power supply circuit

Abstract

The application discloses a power supply circuit, comprising a power supply module, at least one starting power supply module and a control circuit, the power supply module comprising a power supply and an input capacitor, the power supply being configured to start when the voltage drop across the input capacitor is greater than the minimum operating voltage of the power supply circuit; the starting power supply module comprising a starting power supply and a starting transformer, the starting power supply being connected to the primary side of the starting transformer, the secondary side of the starting transformer being connected to the input capacitor, the starting transformer being used to boost the output voltage of the starting power supply module and charge the input capacitor; the control circuit being configured to turn on the starting power supply module when the voltage drop across the input capacitor is less than the minimum operating voltage of the power supply circuit, and turn off the starting power supply module when the voltage drop across the input capacitor is greater than or equal to the minimum operating voltage of the power supply circuit. The power supply circuit provided by the application can run with a starting power supply with a small output voltage, thereby guaranteeing the reliability of the power supply circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, and more particularly, to a power supply circuit. BACKGROUND

[0002] A multi-input multi-output power supply circuit includes multiple power supplies. In order to improve the reliability of the power supply circuit, the entire power supply circuit needs to be able to operate under the condition that any one power supply has power. Therefore, the output voltage of each power supply needs to be greater than the operating voltage of the power supply circuit. When the power supply circuit is completely running, some power supplies need to be turned off to reduce energy consumption. However, the turned-off power supplies still have standby power consumption. In addition, due to the large output voltage of each power supply, the power is also large, and the standby power consumption is also large, so the energy consumption is still large. In addition, due to the large output voltage of the power supply, in order to ensure the reliability of the power supply circuit, the electrical components of the standby power supply also have high voltage resistance requirements, safety distance requirements, and heat dissipation requirements, thereby increasing the cost of the electrical components of the power supply circuit. In addition, in order to meet the safety distance and heat dissipation requirements, the power supply needs to occupy a large space, thereby increasing the volume of the power supply circuit. SUMMARY

[0003] The power supply circuit provided by the embodiments of the present application can solve at least one of the above technical problems.

[0004] The power supply circuit provided by the embodiments of the present application can solve at least one of the above technical problems.

[0005] The power supply module includes a power supply and an input capacitor, and the power supply is configured to be started up when the voltage drop across the input capacitor is greater than the minimum operating voltage of the power supply circuit.

[0006] The at least one starting power supply module includes a starting power supply and a starting transformer, the primary side of the starting transformer is connected to the starting power supply, the secondary side of the starting transformer is connected to the input capacitor, and the starting transformer is used to step up the output voltage of the starting power supply module and charge the input capacitor.

[0007] The control circuit is configured to turn on the starting power supply module when the voltage drop across the input capacitor is less than the minimum operating voltage of the power supply circuit, and turn off the starting power supply module when the voltage drop across the input capacitor is greater than or equal to the minimum operating voltage of the power supply circuit.

[0008] The power supply circuit provided by the application utilizes the starting transformer to step up the output voltage of the starting power supply module, so that the starting power supply module only needs a small output voltage to charge the input capacitor, the voltage drop between the input capacitor is greater than the minimum working voltage of the power supply, so that the power supply circuit can run under the condition that any power supply is powered on, and the reliability of the power supply circuit is ensured. The starting power supply with a small output voltage has a small power, thereby reducing standby power consumption. On the other hand, since the voltage and power of the starting power supply module are small, the electrical elements of the starting power supply module can use a lower voltage rating, which is beneficial to reducing the size of the power supply circuit and reducing production costs.

[0009] In some embodiments, the power supply module includes a power supply diode, and the power supply is connected to the secondary side of the starting transformer through the power supply diode.

[0010] In this way, the power supply diode can block the voltage from the starting power supply module, thereby preventing the power supply module from being impacted.

[0011] In some embodiments, the control circuit includes a first pulse width modulation chip, the power supply module includes a power supply transformer and a power supply switch tube, the primary side of the power supply transformer is connected in parallel with the input capacitor, one end of the primary side of the power supply transformer is connected to the drain of the power supply switch tube, the source of the power supply switch tube is grounded, and one end of the first pulse width modulation chip is connected to the secondary side of the power supply transformer. The first pulse width modulation chip is configured to obtain a first output signal according to the output voltage of the secondary side of the power supply transformer and a first preset reference value, so as to control the on-off time of the power supply switch tube.

