Load current monitoring circuit and load balancing equipment

Abstract

The utility model discloses a load current monitoring circuit and load balancing equipment, and relates to the technical field of power electronics, and the circuit comprises a current sensor, a current detection module and an MCU. The current sensor is used for collecting and outputting load current; the output end of the current sensor is connected to the input end of the MCU through the current detection module; the MCU obtains a load current through the current detection module; wherein the current detection module comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C1 and a capacitor C2; the resistor R1, the resistor R2, the resistor R3 and the resistor R4 form a voltage division circuit, the resistor R5 and the resistor R6 are used for current limiting, and the capacitor C1 and the capacitor C2 are used for filtering. According to the invention, the complexity and cost of a traditional load current monitoring circuit are reduced.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a load current monitoring circuit and a load balancing device. Background Technology

[0002] In power distribution systems, monitoring the system load current is crucial for ensuring charging efficiency and safety. Taking home charging stations as an example, because charging stations have high power and often operate in parallel with other electrical devices, the total current in the distribution box may exceed its rated capacity, leading to overload risks. Therefore, by continuously monitoring the system load current and using load balancing equipment for real-time current regulation, it is possible to ensure that the load current remains within a safe range, avoiding overload hazards.

[0003] Similarly, in charging station scenarios, the simultaneous use of multiple charging piles may cause the charging station's current to exceed its carrying capacity. In this case, monitoring the load current becomes particularly important. By sending current adjustment commands to each charging pile through load balancing equipment, the current of each charging pile can be intelligently allocated, thereby effectively preventing safety accidents from occurring.

[0004] In addition, in charging environments that include photovoltaic systems, monitoring the load current also plays a crucial role. When the power generation of the photovoltaic system exceeds the power consumption of the load, the system will collect a negative current signal. At this time, by adjusting the system configuration, it can be ensured that the charging piles prioritize the use of photovoltaic power, thereby significantly reducing electricity costs and achieving the goal of green energy saving.

[0005] In summary, monitoring the load current of the power distribution system is a crucial measure to ensure the safe and efficient operation of the power system, playing an indispensable role in home charging, charging station management, and photovoltaic charging scenarios. However, existing technologies for monitoring load current typically employ complex and costly circuits. Utility Model Content

[0006] To address the issues of complex and costly circuit designs in existing load current monitoring systems, this application provides a load current monitoring circuit and a load balancing device.

[0007] Firstly, this application provides a load current monitoring circuit, which adopts the following technical solution:

[0008] Load current monitoring circuit, including current sensor, current detection module and MCU;

[0009] The current sensor is used to collect the load current and output the load current; the output terminal of the current sensor is connected to the input terminal of the MCU through the current detection module; the MCU is used to obtain the load current output by the current sensor through the current detection module.

[0010] The current detection module includes resistors R1, R2, R3, R4, R5, and R6, as well as capacitors C1 and C2.

[0011] The first end of resistor R1 is connected to the output terminal of the current sensor, the first end of resistor R3, and the first end of resistor R5, respectively; the first end of resistor R2 is connected to the output terminal of the current sensor, the first end of resistor R4, and the first end of resistor R6, respectively; the second end of resistor R1 is connected to the second end of resistor R2, the second end of resistor R3, the second end of resistor R4, the first end of capacitor C1, and the first end of capacitor C2, respectively.

[0012] The second end of resistor R5 is connected to the second end of capacitor C1 and the input terminal of MCU, respectively, and the second end of resistor R6 is connected to the second end of capacitor C2 and the input terminal of MCU, respectively.

[0013] By adopting the above technical solution, a monitoring path for the load current is formed by a current sensor, a current detection module, and an MCU. In the design of the current detection module, a voltage divider circuit is formed by resistors R1, R2, R3, and R4, while resistors R5 and R6 are used for current limiting, and capacitors C1 and C2 are used for filtering. This simplifies the circuit structure and reduces the complexity and cost of the circuit.

[0014] In one specific implementation scheme, the load current monitoring circuit further includes a current status indicator module; the current status indicator module is connected to the MCU; the MCU is used to control the corresponding light-emitting diode in the current status indicator module to light up when the load current exceeds a preset maximum current threshold, is lower than a preset minimum current threshold, or is within a preset normal current range.

