and the backup power supply module;

[0009] The backup power supply module is used to output the operating voltage to the step-down unit when the main power supply module is powered off;

[0010] The voltage reduction unit is used to reduce the operating voltage and output it to the power supply end of the processing module.

[0011] Optionally, the main power supply module includes a switching power supply chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, an energy storage inductor, a freewheeling subunit, a first filter subunit and a second filter subunit;

[0012] The input end of the switching power supply chip is respectively connected to the mains power and the first filtering subunit, and the input end of the switching power supply chip is also connected to the enable end of the switching power supply chip through the first resistor, and the enable end of the switching power supply chip is grounded through the second resistor; the capacitor end of the switching power supply chip is connected to the output end of the switching power supply chip through the third resistor and the first capacitor in sequence; the output end of the switching power supply chip is respectively connected to the freewheeling subunit and the first end of the energy storage inductor; the second end of the energy storage inductor is the output end of the main power supply module, and the second end of the energy storage inductor is connected to the second filtering subunit; the second end of the energy storage inductor is also connected to the feedback end of the switching power supply chip through the fifth resistor, and the feedback end of the switching power supply chip is grounded through the fourth resistor.

[0013] Optionally, the step-down unit includes: a step-down chip, a third filtering sub-unit and a fourth filtering sub-unit;

[0014] The input end of the buck chip is the input end of the buck unit, and the input end of the buck chip is connected to the third filtering subunit; the output end of the buck chip is the output end of the buck unit, and the output end of the buck chip is connected to the fourth filtering subunit.

[0015] Optionally, the backup power supply module includes a rechargeable battery, a charging management unit, a discharge management unit, and a switch unit; the input end of the charging management unit is the charging end of the backup power supply module, the output end of the charging management unit is connected to the rechargeable battery, the rechargeable battery is connected to the input end of the discharge management unit, the output end of the discharge management unit is connected to the input end of the step-down unit through the switch unit, and the detection end of the switch unit is connected to the output end of the main power supply module, wherein:

[0016] The charging management unit is configured to charge the rechargeable battery via the voltage output by the main power supply module;

[0017] The switch unit is configured to connect the discharge management unit to the voltage reduction unit when detecting that the main power supply module is powered off;

[0018] The switch unit is used to disconnect the discharge management unit and the voltage reduction unit when it is detected that the main power supply module outputs an operating voltage.

[0019] Optionally, the charging management unit includes a charging management chip, a light emitting diode, a sixth resistor and a fifth filtering subunit;

[0020] The input end of the charging management chip is the input end of the charging management unit, and the input end of the charging management chip is respectively connected to the positive pole of the light-emitting diode and the fifth filter unit, and the negative pole of the light-emitting diode is connected to the charging status indication end of the charging management chip; the output end of the charging management chip is the output end of the charging management unit; the charging current setting end of the charging management chip is grounded through the sixth resistor, and the charging voltage setting end of the charging management chip is grounded; the ground end of the charging management chip is grounded.

[0021] Optionally, the discharge management unit includes a discharge management chip, a seventh resistor, an eighth resistor and a second capacitor;

[0022] The positive input terminal of the discharge management chip is connected to the switching unit through the seventh resistor, and the positive input terminal of the discharge management chip is also connected to the positive electrode of the rechargeable battery through the seventh resistor. The positive input terminal of the discharge management chip is also connected to the bypass terminal of the discharge management chip through the eighth resistor; the bypass terminal of the discharge management chip is also connected to the negative electrode of the rechargeable battery through the second capacitor; the negative input terminal of the discharge management chip is connected to the negative electrode of the rechargeable battery; the negative input terminal of the discharge management chip is grounded.

[0023] Optionally, the switch unit includes a first switch tube, a second switch tube, a first diode and a ninth resistor;

[0024] The control end of the first switching tube is connected to the output end of the main power supply module through the ninth resistor, the output end of the first switching tube is connected to the input end of the step-down unit, the output end of the first switching tube is also connected to the cathode of the first diode, and the anode of the first diode is connected to the output end of the main power supply module; the input end of the first switching tube is connected to the input end of the second switching tube; the control end of the second switching tube is connected to the output end of the main power supply module through the ninth resistor, and the output end of the second switching tube is connected to the output end of the discharge management unit.

[0025] Optionally, the backup power supply module further includes a battery detection unit, and the battery detection unit includes a tenth resistor, an eleventh resistor and a sixth filtering subunit;

[0026] The first end of the tenth resistor is connected to the positive electrode of the rechargeable battery, the second end of the tenth resistor is grounded through the eleventh resistor, and the second end of the tenth resistor is also connected to the sixth filter unit and the battery detection end of the processing module respectively.