[0012] In this way, the first pulse width modulation chip is used to control the opening and closing of the power supply switch tube, which is beneficial to simplifying the control logic of the power supply switch tube. In addition, the first pulse width modulation chip has functions of overvoltage protection, overcurrent protection and short circuit protection, which is beneficial to ensuring the safety of the system.

[0013] In some embodiments, the power supply module further includes an output circuit, the secondary side of the power supply transformer is connected to the output circuit, and the output circuit is connected to the first pulse width modulation chip.

[0014] In this way, the output circuit provides a voltage signal for the first pulse width modulation chip, and also supplies power to the first pulse width modulation chip, without the need for an additional power supply for the first pulse width modulation chip, which is beneficial to simplifying the circuit and saving costs.

[0015] In some embodiments, the starting power supply module further includes a starting diode, and the starting power supply module is connected to the input capacitor through the starting diode.

[0016] In this way, the starting diode can block the voltage from the power supply module, avoiding the impact on the starting power supply module, and at the same time, since multiple starting power supply modules are connected to the input capacitor at the same time, if one starting power supply module charges the input capacitor, the voltage of the starting diode of the other starting power supply module will be raised, so that only one starting power supply module charges the input capacitor at all times, which is beneficial to reduce the loss.

[0017] In some embodiments, the number of starting diodes is two, and the two starting diodes are connected in series.

[0018] In this way, the two starting diodes in series can increase the voltage resistance, and compared with using a diode with high voltage resistance, selecting two diodes with low voltage resistance in series is beneficial to reduce the cost.

[0019] In some embodiments, the control circuit includes a second pulse width modulation chip connected to the starting power supply module, and the second pulse width modulation chip is used to turn on the starting power supply module when the voltage of the input capacitor is less than the minimum working voltage of the power supply, and turn off the starting power supply module when the voltage of the input capacitor is greater than or equal to the minimum working voltage of the power supply.

[0020] In this way, using the second pulse width modulation chip to control the starting power supply module is beneficial to simplify the control logic and improve the reliability.

[0021] In some embodiments, the control circuit further includes an isolation sampling circuit connected to one end of the input capacitor and the other end of the second pulse width modulation chip, and the isolation sampling circuit is used to collect the voltage of the input capacitor.

[0022] In this way, the isolation sampling circuit has an electrical isolation function, and collecting the voltage of the input capacitor using the isolation sampling circuit is beneficial to improve the reliability and stability of the circuit, while avoiding interference with the power supply module.

[0023] In some embodiments, the isolation sampling circuit includes an optocoupler connected to one end of the input capacitor and the other end of the second pulse width modulation chip.

[0024] In this way, the isolation sampling circuit sends the voltage difference of the input capacitor collected by the optocoupler to the second pulse width modulation chip, realizing the isolation between the input capacitor and the second pulse width modulation chip, thereby improving the safety of the entire circuit.

[0025] In some embodiments, the starting power module comprises a starting switch tube, the primary side of the starting transformer is connected in parallel with the starting power supply, one end of the primary side of the starting transformer is connected with the starting power supply through the starting switch tube, and the second pulse width modulation chip is configured to obtain a second output signal according to a differential pressure of the input capacitor and a second preset reference value, so as to control the on-off time of the starting switch tube.

[0026] In this way, the starting switch tube is controlled by the second pulse width modulation chip, which is beneficial to simplify the control logic of the starting switch tube. In addition, the second pulse width modulation chip has functions of overvoltage protection, overcurrent protection and short circuit protection, which is beneficial to ensure the safety of the system.

[0027] Additional aspects and advantages of the embodiments disclosed herein will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following description and drawings or can be learned by practice of the embodiments disclosed herein. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a circuit schematic diagram of a power supply circuit in the prior art;

[0030] Figure 2 is a circuit schematic diagram of a power supply circuit of an embodiment of the present application;

[0031] Figure 3 is a module schematic diagram of a power supply circuit of an embodiment of the present application;

[0032] Figure 4 is a circuit schematic diagram of an isolated sampling circuit of an embodiment of the present application.