[0015] By adopting the above technical solution and using a current status indicator module, the current load current status is displayed through LEDs, making it easy for on-site personnel to intuitively grasp the charging status.

[0016] In one specific implementation, the current status indication module includes an LED display submodule, a first LED control submodule, a second LED control submodule, and a third LED control submodule;

[0017] The LED display submodule includes three light-emitting diodes (LEDs); the positive terminal of the first LED is connected to the power supply voltage VDD, and the negative terminal is connected to the first LED control submodule through a series resistor; the positive terminal of the second LED is connected to the power supply voltage VDD, and the negative terminal is connected to the second LED control submodule through a series resistor; the positive terminal of the third LED is connected to the power supply voltage VDD, and the negative terminal is connected to the third LED control submodule through a series resistor; the first LED control submodule, the second LED control submodule, and the third LED control submodule are also connected to the MCU.

[0018] The MCU is configured to control the first LED in the LED display submodule to light up when the load current exceeds a preset maximum current threshold, via the first LED control submodule; to control the second LED in the LED display submodule to light up when the load current is within a preset normal current range, via the second LED control submodule; and to control the third LED in the LED display submodule to light up when the load current is below a preset minimum current threshold, via the third LED control submodule.

[0019] By adopting the above technical solution, each LED can be independently controlled through the first LED control submodule, the second LED control submodule, and the third LED control submodule, thereby improving the reliability of the circuit.

[0020] In one specific implementation, the first LED control submodule includes a switch Q1 and a resistor connected between the MCU and the driving terminal of the switch Q1; wherein, the first terminal of the switch Q1 is connected to the LED display submodule and the second terminal is grounded;

[0021] The second LED control submodule includes a switching transistor Q2 and a resistor connected between the MCU and the driving terminal of the switching transistor Q2; wherein, the first terminal of the switching transistor Q2 is connected to the LED display submodule and the second terminal is grounded;

[0022] The third LED control sub-module includes a switching transistor Q3 and a resistor connected between the MCU and the driving terminal of the switching transistor Q3; wherein, the first terminal of the switching transistor Q3 is connected to the LED display sub-module and the second terminal is grounded.

[0023] In one specific implementation, the LED display submodule may be one, two, or more.

[0024] In one specific implementation, the load current monitoring circuit further includes a power conversion module; the input terminal of the power conversion module is connected to the power grid, and the output terminal is connected to the MCU and the current status indicator module respectively; the power conversion module is used to convert the power grid voltage into a power supply voltage VCC and a power supply voltage VDD; wherein, the power supply voltage VCC is used to provide the operating voltage for the MCU, and the power supply voltage VDD is used to provide the operating voltage for the light-emitting diode in the current status indicator module.

[0025] In one specific implementation, the power conversion module includes a varistor RM1, a varistor RM2, a varistor RM3, a fuse F1, a thermal fuse RT1, a common mode inductor LCM1, a capacitor CX1, a capacitor CY1, a capacitor CY2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, an AC-DC power chip, and an LDO chip.

[0026] Wherein, the first end of the first group of coils of the common mode inductor LCM1 is connected to the live wire of the power grid through the thermal fuse RT1 and the fuse F1; the first end of the second group of coils of the common mode inductor LCM1 is connected to the neutral wire of the power grid; the two ends of the capacitor CX1 are respectively connected to the first end of the first group of coils of the common mode inductor LCM1 and the first end of the second group of coils of the common mode inductor LCM1.

[0027] The second end of the first coil of the common-mode inductor LCM1 is connected to the live input pin of the AC-DC power chip, and the second end of the second coil of the common-mode inductor LCM1 is connected to the neutral input pin of the AC-DC power chip; one end of the capacitor CY1 is connected to the midpoint between the second end of the second coil of the common-mode inductor LCM1 and the neutral input pin of the AC-DC power chip, and the other end is connected to the ground pin of the AC-DC power chip; one end of the capacitor CY2 is connected to the midpoint between the second end of the first coil of the common-mode inductor LCM1 and the live input pin of the AC-DC power chip, and the other end is connected to the ground pin of the AC-DC power chip.

[0028] The varistor RM1 and the varistor RM2 are connected in series, with one end connected to the neutral wire of the power grid and the other end connected to the ground pin of the AC-DC power chip. The intermediate node of the varistor RM1 and the varistor RM2 is also connected to the live wire of the power grid. One end of the varistor RM3 is connected to the intermediate node of the neutral wire of the power grid and the first end of the second coil of the common mode inductor LCM1, and the other end is connected to the intermediate node of the varistor RM2 and the ground pin of the AC-DC power chip.

