Intelligent charging circuit of solar control panel

Abstract

The utility model relates to solar charging control technical field discloses an intelligent charging circuit of solar control panel, including the priority control module that is composed of MCU management unit and voltage detection unit and current detection module, the input source that is composed of adapter input interface Vin1 and energy storage battery input interface Vin2 and photovoltaic input interface Vin3, and charging pile interface CN4 that is for the power supply of electric equipment, current detection module connects between charging pile interface CN4 and MCU management unit, adopts photovoltaic priority charging strategy, has improved the utilization of solar energy, supports multi -source input intelligent scheduling, to energy rational use, no -load energy -conserving optimization to improve system energy efficiency ratio, reduce the power consumption of adapter, and battery replacement period is prolonged from 2 years to 3 years, reduces maintenance cost, and the seamless switching of multiple input sources guarantees the continuous operation of equipment, reduces the loss of failure downtime.

Description

Technical Field

[0001] This utility model relates to the field of solar charging control technology, specifically to an intelligent charging circuit for a solar control panel. Background Technology

[0002] With the acceleration of industrialization and urbanization, global energy consumption continues to grow, but traditional energy reserves are limited, necessitating the search for alternative new energy sources. With advancements in modern technology, photovoltaic power generation, as a clean and renewable energy source, has been widely adopted. Solar energy applications have entered our lives, such as off-grid power supply, outdoor equipment, and Internet of Things (IoT) nodes.

[0003] The use of solar energy must be managed by a solar controller, but traditional solar controllers generally have the following drawbacks: 1. Lack of multi-power management: Most existing solar energy equipment uses a single photovoltaic input, which is not compatible with multiple power sources such as adapters and energy storage batteries. Sometimes, long cloudy days can cause equipment to shut down, the battery to run out of power, and the battery life to be shortened.

[0004] 2. Serious energy waste: The lack of intelligent scheduling strategies when multiple energy sources coexist often leads to the underutilization of high-priority energy sources (such as photovoltaics); 3. Rigid control logic: The system continues to supply power to the entire system even under no-load conditions, which increases static power consumption and violates the concept of green energy saving.

[0005] Therefore, we need to propose an intelligent charging circuit for solar control panels that supports intelligent scheduling of multiple input sources, rational utilization of energy, and optimization of no-load energy saving, so as to improve the system's energy efficiency ratio and solve the problems of power supply conflict, energy waste and no-load power consumption under multiple power input scenarios. Utility Model Content

[0006] The purpose of this invention is to provide an intelligent charging circuit for a solar control panel, which adopts a photovoltaic-first charging strategy to improve the utilization rate of solar energy; supports intelligent scheduling of multi-source input, rational use of energy, and energy-saving optimization under no-load conditions, so as to improve the system's energy efficiency ratio and solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution: an intelligent charging circuit for a solar control panel, comprising a priority control module consisting of an MCU management unit, a voltage detection unit, and a current detection module; an input source consisting of an adapter input interface Vin1, an energy storage battery input interface Vin2, and a photovoltaic input interface Vin3; and a charging pile interface CN4 for powering electrical equipment. The adapter input interface Vin1, the energy storage battery input interface Vin2, the photovoltaic input interface Vin3, and the charging pile interface CN4 are all electrically connected to the MCU management unit through the voltage detection unit, and the current detection module is connected between the charging pile interface CN4 and the MCU management unit. It also includes a solar power supply module and an energy storage power supply module to power the CN4 interface of the charging pile; The MCU management unit is also connected to the charging pile interface CN4 by a switching execution module for switching different power supply paths. The switching execution module includes a power switch M1 connected to the adapter input interface Vin1, a power switch M2 connected to the energy storage power supply module, a power switch M3 connected to the solar power supply module, and a power switch M4 connected to the energy storage battery input interface Vin2.

[0008] Preferably, the voltage detection unit includes an adapter voltage detection module, an energy storage battery voltage detection module, a photovoltaic voltage detection module, and a charging pile voltage detection module. The adapter voltage detection module is connected between the adapter input interface Vin1 and the MCU management unit. The energy storage battery voltage detection module is connected between the energy storage battery input interface Vin2 and the MCU management unit. The photovoltaic voltage detection module is connected between the photovoltaic input interface Vin3 and the MCU management unit. The charging pile voltage detection module and the current detection module are both connected between the charging pile interface CN4 and the MCU management unit.