[0033] Main element symbol explanation: power supply circuit 100, power supply module 10, power supply 11, input capacitor 12, power supply capacitor 13, power supply diode 14, power supply transformer 15, power supply switch tube 16, output circuit 17, output diode 171, output buffer capacitor 172, starting power module 20, starting power supply 21, starting transformer 22, starting diode 23, starting switch tube 24, starting capacitor 25, control circuit 30, first pulse width modulation chip 31, second pulse width modulation chip 32, isolated sampling circuit 33, optocoupler 331, first resistor 332, first capacitor 333, second resistor 334, third resistor 335, voltage stabilizing diode 336, second capacitor 337, fourth resistor 338, fifth resistor 339. DETAILED DESCRIPTION

[0034] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein like or similar constituent elements or features may be denoted by like reference characters, and the embodiments described below are not intended to limit the scope of the present application. The embodiments described below are examples only, and are not exhaustive of possible implementations of the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on the orientations or positional relationships as shown in the drawings, and are used only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be construed as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless explicitly specified and limited otherwise.

[0035] In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounting", "connecting", "connection" should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrally connected. It can be mechanical connection, or electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the present application, unless explicitly specified and limited otherwise, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The "under", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0037] The disclosure herein provides many different embodiments or examples for implementing different structures of the application. For the purpose of simplicity, the members and settings of certain examples are described in the present disclosure. They are, of course, merely examples and are in no way intended to limit the application. Moreover, the application can repeat reference numerals and / or letters in different examples and this repetition is for the purpose of simplicity and clarity and is not in itself indicative of a relationship between the various embodiments and / or settings discussed. Furthermore, the application provides various examples of specific processes and materials, but one of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0038] The power supply circuit of multiple-input and multiple-output includes multiple power supplies, such as Figure 1 As shown, in order to improve the reliability of the power supply circuit, it is required that the entire power supply circuit can be started up under the condition that any one power supply has power, and thus it is required that the output voltage of each power supply is greater than the working voltage of the power supply circuit. When the power supply circuit is completely started up, it is required to turn off part of the power supplies to reduce energy consumption, but the turned-off power supplies still have standby power consumption. Since the output voltage of each power supply is large, the power is also large, the standby power consumption is also large, and the energy consumption is still large. In addition, since the output voltage of the power supply is large, in order to ensure the reliability of the power supply circuit, the electrical components of the standby power supply also have high voltage resistance requirements, safety distance and heat dissipation requirements, thereby increasing the cost of the electrical components of the power supply circuit. In addition, in order to meet the safety distance and heat dissipation requirements, the power supply needs to occupy a large space, increasing the volume of the power supply circuit.

[0039] Please refer to Figure 2 The power supply circuit 100 of the embodiment of the present application includes a power supply module 10, at least one starting power supply module 20 and a control circuit 30. The power supply module 10 includes a power supply 11 and an input capacitor 12. The power supply 11 is configured to start up under the condition that the voltage drop across the input capacitor 12 is greater than the minimum working voltage of the power supply circuit 100. The starting power supply module 20 includes a starting power supply 21 and a starting transformer 22. The starting power supply 21 is connected to the primary side of the starting transformer 22. The secondary side of the starting transformer 22 is connected to the input capacitor 12. The starting transformer 22 is used to boost the output voltage of the starting power supply module 20 and charge the input capacitor 12. The control circuit 30 is configured to turn on the starting power supply module 20 when the voltage drop across the input capacitor 12 is less than the minimum working voltage of the power supply circuit 100, and turn off the starting power supply module 20 when the voltage drop across the input capacitor 12 is greater than or equal to the minimum working voltage of the power supply circuit 100.

[0040] The power supply circuit 100 provided by the present application uses the starting transformer 22 to step up the output voltage of the starting power supply module 20, so that the starting power supply module 20 only needs a small output voltage to meet the charging of the input capacitor 12, and the voltage drop across the input capacitor 12 is greater than the minimum working voltage of the power supply 11. Thus, the starting power supply 21 with a small output voltage can make the power supply circuit 100 run in the case that any power supply is powered, thereby ensuring the reliability of the power supply circuit 100. The starting power supply 21 with a small output voltage has a small power, thereby reducing the standby power consumption. On the other hand, since the voltage and power of the starting power supply module 20 are small, the electrical elements of the starting power supply module 20 can use a lower voltage level, which is beneficial to reduce the size of the power supply circuit 100 and reduce the production cost.