[0029] The capacitors C3 and C4 and the diode D1 are connected in parallel between the positive and negative output pins of the AC-DC power supply chip; the positive output pin of the AC-DC power supply chip is used to output the power supply voltage VDD, and the negative output pin is grounded.

[0030] The input pin of the LDO chip is connected to the positive output pin of the AC-DC power supply chip, and the output pin is used to output the power supply voltage VCC; one end of the capacitor C5 is connected to the input pin of the LDO chip, and the other end is connected to the ground pin of the LDO chip; the ground pin of the LDO chip is grounded.

[0031] Secondly, this application provides a load balancing device, which adopts the following technical solution: the load balancing device includes the load current monitoring circuit of the first aspect or any of the possible implementations of the first aspect.

[0032] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0033] The current sensor, current detection module, and MCU form a monitoring path for the load current. The current detection module is designed with resistors R1, R2, R3, and R4 forming a voltage divider circuit, resistors R5 and R6 for current limiting, and capacitors C1 and C2 for filtering. This simplifies the circuit structure and reduces circuit complexity and cost. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the load current monitoring circuit in the embodiments of this application;

[0035] Figure 2 This is a schematic diagram of the specific circuit of the current detection module in the embodiments of this application;

[0036] Figure 3 This is a schematic diagram of the current status indication module in the embodiments of this application;

[0037] Figure 4 This is a schematic diagram of the power conversion module in the embodiments of this application. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0039] In the description of the embodiments of this application, the words "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design that is described as "for example" or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Rather, the use of the words "for example" or "for instance" is intended to present the relevant concepts in a specific manner.

[0040] This application provides a load current monitoring circuit, such as... Figure 1 As shown, the circuit includes a current sensor, a current detection module, and an MCU;

[0041] The current sensor is used to collect the load current and output the load current; the output terminal of the current sensor is connected to the input terminal of the MCU through the current detection module; the MCU is used to obtain the load current output by the current sensor through the current detection module.

[0042] It should be noted that the load current can be the total load current in the power distribution system, that is, the total load current can be obtained by collecting the current at the three-phase output terminals of the power distribution cabinet.

[0043] Preferably, there are three current detection modules, each corresponding to one phase of the load current. That is, the MCU can obtain the current status of each phase of the load current through these three current detection modules.

[0044] Furthermore, such as Figure 2 As shown, the current detection module includes resistors R1, R2, R3, R4, R5, and R6, as well as capacitors C1 and C2.

[0045] The first end of resistor R1 is connected to the output terminal of the current sensor, the first end of resistor R3, and the first end of resistor R5, respectively; the first end of resistor R2 is connected to the output terminal of the current sensor, the first end of resistor R4, and the first end of resistor R6, respectively; the second end of resistor R1 is connected to the second end of resistor R2, the second end of resistor R3, the second end of resistor R4, the first end of capacitor C1, and the first end of capacitor C2, respectively.

[0046] The second end of resistor R5 is connected to the second end of capacitor C1 and the input terminal of MCU, respectively, and the second end of resistor R6 is connected to the second end of capacitor C2 and the input terminal of MCU, respectively.

[0047] Therefore, the solution in this embodiment forms a monitoring path for the load current using a current sensor, a current detection module, and an MCU. Specifically, the current detection module is designed with resistors R1, R2, R3, and R4 forming a voltage divider circuit, resistors R5 and R6 for current limiting, and capacitors C1 and C2 for filtering. This simplifies the circuit structure and reduces circuit complexity and cost.

[0048] In one possible implementation, refer to Figure 1 The load current monitoring circuit also includes a current status indicator module; the current status indicator module is connected to the MCU; the MCU is used to control the corresponding light-emitting diode in the current status indicator module to light up when the load current exceeds a preset maximum current threshold, is lower than a preset minimum current threshold, or is within a preset normal current range.

[0049] Therefore, a current status indicator module is used to display the current load current status through LEDs, making it easy for on-site personnel to intuitively grasp the charging status.

