Charging circuit and charging device

Abstract

Disclosed in embodiments of the present application are a charging circuit and a charging device. The charging circuit comprises a transformer, a half-bridge flyback circuit, a protocol control circuit, and a detection circuit; the transformer comprises a primary winding on a primary side and a first secondary winding on a secondary side; the half-bridge flyback circuit is connected to the primary winding; the detection circuit is connected to the first secondary winding; and the detection circuit is connected to the protocol control circuit.

Description

Charging circuit and charging device

[0001] The present application claims priority from the Chinese patent application No. 2024110494800 filed on July 31, 2024, and entitled "Charging circuit and charging device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of charging, in particular, to a charging circuit and a charging device. BACKGROUND

[0003] The charging device can include a charger, which generally refers to a static current conversion device. The charger uses power semiconductor devices to convert alternating current with fixed voltage and frequency into direct current.

[0004] In the related art, the rated output power of most chargers is the same within the input voltage range of the charger. When the input voltage of the charger is low, the energy conversion efficiency is reduced due to low efficiency in the voltage conversion process, thereby causing large overall loss of the charger. SUMMARY

[0005] Embodiments of the present application provide a charging circuit and a charging device, which aims to reduce the overall loss of the charger.

[0006] The first aspect of the embodiments of the present application provides a charging circuit, which is applied to a charging device. The charging circuit includes a transformer, a half-bridge flyback circuit, a protocol control circuit and a detection circuit. The transformer includes a primary winding on the primary side and a first secondary winding on the secondary side. The half-bridge flyback circuit is connected with the primary winding. The detection circuit is connected with the first secondary winding and also connected with the protocol control circuit. The detection circuit is configured to detect the input voltage of the half-bridge flyback circuit. When the input voltage of the half-bridge flyback circuit is higher than a first threshold voltage, the protocol control circuit supports the charging device to output a first charging power. The first charging power is greater than the rated power of the charging device.

[0007] The second aspect of the embodiments of the present application provides a charging device, which includes a housing, a circuit board and the above-mentioned charging circuit. The circuit board is arranged in the housing. The transformer, the half-bridge flyback circuit, the protocol control circuit and the detection circuit are all made on the circuit board.

[0008] The detection circuit arranged on the first secondary winding on the secondary side can detect the input voltage of the half-bridge flyback circuit, and the input voltage of the half-bridge flyback circuit is 1.414 times of the mains. That is, when the input voltage of the half-bridge flyback circuit is higher than the first threshold voltage, the protocol control circuit supports the charger to output the first charging power, and the first charging power is greater than the rated power of the charger, so as to realize the overclocking charging of the charger to the external device, that is, the overall charging efficiency of the charger to the external device is improved, and thus the overall loss of the charger is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a module schematic diagram of a charging device in an embodiment of the present application;

[0010] FIG. 2 is a module schematic diagram of a charging circuit in an embodiment of the present application;

[0011] FIG. 3 is a partial circuit schematic diagram of a charging circuit in an embodiment of the present application;

[0012] FIG. 4 is a circuit schematic diagram of a detection circuit in an embodiment of the present application;

[0013] FIG. 5 is a circuit schematic diagram of an integrated control circuit in an embodiment of the present application;

[0014] FIG. 6 is another module schematic diagram of a charging circuit in an embodiment of the present application;

[0015] FIG. 7 is a circuit schematic diagram of a power supply circuit in an embodiment of the present application;

[0016] FIG. 8 is a circuit schematic diagram of a power factor correction circuit in an embodiment of the present application;

[0017] FIG. 9 is a circuit schematic diagram of a power factor correction adjustment module in an embodiment of the present application.

[0018] Brief Description of Drawings: 1 - charging device; 10 - housing; 20 - circuit board; 30 - charging circuit; 31 - half-bridge flyback circuit; Q1 - high-side switching device; Q2 - low-side switching device; VCR - resonant capacitor; 32 - synchronous rectification circuit; 33 - protocol control circuit; 34 - detection circuit; 341 - first rectification module; D50 - first diode; C50 - first capacitor; 342 - voltage division module; R50 - first resistor; R51 - second resistor; T - transformer; NP - primary winding; NSS - first secondary winding; NS - second secondary winding; NAUX - auxiliary winding; 35 - integrated control circuit; 36 - power supply circuit; 361 - second rectification module; D12 - second diode; C27 - second capacitor; R49 - third resistor; 362 - voltage boosting module; Ec10 - first electrolytic capacitor; U40 - voltage boosting converter; L40 - first inductor; D40 - third diode; R41 - fourth resistor; R43 - fifth resistor; C40 - third capacitor; C41 - fourth capacitor; 37 - power factor correction circuit; 371 - filtering module; 372 - input rectification module; 373 - power factor correction regulation module; L3 - second inductor; U1 - switching device; D1 - fourth diode; D2 - fifth diode; Ec1 - second electrolytic capacitor; Ec2 - third electrolytic capacitor; C5 - fifth capacitor; VA - sampling input voltage terminal; 3731 - control circuit; R44 - sixth resistor; R45 - seventh resistor; R47 - eighth resistor; C42 - sixth capacitor; U41 - voltage stabilizing IC; R48 - ninth resistor; Q41 - first switching transistor; 38 - external device.