[0041] Specifically, please refer to Figure 2 and Figure 3 In the embodiment of the present application, the power supply 11 is the power supply for normal working, and the power supply capacitor 13 is also connected in parallel across the power supply 11. The input capacitor 12 is connected in parallel across the power supply 11, and its main functions are to absorb high-frequency pulse peaks, buffer energy, and filter differential mode interference of the circuit. The starting capacitor stores energy from the starting power supply 11.

[0042] In the embodiment of the present application, the starting power supply module 20 mainly assists the power supply of the power supply module 10 when the voltage of the power supply 11 is zero. The output of the starting power supply module 20 is directly connected to the input of the power supply module 10. When the power supply 11 has voltage, the starting power supply module 20 stops working. The starting power supply 21 mainly supplies power to the starting power supply 21.

[0043] In some embodiments, the power supply module 10 includes the supply diode 14, and the power supply 11 is connected to the secondary side of the starting transformer 22 through the supply diode 14.

[0044] In this way, the supply diode 14 can block the voltage from the starting power supply module 20, thereby avoiding the impact on the power supply module 10.

[0045] Specifically, in the embodiment of the present application, the positive electrode of the power supply 11 is connected to one end of the power supply capacitor 13, the anode of the supply diode 14, and the cathode of the supply diode 14 is connected to the input capacitor 12 and the secondary side of the starting transformer 22, so that the power supply capacitor 13 is separated from the input capacitor 12, thereby avoiding the charging of the power supply capacitor 13 by the starting power supply module 20 and generating an impact current.

[0046] In some embodiments, the control circuit 30 comprises a first pulse width modulation chip 31, the power supply module 10 comprises a power supply transformer 15 and a power supply switch tube 16, one end of the primary side of the power supply transformer 15 is connected to the drain of the power supply switch tube 16, the source of the power supply switch tube 16 is grounded, and one end of the primary side of the power supply transformer 15 is connected to the input capacitor 12 through the power supply switch tube 16. One end of the first pulse width modulation chip 31 is connected to the secondary side of the power supply transformer 15, and the first pulse width modulation chip 31 is configured to obtain a first output signal according to the output voltage of the secondary side of the power supply transformer 15 and a first preset reference value, so as to control the on-off time of the power supply switch tube 16.

[0047] In this way, the first pulse width modulation chip 31 is used to control the opening and closing of the power supply switch tube 16, which is conducive to simplifying the control logic of the power supply switch tube 16. In addition, the first pulse width modulation chip 31 has functions such as overvoltage protection, overcurrent protection and short circuit protection, which is conducive to ensuring the safety of the system.

[0048] Specifically, in the embodiment of the present application, the power supply transformer 15 can step down the high voltage input by the power supply 11 to a low voltage suitable for use by electronic devices, ensuring normal operation of the electronic devices. At the same time, the power supply transformer 15 can also electrically isolate the power supply 11 from the electronic devices, avoiding short circuits or other dangerous situations, which helps to protect the safety of the devices and the operators.

[0049] The main function of the power supply switch tube 16 is to convert direct current into pulse current and output two groups of alternating voltages through the power supply transformer 15.

[0050] The first pulse width modulation chip 31 is the control center of the entire power supply circuit 100 and performs closed-loop control on the power supply module 10. The output voltage of the secondary side of the power supply transformer 15 is compared with the first preset reference value, and after loop compensation, the first output signal is provided to the power supply switch tube 16 to control the on-off time of the power supply switch tube 16. This control method can output stable switching frequency and accurate output voltage control, and the output frequency of the first output signal can also be adjusted and compensated by peripheral devices.