[0009] Preferably, it also includes a 5V power supply module, the input terminal of which is electrically connected to the photovoltaic input interface Vin3 and the adapter input interface Vin1 respectively, and the output terminal of which is electrically connected to the MCU management unit.

[0010] Preferably, the MCU management unit includes a chip IC1, pin 2 of the chip IC1 is connected to a resistor R56, pin 3 of the chip IC1 is connected to a resistor R57, a diode LED1 for displaying the photovoltaic and adapter status is connected between resistors R56 and R57, pin 7 of the chip IC1 is connected to a resistor R58, pin 8 of the chip IC1 is connected to a resistor R59, and a diode LED2 for displaying the energy storage status is connected between resistors R58 and R59.

[0011] Preferably, the adapter voltage detection module includes a signal switch Q1, resistors R72 and R74 connected between pins 1 and 2 of the adapter input interface Vin1, the base of the signal switch Q1 being connected to pin 5 of the chip IC1, resistors R1 and R2 being connected between the collector of the signal switch Q1 and the source of the power switch M1, and the emitter of the signal switch Q1 being connected to pin 2 of the adapter input interface Vin1.

[0012] Preferably, the energy storage battery voltage detection module includes a signal switch Q2 and a MOS switch M6. A resistor R10 is connected between the drain of the MOS switch M6 and pin 4 of the energy storage battery input interface Vin2. Resistors R9 and R11 are connected between the source of the MOS switch M6 and pin 1 of the energy storage battery input interface Vin2. A diode D2 is connected between the drain of the power switch M4 and pin 1 of the energy storage battery input interface Vin2. A resistor R6 is connected between the gate of the power switch M4 and the collector of the signal switch Q2. A resistor R7 is connected between the base of the signal switch Q2 and pin 12 of the chip IC1. A resistor R12 is connected between the drain of the MOS switch M6 and pin 17 of the chip IC1.

[0013] Preferably, the photovoltaic voltage detection module includes a signal switch Q6, a Zener diode ZVS and a capacitor EC1 connected in parallel between pins 1 and 2 of the photovoltaic input interface Vin3, a resistor R40 connected between the collector of the signal switch Q6 and the gate of the power switch M3, and the emitter of the signal switch Q6 connected to pin 2 of the photovoltaic input interface Vin3.

[0014] Preferably, the charging pile voltage detection module includes a filter LF1, with a capacitor EC3 connected in parallel to pin 3 of the filter LF1, and resistors R43, R45, and R44 connected in series. Pin 3 of the filter LF1 is connected to pin 1 of the charging pile interface CN4.

[0015] Preferably, the current detection module includes an amplifier U2, a resistor R63 is connected between pin 1 of the amplifier U2 and pin 16 of the chip IC1, and pin 3 of the amplifier U2 is connected to pin 2 of the charging pile interface CN4.

[0016] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model adopts a photovoltaic-first charging strategy, which improves the utilization rate of solar energy; it supports intelligent scheduling of multi-source input, rational use of energy, and energy-saving optimization under no-load conditions, so as to improve the system's energy efficiency ratio.

[0017] 2. The MCU of this utility model implements an intelligent charging and discharging strategy to extend the cycle life of the energy storage battery.

[0018] 3. This utility model reduces the power consumption of the adapter, extends the battery replacement cycle from 2 years to 3 years, reduces maintenance costs, and ensures continuous operation of the equipment with power through seamless switching of multiple input sources, reducing downtime losses due to malfunctions. Attached Figure Description

[0019] Figure 1 This is a system block diagram of the present invention; Figure 2 This is a circuit diagram of the adapter voltage detection module of this utility model; Figure 3 This is a circuit diagram of the energy storage battery voltage detection module of this utility model; Figure 4 This is a circuit diagram of the energy storage power supply module of this utility model; Figure 5 This is the circuit diagram of the photovoltaic voltage detection module of this utility model.