[0027] In addition, to achieve the above objectives, the present invention also provides an electric energy meter, which includes a shell and an electric energy meter power supply circuit, the electric energy meter power supply circuit is arranged in the shell, and the electric energy meter power supply circuit is configured as the electric energy meter power supply circuit described above.

[0028] The present invention proposes an electric energy meter power supply circuit and an electric energy meter, wherein the circuit includes a main power supply module and a backup power supply module, wherein the first output end of the main power supply module is connected to the power supply end of the processing module of the electric energy meter, the second output end of the main power supply module is connected to the charging end of the backup power supply module, and the output end of the backup power supply module is connected to the power supply end of the processing module of the electric energy meter, wherein: the main power supply module is used to supply power to the processing module and the backup power supply module; and the backup power supply module is used to supply power to the processing module when the main power supply module is powered off. By adopting a rechargeable backup power supply module, when there is an external power supply, the backup power supply module is powered by the external power supply, and when there is no external power supply, the processing module is powered by the backup power supply module, so that the electric energy meter can communicate with the terminal device during a power outage, and at the same time, the backup power supply module does not need to be replaced due to exhaustion of power, which greatly extends the service life of the backup power supply and reduces the cost of power replacement. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0030] Figure 1 This is a functional module diagram of an embodiment of an electric energy meter power supply circuit of the present invention;

[0031] Figure 2 The power supply circuit of the electric energy meter of the present invention is applied in Figure 1 Circuit structure diagram in the embodiment;

[0032] Figure 3 This is a schematic diagram of the structure of the main power supply module in the power supply circuit of the electric energy meter of the present invention when supplying power;

[0033] Figure 4 This is a structural diagram of the backup power supply module in the power supply circuit of the electric energy meter of the present invention when supplying power.

[0034] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments.

[0035] Description of Figure Numbers:

[0036] Label name Label name 100 Main power supply module R1~R11 Resistors 1 to 11 101 The first filtering subunit D1~D2 First diode to second diode 102 The second filtering subunit C1~C2 First capacitor to second capacitor 103 Freewheeling subunit U1 Switching power supply chip 200 Backup power supply module U2 Charging management chip 210 Charge management unit U3 Discharge management chip 211 Fifth filtering subunit U4 Buck chip 220 Discharge management unit L1 Energy storage inductor 230 Switch unit LED1 light-emitting diodes 240 Battery detection unit Q1 The first MOS tube 241 Sixth filtering subunit Q2 The second MOS tube 300 Step-down unit B1 rechargeable batteries 302 Fourth filtering subunit 301 The third filtering subunit DETAILED DESCRIPTION

[0037] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0040] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] The present invention provides an electric energy meter power supply circuit, which is used in electric energy meters. Figure 1 , Figure 1 This is a functional block diagram of an embodiment of an electric energy meter power supply circuit of the present invention. In this embodiment, the circuit includes a main power supply module 100 and a backup power supply module 200. The first output terminal of the main power supply module 100 is connected to the power supply terminal of the processing module (not shown) of the electric energy meter, the second output terminal of the main power supply module 100 is connected to the charging terminal of the backup power supply module 200, and the output terminal of the backup power supply module 200 is connected to the power supply terminal of the processing module of the electric energy meter, wherein:

[0042] The main power supply module 100 is used to supply power to the processing module and the backup power supply module 200;

[0043] The backup power supply module 200 is used to supply power to the processing module when the main power supply module 100 is powered off.

[0044] The main power supply module 100 is used to convert the grid voltage into the operating voltage of the energy meter and then supply power to the processing module and charge the backup power supply module 200. The main power supply module 100 generally includes an AC-DC circuit and a step-down circuit.

[0045] The backup power supply module 200 does not supply power to the processing module when the main power supply module 100 supplies power, and switches to supply power to the processing module only when the main power supply module 100 is powered off.

[0046] The processing module includes the control circuit and peripheral circuit of the energy meter. Please refer to Figure 3 and Figure 4 The processing module includes an MCU, an RF (Radio Frequency) wireless module, an infrared communication circuit, an electricity theft detection circuit, a memory, an LCD, a metering unit, and voltage and current sampling circuits. The RF wireless module is used for wireless meter reading with terminal devices; the infrared communication circuit is used for communication with terminal devices; the MCU, memory, metering unit, voltage and current sampling circuits, and LCD are used for daily metering operations, namely human-computer interaction; and the electricity theft detection circuit is used to prevent electricity theft.