[0051] In the embodiment of the present application, the first preset reference value is 3.3V, which is a widely used voltage standard. Selecting 3.3V as the first preset reference value helps to ensure the compatibility and interoperability between the first pulse width modulation chip 31 and other digital circuit components. At the same time, a lower first preset reference value (such as 3.3V) relative to a higher voltage can reduce power consumption while ensuring the performance of the power supply circuit 100, and can more efficiently control the power supply switch tube 16, thereby reducing energy loss and improving power conversion efficiency.

[0052] Further, the first pulse width modulation chip 31 has overvoltage and overcurrent short circuit protection function, ensuring the safety and reliability of the power supply circuit 100.

[0053] Please refer to Figure 2 and Figure 3 In some embodiments, the power supply module 10 further comprises an output circuit 17, the secondary side of the power supply transformer 15 is connected with the output circuit 17, and the output circuit 17 is connected with the first pulse width modulation chip 31.

[0054] In this way, the output circuit 17 provides a voltage signal for the first pulse width modulation chip 31, and also supplies power for the first pulse width modulation chip 31, without the need to additionally provide a power supply for the first pulse width modulation chip 31, which is conducive to simplifying the circuit and saving costs.

[0055] Specifically, in the embodiments of the present application, the output circuit 17 comprises an output diode 171 and an output buffer capacitor 172, one end of the secondary side of the power supply transformer 15 is connected with the anode of the output diode 171, the cathode of the output diode 171 is connected with the output buffer capacitor 172, and the other end of the output buffer capacitor 172 is connected with the other end of the secondary side of the power supply transformer 15.

[0056] In the embodiments of the present application, the output diode 171 has the function of high-frequency rectification, which converts the high-frequency pulse output by the winding of the power supply transformer 15 into direct current. The output buffer capacitor 172 has the function of storing energy and filtering high-frequency ripples, and provides a stable direct current power supply for the load.

[0057] Further, the number of output circuits 17 can be multiple, and in the embodiments of the present application, the number of output circuits 17 is three. One of the output circuits 17 supplies power for the first pulse width modulation chip 31, and also provides a voltage signal for the first pulse width modulation chip 31.

[0058] Please refer to Figure 2 In some embodiments, the starting power supply module 20 further comprises a starting diode 23, and the starting power supply module 20 is connected with the input capacitor 12 through the starting diode 23.

[0059] In this way, the starting diode 23 can block the voltage from the power supply module 10, avoiding the impact on the starting power supply module 20, and at the same time, since multiple starting power supply modules 20 are connected with the input capacitor 12 at the same time, if one of the starting power supply modules 20 charges the input capacitor 12, the voltage of the starting diode 23 of the other starting power supply modules 20 will be lifted, so that only one starting power supply module 20 charges the input capacitor 12 at all times, which is conducive to reducing the loss.

[0060] Specifically, in the embodiment of the present application, the negative electrode of the secondary side of the starting transformer 22 is grounded, and the positive electrode is connected with the anode of the starting diode 23, and the cathode of the starting diode 23 is connected with the input capacitor 12. The starting diode 23 performs high-frequency rectification and charges the input capacitor 12, and at the same time blocks the voltage from the power supply 11.

[0061] In some embodiments, the number of starting diodes 23 is two, and the two starting diodes 23 are connected in series.

[0062] In this way, the two starting diodes 23 connected in series can increase the withstand voltage, and compared with using diodes with higher withstand voltage, selecting two diodes with lower withstand voltage connected in series is conducive to reducing costs.

[0063] Specifically, in the embodiment of the present application, two starting diodes 23 connected in series are arranged in each starting power supply module 20 to increase the withstand voltage. In other embodiments, the starting diode 23 can also be designed in other quantities, and the number and type of the starting diode 23 can be selected according to actual needs.

[0064] It should be noted that the fewer the number of starting diodes 23, the higher the required withstand voltage, but the number of starting diodes 23 should not be too large. When the number of starting diodes 23 connected in series is greater than two, a parasitic Darlington transistor will be generated inside the diode string. The parasitic Darlington transistor will in turn reduce the triggering voltage of the diode string, and as the number of diodes connected in series increases, the leakage current also becomes larger and larger, resulting in increased energy consumption, reduced service life, and even negative impact on the stability of the circuit.