[0020] Figure 6 This is the circuit diagram of the solar power supply module of this utility model; Figure 7 This is a circuit diagram of the charging pile voltage detection module of this utility model; Figure 8 This is a circuit diagram of the MCU management unit of this utility model; Figure 9 This is the circuit diagram of the current detection module of this utility model; Figure 10 This is the circuit diagram of the 5V power supply module of this utility model. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Please see Figure 1-10This utility model provides an intelligent charging circuit for a solar control panel, including a priority control module composed of an MCU management unit, a voltage detection unit, and a current detection module; an input source composed of an adapter input interface Vin1, an energy storage battery input interface Vin2, and a photovoltaic input interface Vin3; and a charging pile interface CN4 for powering electrical equipment. The adapter input interface Vin1, the energy storage battery input interface Vin2, the photovoltaic input interface Vin3, and the charging pile interface CN4 are all electrically connected to the MCU management unit through the voltage detection unit, and the current detection module is connected between the charging pile interface CN4 and the MCU management unit.

[0023] The MCU management unit is used to prioritize power supply, which follows a power supply strategy of photovoltaic > energy storage battery > adapter.

[0024] The MCU management unit reserves the minimum current for transmitting signals to the charging pile interface CN4, and only reserves the charging path to the photovoltaic input interface Vin3 and the energy storage battery input interface Vin2.

[0025] It also includes a solar power supply module and an energy storage power supply module to power the CN4 interface of the charging pile; The circuit diagram of the energy storage power supply module is as follows: Figure 4 As shown, the circuit diagram of the solar power module is as follows: Figure 6 As shown.

[0026] The MCU management unit is also connected to the charging pile interface CN4 by a switching execution module for switching different power supply paths. The switching execution module includes a power switch M1 connected to the adapter input interface Vin1, a power switch M2 connected to the energy storage power supply module, a power switch M3 connected to the solar power supply module, and a power switch M4 connected to the energy storage battery input interface Vin2.

[0027] The voltage detection unit includes an adapter voltage detection module, an energy storage battery voltage detection module, a photovoltaic voltage detection module, and a charging pile voltage detection module; The adapter voltage detection module is connected between the adapter input interface Vin1 and the MCU management unit; the energy storage battery voltage detection module is connected between the energy storage battery input interface Vin2 and the MCU management unit; the photovoltaic voltage detection module is connected between the photovoltaic input interface Vin3 and the MCU management unit; and the charging pile voltage detection module and current detection module are both connected between the charging pile interface CN4 and the MCU management unit.

[0028] It also includes a 5V power supply module, the circuit diagram of which is shown below. Figure 10As shown, the input terminal of the 5V power supply module is electrically connected to the photovoltaic input interface Vin3 and the adapter input interface Vin1, respectively, and the output terminal of the 5V power supply module is electrically connected to the MCU management unit.

[0029] The 5V power supply module has two power supply paths: one path is the adapter V_adp, which is regulated by the Zener diode ZD2 to the voltage regulator chip U1 and outputs 5V; the other path is the photovoltaic V_pv, which has a voltage greater than 16V. After being processed by comparators U3A and U3B, the output is high level, which turns on transistor Q8 and then turns on transistor Q7, thus supplying power to the voltage regulator chip U1 and regulating it to 5V.

[0030] like Figure 8 As shown, the MCU management unit includes a chip IC1. Pin 2 of the chip IC1 is connected to a resistor R56, pin 3 of the chip IC1 is connected to a resistor R57, and a diode LED1 for displaying the photovoltaic and adapter status is connected between resistors R56 and R57. Pin 7 of the chip IC1 is connected to a resistor R58, pin 8 of the chip IC1 is connected to a resistor R59, and a diode LED2 for displaying the energy storage status is connected between resistors R58 and R59.

[0031] like Figure 2 As shown, the adapter voltage detection module includes a signal switch Q1, resistors R72 and R74 connected between pins 1 and 2 of the adapter input interface Vin1, the base of the signal switch Q1 connected to pin 5 of the chip IC1, resistors R1 and R2 connected between the collector of the signal switch Q1 and the source of the power switch M1, and the emitter of the signal switch Q1 connected to pin 2 of the adapter input interface Vin1.