[0050] In one possible implementation, refer to Figure 3 The current status indication module includes an LED display submodule, a first LED control submodule, a second LED control submodule, and a third LED control submodule;

[0051] The LED display submodule includes three light-emitting diodes (LEDs); the positive terminal of the first LED is connected to the power supply voltage VDD, and the negative terminal is connected to the first LED control submodule through a series resistor; the positive terminal of the second LED is connected to the power supply voltage VDD, and the negative terminal is connected to the second LED control submodule through a series resistor; the positive terminal of the third LED is connected to the power supply voltage VDD, and the negative terminal is connected to the third LED control submodule through a series resistor; the first LED control submodule, the second LED control submodule, and the third LED control submodule are also connected to the MCU.

[0052] The MCU is configured to control the first LED in the LED display submodule to light up when the load current exceeds a preset maximum current threshold, via the first LED control submodule; to control the second LED in the LED display submodule to light up when the load current is within a preset normal current range, via the second LED control submodule; and to control the third LED in the LED display submodule to light up when the load current is below a preset minimum current threshold, via the third LED control submodule.

[0053] Those skilled in the art will understand that each LED has a different color for easy differentiation; in addition, there can be one, two or more LED display submodules, and this application does not make any specific limitation in this regard.

[0054] In one possible implementation, continue to refer to Figure 3 The first LED control submodule includes a switching transistor Q1 and a resistor connected between the MCU and the driving terminal of the switching transistor Q1; wherein, the first terminal of the switching transistor Q1 is connected to the LED display submodule and the second terminal is grounded;

[0055] The second LED control submodule includes a switching transistor Q2 and a resistor connected between the MCU and the driving terminal of the switching transistor Q2; wherein, the first terminal of the switching transistor Q2 is connected to the LED display submodule and the second terminal is grounded;

[0056] The third LED control sub-module includes a switching transistor Q3 and a resistor connected between the MCU and the driving terminal of the switching transistor Q3; wherein, the first terminal of the switching transistor Q3 is connected to the LED display sub-module and the second terminal is grounded.

[0057] Those skilled in the art will understand that the resistors connected to the switching transistors Q1, Q2, and Q3 serve a current-limiting function, and the resistor connected in series with the light-emitting diode is also used for current limiting, thus providing protection.

[0058] The working process of this circuit is explained below:

[0059] When the load current exceeds the preset maximum current threshold, the MCU outputs a high level at one end connected to the first LED control submodule, driving the switch Q1 to turn on, and the first light-emitting diode in the LED display submodule lights up.

[0060] Similarly, when the load current is within the preset normal current range, the MCU outputs a high level at one end connected to the second LED control submodule, driving the switch Q2 to turn on, and the second light-emitting diode in the LED display submodule lights up.

[0061] When the load current is lower than the preset minimum current threshold, the end of the MCU connected to the third LED control submodule outputs a low level, driving the switch Q3 to turn on, and the third light-emitting diode in the LED display submodule lights up.

[0062] Therefore, by using the first LED control submodule, the second LED control submodule, and the third LED control submodule, each LED can be independently controlled, thus improving the reliability of the circuit.

[0063] In one possible implementation, refer to Figure 1 The load current monitoring circuit also includes a power conversion module; the input terminal of the power conversion module is used to connect to the power grid, and the output terminal is connected to the MCU and the current status indicator module respectively; the power conversion module is used to convert the power grid voltage into a power supply voltage VCC and a power supply voltage VDD; wherein, the power supply voltage VCC is used to provide the operating voltage for the MCU, and the power supply voltage VDD is used to provide the operating voltage for the light-emitting diode in the current status indicator module.

[0064] Since the voltage provided by the mains grid cannot directly power the LEDs in the MCU and current status indicator module, a power conversion module is used to convert the mains voltage into power supply voltages VDD and VCC.

[0065] In one possible implementation, refer to Figure 4 The power conversion module includes a varistor RM1, a varistor RM2, a varistor RM3, a fuse F1, a thermal fuse RT1, a common mode inductor LCM1, a capacitor CX1, a capacitor CY1, a capacitor CY2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, an AC-DC power chip, and an LDO chip.

[0066] Wherein, the first end of the first group of coils of the common mode inductor LCM1 is connected to the live wire of the power grid through the thermal fuse RT1 and the fuse F1; the first end of the second group of coils of the common mode inductor LCM1 is connected to the neutral wire of the power grid; the two ends of the capacitor CX1 are respectively connected to the first end of the first group of coils of the common mode inductor LCM1 and the first end of the second group of coils of the common mode inductor LCM1.