[0065] Please refer to Figure 2 and Figure 3 In some embodiments, the control circuit 30 includes a second pulse width modulation chip 32, the second pulse width modulation chip 32 is connected with the starting power supply module 20, and the second pulse width modulation chip 32 is used to start the starting power supply module 20 when the voltage of the input capacitor 12 is less than the minimum working voltage of the power supply 11, and to stop the starting power supply module 20 when the voltage of the input capacitor 12 is greater than or equal to the minimum working voltage of the power supply 11.

[0066] In this way, the starting power supply module 20 is controlled by the second pulse width modulation chip 32, which is conducive to simplifying the control logic and improving reliability.

[0067] Specifically, in the embodiment of the present application, the starting power module 20 comprises a starting switch tube 24, and the second pulse width modulation chip 32 is connected with the starting switch tube 24. When the voltage of the power supply module 10 is 0, the starting power module 20 starts to work by controlling the switch tube, thereby charging the input capacitor 12. When the voltage of the input capacitor 12 is equal to the minimum working voltage of the power supply 11, the starting power module 20 stops working by controlling the switch tube.

[0068] In the embodiment of the present application, the number of the starting power module 20 is multiple. With the increase of the starting power module 20, the control circuit 30 increases a pulse width modulation chip to control the starting power module 20.

[0069] In some embodiments, the control circuit 30 further comprises an isolation sampling circuit 33, one end of which is connected with the input capacitor 12, and the other end of which is connected with the second pulse width modulation chip 32. The isolation sampling circuit 33 is used to collect the voltage of the input capacitor 12.

[0070] In this way, the isolation sampling circuit 33 has the electrical isolation function. The voltage of the input capacitor 12 is collected by the isolation sampling circuit 33, which is beneficial to improve the reliability and stability of the circuit, and at the same time, avoids interfering with the power supply module 10.

[0071] Specifically, in the embodiment of the present application, the second pulse width modulation chip 32 acquires the voltage of the input capacitor 12 through the isolation sampling circuit 33.

[0072] In the embodiment of the present application, since the number of the starting power module 20 is multiple, multiple pulse width modulation chips need to be set correspondingly. Therefore, the number of the isolation sampling circuit 33 should also be multiple, so that the isolation sampling circuit 33 is set one by one corresponding to the pulse width modulation chip.

[0073] Please refer to Figure 4 In some embodiments, the isolation sampling circuit 33 comprises an optical coupler 331, one end of which is connected with the input capacitor 12, and the other end of which is connected with the second pulse width modulation chip 32.

[0074] In this way, the voltage difference of the input capacitor 12 collected by the isolation sampling circuit 33 is sent to the second pulse width modulation chip 32 through the optical coupler 331, which realizes the isolation between the input capacitor 12 and the second pulse width modulation chip 32, thereby improving the safety of the entire circuit.

[0075] Specifically, in the embodiment of the present application, the isolation sampling circuit 33 comprises an optocoupler 331, a first resistor 332, a first capacitor 333, a second resistor 334, a third resistor 335, a voltage stabilizing diode 336, a second capacitor 337, a fourth resistor 338 and a fifth resistor 339. The pin 1 of the optocoupler 331 is connected with the second pulse width modulation chip 32 through the first resistor 332. The pin 2 of the optocoupler 331 is connected with one end of the first capacitor 333. The other end of the first capacitor 333 is connected with the second pulse width modulation chip 32 through the second resistor 334. The other end of the first capacitor 333 is also connected with the ground through the third resistor 335. The pin 2 of the optocoupler 331 is also connected with the output end of the voltage stabilizing diode 336. The input end of the voltage stabilizing diode 336 is connected with the ground. The ground end of the voltage stabilizing diode 336 is connected with the ground through the third resistor 335. The second capacitor 337 and the fourth resistor 338 are connected in series and then connected in parallel with the two ends of the first capacitor 333. The pin 3 of the optocoupler 331 is connected with the ground. The pin 4 of the optocoupler 331 is connected with the input capacitor 12 through the fifth resistor 339.

[0076] In some embodiments, the starting power module 20 comprises a starting switch tube 24. The primary side of the starting transformer 22 is connected in parallel with the starting power 21. One end of the primary side of the starting transformer 22 is connected with the starting power 21 through the starting switch tube 24. The second pulse width modulation chip 32 is configured to obtain a second output signal according to the voltage difference of the input capacitor 12 and a second preset reference value, so as to control the on-off time of the starting switch tube 24.