[0032] Adapter voltage detection module: The adapter voltage is divided by resistors R72, R73, and R74, and then transmitted to pin 14 of chip IC1 via resistor R75 to sample the voltage value. Signal switch Q1 is the signal switch for signal S1 of chip IC1, indirectly controlling power switch M1 to control the power supply of the adapter to the charging pile.

[0033] like Figure 3As shown, the energy storage battery voltage detection module includes a signal switch Q2 and a MOS switch M6. A resistor R10 is connected between the drain of the MOS switch M6 and pin 4 of the energy storage battery input interface Vin2. Resistors R9 and R11 are connected between the source of the MOS switch M6 and pin 1 of the energy storage battery input interface Vin2. A diode D2 is connected between the drain of the power switch M4 and pin 1 of the energy storage battery input interface Vin2. A resistor R6 is connected between the gate of the power switch M4 and the collector of the signal switch Q2. A resistor R7 is connected between the base of the signal switch Q2 and pin 12 of the chip IC1. A resistor R12 is connected between the drain of the MOS switch M6 and pin 17 of the chip IC1.

[0034] Energy storage battery voltage detection module: When the energy storage battery does not supply power to the charging pile or enters low voltage protection, in order to reduce energy storage power consumption, the MOS switch M6 is turned off. If there is external power supply or photovoltaic charging of the energy storage, the MOS switch M6 will be turned on.

[0035] Voltage detection is controlled to be turned off by MOS switch M6 and turned on again when needed. The stored voltage is divided by resistors R9, R11 and R10 and then transmitted to pin 4 of the analog port of chip IC1 through resistor R12 to sample the voltage value.

[0036] like Figure 5 As shown, the photovoltaic voltage detection module includes a signal switch Q6, a Zener diode ZVS and a capacitor EC1 connected in parallel between pins 1 and 2 of the photovoltaic input interface Vin3, a resistor R40 connected between the collector of the signal switch Q6 and the gate of the power switch M3, and the emitter of the signal switch Q6 connected to pin 2 of the photovoltaic input interface Vin3.

[0037] Photovoltaic voltage detection module: The photovoltaic voltage is divided by resistors R24, R25, and R26, and then transmitted to pin 19 of chip IC1 via resistor R27 to sample the voltage value. Signal switch Q6 is the signal switch for signal S3 of chip IC1, indirectly controlling power switch M3 to control the external power supply of the photovoltaic system.

[0038] like Figure 7 As shown, the charging pile voltage detection module includes a filter LF1. A capacitor EC3 is connected in parallel to pin 3 of the filter LF1, and resistors R43, R45, and R44 are connected in series. Pin 3 of the filter LF1 is connected to pin 1 of the charging pile interface CN4.

[0039] Charging pile voltage detection module: The charging pile voltage is divided by resistors R43, R45 and R44, and then transmitted to pin 18 of the analog port of chip IC1 through resistor R47 to sample the voltage value.

[0040] The MCU management unit determines whether an input source is connected based on the voltage detected by each voltage detection module.

[0041] like Figure 9 As shown, the current detection module includes an amplifier U2. A resistor R63 is connected between pin 1 of the amplifier U2 and pin 16 of the chip IC1. Pin 3 of the amplifier U2 is connected to pin 2 of the charging pile interface CN4.

[0042] A resistor R48 is connected to pin 3 of amplifier U2. A capacitor C15 and a resistor R49 are connected between pins 2 and 3 of amplifier U2. A resistor R50 is connected between pins 1 and 2 of amplifier U2.

[0043] Resistor R48 obtains the voltage across the sampling resistor, resistors R49 and R50 are the amplification ratios, and the amplified value is sent to pin 16 of chip IC1 via resistor R63.

[0044] The solar control panel detects the current magnitude through the current detection module. The MCU management unit can determine whether there is power output to the charging pile or whether the photovoltaic system is charging the energy storage battery.

[0045] The voltage sampled by the solar control panel through resistor RS2 is amplified by amplifier U2 and transmitted through resistor R63 to pin 16 of chip IC1 for sampling. The voltage value can be determined based on the voltage magnitude. For energy saving, only the photovoltaic system charges the energy storage battery. When no vehicle is charging at the charging station, the energy storage battery is charged; similarly, there is voltage on resistor RS2, which is detected to determine whether charging is in progress.

