Charging circuit and charging module

Abstract

The embodiment of the utility model discloses a charging circuit and a charging module. The charging circuit comprises a first transformer, a second transformer, a first rectification filter circuit, a second rectification filter circuit, a third rectification filter circuit, a fan power supply control circuit and a button and display circuit. A first primary winding of the first transformer receives an input voltage; the input side of the first rectification filter circuit is connected with the first secondary winding, the first end of the output side outputs a first output voltage, and the second end is connected with a first reference ground; a second primary winding of the second transformer receives the input voltage; the input side of the second rectification filter circuit is connected with the second secondary winding, and the output side is connected with the fan power supply control circuit; the input side of the third rectification filter circuit is connected with the third secondary winding, and the output side is connected with the button and display circuit. Through the above mode, the charging module provided by the embodiment of the utility model can solve the problem of ground detection faults caused by environmental factors of a traditional charging module, and improves the safety and reliability of the charging module.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of electronic technology, and in particular to a charging circuit and a charging module. Background Art

[0002] The charging module is a high-power power electronic module. When used in a charging pile, the charging module generates severe heat and requires a fan to dissipate heat. Therefore, most charging piles currently use air-cooled systems.

[0003] The air-cooled charging pile system is greatly affected by external natural environmental factors. The main environmental factors are condensation caused by changes in temperature and severe dust, oil, water vapor and other conductive ions and particles mixed in the air inlet. In particular, the fan housing at the air inlet and its power supply control circuit and human-machine interface circuit (button and display circuit) are more susceptible to these external environmental factors. These external environmental factors will cause the insulation impedance of these circuits to the ground to decrease, causing the charging system to detect the insulation impedance to the ground to fail, resulting in the potential risk of jumping the gun to stop charging or possibly causing electric shock, reducing the reliability and safety of the system operation. At present, the fan circuit and components are directly exposed to the external air intake system, which is the most seriously polluted, and the probability of causing the charging system to detect the insulation impedance to the ground is also the most prominent. Utility Model Content

[0004] The main technical problem solved by the embodiments of the utility model is to provide a charging circuit and a charging module, which can solve some problems caused by the charging module being affected by environmental pollutants.

[0005] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide a charging circuit, including: a first transformer for converting an input voltage into a first AC voltage, having a first primary winding and a first secondary winding, the first primary winding receiving the input voltage; a first rectifier filter circuit connected to the first secondary winding on the input side, for converting the first AC voltage into a first output voltage, a first end of the output side of which outputs the first output voltage, and a second end of the output side of which is connected to a first reference ground; a second transformer for converting the input voltage into a second AC voltage and a third AC voltage, respectively, having a second primary winding, a second secondary winding and a third secondary winding, the second The primary winding receives the input voltage; the input side is connected to the second rectifier and filter circuit of the second secondary winding, which is used to convert the second AC voltage into a second output voltage, and the first end of its output side outputs the second output voltage, and the second end of its output side is connected to the second reference ground; the input side is connected to the third rectifier and filter circuit of the third secondary winding, which is used to convert the third AC voltage into a third output voltage, and the first end of its output side outputs the third output voltage, and the second end of its output side is connected to the third reference ground; the fan power supply control circuit, whose power input side is connected to the output side of the second rectifier and filter circuit; the button and display circuit, whose power input side is connected to the output side of the third rectifier and filter circuit.

[0006] Optionally, the first end of the first primary winding receives the input voltage, and the second end of the first primary winding is connected to the fourth reference ground through the second control switch; the first end of the second primary winding receives the input voltage, and the second end of the second primary winding is connected to the fourth reference ground through the first control switch.

[0007] Optionally, the charging circuit also includes: an isolated feedback circuit, whose input side is connected to the output side of the second rectifier and filter circuit, and whose output end is connected to the controlled end of the first control switch; a digital signal processor, whose power input end receives the third output voltage and is connected to the first reference ground through a filter capacitor; a first signal isolation circuit, whose output side is connected to the signal input side of the fan power supply control circuit, and whose input side is connected to the first signal output side of the digital signal processor; a second signal isolation circuit, whose output side is connected to the signal input side of the button and display circuit, and whose input side is connected to the second signal output side of the digital signal processor.