[0019] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the embodiments of the present application in combination with the accompanying drawings.

[0021] The following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Instead, they are merely examples of apparatuses and methods consistent with some aspects of the present application as detailed in the appended claims.

[0022] In the description of the present application, it is understood that the terms "first", "second" and the like are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, "a plurality of" means two or more, unless otherwise specified. The association relationship of the associated objects is described, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more associated listed items.

[0024] Referring to FIG. 1, the present application provides a charging device 1, which is a common device in life, and the charging device 1 can include a charger. The charging device 1 includes a housing 10, a circuit board 20, and a charging circuit 30. The housing 10 is arranged to protect the electronic devices inside the charging device 1. The following describes the charging device 1 as a charger.

[0025] The charger can be divided into wired charger and wireless charger according to whether there is a charging line. The wired charger is a charging device on the market that needs to connect the charging line to the device to be charged, that is, the wired charger converts direct current or alternating current into direct current that can charge the battery, and is widely used in consumer electronic products, such as smart phones, tablet computers, notebooks, electric toothbrushes, wireless earphones, smart speakers, etc. Compared with the wired charger, the wireless charger usually does not need to use the charging line, and mainly uses the principle of electromagnetic induction for power input. The charger can be divided into public protocol and private protocol according to the charging protocol. Among them, the public protocol mainly includes USB PD (Power Delivery) charging protocol and QC (Quick Charge) charging protocol.

[0026] Exemplarily, the housing 10 is usually made of PC (Poly Carbonate) material. The PC material has excellent electrical insulation, heat resistance and impact resistance, etc. Therefore, the housing 10 made of PC material not only can protect the electronic devices of the charger from the influence of the external environment, but also can improve the safety and durability of the charger in use.

[0027] The circuit board 20 is a carrier of the electronic devices of the charger, connects the electronic devices with different functions, and forms a circuit with a specific function. For example, the charging circuit 30 is made on the circuit board 20. The application of the circuit board 20 can save the internal space of the charger, so that the charger has a smaller size.

[0028] The charging circuit 30 will be described in detail below.

[0029] Referring to FIG. 2, the charging circuit 30 includes a transformer T, a half-bridge flyback circuit 31, a synchronous rectification circuit 32, and a protocol control circuit 33.

[0030] The transformer T can include a primary winding NP on the primary side, a first secondary winding NSS and a second secondary winding NS on the secondary side. The half-bridge flyback circuit 31 is connected to the primary winding NP, the synchronous rectification circuit 32 is connected to the second secondary winding NS, and the protocol control circuit 33 is connected to the synchronous rectification circuit 32.

[0031] Referring to FIGS. 2-3, specifically, the half-bridge flyback circuit 31 includes a high-side switching device Q1, a low-side switching device Q2, and a resonance capacitor VCR. The high-side switching device Q1 and the low-side switching device Q2 are complementary on, and are connected to a common voltage input terminal to form a half-bridge structure. The first end of the primary winding NP is connected to the source of the high-side switching device Q1, and the second end of the primary winding NP is grounded through the resonance capacitor VCR.

[0032] When the half-bridge flyback circuit 31 is working, the input terminal of the high-side switching device Q1 is connected to the input voltage, and the conduction or turn-off of the high-side switching device Q1 is controlled by a first drive signal, and the conduction or turn-off of the low-side switching device Q2 is controlled by a second drive signal. When the high-side switching device Q1 is on, the low-side switching device Q2 is off, at which time the current of the primary winding NP increases linearly, so that the energy is stored in the primary winding NP, that is, the primary winding NP does not transfer energy to the second secondary winding NS; when the high-side switching device Q1 is off, the low-side switching device Q2 is on, at which time the resonance capacitor VCR on the primary winding NP resonates, the energy stored in the primary winding NP is input to the second secondary winding NS, and a stable output voltage is output through the synchronous rectification circuit 32. The output voltage does not change with the change of the input voltage VHV, which is 1.414 times of the mains voltage. When the charging port is connected to the external device 38 to be charged, since the protocol control circuit 33 is connected to the synchronous rectification circuit 32, under the control of the protocol control circuit 33, the output voltage charges the external device 38 through the charging port.

[0033] It should be noted that the high-side switch device Q1 and the low-side switch device Q2 can be gallium nitride transistors, silicon carbide transistors, or power MOS tubes, or other devices having a switching function, and the embodiments of the present application do not make specific limitations thereto.