[0047] Furthermore, the circuit further includes a step-down unit 300, the input end of the step-down unit 300 is connected to the output end of the main power supply module 100 and the output end of the backup power supply module 200 respectively, and the output end of the step-down unit 300 is connected to the power supply end of the processing module, wherein:

[0048] The main power supply module 100 is used to convert the voltage of the mains electricity into the operating voltage of the electric energy meter and output it to the step-down unit 300 and the backup power supply module 200;

[0049] The backup power supply module 200 is used to output the operating voltage to the step-down unit 300 when the main power supply module 100 is powered off;

[0050] The step-down unit 300 is used to step down the operating voltage and output the voltage to the power supply terminal of the processing module.

[0051] The voltage output by the main power supply module 100 and the backup power supply module 200 needs to be stepped down by the step-down unit 300 before being input to the processing module, so that the voltage input to the processing module meets the operating voltage of each device and circuit in the processing module.

[0052] This embodiment adopts a rechargeable backup power supply module 200, so that when there is an external power supply, the backup power supply module 200 is powered by the external power supply. When there is no external power supply, the backup power supply module 200 is used to power the processing module. This ensures that the backup power supply module 200 does not need to be replaced due to power exhaustion, greatly extending the service life of the backup power supply and reducing the cost of power supply replacement.

[0053] Further, see Figure 2 The main power supply module 100 includes a switching power supply chip U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, an energy storage inductor L1, a freewheeling subunit 103, a first filter subunit 101 and a second filter subunit 102;

[0054] The input end of the switching power supply chip U1 is respectively connected to the mains and the first filtering subunit 101, and the input end of the switching power supply chip U1 is also connected to the enable end of the switching power supply chip U1 through the first resistor R1, and the enable end of the switching power supply chip U1 is grounded through the second resistor R2; the capacitor end of the switching power supply chip U1 is connected to the output end of the switching power supply chip U1 through the third resistor R3 and the first capacitor C1 in sequence; the output end of the switching power supply chip U1 is respectively connected to the freewheeling subunit 103 and the first end of the energy storage inductor L1; the second end of the energy storage inductor L1 is the output end of the power supply unit, and the second end of the energy storage inductor L1 is connected to the second filtering subunit 102; the second end of the energy storage inductor L1 is also connected to the feedback end of the switching power supply chip U1 through the fifth resistor R5, and the feedback end of the switching power supply chip U1 is grounded through the fourth resistor R4.

[0055] In this embodiment, the switching power supply chip U1 is LV2843 switching power supply chip U1 produced by TI. The freewheeling subunit 103 includes a second diode D2, the anode of the second diode D2 is grounded, and the cathode of the second diode D2 is connected to the output end of the switching power supply chip U1.

[0056] The first filter subunit 101 includes a capacitor, and the input end is grounded through the capacitor; the second filter subunit 102 includes an electrolytic capacitor and a ceramic chip capacitor, the second end of the energy storage inductor L1 is connected to the positive pole of the electrolytic capacitor, the negative pole of the electrolytic capacitor is grounded, and the capacitor is connected in parallel with the electrolytic capacitor; it should be noted that the capacitors in the first filter subunit 101 and the second filter subunit 102 can be set according to actual needs by connecting multiple capacitors in parallel.

[0057] In this embodiment, the input end of the switching power supply chip U1 receives a 9V voltage obtained after the AC power is rectified and stepped down by the AC-DC circuit. The voltage is stepped down by the switching power supply chip U1 to obtain a 5V voltage, and the 5V voltage is output to the step-down unit 300 and the backup power supply module 200 respectively.

[0058] Furthermore, the buck unit 300 includes: a buck chip U4, a third filtering subunit 301 and a fourth filtering subunit 302;

[0059] The input end of the buck chip U4 is the input end of the buck unit 300 , and the input end of the buck chip U4 is connected to the third filter subunit 301 ; the output end of the buck chip U4 is the output end of the buck unit 300 , and the output end of the buck chip U4 is connected to the fourth filter subunit 302 .

[0060] In this embodiment, the step-down chip U4 utilizes the SGM2034 step-down chip U4 from Shengbang Microelectronics. The third filter subunit 301 and the fourth filter subunit 302 both include capacitors, and the input and output terminals of the step-down chip U4 are grounded via capacitors. It should be noted that the capacitance of the capacitors in the third filter subunit 301 and the fourth filter subunit 302 can be adjusted based on actual needs by connecting multiple capacitors in parallel.