[0008] Optionally, the second reference ground and the third reference ground are the same reference ground.

[0009] Optionally, the first signal isolation circuit includes at least a first optocoupler; and the second signal isolation circuit includes at least a second optocoupler.

[0010] In order to solve the above technical problem, another technical solution adopted by the present invention is: to provide a charging module, including: the charging circuit as described above.

[0011] Optionally, the distance between the primary winding pin of the first transformer and its secondary winding pin is greater than a first preset distance; the distance between the primary winding pin of the second transformer and its secondary winding pin is greater than the first preset distance; the distance between the primary winding pin or the secondary winding pin of the first transformer and its magnetic core is the second preset distance; the distance between the primary winding pin or the secondary winding pin of the second transformer and its magnetic core is the second preset distance.

[0012] Optionally, the first preset distance is 10 mm; the second preset distance is 10 mm.

[0013] Optionally, the coil of the first primary winding and the coil of the second primary winding both use fully insulated wires; the coil of the first secondary winding, the coil of the second secondary winding and the coil of the third secondary winding all use fully insulated wires or triple insulated wires.

[0014] Optionally, the distance between the primary pin and the secondary pin of the first optical coupler is a third preset distance; and the distance between the primary pin and the secondary pin of the second optical coupler is the third preset distance.

[0015] Optionally, the third preset distance is 10 mm.

[0016] The beneficial effects of the embodiments of the utility model are as follows: Different from the prior art, the utility model first separates the reference ground of the main power output from the reference area of ​​the fan power supply module and the display and key module at the circuit level, and secondly improves the device aspects, such as the pin distance and the coil material, to enhance the insulation effect of the corresponding device. In this way, the ground detection failure problem caused by environmental factors in the traditional charging module is solved, and the safety and reliability of the charging module are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an existing charging circuit;

[0018] Figure 2 It is a structural schematic diagram of a charging circuit provided by the utility model; DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the utility model, the utility model is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0021] Conventional charging circuits such as Figure 1 As shown, it includes a first capacitor C1, a second capacitor C2, a first control switch Q1, a second control switch Q2, a fan power supply control circuit 110, a button and display circuit 120, a main power transformer T2, a main power rectification and filtering circuit 130, an auxiliary power transformer T1, an auxiliary power rectification and filtering circuit 140, an isolation feedback circuit 150 and a digital signal processor 160.

[0022] The main power transformer T2 has a primary winding K3 and a secondary winding K4. One end of the primary winding K3 of the main power transformer T2 is connected to the input power supply Vin, and the other end is connected to the first fourth reference ground PGND through the second control switch Q2. The secondary winding K4 is connected to the input side of the main power rectifier and filter circuit 130. One end of the output side of the main power rectifier and filter circuit 130 outputs the first output voltage 1000Vdc_out, and the other end is connected to the first reference ground AGND; the auxiliary power transformer T1 has a primary winding K1 and a secondary winding K2. One end of the primary winding K1 of the auxiliary power transformer T1 is connected to the input power supply Vin, and the other end is connected to the first fourth reference ground PGND through the first control switch Q1. The secondary winding K2 is connected to the input side of the auxiliary power rectifier and filter circuit 140. One end of the output side of the auxiliary power rectifier and filter circuit 140 outputs the second output voltage +12VDC_FAN, and the other end is connected to the first reference ground AGND.

