Switching power supply controller and flyback rectification circuit

Abstract

The invention discloses a switching power supply controller and a flyback rectifier circuit, and relates to the technical field of switching power supply control, and the switching power supply controller comprises a feedback detection module, a comparison module, a pulse modulation module, a trigger module and a driving module. Through cooperative work of a feedback detection module, a comparison module, a pulse modulation module, a trigger module and a driving module, accurate control and trigger signal generation based on feedback voltage are realized, and a complex combination scheme is not needed; the modules are optimally designed, for example, an error amplifier, a comparator, a timer and a signal generator in the comparison module are matched, so that the duty ratio of a setting signal is dynamically adjusted; meanwhile, a power supply module, a temperature protection module, an overcurrent protection module and a blanking module are integrated, so that stable power supply, multiple protection and false triggering shielding functions are provided; the trigger module adopts an RS trigger and a logic control sub-module to ensure accurate generation and transmission of a trigger signal.

Description

Technical Field

[0001] This application relates to the field of switching power supply control technology, and particularly to a switching power supply controller and a flyback rectifier circuit. Background Art

[0002] In the design of traditional switching power supplies, such as AC-DC adapters, chargers, etc., achieving high-precision constant voltage output and reliable protection functions is a key technical requirement to ensure the safety and stability of the equipment. However, the existing technologies generally rely on a combined solution of secondary-side feedback components, optocoupler isolation devices, and TL431 reference voltage sources to complete voltage feedback and control closed-loop, and its design architecture has the following inherent defects: The traditional solution needs to detect the output voltage through a secondary-side resistor voltage division network, and transmit the signal to the primary controller through an optocoupler, while relying on TL431 to provide a reference voltage and error amplification function. This combination of multiple components increases the circuit complexity and cost, and discrete devices such as optocouplers and TL431 occupy a large PCB area, which is not conducive to miniaturization design.

[0003] The transmission delay and aging characteristics of the optocoupler may cause feedback signal distortion. Especially in dynamic load or high-temperature environments, it is easy to cause output voltage fluctuations or even overvoltage / undervoltage faults. The temperature drift characteristic of TL431 (typical value ±100ppm / ℃) further limits the accuracy stability of the system in a wide temperature range. Although the isolation characteristic of the optocoupler ensures electrical safety, its non-linear transmission characteristic and parasitic parameters (such as capacitance) limit the transmission efficiency of high-frequency signals, resulting in limited system dynamic response speed (typical bandwidth less than 100kHz). In addition, the current limiting characteristic of TL431 needs to be matched by external resistors, increasing the design complexity.

[0004] Traditional protection mechanisms such as overvoltage protection and short-circuit protection usually rely on the feedback signal transmitted by the optocoupler to trigger, but optocoupler failure may cause the protection function to fail. At the same time, the single reference voltage (2.5V) of TL431 limits the flexibility of the multi-voltage output system, and additional circuits need to be added to achieve multi-channel feedback.

[0005] Therefore, there is an urgent need for a new switching power supply control architecture, which can achieve high power factor correction (PFC), high-precision constant voltage output and reliable protection functions without secondary-side feedback components, optocouplers and TL431 through innovative topologies and digital control technologies, while meeting the application requirements of miniaturization, high efficiency and wide temperature range. Summary of the Invention

[0006] The main purpose of this application is to provide a switching power supply controller and a flyback rectifier circuit, aiming to solve the technical problems that the existing rectifier circuit relies on secondary-side feedback, has a relatively complex structure and high cost.

[0007] To achieve the above object, the present application provides a switching power supply controller, which includes a feedback detection module, a comparison module, a pulse modulation module, a trigger module, and a drive module; the feedback detection module is respectively connected to the pulse modulation module, the comparison module, and the object to be measured; the trigger module is respectively connected to the pulse modulation module, the comparison module, and the drive module; the drive module is further connected to the controlled object; the feedback detection module is configured to collect the feedback voltage of the object to be measured and transmit the feedback voltage to the pulse modulation module and the comparison module through the quasi-resonant mode; the pulse modulation module is configured to convert the feedback voltage into a reset signal and transmit it to the trigger module; the comparison module compares the feedback voltage with a reference voltage and generates a set signal based on the comparison result and transmits it to the trigger module; the trigger module generates a trigger signal based on the reset signal and the set signal and transmits it to the drive module; the drive module is configured to output a drive voltage to the controlled object after receiving the trigger signal.