[0034] Referring to FIGS. 2-4, further, the charging circuit 30 further comprises a detection circuit 34 connected with the first secondary winding NSS, and the primary winding NP and the first secondary winding NSS are same-named terminals, which means that when the two mutual inductance coils are input with currents, the magnetic flux directions generated thereby are the same, at this time, the voltage of the first secondary winding NSS will change following the change of the input voltage VHV of the half-bridge flyback circuit 31, that is, the voltage V of the first secondary winding NSS will change following the change of the input voltage VHV of the primary winding NP, and the voltage of the first secondary winding NSS is in a proportional relationship with the input voltage of the primary winding NP, and the corresponding formula is V=VHV×NSS / NP×D×R51 / (R50+R51), wherein VHV is the bus voltage (that is, the input voltage VHV described above), NSS is the number of turns of the first secondary winding NSS, NP is the number of turns of the primary winding NP, D is the duty cycle, R50 is the first resistance, and R51 is the second resistance; that is, the voltage V of the first secondary winding NSS and the input voltage VHV of the primary winding NP are related to the turns ratio and the duty cycle D.

[0035] Exemplarily, when the number of turns of the primary winding NP is 20, the input voltage VHV of the primary winding NP is 200V, and the number of turns of the first secondary winding NSS is 2, the voltage of the first secondary winding NSS is 20V. The detection circuit 34 is further connected with the protocol control circuit 33, and the detection circuit 34 is configured to detect the input voltage VHV of the half-bridge flyback circuit 31 and feed back to the protocol control circuit 33.

[0036] It can be understood that, since the primary winding NP and the first secondary winding NSS are same-named terminals, when the primary winding NP works, the first secondary winding NSS also works, so that the first secondary winding NSS has a voltage, which is the forward winding voltage V, and the voltage is input to the protocol control circuit 33 through the detection circuit 34, and the protocol control circuit 33 can distinguish the input voltage VHV of the half-bridge flyback circuit 31 through the forward winding voltage V, and adjust the charging power of the charging port connected with the protocol control circuit 33 according to the input voltage VHV.

[0037] Specifically, the forward winding voltage V is input to the protocol control circuit 33 after being detected by the detection circuit 34, and the protocol control circuit 33 distinguishes the input voltage VHV of the half-bridge flyback circuit 31 through the forward winding voltage V; when the input voltage VHV of the half-bridge flyback circuit 31 is higher than the first threshold voltage, the protocol control circuit 33 supports the charger to output at a first charging power, and the first charging power is greater than the rated power of the charger, thereby realizing the overclocking charging of the charger to the external device 38. For example, the rated power of the charger is 100W, and the input voltage VHV of the half-bridge flyback circuit 31 is 230V AC power. Since the high-voltage AC input has relatively small loss, the charger can support an output voltage of 28V and an output current of 5A. At this time, the first charging power that the charger can support is 140W, and the external device 38 can select 140W for charging according to the charging demand, thereby realizing the overclocking charging of the charger and reducing the overall loss of the charger.

[0038] It should be noted that the first threshold voltage described above can be set according to the power grid usage range of different countries, and the embodiment of the present application does not make specific limitation.

[0039] It should be noted that when the charging circuit 30 starts, the half-bridge flyback circuit 31 will work first. At this time, the forward winding voltage V is mainly detected by the second secondary winding NS. That is, when the charging circuit 30 starts, the input end of the half-bridge flyback circuit 31 inputs the input voltage VHV. At this time, the input voltage VHV is 1.414 times the mains voltage, and the voltage value of the forward winding voltage V can be obtained in combination with the voltage V of the second secondary winding NS, the turns ratio of the input voltage VHV of the primary winding NP, and the proportional relationship of the duty cycle D.

[0040] It should be noted that the input voltage VHV can be 120V AC, 230V AC, or other voltage values, and the embodiment of the present application does not make specific limitation.

[0041] The embodiment of the present application sets the detection circuit 34 on the first secondary winding NSS on the secondary side. The detection circuit 34 can detect the input voltage VHV of the half-bridge flyback circuit 31, and the input voltage VHV is 1.414 times the mains voltage. That is, when the input voltage VHV of the half-bridge flyback circuit 31 is higher than the first threshold voltage, the protocol control circuit 33 supports the charger to output at a first charging power, and the first charging power is greater than the rated power of the charger, thereby realizing the overclocking charging of the charger to the external device 38, that is, improving the charging efficiency of the charger to the external device 38, thereby reducing the overall loss of the charger.

[0042] Further, in some embodiments, when the input voltage VHV of the half-bridge flyback circuit 31 is lower than the first threshold voltage, the protocol control circuit 33 supports the charger to output a second charging power, which is less than the rated power of the charger. That is, the protocol control circuit 33 controls the charger to output the second charging power, which is less than the rated power of the charger, to reduce the charging efficiency of the charger to the external device 38, thereby reducing the heating condition of the charger during charging, and thus reducing the overall loss of the charger. For example, the rated power of the charger is 100W, and the input voltage VHV of the half-bridge flyback circuit 31 is 120V AC (e.g., the US power grid), and the overall charging efficiency is poor. If the charger still outputs according to the rated power, it will cause a temperature rise problem. Therefore, the output power (i.e., the second charging power) that the charger can support is reduced to, for example, 80W. The external device 38 can select 80W for charging according to the charging demand, thereby reducing the charging efficiency of the charger to the external device 38, to reduce the heating condition of the charger, and thus reduce the overall loss of the charger.