[0077] In this way, the starting switch tube 24 is controlled by the second pulse width modulation chip 32, which is beneficial to simplify the control logic of the starting switch tube 24. In addition, the second pulse width modulation chip 32 has functions of overvoltage protection, overcurrent protection and short circuit protection, which is beneficial to ensure the safety of the system.

[0078] Specifically, the second pulse width modulation chip 32 controls the starting power module 20 in a closed loop. The output voltage of the secondary side of the starting transformer 22 is compared with a first preset reference value, and then a loop compensation is added, so as to provide a second output signal for the starting switch tube 24, so as to control the on-off time of the starting switch tube 24. This control mode can output stable switching frequency and accurate output voltage control. The output frequency of the second output signal can also be adjusted and compensated through peripheral devices.

[0079] Please refer to Figure 2 In some embodiments, the starting power module 20 further comprises a starting capacitor 25, which is connected in parallel with the starting power 21.

[0080] In this way, the starting capacitor 25 can absorb pulse peaks, store energy and filter differential mode interference in the circuit.

[0081] Specifically, in the embodiment of the present application, one end of the starting capacitor 25 is connected with the primary side of the starting transformer 22, and the other end is grounded.

[0082] In summary, in the embodiment of the present application, the principle of the power supply circuit 100 is as follows:

[0083] The power supply 11 and the power supply capacitor 13 charge the input capacitor 12 through the power supply diode 14, and the power supply diode 14 separates the power supply capacitor 13 and the input capacitor 12 to prevent the starting power supply module 20 from charging the power supply capacitor 13 and causing an impact current. The input capacitor 12 supplies power to the power supply 11. When the power supply switch tube 16 is turned on, the power supply transformer 15 stores energy, the output diode 171 is cut off, and the output buffer capacitor 172 supplies power to the load. When the power supply switch tube 16 is turned off, the power supply transformer 15 releases energy, the output diode 171 is turned on, and the output buffer capacitor 172 stores energy while supplying power to the load. The first pulse width modulation chip 31 outputs a voltage of the circuit 17 and compares it with a first preset reference value. After loop compensation, the first output signal is generated internally to drive the power supply switch tube 16.

[0084] The starting diode 23 rectifies the input capacitor 12 at high frequency and blocks the voltage of the input capacitor 12. Two starting diodes 23 are connected in series to increase the withstand voltage. The second pulse width modulation chip 32 sends a second output signal to drive the starting switch tube 24. When the starting switch tube 24 is turned on, the starting transformer 22 stores energy. The starting power supply 21 and the starting capacitor 25 supply power to the starting transformer 22. When the starting switch tube 24 is turned off, the starting transformer 22 releases energy, and the starting diode 23 charges the input capacitor 12. The isolation sampling circuit 33 samples the voltage across the input capacitor 12, sends it to the second pulse width modulation chip 32 through an optical coupling, and compares it with a reference signal inside the chip. The loop compensation is performed internally, and the parameters of the loop compensation can be set externally. When the voltage of the input capacitor 12 is 0, the starting transformer 22 receives a start signal from the second pulse width modulation chip 32 to start outputting, and continues until the voltage of the input capacitor 12 is charged to the minimum working voltage of the power supply 11. When the system is running stably, the starting power supply circuit 100 receives a shutdown signal from the second pulse width modulation chip 32 to stop outputting and enter a standby state.

[0085] In the description of the application, the description of the terms "certain embodiments", "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the application. The illustrative appearance of the above terms in various places in the description are not necessarily intended to refer to the same embodiment or example. Moreover, the particular features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0086] Furthermore, the terms "first", "second" or the like are used merely to describe corresponding features, and do not imply or connote relative importance or a quantity of the specified technical features. Thus, a feature defined with "first", "second" can include at least one of the features explicitly or implicitly. In the description of the application, the meaning of "plurality" is at least two, for example two, three, unless otherwise explicitly and specifically limited.