[0008] In one embodiment, the comparison module includes an error amplifier, a comparator, a timer, and a signal generator; the positive input terminal and the negative input terminal of the error amplifier are respectively connected to a reference voltage source and the feedback detection module; the positive input terminal and the negative input terminal of the comparator are respectively connected to the signal generator and the output terminal of the error amplifier; the output terminal of the comparator is connected to the trigger module; the timer is coupled to the signal generator; the timer is configured to control the signal generator to generate a periodic ramp signal; the error amplifier generates an error voltage by comparing the feedback voltage with the reference voltage; the comparator generates a set signal by comparing the error voltage with the periodic ramp signal and transmits it to the trigger module, and the duty cycle of the set signal is dynamically adjusted by the intersection point of the error voltage and the ramp signal.

[0009] In one embodiment, the output terminal of the error amplifier is grounded through a capacitor to achieve loop compensation.

[0010] In one embodiment, the switching power supply controller further includes a power supply module; the power supply module is connected to the object to be measured and each module of the switching power supply controller; the power supply module receives the current of the object to be measured and converts it into a startup voltage, and supplies power to each module of the switching power supply controller when the startup voltage exceeds a preset startup voltage threshold.

[0011] In one embodiment, the switching power supply controller further includes: a temperature protection module; the temperature protection module is connected to the trigger module; the temperature protection module is further configured to detect the overall operating temperature of the switching power supply controller, and when the operating temperature exceeds a preset operating temperature threshold, output a temperature cut-off signal to the trigger module; the trigger module stops generating a trigger signal when receiving the temperature cut-off signal.

[0012] In one embodiment, the switching power supply controller further includes: an overcurrent protection module and a blanking module; the overcurrent protection module is respectively connected to the blanking module and the trigger module; the blanking module is further connected to the controlled object; the overcurrent protection module receives the operating current of the controlled object through the blanking module; the overcurrent protection module is further configured to output an overcurrent cut-off signal to the trigger module when the operating current exceeds a preset overcurrent threshold; the trigger module stops generating a trigger signal when receiving the overcurrent cut-off signal; the blanking module is configured to shield the operating current when the controlled object starts, to prevent the overcurrent protection module from being falsely triggered.

[0013] In one embodiment, the trigger module includes: an RS flip-flop and a logic control sub-module; the reset terminal and the set terminal of the RS flip-flop are respectively connected to the pulse modulation module and the comparison module; the output terminal of the RS flip-flop is connected to the logic control sub-module; the logic control sub-module is further connected to the overcurrent protection module, the temperature protection module and the drive module; the RS flip-flop generates an initial trigger signal based on the reset signal and the set signal and outputs it to the logic control sub-module; the logic control sub-module generates a trigger signal based on the initial trigger signal, the temperature cut-off signal and the overcurrent cut-off signal and transmits it to the drive module.

[0014] In addition, to achieve the above object, the present application further provides a flyback rectifier circuit, which includes: a switching power supply control module, a rectification module and a flyback conversion module; the switching power supply control module includes the switching power supply controller as described above; the rectification module is respectively connected to an AC power supply, the switching power supply control module and the flyback conversion module; the switching power supply control module is further connected to the flyback conversion module; the rectification module is configured to rectify alternating current into high-voltage direct current and transmit it to the flyback conversion module; the flyback conversion module performs flyback conversion on the high-voltage direct current based on the trigger signal of the switching power supply control module and outputs a direct current voltage.

[0015] In one embodiment, the flyback conversion module includes an RCD clamp sub-module, a transformer, and a MOS transistor; the transformer includes a primary winding, an auxiliary winding, and a secondary winding; a first end of the primary winding of the transformer is connected to the rectification module, and a second end of the primary winding of the transformer is connected to the drain of the MOS transistor; the RCD clamp sub-module is respectively connected to the first end and the second end of the primary winding; the source of the MOS transistor is grounded through a resistor; the gate of the MOS transistor is connected to the switching power supply control module; a first end of the auxiliary winding of the transformer is connected to the switching power supply control module, and a second end of the auxiliary winding is grounded; the secondary winding of the transformer is connected to a load; the RCD clamp sub-module is configured to absorb the voltage spike generated by the leakage inductance of the transformer when the MOS transistor is turned off to protect the MOS transistor from being broken down.