[0043] Referring to FIG. 4, in some embodiments, the detection circuit 34 includes a first rectification module 341 and a voltage division module 342. The first rectification module 341 is connected with the first secondary winding NSS, the voltage division module 342 is connected with the first rectification module 341, and the voltage division module 342 is also connected with the protocol control circuit 33. It can be understood that when the first secondary winding NSS has a voltage, the voltage is the forward winding voltage V, and after passing through the first rectification module 341 and the voltage division module 342, the forward winding voltage V is input into the protocol control circuit 33, so that the protocol control circuit 33 can determine whether the input voltage VHV corresponding to the forward winding voltage V is higher than the first threshold voltage or lower than the first threshold voltage according to the above formula.

[0044] Please continue to refer to FIG. 4, further, in some embodiments, the first rectification module 341 includes a first diode D50 and a first capacitor C50. It can be understood that the anode of the first diode D50 is connected with the first end of the first secondary winding NSS, the cathode of the first diode D50 is connected with the voltage division module 342, and the second end of the first secondary winding NSS is grounded; one end of the first capacitor C50 is connected with the cathode of the first diode D50, and the other end of the first capacitor C50 is grounded; that is, the unidirectional conduction characteristic of the first diode D50 is used to rectify the forward winding voltage; further, the first capacitor C50 can smooth the forward winding voltage, and the first capacitor C50 also plays a role in buffering and protecting the first diode D50; that is, at the moment when the half-bridge flyback circuit 31 starts to work, the charging circuit 30 will generate a large current, and the first capacitor C50 has the function of instantaneous charging at this time to share the large voltage impact generated when the first diode D50 starts.

[0045] Please continue to refer to FIG. 4, further, the voltage dividing module 342 includes the first resistor R50 and the second resistor R51 mentioned above. One end of the first resistor R50 is connected with the output end of the first rectifier module 341, the other end of the first resistor R50 is connected to the protocol control circuit 33, and is also connected with one end of the second resistor R51; the other end of the second resistor R51 is grounded, that is, the forward winding voltage V is input to the first resistor R50 after being rectified by the first rectifier module 341, the first resistor R50 and the second resistor R51 input the forward winding voltage V to the protocol control circuit 33 after voltage dividing, so that the protocol control circuit 33 distinguishes whether the input voltage VHV of the half-bridge flyback circuit is higher than the first threshold voltage or lower than the first threshold voltage according to the forward winding voltage V.

[0046] Please refer to FIG. 5-FIG. 6, in some embodiments, the charging circuit 30 further includes a power factor correction circuit 37 and an integrated control circuit 35. The input end of the power factor correction circuit 37 is set to access the mains, and the output end of the power factor correction circuit 37 is connected with the input end of the half-bridge flyback circuit 31, so as to input the input voltage VHV to the half-bridge flyback circuit 31.

[0047] Please refer to FIG. 5-FIG. 6, the integrated control circuit 35 is set to control the half-bridge flyback circuit 31 and the power factor correction circuit 37 to work. It can be understood that the integrated control circuit 35 can send the first drive signal mentioned above to the high-side switching device Q1 to control the conduction or cut-off of the high-side switching device Q1; the integrated control circuit 35 can also send the second drive signal mentioned above to the low-side switching device Q2 to control the conduction or cut-off of the low-side switching device Q2, thereby controlling the working of the half-bridge flyback circuit 31. Furthermore, the protocol control circuit 33 includes an optical coupling transmitter, and the integrated control circuit 35 includes an optical coupling receiver, so that the integrated control circuit 35 receives the signal sent by the protocol control circuit 33.

[0048] For example, the output voltage of the charger is in the range of 5V to 28V, that is, the amplitude range of the output voltage of the charger is large, which easily causes the supply voltage of the integrated control circuit 35 to be unstable. Therefore, in the related art, a single winding design is usually used, that is, the single winding is only one winding, and the principle is to use one winding as input and output to improve the stability of the supply voltage of the integrated control circuit 35, but this easily causes large loss. Alternatively, a double winding design is used, that is, the double winding transformer refers to a transformer T with two windings, one of which is a high-voltage side winding and the other of which is a low-voltage side winding. The double winding transformer transfers electrical energy from the high-voltage winding to the low-voltage winding through the induction of the magnetic field to realize the functions of step-up or step-down, thereby improving the stability of the supply voltage of the integrated control circuit 35, but more devices are needed.