[0023] The input side of the isolated feedback circuit 150 is connected to the output side of the auxiliary power rectification and filtering circuit 140, and the output end of the isolated feedback circuit 150 is connected to the controlled end of the first control switch Q1; the power input side of the fan power supply control circuit 110 is connected to the output side of the auxiliary power supply rectification and filtering circuit 140, and the signal input side of the fan power supply control circuit 110 is connected to the first signal input side of the digital signal processor 160; the first end of the power input side of the key and display circuit 120 is connected to the first end of the second capacitor C2 to receive the power supply voltage 3.3Vdc, and the first end of the power input side of the key and display circuit 120 is connected to the second end of the second capacitor C2 and connected to the first reference ground AGND. The power input end of the digital signal processor 160 is connected to the first end of the first capacitor C1 to receive the power supply voltage 3.3Vdc, and the ground end of the digital signal processor 160 is connected to the second end of the first capacitor C1 and connected to the first reference ground AGND.

[0024] The fan power supply control circuit 110 is usually used to control the speed or switch of the fan to meet different heat dissipation requirements or energy saving requirements. Common fan power supply control circuits include: a speed control circuit that uses a variable resistor or a voltage regulator to control the speed of the fan; a pulse width modulation circuit that controls the speed of the fan by changing the duty cycle of a pulse width modulation signal (PWM); and a temperature control circuit that detects the temperature of the environment or application equipment through a temperature sensor and controls the speed of the fan according to a preset temperature threshold, etc.

[0025] The key and display circuit 120 is used for key operation and information display in the control and display device, and usually includes three parts: a key part: at least including keys, key matrix encoders and key drive circuits; a display part: at least including a display, a drive circuit and a controller connected to the display; a connection control part: at least including an MCU or a processor.

[0026] The main power rectifier and filter circuit 130 is mainly used to extract DC power from AC power and filter the power to reduce pulsation. It usually includes two parts: a rectifier part including at least a rectifier bridge and a filter capacitor; and a filter part including at least a filter inductor and an impedance matching circuit to improve power transmission efficiency.

[0027] The auxiliary power supply rectifier and filter circuit 140 is mainly used to extract a stable DC power supply from the auxiliary power supply and filter the power supply to remove pulsation and noise. It usually includes three parts: at least a rectifying part including a rectifier diode, usually using a single rectifier diode or a rectifier bridge for rectification; at least a filtering part including a filter capacitor; at least a voltage stabilizing part of a voltage stabilizing circuit to ensure the stability of the output voltage.

[0028] The isolation feedback circuit 150 is a circuit for providing electrical isolation and signal feedback. It is mainly used to isolate input and output signals, prevent signal interference and protect equipment. It usually includes two parts: at least the isolation part of the isolation transformer to effectively isolate the input and output ends; at least the feedback part of the feedback circuit to achieve signal stability and reliability, so that the output signal corresponds more accurately to the input signal.

[0029] The digital signal processor 160 (Digital Signal Processor, DSP) is a microprocessor specially used for processing digital signals. Compared with general-purpose microprocessors, DSP is more focused on algorithms and applications in the field of digital signal processing.

[0030] Depend on Figure 1 It can be seen that the fan power supply control circuit and the button and display circuit share the same ground with the main power rectifier and filter circuit, which is the first reference ground AGND. From the perspective of electrical safety, the fan power supply control circuit, the button and display circuit, and the main power rectifier and filter circuit belong to different functional attribute circuits with the same electrical safety attribute.

[0031] Based on the above situation, the fan power supply control circuit and the button and display circuit in the existing charging circuit are isolated from the AC input circuit (i.e., the input circuit connected to the primary winding of the main power transformer) based on basic insulation. There is no safety insulation design between the fan power supply control circuit and the DC high-voltage output circuit (i.e., the main power rectifier and filter circuit), only functional insulation. Therefore, there is a dangerous voltage of 200Vdc-1000Vdc between the fan power supply control and button and display circuit and the housing and external signal circuit.

[0032] The touchable insulating operating parts such as buttons and display circuits related to the human-machine interface do not belong to high-integrity insulating parts. They are only insulating parts in a general sense and cannot be used as safe insulating parts. The fan and its components and the human-machine interface circuit (in this embodiment, the buttons and display circuit) and its components are all installed and fixed on the frame of the metal shell of the charging module for easy operation and fixation. The metal shell is grounded (the ground here is the earth).