[0016] In one embodiment, the switching power supply control module further includes: a first resistor, a first capacitor, a first diode, a second resistor, a third resistor, a fourth resistor, and a second capacitor; a first end of the first resistor is connected to the rectification module, and a second end of the first resistor is respectively connected to the cathode of the first diode, a first end of the first capacitor, and a power supply module of the switching power supply controller; a second end of the first capacitor is grounded; an anode of the first diode is respectively connected to a first end of the auxiliary winding of the transformer and a first end of the second resistor; a second end of the second resistor is respectively connected to a feedback detection module of the switching power supply controller and a first end of the third resistor; a second end of the third resistor is grounded; a driving module of the switching power supply controller is connected to the gate of the MOS transistor; a blanking module of the switching power supply controller is connected to a first end of the fourth resistor; a second end of the fourth resistor is connected to the source of the MOS transistor; an output end of an error amplifier of the switching power supply controller is grounded through the second capacitor.

[0017] One or more technical solutions proposed by this application have at least the following technical effects: The switching power supply controller works in cooperation with the feedback detection module, the comparison module, the pulse modulation module, the trigger module, and the driving module to achieve precise control based on the feedback voltage and generate trigger signals, without the need for complex combination schemes; each module is optimized, such as the cooperation of the error amplifier, comparator, timer, and signal generator in the comparison module, to achieve dynamic adjustment of the duty cycle of the set signal; at the same time, a power supply module, a temperature protection module, an overcurrent protection module, and a blanking module are integrated to provide stable power supply, multiple protection, and false trigger shielding functions; the trigger module uses an RS flip-flop and a logic control sub-module to ensure accurate generation and transmission of trigger signals. Overall, it achieves the beneficial effects of circuit simplification, cost reduction, precise control, improved stability, and perfect protection functions. Description of the Drawings

[0018] The accompanying drawings here are incorporated into and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a structural block diagram provided for Embodiment 1 of the switching power supply controller of the present application; Figure 2 It is the internal block diagram of the switching power supply controller provided for Embodiment 1 of the present application; Figure 3 It is a structural block diagram provided for Embodiment 2 of the flyback rectifier circuit of the present application; Figure 4 It is the connection diagram of the flyback rectifier circuit provided for Embodiment 2 of the present application.

[0021] Explanation of the reference numerals in the drawings:

[0022] The realization of the purpose, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0023] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0024] To better understand the technical solutions of the present application, the following will be described in detail in combination with the drawings in the specification and the specific embodiments.

[0025] In the design of traditional switching power supplies, such as AC-DC adapters, chargers, etc., achieving high-precision constant voltage output and reliable protection functions is a key technical requirement to ensure the safety and stability of the equipment. However, the existing rectifier circuits generally rely on the combined scheme of secondary-side feedback components, opto-isolation devices and TL431 reference voltage sources to complete voltage feedback and control closed-loop, resulting in technical problems such as increased circuit complexity and rising costs.

[0026] Based on this, the present application proposes a switching power supply controller applied to a flyback rectifier circuit. Please refer to Figure 1 , Figure 1 It is a structural block diagram provided for Embodiment 1 of the switching power supply controller of the present application.

[0027] In this embodiment, the switching power supply controller includes: a feedback detection module 10, a comparison module 20, a pulse modulation module 30, a trigger module 40, and a drive module 50. Among them, the feedback detection module 10 is respectively connected to the pulse modulation module 30, the comparison module 20, and the object to be measured; the trigger module 40 is respectively connected to the pulse modulation module 30, the comparison module 20, and the drive module 50; the drive module 50 is also connected to the controlled object.

[0028] It can be understood that the object to be measured refers to the part in the switching power supply system that needs to be monitored and its output characteristics are fed back. In the application scenario of the switching power supply controller described in this application, the object to be measured is usually the parameters related to the output load of the switching power supply. The most core one is the output voltage, and it may also include the output current.