[0049] Referring to FIGS. 6-7, in some embodiments, the transformer T further comprises an auxiliary winding NAUX on the primary side; the charging circuit 30 further comprises a power supply circuit 36, wherein one end of the auxiliary winding NAUX is grounded; an input end VIN of the power supply circuit 36 is connected to the other end of the auxiliary winding NAUX, and an output end VOUT of the power supply circuit 36 is connected to the integrated control circuit 35 to supply power to the integrated control circuit 35. The auxiliary winding NAUX is coupled to the second secondary winding NS, and the second secondary winding NS is coupled to the primary winding NP, so that the auxiliary winding NAUX supplies power to the integrated control circuit 35 through the power supply circuit 36.

[0050] Referring to FIG. 7, specifically, in some embodiments, the power supply circuit 36 comprises a second rectifier module 361 and a boost module 362. An input end of the second rectifier module 361 is connected to the other end of the auxiliary winding NAUX, an input end of the boost module 362 is connected to an output end of the second rectifier module 361, and an output end VOUT of the boost module 362 is connected to the integrated control circuit 35. It can be understood that the change of the second secondary winding NS voltage is related to the voltage of the primary winding NP, and the voltage of the auxiliary winding NAUX will change with the change of the second secondary winding NS voltage. For example, when the turns ratio of the second secondary winding NS to the auxiliary winding NAUX is 2:1, and the voltage of the second secondary winding NS is 20V, the voltage of the auxiliary winding NAUX is rectified to 10V by the second rectifier module 361, and the voltage of the auxiliary winding NAUX is processed by the boost module 362, and the power supply circuit 36 outputs an output voltage VOUT of 13.85V to supply power to the integrated control circuit 35.

[0051] Referring to FIG. 7, specifically, the second rectifier module 361 comprises a second diode D12, a second capacitor C27, and a third resistor R49. An anode of the second diode D12 is connected to the other end of the auxiliary winding NAUX, and the anode of the second diode D12 is also connected to one end of the second capacitor C27; the other end of the second capacitor C27 is connected to one end of the third resistor R49, the other end of the third resistor R49 is connected to a cathode of the second diode D12, and the other end of the third resistor R49 is connected to an input end of the boost module 362.

[0052] Please continue to refer to Figure 7, and further, the boost module 362 includes a first electrolytic capacitor Ec10, a boost converter U40, a first inductor L40, a third diode D40, a fourth resistor R41, a fifth resistor R43, a third capacitor C40, and a fourth capacitor C41. The input end IN and the enable end EN of the boost converter U40 are connected with the output end of the second rectification module 361, one end of the first electrolytic capacitor Ec10, and one end of the first inductor L40, and the other end of the first electrolytic capacitor Ec10 is grounded; the output end LX of the boost converter U40 is connected with the other end of the first inductor L40, and the output end LX of the boost converter U40 is connected with the integrated control circuit 35 through the third diode D40; the cathode of the third diode D40 is connected with one end of the fourth resistor R41, one end of the third capacitor C40, and one end of the fourth capacitor C41; the feedback end FB of the boost converter U40 is connected with the other end of the fourth resistor R41 and one end of the fifth resistor R43; the ground end GND of the boost converter U40, the other end of the fifth resistor R43, the other end of the third capacitor C40, and the other end of the fourth capacitor C41 are all grounded.

[0053] The specific working principle of the boost module 362: the input end IN of the boost converter U40 obtains the first power supply voltage VIN from the auxiliary winding NAUX, that is, the first power supply voltage VIN is input to the input end IN of the boost converter U40; if the first power supply voltage VIN is greater than the required power supply voltage of the integrated control circuit 35, the switch tube in the boost converter U40 is turned off, the first power supply voltage VIN passes through the first inductor L40 and the third diode D40, and directly supplies power to the Vcc-AHB of the integrated control circuit 35; if the first power supply voltage VIN is less than the required power supply voltage of the integrated control circuit 35, the switch tube in the boost converter U40 is turned on, the first inductor L40 releases energy, so that the voltage on the third capacitor C40 rises, and is fed back to the feedback end FB of the boost converter U40 after being divided by the fourth resistor R41 and the fifth resistor R43. Exemplarily, the reference voltage set in the boost converter U40 is 0.6V, and the corresponding duty cycle of the boost module 362 is D=1-VIN / VOUT; that is, the boost module 362 can perform voltage boosting in the boost converter U40 through the voltage fed back to the feedback end FB of the boost converter U40, so as to increase the output voltage VOUT of the power supply circuit 36. Exemplarily, the voltage of the first charging power or the second charging power of the charging port connected to the protocol control circuit 33 is 5V, at this time, the first power supply voltage VIN of the boost module 362 is 2.5V and is input to the input end IN of the boost module 362, and the boost module 362 outputs an output voltage VOUT of 13.85V after processing to supply power to the integrated control circuit 35, so as to control the integrated control circuit 35 to start and continuously work. And the embodiment of the application adopts a single winding plus boost circuit technical solution, so on the one hand, the use of devices can be reduced and the size of the circuit can be reduced, and on the other hand, the loss of the single winding is less and combined with the boost module 362, the power supply efficiency of the circuit can be improved.