[0033] Therefore, the above circuit solution has the following potential defects:

[0034] 1. The insulation impedance detection of the charging circuit to the ground of the charging system is to determine whether the impedance is too low by detecting the insulation impedance of the positive and negative positions of the charging circuit to the ground (shell grounding). When the insulation impedance of any positive and negative position of the charging circuit to the ground is less than 100 ohms / V, it will be judged that the insulation impedance to the ground is too low, and the gun will jump and stop charging. The fan power supply control circuit and the main power rectifier filter circuit belong to circuits with different functional attributes of the same electrical safety attributes. The fan power supply control circuit and its plastic casing are at the air inlet. Under the influence of the above-mentioned environmental factors, its circuit and the outer surface of the fan will form a conductive pollution path. When the impedance of the fan power supply control circuit and its plastic casing and the grounded casing is lower than 100 ohms / V (output 1000Vdc corresponds to 0.1 megohm impedance), it will be judged that the insulation impedance detection is too low, and the gun will jump and stop charging.

[0035] 2. Similarly, the button and display circuit also uses the same reference ground as the main power rectifier and filter circuit, and is a circuit with the same electrical safety properties. It is also located at the air inlet. This circuit and its components also have potential conductive pollution paths with the grounded shell. Therefore, when the button and display circuit and its components are contaminated and the insulation impedance of the grounded shell is too low, a low insulation impedance fault will be reported and charging will stop.

[0036] 3. The touchable insulated operating parts such as the display and buttons of the human-machine interface circuit are not high-integrity insulating parts. Therefore, there may be a potential risk of electric shock when operating these insulating parts.

[0037] 4. Especially when the system is poorly grounded and there are conductive pollution paths, the insulation between the above circuits and their components and the grounded casing or operating interface is reduced, which may cause potential electric shock safety risks for operators and maintenance personnel when they are working.

[0038] 5. As an optimization, some systems have glued the fan power supply control circuit or strengthened the CTI level of the fan plastic shell to reduce the conductive path caused by environmental factors, but the fan is a third-party standard device material, which has factors such as unchangeable or difficult to replace control. And because these optimization measures have not optimized and changed the circuit isolation design, there is still a probability of insulation impedance detection failure and potential safety risks.

[0039] To solve the above problems, the present application provides a charging circuit, the structural diagram of which is shown in FIG. Figure 2As shown, the charging circuit includes a filter capacitor C1, a first control switch Q1, a second control switch Q2, a fan power supply control circuit 210, a button and display circuit 220, a first transformer T1, a second transformer T2, a first rectifier and filter circuit 230, a second rectifier and filter circuit 240, a third rectifier and filter circuit 250, an isolation feedback circuit 260, a first signal isolation circuit 270, a second signal isolation circuit 280 and a digital signal processor 290.

[0040] The first end of the first primary winding K1 of the first transformer T1 receives the input voltage Vin, the second end of the first primary winding K1 is connected to the fourth reference ground PGND through the second control switch Q2, and the first secondary winding K2 of the first transformer T1 is connected to the input side of the first rectifier and filter circuit 230; the first end of the output side of the first rectifier and filter circuit 230 outputs the first output voltage 1000Vdc_out, and the second end of the output side of the first rectifier and filter circuit 230 is connected to the first reference ground AGND. The first transformer T1 is used to convert the input voltage into a first AC voltage, and the first rectifier and filter circuit 230 rectifies and filters the first AC voltage to output a first output voltage 1000Vdc_out.

[0041] In the embodiment of the present application, the input voltage Vin is a bus supply voltage of 800V.