[0061] The step-down unit 300 converts the received 5V voltage into a 3.3V voltage and then outputs it to the processing module.

[0062] Furthermore, the backup power supply module 200 includes a rechargeable battery B1, a charging management unit 210, a discharge management unit 220, and a switch unit 230. The input end of the charging management unit 210 is the charging end of the backup power supply module 200, the output end of the charging management unit 210 is connected to the rechargeable battery B1, the rechargeable battery B1 is connected to the input end of the discharge management unit 220, the output end of the discharge management unit 220 is connected to the input end of the step-down unit 300 through the switch unit 230, and the detection end of the switch unit 230 is connected to the output end of the main power supply module 100, wherein:

[0063] The charging management unit 210 is configured to charge the rechargeable battery B1 using the voltage output by the main power supply module 100;

[0064] The switch unit 230 is configured to connect the discharge management unit 220 to the voltage reduction unit 300 when detecting that the main power supply module 100 is powered off;

[0065] The switch unit 230 is configured to disconnect the discharge management unit 220 from the voltage reduction unit 300 when detecting that the main power supply module 100 outputs an operating voltage.

[0066] The rechargeable battery B1 in this embodiment is a rechargeable lithium battery, which is an IFR14500 battery.

[0067] The charging management unit 210 is used to manage the charging of the rechargeable battery B1, such as setting the charging cut-off voltage and charging current, indicating the charging status, etc. The discharging management unit 220 is used to manage the discharging of the rechargeable battery B1, such as setting the discharge cut-off voltage and discharge overcurrent protection, etc.

[0068] Furthermore, the charging management unit 210 includes a charging management chip U2, a light emitting diode LED1, a sixth resistor R6 and a fifth filtering subunit 211;

[0069] The input end of the charging management chip U2 is the input end of the charging management unit 210, and the input end of the charging management chip U2 is respectively connected to the positive pole of the light-emitting diode LED1 and the fifth filter unit 211, and the negative pole of the light-emitting diode LED1 is connected to the charging status indication end of the charging management chip U2; the output end of the charging management chip U2 is the output end of the charging management unit 210; the charging current setting end of the charging management chip U2 is grounded through the sixth resistor R6, and the charging voltage setting end of the charging management chip U2 is grounded; the grounding end of the charging management chip U2 is grounded.

[0070] In this embodiment, the charging management chip U2 uses the SGM40560A charging management chip U2 from Shengbang Micro. The charging cutoff voltage is set to 3.65V; that is, charging stops when the voltage of the rechargeable battery B1 reaches 3.65V. The maximum charging current can be adjusted by adjusting the resistance of the sixth resistor R6. Specifically, the maximum charging current is 24000 / resistance of the sixth resistor R6, mA.

[0071] When charging, the charging status indicator terminal of the charging management chip U2 absorbs current intermittently at a period of 1 / 8 of 1280ms; after charging is completed, it continues to absorb current for 40 indication cycles, that is, 51.2s, and then enters a high-impedance state. That is, the light-emitting diode LED1 flashes during charging and stays on after charging is completed. The light-emitting diode LED1 in this embodiment is a red light-emitting diode LED1. The fifth filter subunit 211 includes a capacitor, and the input terminal of the charging management chip U2 is grounded through the capacitor. It should be noted that the capacitance of the capacitor in the fifth filter subunit 211 can be set according to actual needs by connecting multiple capacitors in parallel.

[0072] Furthermore, the discharge management unit 220 includes a discharge management chip U3, a seventh resistor R7, an eighth resistor R8 and a second capacitor C2;

[0073] The positive input terminal of the discharge management chip U3 is connected to the switch unit 230 through the seventh resistor R7, and the positive input terminal of the discharge management chip U3 is also connected to the positive electrode of the rechargeable battery B1 through the seventh resistor R7. The positive input terminal of the discharge management chip U3 is also connected to the bypass terminal of the discharge management chip U3 through the eighth resistor R8; the bypass terminal of the discharge management chip U3 is also connected to the negative electrode of the rechargeable battery B1 through the second capacitor C2; the negative input terminal of the discharge management chip U3 is connected to the negative electrode of the rechargeable battery B1; the negative input terminal of the discharge management chip U3 is grounded.

[0074] In this embodiment, the discharge management chip U3 is a SGM41101 discharge management chip U3 from Shengbang Micro. A discharge cut-off voltage can be set. In this embodiment, the discharge cut-off voltage is set to 3V, that is, the discharge is stopped when the voltage of the rechargeable battery B1 is less than or equal to 3V.