[0087] Although the embodiments of the application have been shown and described above, it is to be understood that the above-described embodiments are merely exemplary, and are not to be taken as limiting the present application. Within the scope of the present application, various changes, modifications, substitutions and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present application, which are defined by the claims and their equivalents.

Claims

1. A power supply circuit (100), characterized in that: include: A power supply module (10), the power supply module (10) comprising a power supply (11) and an input capacitor (12), the power supply (11) being configured to start when a voltage drop across the input capacitor (12) is greater than a minimum operating voltage of the power supply circuit (100); At least one starting power supply module (20), the starting power supply module (20) comprising a starting power supply (21) and a starting transformer (22), the starting power supply (21) being connected to the primary side of the starting transformer (22), the secondary side of the starting transformer (22) being connected to the input capacitor (12), and the starting transformer (22) being used to boost the output voltage of the starting power supply module (20) and charge the input capacitor (12); A control circuit (30) is configured to turn on the startup power module (20) when the voltage drop across the input capacitor (12) is less than the minimum operating voltage of the power circuit (100), and to turn off the startup power module (20) when the voltage drop across the input capacitor (12) is greater than or equal to the minimum operating voltage of the power circuit (100).

2. The power supply circuit (100) according to claim 1, characterized in that The power supply module (10) includes a power supply diode (14), and the power supply (11) is connected to the secondary side of the starting transformer (22) via the power supply diode (14).

3. The power supply circuit (100) according to claim 1, characterized in that The control circuit (30) includes a first pulse width modulation chip (31); the power supply module (10) includes a power transformer (15) and a power switch tube (16); the primary side of the power transformer (15) is connected in parallel with the input capacitor (12); one end of the primary side of the power transformer (15) is connected to the drain of the power switch tube (16); the primary electrode of the power switch tube (16) is grounded; one end of the first pulse width modulation chip (31) is connected to the secondary side of the power transformer (15); the first pulse width modulation chip (31) is configured to obtain a first output signal according to the output voltage of the secondary side of the power transformer (15) and a first preset reference value, so as to control the on-off time of the power switch tube (16).

4. The power supply circuit (100) according to claim 3, characterized in that The power supply module (10) further includes an output circuit (17), the secondary side of the power supply transformer (15) is connected to the output circuit (17), and the output circuit (17) is connected to the first pulse width modulation chip (31).

5. The power supply circuit (100) according to claim 1, characterized in that The starting power supply module (20) further includes a starting diode (23), and the starting power supply module (20) is connected to the input capacitor (12) via the starting diode (23).

6. The power supply circuit (100) according to claim 5, characterized in that The number of the starting diodes (23) is two, and the two starting diodes (23) are connected in series.

7. The power supply circuit (100) according to claim 1, characterized in that The control circuit (30) includes a second pulse width modulation chip (32), the second pulse width modulation chip (32) being connected to the startup power supply module (20), and the second pulse width modulation chip (32) being used to turn on the startup power supply module (20) when the voltage of the input capacitor (12) is less than the minimum operating voltage of the power supply (11), and to turn off the startup power supply module (20) when the voltage of the input capacitor (12) is greater than or equal to the minimum operating voltage of the power supply (11).

8. The power supply circuit (100) according to claim 7, characterized in that The control circuit (30) further includes an isolation sampling circuit (33), one end of the isolation sampling circuit (33) is connected to the input capacitor (12), and the other end is connected to the second pulse width modulation chip (32), and the isolation sampling circuit (33) is used to collect the voltage of the input capacitor (12).

9. The power supply circuit (100) according to claim 8, characterized in that: The isolation sampling circuit (33) comprises an optical coupler (331), one end of the optical coupler (331) is connected to the input capacitor (12), and the other end is connected to the second pulse width modulation chip (32).

10. The power supply circuit (100) according to claim 7, characterized in that: The starting power supply module (20) includes a starting switch tube (24), the primary side of the starting transformer (22) is connected in parallel with the starting power supply (21), one end of the primary side of the starting transformer (22) is connected to the starting power supply (21) through the starting switch tube (24), and the second pulse width modulation chip (32) is configured to obtain a second output signal according to the voltage difference of the input capacitor (12) and a second preset reference value, so as to control the on-off time of the starting switch tube (24).

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