[0054] It should be noted that the boost converter U40 can be a SY7208L chip, or other devices or circuits with a boosting function, and the embodiment of the application does not make specific limitations thereto.

[0055] Please refer to FIG. 8, in some embodiments, the power factor correction circuit 37 comprises a filter module 371, an input rectifier module 372 and a power factor correction regulating module 373. The input end of the filter module 371 is set to access the commercial power; the input end of the input rectifier module 372 is connected with the output end of the filter module 371; the input end of the power factor correction regulating module 373 is connected with the output end of the input rectifier module 372, and the output end of the power factor correction regulating module 373 is connected with the input end of the half-bridge flyback circuit 31. That is, through the above setting, the voltage of the input commercial power is filtered and rectified and then input to the power factor correction regulating module 373, wherein the filter module 371 is set to reduce the fluctuation of the input voltage, the input rectifier module 372 converts the alternating input voltage into direct input voltage, and the input rectifier module 372 usually adopts the full-wave rectification method, that is, four diodes are configured into an electric bridge, so that the stable direct current output can be maintained regardless of the change of the input voltage (that is, the above-mentioned commercial power).

[0056] Please refer to FIG. 8, further, in some embodiments, the power factor correction regulating module 373 comprises a second inductor L3, a switching device U1, a fourth diode D1, a fifth diode D2, a second electrolytic capacitor Ec1, a third electrolytic capacitor Ec2 and a fifth capacitor C5.

[0057] One end of the second inductor L3 is connected with the output end of the input rectifier module 372 and the anode of the fourth diode D1; the switching device U1 is connected with the other end of the second inductor L3, and the switching device U1 is connected with the anode of the fifth diode D2; the cathode of the fifth diode D2 is connected with the cathode of the fourth diode D1, one end of the second electrolytic capacitor Ec1, one end of the third electrolytic capacitor Ec2 and one end of the fifth capacitor C5; the other end of the second electrolytic capacitor Ec1, the other end of the third electrolytic capacitor Ec2 and the other end of the fifth capacitor C5 are all grounded. It can be understood that when the switching device U1 is turned on, the commercial power passing through the filter module 371 and the input rectifier module 372 is input through the D pole of the switching device U1 and the S pole of the switching device U1 is grounded; when the switching device U1 is turned off, the power factor correction regulating module 373 does not work, the magnetic field energy in the second inductor L3 is converted into electric energy and charges the second electrolytic capacitor Ec1 and the third electrolytic capacitor Ec2 through the fifth diode D2; at this time, the second inductor L3, the second electrolytic capacitor Ec1 and the third electrolytic capacitor Ec2 form a loop to maintain the continuity of the current and the output voltage (that is, the input voltage VHV of the half-bridge flyback circuit 31). Furthermore, the power factor correction regulating module 373 can adjust the frequency and duty cycle of the switching device U1 by detecting the output voltage and input current to ensure the stability of the input voltage VHV of the half-bridge flyback circuit 31, thereby improving the power factor.

[0058] The fifth capacitor C5 is mainly configured to filter high frequency noise to prevent interference of high frequency and pulse signals. The fourth diode D1 is equivalent to a branch in parallel with the second inductor L3 and the fifth diode D2, and the main function of the fourth diode D1 is to provide a charging path for the second electrolytic capacitor Ec1 and the third electrolytic capacitor Ec2 in abnormal conditions such as charger charging moment, charger short circuit, output voltage of the power factor correction adjustment module 373 lower than input voltage, etc., to prevent the second inductor L3 from causing danger to the switching device U1 after saturation, and to reduce the large voltage impact generated by the second inductor L3 and the fifth diode D2 when working, thereby protecting the second inductor L3 and the fifth diode D2.

[0059] It should be noted that the switching device U1 can be an NMOS tube, a PMOS tube, an NPN transistor, a PNP transistor, a gallium nitride transistor, a silicon carbide transistor, a relay, etc. having a switching function, and can also be other devices or circuits having a switching function, which are not limited in the embodiments of the present application.

[0060] Further, when the input voltage VA of the power factor correction adjustment module 373 is less than the second threshold voltage, the power factor correction adjustment module 373 starts working; when the input voltage VA of the power factor correction adjustment module 373 is greater than the second threshold voltage, the power factor correction adjustment module 373 stops working.

[0061] Please refer to FIGS. 8-9. Specifically, in some embodiments, the input rectification module 372 has a sampling input voltage terminal VA. The power factor correction adjustment module 373 further includes a control circuit 3731, wherein an input terminal of the control circuit 3731 is connected with the sampling input voltage terminal VA, and an output terminal of the control circuit 3731 is connected with the switching device U1; that is, the input terminal of the control circuit 3731 can receive the input voltage VA, and compare the input voltage VA with the second threshold voltage, when the input voltage VA is greater than the second threshold voltage, the control circuit 3731 controls the switching device U1 to be turned off; when the input voltage VA is less than the second threshold voltage, the control circuit 3731 controls the switching device U1 to be turned on, so as to realize the automatic start-stop function of the power factor correction adjustment module 373.