[0042] The first end of the second primary winding K3 of the second transformer T2 receives the input voltage Vin, the second end of the second primary winding K3 is connected to the fourth reference ground PGND through the first control switch Q1, the second secondary winding K4 of the second transformer T2 is connected to the input side of the second rectifier and filter circuit 240, and the third secondary winding K5 of the second transformer T2 is connected to the input side of the third rectifier and filter circuit 250; the first end of the output side of the second rectifier and filter circuit 240 outputs the second output voltage +12VDC_FAN, and the second end of the output side of the second rectifier and filter circuit 240 is connected to the second reference ground SGND; the first end of the output side of the third rectifier and filter circuit 250 outputs the third output voltage 3.3Vdc, and the second end of the output side of the third rectifier and filter circuit 250 is connected to the third reference ground. The second transformer T2 is a multi-winding transformer, which is used to convert the input voltage into a second AC voltage and a third AC voltage respectively; the second rectifier and filter circuit 240 is used to rectify and filter the second AC voltage to output a second output voltage +12VDC_FAN; the third rectifier and filter circuit 250 is used to rectify and filter the third AC voltage to output a third output voltage 3.3Vdc.

[0043] In this embodiment, the third reference ground and the second reference ground are the same reference ground SGND. In other embodiments, the third reference ground may also be an independent reference ground, such as DGND.

[0044] The input side of the isolated feedback circuit 260 is connected to the output side of the second rectifying and filtering circuit 240 , and the output end of the isolated feedback circuit 260 is connected to the controlled end of the first control switch Q1 .

[0045] The power input side of the fan power supply control circuit 210 is connected to the output side of the second rectifier filter circuit 240, the signal input side of the fan power supply control circuit 210 is connected to the output side of the first signal isolation circuit 270, and the input side of the first signal isolation circuit 270 is connected to the first signal output side of the digital signal processor 290; the power input side of the key and display circuit 220 is connected to the output side of the third rectifier filter circuit 250, the signal input side of the key and display circuit 220 is connected to the output side of the second signal isolation circuit 280, and the input side of the second signal isolation circuit 280 is connected to the second signal output side of the digital signal processor 290. The power input end of the digital signal processor 290 receives the third output voltage 3.3Vdc and is connected to the first reference ground AGND through the filter capacitor C1.

[0046] The button and display circuit 220 is used to receive the display signal output by the digital signal processor 290 to display relevant information, and also outputs a first control signal to the digital signal processor 290 in response to the control of the operator. During this process, the second signal isolation circuit 280 serves to strengthen the electrical isolation between the button and display circuit 220 and the digital signal processor 290 to prevent mutual influence between the two; the digital signal processor 290 responds to the first control signal output by the button and display circuit 220 to output a second control signal to the fan power supply control circuit 210, thereby realizing the control of the fan speed. During this process, the first signal isolation circuit 270 serves to strengthen the electrical isolation between the fan power supply control circuit 210 and the digital signal processor 290 to prevent mutual influence between the two.

[0047] In the embodiment of the present application, the first signal isolation circuit 270 includes a first optocoupler, and the second signal isolation circuit 280 includes a second optocoupler, so as to realize isolation control between the digital signal processor 290 and the fan power supply control circuit 210 and the key and display circuit 220 .

[0048] Depend on Figure 2It can be seen that the reference ground of the fan power supply control circuit 210 and the reference ground of the first rectifier and filter circuit 230 are two independent grounds, wherein the reference ground of the fan power supply control circuit 210 is the second reference ground SGND, the reference ground of the first rectifier and filter circuit 230 is the first reference ground AGND, and the reference ground of the key and display circuit 220 is consistent with the reference ground of the fan power supply control circuit 210, which is the second reference ground SGND. The fan power supply control circuit 210 and the key and display circuit 220 isolate the input 800V bus power supply through the second transformer T2, and implement the isolation design of reinforced insulation between the input and output through the second transformer T2, so that the power supply circuits of the fan power supply control circuit 210 and the key and display circuit 220 are designed as safety extra low voltage SELV circuits.