[0067] The second end of the first coil of the common-mode inductor LCM1 is connected to the live input pin of the AC-DC power chip, and the second end of the second coil of the common-mode inductor LCM1 is connected to the neutral input pin of the AC-DC power chip; one end of the capacitor CY1 is connected to the midpoint between the second end of the second coil of the common-mode inductor LCM1 and the neutral input pin of the AC-DC power chip, and the other end is connected to the ground pin of the AC-DC power chip; one end of the capacitor CY2 is connected to the midpoint between the second end of the first coil of the common-mode inductor LCM1 and the live input pin of the AC-DC power chip, and the other end is connected to the ground pin of the AC-DC power chip.

[0068] The varistor RM1 and the varistor RM2 are connected in series, with one end connected to the neutral wire of the power grid and the other end connected to the ground pin of the AC-DC power chip. The intermediate node of the varistor RM1 and the varistor RM2 is also connected to the live wire of the power grid. One end of the varistor RM3 is connected to the intermediate node of the neutral wire of the power grid and the first end of the second coil of the common mode inductor LCM1, and the other end is connected to the intermediate node of the varistor RM2 and the ground pin of the AC-DC power chip.

[0069] The capacitors C3 and C4 and the diode D1 are connected in parallel between the positive and negative output pins of the AC-DC power supply chip; the positive output pin of the AC-DC power supply chip is used to output the power supply voltage VDD, and the negative output pin is grounded.

[0070] The input pin of the LDO chip is connected to the positive output pin of the AC-DC power supply chip, and the output pin is used to output the power supply voltage VCC; one end of the capacitor C5 is connected to the input pin of the LDO chip, and the other end is connected to the ground pin of the LDO chip; the ground pin of the LDO chip is grounded.

[0071] In this circuit, varistors RM1, RM2, and RM3 are used for surge protection; fuse F1 is used for overcurrent and short-circuit protection; thermal fuse RT1 is used to protect the circuit when the temperature rises; common-mode inductor LCM1, capacitors CX1, CY1, and CY2 are all EMC devices used to suppress electromagnetic interference; capacitors C3, C4, and C5 are used for filtering; and diode D1 is used for protection.

[0072] Preferably, the AC-DC power supply chip is model ACDC-HP10-S05. The power supply voltage VDD is 5V, and the power supply voltage VCC is 3.3V.

[0073] In one possible implementation, the load current monitoring circuit further includes an Ethernet transmission module connected to the MCU. The MCU also has Wi-Fi functionality, enabling it to send commands to other devices via Wi-Fi or Ethernet. The MCU also receives real-time charging data from other devices via Wi-Fi or Ethernet and performs calculations.

[0074] This application provides a load balancing device, including the load current monitoring circuit described above.

[0075] Furthermore, the load balancing device can be installed in a distribution box, i.e., on the secondary side of the power grid.

[0076] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A load current monitoring circuit, characterized by, The current sensor, the current detection module and the MCU are included. The current sensor is used for collecting a load current and outputting the load current. The current detection module includes resistors R1, R2, R3, R4, R5, R6, capacitors C1 and C2. The first end of the resistor R1 is connected with the output end of the current sensor, the first end of the resistor R3 and the first end of the resistor R5 respectively. The second end of the resistor R5 is connected with the second end of the capacitor C1 and the input end of the MCU respectively, and the second end of the resistor R6 is connected with the second end of the capacitor C2 and the input end of the MCU respectively.

2. The load current monitoring circuit of claim 1, wherein, The current state indication module is further included.

3. The load current monitoring circuit of claim 2, wherein, The current state indication module is connected with the MCU. The MCU is used for controlling corresponding light-emitting diodes in the current state indication module to light up when the load current exceeds a preset maximum current threshold, is lower than a preset minimum current threshold or is in a preset normal current range. The current state indication module includes an LED display submodule, a first LED control submodule, a second LED control submodule and a third LED control submodule. The first LED control submodule, the second LED control submodule and the third LED control submodule are further connected with the MCU. The MCU is used for controlling the first light-emitting diode in the LED display submodule to light up through the first LED control submodule when the load current exceeds the preset maximum current threshold, is used for controlling the second light-emitting diode in the LED display submodule to light up through the second LED control submodule when the load current is in the preset normal current range, and is used for controlling the third light-emitting diode in the LED display submodule to light up through the third LED control submodule when the load current is lower than the preset minimum current threshold.