[0075] Furthermore, the switch unit 230 includes a first switch tube, a second switch tube, a first diode D1 and a ninth resistor R9;

[0076] The control end of the first switching tube is connected to the output end of the main power supply module 100 through the ninth resistor R9, the output end of the first switching tube is connected to the input end of the step-down unit 300, the output end of the first switching tube is also connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the output end of the main power supply module 100; the input end of the first switching tube is connected to the input end of the second switching tube; the control end of the second switching tube is connected to the output end of the main power supply module 100 through the ninth resistor R9, and the output end of the second switching tube is connected to the output end of the discharge management unit 220.

[0077] In this embodiment, the first switching transistor is a first MOS transistor Q1, and the second switching transistor is a second MOS transistor Q2. Both the first MOS transistor Q1 and the second MOS transistor Q2 are PMOS transistors. Because the diode voltage drop is too large, while the MOS transistor conduction voltage drop is small, PMOS transistors are used as the first MOS transistor Q1 and the second MOS transistor Q2.

[0078] When the main power supply module 100 supplies power, the gates of the first MOS transistor Q1 and the second MOS transistor Q2 receive a high level, the first MOS transistor Q1 and the second MOS transistor Q2 are both turned off, and the voltage of the rechargeable battery B1 cannot be output for power supply.

[0079] When the main power supply module 100 is powered off, the gates of the first MOS transistor Q1 and the second MOS transistor Q2 receive a low level, the first MOS transistor Q1 and the second MOS transistor Q2 are both turned on, and the voltage of the rechargeable battery B1 is output to the step-down unit 300 through the first MOS transistor Q1 and the second MOS transistor Q2.

[0080] The first diode D1 is used to prevent backflow, so as to prevent the backflow of electricity from the rechargeable battery B1 when the main power supply module 100 is powered off, such as causing damage to the main power supply module 100.

[0081] Furthermore, the backup power supply module 200 further includes a battery detection unit 240 , and the battery detection unit 240 includes a tenth resistor R10 , an eleventh resistor R11 and a sixth filter subunit 241 ;

[0082] A first end of the tenth resistor R10 is connected to the positive electrode of the rechargeable battery B1, a second end of the tenth resistor R10 is grounded via the eleventh resistor R11, and a second end of the tenth resistor R10 is also connected to the sixth filter unit 241 and the battery detection end of the processing module.

[0083] The battery detection unit 240 is used to detect the voltage of the rechargeable battery B1 and send it to the MCU in real time; when the MCU detects that the voltage of the rechargeable battery B1 is lower than a preset voltage threshold, it performs an alarm operation to remind the user that the energy meter is about to be powered off.

[0084] Through the above specific circuit structure, this embodiment can realize the functions of charge and discharge management of the rechargeable battery and low voltage early warning, thereby improving the reliability and stability of the electric energy meter.

[0085] The present invention also provides an electric energy meter comprising a housing and an electric energy meter power supply circuit, wherein the electric energy meter power supply circuit is disposed within the housing and is configured as the electric energy meter power supply circuit described above. As such, since the electric energy meter of this embodiment employs the technical solution of the electric energy meter power supply circuit described above, the electric energy meter has all the beneficial effects of the electric energy meter power supply circuit described above.

[0086] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or system comprising the element. The serial numbers of the above-mentioned embodiments of the present invention are for description only and do not represent the advantages and disadvantages of the embodiments.