[0049] Based on the above charging circuit, the embodiment of the present application provides a charging module, which can be understood as a PCB board corresponding to the charging circuit. Different from the above embodiment, the embodiment of the present application also makes improvements in the device, such as the pin distance and the coil material, to enhance the insulation effect of the corresponding device, specifically including:

[0050] Reinforced insulation between input voltage and output voltage:

[0051] On the PCB board, the distance between the primary winding pin of the first transformer and its secondary winding pin is greater than the first preset distance, and the distance between the primary winding pin of the second transformer and its secondary winding pin is greater than the first preset distance; the distance between the primary winding pin or the secondary winding pin of the first transformer and its magnetic core is the second preset distance, and the distance between the primary winding pin or the secondary winding pin of the second transformer and its magnetic core is the second preset distance, which can be achieved by designing the height of the skeleton or by wrapping the magnetic core.

[0052] In the embodiment of the present application, the first preset distance is 10 mm, and the second preset distance is 10 mm.

[0053] The coil of the first primary winding of the first transformer and the coil of the second primary winding of the second transformer are all made of fully insulated wires, and the coil of the first secondary winding of the first transformer, the coil of the second secondary winding of the second transformer, and the coil of the third secondary winding of the second transformer are all made of fully insulated wires or triple insulated wires; at least 3 layers of polyimide insulation tape are used between the primary winding of the first transformer and its secondary winding to meet the insulation design of high frequency and high voltage with a peak value of 2000V and at least 3000Vac power frequency insulation voltage; similarly, at least 3 layers of polyimide insulation tape are used between the primary winding of the second transformer and its secondary winding. And the second rectifier and filter circuits and the third rectifier and filter circuits need to meet the heat dissipation requirements under windless conditions.

[0054] Strengthen the insulation between the digital signal processor and the fan power supply control circuit and between the key and display circuit:

[0055] The distance between the primary pin of the first optocoupler and its secondary pin is a third preset distance, and the distance between the primary pin of the second optocoupler and its secondary pin is a third preset distance to meet the electrical safety distance design and the power frequency insulation voltage of at least 3000Vac.

[0056] In the embodiment of the present application, the third preset distance is 10 mm.

[0057] The first optical coupler and the second optical coupler are protected by varnish dipping or glue potting. The varnish dipping is to immerse the optical coupler in insulating plastic paint liquid so that its surface is completely covered. This can increase the insulation strength of the optical coupler, block the invasion of external moisture and pollutants into internal components, and improve its voltage resistance and environmental corrosion resistance. Glue potting is to place the optical coupler in a packaging container, fill the packaging container with colloids such as epoxy resin, and form a protective layer after curing. This method can provide better mechanical protection and protective performance, and increase the vibration and impact resistance of the optical coupler.

[0058] Both varnishing and potting can effectively protect the optocoupler and improve its environmental adaptability and reliability. The specific protection method to be used depends on factors such as the environmental requirements, cost and performance requirements of the application. For applications in special environments, a higher level of protection can also be used, such as fully enclosed metal packaging.

[0059] In addition, the embodiment of the present application also uses paint dipping or glue pouring to protect the PCB board, preventing the PCB board from being directly exposed to a contaminated environment. The high-charged components on the PCB that cannot be painted or glued are spatially separated from the fan housing and other fan power supply control circuits and human-machine interface circuits by at least 5.5 mm, thereby achieving spatial isolation between the fan housing and these SELV circuits and the live components.

[0060] Different from the prior art, the present invention first separates the reference ground of the main power output from the reference area of ​​the fan power supply module and the display and key module at the circuit level, and then improves the device aspects, such as the pin distance and the coil material, to enhance the insulation effect of the corresponding device. This solves the problem of ground detection failure caused by environmental factors in traditional charging modules, and further improves the safety and reliability of the charging module.

[0061] It should be noted that the preferred embodiments of the utility model are given in the specification and drawings of the utility model, but the utility model can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not used as additional restrictions on the content of the utility model. The purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the description of the utility model; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the scope of protection of the claims attached to the utility model.