[0062] For example, the second threshold voltage can be 250V AC, that is, when the input voltage VA is greater than 250V AC, the control circuit 3731 controls the switching device U1 to be turned off; when the input voltage VA is less than 250V AC, the control circuit 3731 controls the switching device U1 to be turned on.

[0063] Please continue to refer to Figure 9, further, in some embodiments, the control circuit 3731 comprises a sixth resistor R44, a seventh resistor R45, an eighth resistor R47, a sixth capacitor C42, a voltage stabilizing IC U41, a ninth resistor R48 and a first switch tube Q41. One end of the sixth resistor R44 is connected with the sampling input voltage terminal VA, the other end of the sixth resistor R44 is grounded through the seventh resistor R45 and the eighth resistor R47; one end of the sixth capacitor C42 is connected with the junction of the seventh resistor R45 and the eighth resistor R47, the other end of the sixth capacitor C42 is grounded; the first end of the voltage stabilizing IC U41 is connected with the control end of the first switch tube Q41 and one end of the ninth resistor R48, the second end of the voltage stabilizing IC U41 is connected with the junction of the seventh resistor R45 and the eighth resistor R47, the third end of the voltage stabilizing IC U41 is grounded; the control end of the first switch tube Q41 is connected with one end of the ninth resistor R48, the input end of the first switch tube Q41 and the other end of the ninth resistor R48 are connected with the power supply VCC-PFC, the output end of the first switch tube Q41 is connected with the switching device U1.

[0064] The specific working principle of the control circuit 3731: the input voltage VA of the control circuit 3731 is sampled from the sampling input voltage terminal VA, the sixth resistor R44, the seventh resistor R45 and the eighth resistor R47 divide the input voltage, and the sixth capacitor C42 filters the divided input voltage VA; when the divided input voltage VA is less than 2.5V, the voltage stabilizing IC U41 has no current passing through; at this time, the current of the power supply VCC-PFC flows from the control end of the first switch tube Q41 to the output end of the first switch tube Q41, so that the first switch tube Q41 is turned on, and the voltage of the power supply VCC-PFC enters the switching device U1, so that the switching device U1 is turned on; when the divided input voltage VA is greater than 2.5V, the voltage stabilizing IC U41 has current passing through; at this time, the current of the power supply VCC-PFC flows to the voltage stabilizing IC U41, so that the first switch tube Q41 is turned off, and the voltage of the power supply VCC-PFC cannot enter the switching device U1, so that the switching device U1 is turned off.

[0065] That is, when the power factor correction circuit 37 is working, the power factor correction circuit 37 loses efficiency, and when the input voltage (i.e. the above-mentioned mains) is high, the peak of the input voltage is greater than the output voltage of the power factor correction circuit 37 (i.e. the input voltage VHV of the half-bridge flyback circuit 31), the power factor correction circuit 37 will stop working, that is, the peak of the input current waveform of the power factor correction circuit 37 is prone to oscillation, to produce a larger noise; therefore, when the input voltage is high, the control circuit 3731 controls the switching device U1 to be turned off, to avoid generating a larger noise, and to reduce the loss of efficiency, to improve the working efficiency of the power factor correction circuit 37.

[0066] Furthermore, in the related art, the withstand voltage of the output capacitor (the output capacitor is the second electrolytic capacitor Ec1 and the third electrolytic capacitor Ec2 described above) of the power factor correction circuit 37 is generally 450 V or 420 V, which easily makes the size of the output capacitor large, and thus makes the overall size of the power factor correction circuit 37 large. However, in the embodiment of the present application, when the input voltage is higher than 250 V AC, the control circuit 3731 controls the switch device U1 to be off, at this time, the power factor correction circuit 37 does not work, therefore, the withstand voltage of the output capacitor is changed to 400 V in the embodiment of the present application, which also satisfies the normal work of the power factor correction circuit 37, so as to reduce the size of the output capacitor, and thus reduce the overall size of the power factor correction circuit 37.

[0067] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components; in the description of the present application, it is understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation of the present patent, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0068] The above is only a preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A charging circuit, wherein, The application is applied to a charging device, and the charging circuit comprises: a transformer comprising a primary winding on a primary side and a first secondary winding on a secondary side; a half-bridge flyback circuit connected with the primary winding; a protocol control circuit; and a detection circuit connected with the first secondary winding and also connected with the protocol control circuit, the detection circuit being arranged to detect an input voltage of the half-bridge flyback circuit; wherein when the input voltage of the half-bridge flyback circuit is higher than a first threshold voltage, the protocol control circuit supports the charging device to output a first charging power, the first charging power being greater than a rated power of the charging device.

2. The charging circuit of claim 1, wherein, when the input voltage of the half-bridge flyback circuit is lower than the first threshold voltage, the protocol control circuit supports the charging device to output a second charging power, the second charging power being less than the rated power of the charging device.