[0046] When the photovoltaic (Vin3) is connected and effective (PV effective: that is, the PV can output ≥200mA current), if there is electrical equipment at the charging pile end, close power switch M3 to supply power to the charging pile, and disconnect power switches M1, M2, and M4; if there is no electrical equipment at the charging pile end, close power switch M4 to charge the energy storage battery, keep power switch M3 powered on to maintain a small current transmission signal from the charging pile, and disconnect power switches M1 and M2.

[0047] When the photovoltaic (Vin3) is not connected or is connected but ineffective (photovoltaic ineffective: i.e., the photovoltaic can output <200mA current), and the energy storage battery (Vin2) is effective (energy storage effective: battery voltage > low voltage protection 14V voltage), the power switch M2 is closed to supply power to the charging pile, and the power switches M1, M3, and M4 are disconnected.

[0048] When only the adapter (Vin1) is active, power switch M1 is closed to supply power to the charging station, while power switches M2, M3, and M4 are disconnected.

[0049] When all three input sources are valid, the power supply priority is: photovoltaic > energy storage battery > adapter. During operation, for example, if the weather changes from sunny to cloudy, the photovoltaic power supply may become invalid, and the MCU management unit will automatically switch to the lower priority energy storage power supply. If the energy storage discharges to the point where the low voltage protection becomes invalid, the MCU management unit will automatically switch to the adapter power supply. If the invalid high priority power supply recovers during operation, it will automatically switch back to the high priority power supply. The MCU management unit makes a logical judgment every 6 seconds to determine the optimal power supply method.

[0050] For example, the equipment at the charging station is a smart lawnmower cart. It needs to send signals to the cart in real time to guide it to automatically return to the charging station for charging. Therefore, the charging station will not be powered off and will remain in standby mode.

[0051] When the charging pile has no electrical equipment but transmits a signal: the MCU management unit determines that the output is unloaded based on the voltage detected by the charging pile voltage detection module and the current detected by the current detection module. If the photovoltaic is invalid, the lower-priority energy storage battery is retained to supply power, and the minimum power supply energy-saving mode is entered, cutting off other power supply paths; if there are other situations, the MCU management unit will switch to the next priority power supply; if the photovoltaic is valid, the photovoltaic → energy storage battery charging path is started (power switch M4 → load output path Vout4).

[0052] When the charging pile has no electrical equipment and the signal transmitting device is removed: the output current is <10mA, the MCU management unit determines that it has entered the no-load energy-saving mode, cuts off all power supply paths, and the system automatically shuts down.

[0053] Let's take the power supply of a smart lawnmower as an example: When there is sufficient sunlight during the day: When the charging station is loaded with a lawnmower, the photovoltaic system will prioritize powering the charging station.

[0054] When the equipment is in standby mode: only the photovoltaic system charges the energy storage battery, prioritizing energy conservation and using clean and energy-saving energy sources.

[0055] On cloudy days or at night when there is no sunlight: the energy storage battery supplies power to the charging station, and switches the adapter when the voltage is insufficient.

[0056] Input power supply priority logic control: Prioritize economic energy saving, power supply priority: photovoltaic > energy storage battery > adapter; according to changes in input conditions (e.g., photovoltaic weather changes from sunny to cloudy, input becomes invalid; when the sun comes out, input becomes valid again), the priority switches from high to low or from low to high, and automatically switches back and forth according to energy saving control logic.

[0057] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smart charging circuit for a solar control panel, characterized in that: It includes a priority control module consisting of an MCU management unit, a voltage detection unit, and a current detection module; an input source consisting of an adapter input interface Vin1, an energy storage battery input interface Vin2, and a photovoltaic input interface Vin3; and a charging pile interface CN4 for powering the electrical equipment. The adapter input interface Vin1, the energy storage battery input interface Vin2, the photovoltaic input interface Vin3, and the charging pile interface CN4 are all electrically connected to the MCU management unit through the voltage detection unit. The current detection module is connected between the charging pile interface CN4 and the MCU management unit. It also includes a solar power supply module and an energy storage power supply module to power the CN4 interface of the charging pile; The MCU management unit is also connected to the charging pile interface CN4 by a switching execution module for switching different power supply paths. The switching execution module includes a power switch M1 connected to the adapter input interface Vin1, a power switch M2 connected to the energy storage power supply module, a power switch M3 connected to the solar power supply module, and a power switch M4 connected to the energy storage battery input interface Vin2.