Claims

1. A charging circuit, characterized in that: include: a first transformer for converting an input voltage into a first AC voltage, comprising a first primary winding and a first secondary winding, wherein the first primary winding receives the input voltage; A first rectifier and filter circuit having an input side connected to the first secondary winding, configured to convert the first AC voltage into a first output voltage, wherein a first end of the output side thereof outputs the first output voltage, and a second end of the output side thereof is connected to a first reference ground; a second transformer for converting the input voltage into a second AC voltage and a third AC voltage respectively, comprising a second primary winding, a second secondary winding and a third secondary winding, wherein the second primary winding receives the input voltage; A second rectifier and filter circuit having an input side connected to the second secondary winding, configured to convert the second AC voltage into a second output voltage, wherein a first end of the output side of the second rectifier and filter circuit outputs the second output voltage, and a second end of the output side of the second rectifier and filter circuit is connected to a second reference ground; A third rectifier and filter circuit having an input side connected to the third secondary winding, configured to convert the third AC voltage into a third output voltage, wherein a first end of the output side of the third rectifier and filter circuit outputs the third output voltage, and a second end of the output side of the third rectifier and filter circuit is connected to a third reference ground; A fan power supply control circuit, whose power input side is connected to the output side of the second rectifier and filter circuit; The key and display circuit has an electric energy input side connected to the output side of the third rectifying and filtering circuit.

2. The charging circuit according to claim 1, characterized in that: The first end of the first primary winding receives the input voltage, and the second end of the first primary winding is connected to a fourth reference ground through a second control switch; A first end of the second primary winding receives the input voltage, and a second end of the second primary winding is connected to the fourth reference ground through a first control switch.

3. The charging circuit according to claim 2, characterized in that: Also includes: an isolation feedback circuit, wherein an input side of the isolation feedback circuit is connected to an output side of the second rectifying and filtering circuit, and an output end of the isolation feedback circuit is connected to a controlled end of the first control switch; A digital signal processor, whose power input terminal receives the third output voltage and is connected to the first reference ground via a filter capacitor; A first signal isolation circuit, an output side of which is connected to a signal input side of the fan power supply control circuit, and an input side of which is connected to a first signal output side of the digital signal processor; The second signal isolation circuit has an output side connected to the signal input side of the key and display circuit, and an input side connected to the second signal output side of the digital signal processor.

4. The charging circuit according to claim 1, characterized in that: The second reference ground and the third reference ground are the same reference ground.

5. The charging circuit according to claim 3, characterized in that: The first signal isolation circuit comprises at least a first optical coupler; The second signal isolation circuit includes at least a second optical coupler.

6. A charging module, characterized in that: include: A charging circuit as claimed in any one of claims 1 to 5.

7. The charging module according to claim 6, characterized in that: The distance between the primary winding pin of the first transformer and the secondary winding pin thereof is greater than a first preset distance; The distance between the primary winding pin of the second transformer and the secondary winding pin thereof is greater than the first preset distance; The distance between the primary winding pin or the secondary winding pin of the first transformer and its magnetic core is a second preset distance; The distance between the primary winding pin or the secondary winding pin of the second transformer and its magnetic core is the second preset distance.

8. The charging module according to claim 7, characterized in that: The first preset distance is 10 mm; The second preset distance is 10 mm.

9. The charging module according to claim 6, characterized in that: The coil of the first primary winding and the coil of the second primary winding both use completely insulated wires; The coil of the first secondary winding, the coil of the second secondary winding and the coil of the third secondary winding are all made of fully insulated wires or triple insulated wires.

10. The charging module according to claim 6, characterized in that: The distance between the primary pin of the first optical coupler and the secondary pin thereof is a third preset distance; The distance between the primary pin of the second optical coupler and the secondary pin thereof is the third preset distance.

11. The charging module according to claim 10, characterized in that: The third preset distance is 10 mm.

Images