4. The load current monitoring circuit of claim 3, wherein, The first LED control submodule comprises a switch tube Q1 and a resistor connected between the MCU and a driving end of the switch tube Q1; wherein a first end of the switch tube Q1 is connected with the LED display submodule and a second end thereof is grounded; The second LED control submodule comprises a switch tube Q2 and a resistor connected between the MCU and a driving end of the switch tube Q2; wherein a first end of the switch tube Q2 is connected with the LED display submodule and a second end thereof is grounded; The third LED control submodule comprises a switch tube Q3 and a resistor connected between the MCU and a driving end of the switch tube Q3; wherein a first end of the switch tube Q3 is connected with the LED display submodule and a second end thereof is grounded.

5. The load current monitoring circuit of claim 3, wherein, The LED display submodule is one or two or more.

6. The load current monitoring circuit of claim 2, wherein, The power conversion module is further included; an input end of the power conversion module is used for connecting a power grid, and output ends thereof are connected with the MCU and the current state indication module respectively; the power conversion module is used for converting a grid voltage into a power voltage VCC and a power voltage VDD; wherein the power voltage VCC is used for providing a working voltage for the MCU, and the power voltage VDD is used for providing a working voltage for a light emitting diode in the current state indication module.

7. The load current monitoring circuit of claim 6, wherein, The power conversion module comprises a pressure sensitive resistor RM1, a pressure sensitive resistor RM2, a pressure sensitive resistor RM3, a fuse F1, a temperature fuse RT1, a common mode inductor LCM1, a capacitor CX1, a capacitor CY1, a capacitor CY2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, an AC-DC power chip and an LDO chip; wherein a first end of a first group of coils of the common mode inductor LCM1 is connected to a live wire of the power grid through the temperature fuse RT1 and the fuse F1; a first end of a second group of coils of the common mode inductor LCM1 is connected to a zero wire of the power grid; two ends of the capacitor CX1 are connected with the first end of the first group of coils of the common mode inductor LCM1 and the first end of the second group of coils of the common mode inductor LCM1 respectively; a second end of the first group of coils of the common mode inductor LCM1 is connected to a live wire input pin of the AC-DC power chip, and a second end of the second group of coils of the common mode inductor LCM1 is connected to a zero wire input pin of the AC-DC power chip; one end of the capacitor CY1 is connected to an intermediate node between the second end of the second group of coils of the common mode inductor LCM1 and the zero wire input pin of the AC-DC power chip, and the other end thereof is connected to a ground pin of the AC-DC power chip; one end of the capacitor CY2 is connected to an intermediate node between the second end of the first group of coils of the common mode inductor LCM1 and the live wire input pin of the AC-DC power chip, and the other end thereof is connected to the ground pin of the AC-DC power chip; The pressure sensitive resistor RM1 and the pressure sensitive resistor RM2 are connected in series, one end of which is connected to the zero line of the power grid, the other end of which is connected to the ground pin of the AC-DC power supply chip, and the middle node of the pressure sensitive resistor RM1 and the pressure sensitive resistor RM2 is also connected to the live line of the power grid; one end of the pressure sensitive resistor RM3 is connected to the middle node of the zero line of the power grid and the first end of the second group of coils of the common mode inductor LCM1, the other end of which is connected to the middle node of the pressure sensitive resistor RM2 and the ground pin of the AC-DC power supply chip; The capacitor C3, the capacitor C4 and the diode D1 are connected in parallel between the positive output pin and the negative output pin of the AC-DC power supply chip; the positive output pin of the AC-DC power supply chip is used for outputting the power supply voltage VDD, and the negative output pin is grounded; The input pin of the LDO chip is connected to the positive output pin of the AC-DC power supply chip, and the output pin is used for outputting the power supply voltage VCC; one end of the capacitor C5 is connected to the input pin of the LDO chip, and the other end is connected to the ground pin of the LDO chip; the ground pin of the LDO chip is grounded.

8. A load balancing device, characterized by The load current monitoring circuit comprises the load current monitoring circuit according to any one of claims 1-7.

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