2. The intelligent charging circuit for a solar control panel according to claim 1, characterized in that: The voltage detection unit includes an adapter voltage detection module, an energy storage battery voltage detection module, a photovoltaic voltage detection module, and a charging pile voltage detection module. The adapter voltage detection module is connected between the adapter input interface Vin1 and the MCU management unit. The energy storage battery voltage detection module is connected between the energy storage battery input interface Vin2 and the MCU management unit. The photovoltaic voltage detection module is connected between the photovoltaic input interface Vin3 and the MCU management unit. The charging pile voltage detection module and the current detection module are both connected between the charging pile interface CN4 and the MCU management unit.

3. The intelligent charging circuit for a solar control panel according to claim 2, characterized in that: It also includes a 5V power supply module, the input of which is electrically connected to the photovoltaic input interface Vin3 and the adapter input interface Vin1, respectively, and the output of which is electrically connected to the MCU management unit.

4. The intelligent charging circuit for a solar control panel according to claim 3, characterized in that: The MCU management unit includes a chip IC1. Pin 2 of the chip IC1 is connected to a resistor R56, pin 3 of the chip IC1 is connected to a resistor R57, and a diode LED1 for displaying the photovoltaic and adapter status is connected between resistors R56 and R57. Pin 7 of the chip IC1 is connected to a resistor R58, pin 8 of the chip IC1 is connected to a resistor R59, and a diode LED2 for displaying the energy storage status is connected between resistors R58 and R59.

5. The intelligent charging circuit for a solar control panel according to claim 4, characterized in that: The adapter voltage detection module includes a signal switch Q1, resistors R72 and R74 connected between pins 1 and 2 of the adapter input interface Vin1, the base of the signal switch Q1 connected to pin 5 of the chip IC1, resistors R1 and R2 connected between the collector of the signal switch Q1 and the source of the power switch M1, and the emitter of the signal switch Q1 connected to pin 2 of the adapter input interface Vin1.

6. The intelligent charging circuit for a solar control panel according to claim 5, characterized in that: The energy storage battery voltage detection module includes a signal switch Q2 and a MOS switch M6. A resistor R10 is connected between the drain of the MOS switch M6 and pin 4 of the energy storage battery input interface Vin2. Resistors R9 and R11 are connected between the source of the MOS switch M6 and pin 1 of the energy storage battery input interface Vin2. A diode D2 is connected between the drain of the power switch M4 and pin 1 of the energy storage battery input interface Vin2. A resistor R6 is connected between the gate of the power switch M4 and the collector of the signal switch Q2. A resistor R7 is connected between the base of the signal switch Q2 and pin 12 of the chip IC1. A resistor R12 is connected between the drain of the MOS switch M6 and pin 17 of the chip IC1.

7. The intelligent charging circuit for a solar control panel according to claim 6, characterized in that: The photovoltaic voltage detection module includes a signal switch Q6, a Zener diode ZVS and a capacitor EC1 connected in parallel between pins 1 and 2 of the photovoltaic input interface Vin3, a resistor R40 connected between the collector of the signal switch Q6 and the gate of the power switch M3, and the emitter of the signal switch Q6 connected to pin 2 of the photovoltaic input interface Vin3.

8. The intelligent charging circuit for a solar control panel according to claim 7, characterized in that: The charging pile voltage detection module includes a filter LF1. A capacitor EC3 is connected in parallel to pin 3 of the filter LF1, and resistors R43, R45, and R44 are connected in series. Pin 3 of the filter LF1 is connected to pin 1 of the charging pile interface CN4.

9. The intelligent charging circuit for a solar control panel according to claim 8, characterized in that: The current detection module includes an amplifier U2. A resistor R63 is connected between pin 1 of the amplifier U2 and pin 16 of the chip IC1. Pin 3 of the amplifier U2 is connected to pin 2 of the charging pile interface CN4.

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