[0087] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An electric energy meter power supply circuit, characterized in that: The circuit includes a main power supply module and a backup power supply module, wherein the first output end of the main power supply module is connected to the power supply end of the processing module of the electric energy meter, the second output end of the main power supply module is connected to the charging end of the backup power supply module, and the output end of the backup power supply module is connected to the power supply end of the processing module of the electric energy meter, wherein: The main power supply module is used to supply power to the processing module and charge the backup power supply module; The backup power supply module is used to supply power to the processing module when the main power supply module is powered off; The circuit further includes a step-down unit, the input end of the step-down unit is connected to the output end of the main power supply module and the output end of the backup power supply module respectively, and the output end of the step-down unit is connected to the power supply end of the processing module, wherein: The main power supply module is used to convert the voltage of the mains electricity into the operating voltage of the electric energy meter and output it to the step-down unit and the backup power supply module; The backup power supply module is used to output the operating voltage to the step-down unit when the main power supply module is powered off; The step-down unit is used to step down the operating voltage and output it to the power supply terminal of the processing module; The main power supply module includes a switching power supply chip, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, an energy storage inductor, a freewheeling subunit, a first filter subunit and a second filter subunit; The input end of the switching power supply chip is respectively connected to the mains power and the first filtering subunit, the input end of the switching power supply chip is also connected to the enable end of the switching power supply chip through the first resistor, and the enable end of the switching power supply chip is grounded through the second resistor; the capacitor end of the switching power supply chip is connected to the output end of the switching power supply chip through the third resistor and the first capacitor in sequence; the output end of the switching power supply chip is respectively connected to the freewheeling subunit and the first end of the energy storage inductor; the second end of the energy storage inductor is the output end of the main power supply module, and the second end of the energy storage inductor is connected to the second filtering subunit; the second end of the energy storage inductor is also connected to the feedback end of the switching power supply chip through the fifth resistor, and the feedback end of the switching power supply chip is grounded through the fourth resistor; The step-down unit includes: a step-down chip, a third filtering sub-unit and a fourth filtering sub-unit; The input end of the step-down chip is the input end of the step-down unit, and the input end of the step-down chip is connected to the third filtering sub-unit; the output end of the step-down chip is the output end of the step-down unit, and the output end of the step-down chip is connected to the fourth filtering sub-unit; The backup power supply module includes a rechargeable battery, a charging management unit, a discharge management unit, and a switch unit; the input end of the charging management unit is the charging end of the backup power supply module, the output end of the charging management unit is connected to the rechargeable battery, the rechargeable battery is connected to the input end of the discharge management unit, the output end of the discharge management unit is connected to the input end of the step-down unit through the switch unit, and the detection end of the switch unit is connected to the output end of the main power supply module, wherein: The charging management unit is configured to charge the rechargeable battery via the voltage output by the main power supply module; The switch unit is configured to connect the discharge management unit to the voltage reduction unit when detecting that the main power supply module is powered off; The switch unit is configured to disconnect the discharge management unit from the voltage reduction unit when detecting that the main power supply module outputs an operating voltage; The charging management unit includes a charging management chip, a light emitting diode, a sixth resistor and a fifth filtering subunit; The input end of the charging management chip is the input end of the charging management unit, the input end of the charging management chip is respectively connected to the positive electrode of the light-emitting diode and the fifth filter subunit, and the negative electrode of the light-emitting diode is connected to the charging status indication end of the charging management chip; the output end of the charging management chip is the output end of the charging management unit; the charging current setting end of the charging management chip is grounded through the sixth resistor, and the charging voltage setting end of the charging management chip is grounded; the ground end of the charging management chip is grounded; The discharge management unit includes a discharge management chip, a seventh resistor, an eighth resistor and a second capacitor; The positive input terminal of the discharge management chip is connected to the switch unit through the seventh resistor, the positive input terminal of the discharge management chip is also connected to the positive electrode of the rechargeable battery through the seventh resistor, and the positive input terminal of the discharge management chip is also connected to the bypass terminal of the discharge management chip through the eighth resistor; the bypass terminal of the discharge management chip is also connected to the negative electrode of the rechargeable battery through the second capacitor; the negative input terminal of the discharge management chip is connected to the negative electrode of the rechargeable battery; the negative input terminal of the discharge management chip is grounded; The switch unit includes a first switch tube and a second switch tube, a first diode and a ninth resistor; The control end of the first switching tube is connected to the output end of the main power supply module via the ninth resistor, the output end of the first switching tube is connected to the input end of the step-down unit, the output end of the first switching tube is further connected to the cathode of the first diode, and the anode of the first diode is connected to the output end of the main power supply module; the input end of the first switching tube is connected to the input end of the second switching tube; the control end of the second switching tube is connected to the output end of the main power supply module via the ninth resistor, and the output end of the second switching tube is connected to the output end of the discharge management unit; The backup power supply module further includes a battery detection unit, and the battery detection unit includes a tenth resistor, an eleventh resistor and a sixth filter subunit; The first end of the tenth resistor is connected to the positive electrode of the rechargeable battery, the second end of the tenth resistor is grounded through the eleventh resistor, and the second end of the tenth resistor is also connected to the sixth filter unit and the battery detection end of the processing module respectively.

2. An electric energy meter, characterized in that: The electric energy meter includes a shell and an electric energy meter power supply circuit. The electric energy meter power supply circuit is arranged in the shell. The electric energy meter power supply circuit is configured as the electric energy meter power supply circuit according to claim 1.

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