3. The charging circuit of claim 1, wherein, The transformer further comprises an auxiliary winding on the primary side and a second secondary winding on the secondary side, one end of the auxiliary winding being grounded; the charging circuit further comprises: an integrated control circuit connected with the half-bridge flyback circuit to control the half-bridge flyback circuit; and a power supply circuit, an input end of which is connected with the other end of the auxiliary winding, and an output end of which is connected with the integrated control circuit to supply power to the integrated control circuit; wherein the auxiliary winding and the second secondary winding are mutually coupled, and the second secondary winding and the primary winding are mutually coupled, so that the auxiliary winding supplies power to the integrated control circuit through the power supply circuit.

4. The charging circuit of claim 3, wherein, The power supply circuit comprises: a second rectification module, an input end of which is connected with the other end of the auxiliary winding; and a boost module, an input end of which is connected with an output end of the second rectification module, and an output end of which is connected with the integrated control circuit.

5. The charging circuit of claim 4, wherein, The boost module comprises a first electrolytic capacitor, a boost converter, a first inductor, a third diode, a fourth resistor, a fifth resistor, a third capacitor and a fourth capacitor; an input end and an enable end of the boost converter are connected with the output end of the second rectification module, one end of the first electrolytic capacitor and one end of the first inductor, and the other end of the first electrolytic capacitor is grounded; an output end of the boost converter is connected with the other end of the first inductor and connected with the integrated control circuit through the third diode; a cathode of the third diode is connected with one end of the fourth resistor, one end of the third capacitor and one end of the fourth capacitor; a feedback end of the boost converter is connected with the other end of the fourth resistor and one end of the fifth resistor; a ground end of the boost converter, the other end of the fifth resistor, the other end of the third capacitor and the other end of the fourth capacitor are all grounded; wherein the input end of the boost converter obtains a first power supply voltage from the auxiliary winding, when the first power supply voltage is greater than a required power supply voltage of the integrated control circuit, the boost converter is turned off, and when the first power supply voltage is less than the required power supply voltage of the integrated control circuit, the boost converter is turned on to make the voltage across the third capacitor rise to boost the first power supply voltage.

6. The charging circuit of claim 1, wherein, The charging circuit further comprises a power factor correction circuit, the power factor correction circuit comprising: a filter module, an input end of which is configured to be connected to a commercial power supply; an input rectifier module, an input end of which is connected to an output end of the filter module; and a power factor correction regulating module, an input end of which is connected to an output end of the input rectifier module, and an output end of which is connected to the half-bridge flyback circuit; wherein, when an input voltage of the power factor correction regulating module is less than a second threshold voltage, the power factor correction regulating module starts to work; and when the input voltage of the power factor correction regulating module is greater than the second threshold voltage, the power factor correction regulating module stops working.

7. The charging circuit of claim 6, wherein, The power factor correction regulating module comprises a second inductor, a switching device, a fourth diode, a fifth diode, a second electrolytic capacitor, a third electrolytic capacitor, and a fifth capacitor; one end of the second inductor is connected to an output end of the input rectifier module and an anode of the fourth diode, the switching device is connected to the other end of the second inductor and an anode of the fifth diode; a cathode of the fifth diode is connected to a cathode of the fourth diode, one end of the second electrolytic capacitor, one end of the third electrolytic capacitor, and one end of the fifth capacitor; the other end of the second electrolytic capacitor, the other end of the third electrolytic capacitor, and the other end of the fifth capacitor are all grounded.

8. The charging circuit of claim 7, wherein, The input rectifier module has a sampling input voltage end; the power factor correction regulating module further comprises: a control circuit, an input end of which is connected to the sampling input voltage end, and an output end of which is connected to the switching device, so as to control the switching device to be turned off or turned on.

9. The charging circuit of claim 8, wherein, The control circuit comprises a sixth resistor, a seventh resistor, an eighth resistor, a sixth capacitor, a voltage stabilizing IC, a ninth resistor, and a first switch tube; one end of the sixth resistor is connected to the sampling input voltage end, and the other end of the sixth resistor is grounded through the seventh resistor and the eighth resistor; one end of the sixth capacitor is connected to the intersection of the seventh resistor and the eighth resistor, and the other end of the sixth capacitor is grounded; a first end of the voltage stabilizing IC is connected to a control end of the first switch tube and one end of the ninth resistor, a second end of the voltage stabilizing IC is connected to the intersection of the seventh resistor and the eighth resistor, and a third end of the voltage stabilizing IC is grounded; the control end of the first switch tube is connected to one end of the ninth resistor, an input end of the first switch tube and the other end of the ninth resistor are connected to a power supply, and an output end of the first switch tube is connected to the switching device.

10. A charging device, wherein, The charging device comprises: a shell; a circuit board arranged in the shell; and the charging circuit according to any one of the above 1-9, the transformer, the half-bridge flyback circuit, the protocol control circuit, and the detection circuit are all made on the circuit board.

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