[0029] It can be understood that the controlled object refers to the part of the switching power supply controller that adjusts its working state by outputting a control signal to achieve the control of the output characteristics of the switching power supply. In this application, the controlled object is mainly the switching tube in the switching power supply. From a more macroscopic perspective, the controlled object can also be understood as the overall working state of the switching power supply, including parameters such as output voltage, output current, and power. By controlling the on and off time of the switching tube (i.e., the duty cycle of the PWM signal), the output characteristics of the switching power supply can be precisely adjusted to meet the needs of the load.

[0030] It should be noted that the feedback detection module 10 is used to collect the feedback voltage of the object to be measured. The feedback voltage refers to the voltage signal collected from the output end of the switching power supply or other key nodes in the switching power supply system and fed back to the controller. This signal is used to reflect the actual state of the output characteristics of the switching power supply (such as output voltage, output current, etc.), so that the controller can adjust the working parameters of the switching power supply according to the feedback voltage to achieve precise control of the output.

[0031] It can be understood that the feedback voltage of the object to be measured can be collected by a high-precision voltage division resistor network to collect the output voltage or by a Hall sensor to detect the current and convert it into a voltage signal.

[0032] It should be noted that the feedback detection module 10 transmits the feedback voltage to the pulse modulation module 30 and the comparison module 20 through the quasi-resonant mode.

[0033] It can be understood that the quasi-resonant mode transmission utilizes the characteristics of the resonant circuit to transmit the feedback signal during the off period of the switching tube (zero voltage switching ZVS or zero current switching ZCS), reducing noise interference. By adopting the primary side feedback technology without optocoupler (PSR), the secondary side output voltage is indirectly deduced by detecting the primary side inductor current or winding voltage of the transformer, replacing the traditional optocoupler isolation and simplifying the circuit design.

[0034] It should be noted that the pulse modulation module 30 is used to convert the feedback voltage into a reset signal and transmit it to the trigger module 40. For example, in a switching power supply designed to output 12V, the feedback voltage is compared with the reference voltage corresponding to 12V. If the actual output voltage deviates from 12V due to load changes or other factors, the feedback voltage will also change accordingly.

[0035] It can be understood that based on the change of the feedback voltage, the module dynamically adjusts the duty cycle of the PWM (pulse width modulation) signal. The duty cycle is the ratio of the high-level duration of the PWM signal to a cycle time. When the feedback voltage indicates that the output voltage is too high, the module reduces the duty cycle. For example, if the original duty cycle is 50%, it may be reduced to 30% at this time to reduce the energy transferred to the output end and prompt the output voltage to drop.

[0036] It can be understood that when the feedback voltage is too high and the duty cycle is reduced to a certain extent (such as less than 20%), the pulse modulation module 30 determines that the output voltage is abnormal, and at this time, a reset signal is generated. This reset signal is an electrical signal with a specific pulse width and amplitude, and its function is to notify the trigger module 40 to perform a reset operation.

[0037] It should be noted that in this process, combined with the quasi-resonant mode, the pulse modulation module 30 monitors the state of the resonant module 11 in real time and accurately captures the resonant point. The resonant point refers to the moment when the voltage or current in the resonant module 11 reaches a specific value. For example, when the primary inductance and parasitic capacitance of the transformer resonate, the primary voltage will change periodically. When the voltage reaches a preset threshold, it is considered that the resonant point is reached.

[0038] It can be understood that while monitoring the resonant point, the pulse modulation module 30 also makes a comprehensive judgment in combination with the magnitude of the feedback voltage. If the feedback voltage indicates that the output voltage is too high and the preset resonant point is reached at this time, the module determines that a reset signal needs to be generated. For example, in a switching power supply with a 12V output, if the feedback voltage shows that the output voltage is 13V and the resonant point is monitored to arrive at the same time, the module will trigger the reset signal generation mechanism.

[0039] It can be understood that when the above conditions are met, the pulse modulation module 30 generates a reset signal at the resonant point. This reset signal is an electrical signal with a specific pulse width and amplitude, and its generation timing is precisely synchronized with the resonant point. In this way, it is ensured that the reset signal is generated under the zero-voltage or zero-current condition during the turn-off period of the switching tube, avoiding operating when the switching tube bears high voltage or large current, thereby reducing the switching loss.

[0040] It should be noted that the comparison module 20 compares the feedback voltage with the reference voltage and generates a set signal based on the comparison result for transmission to the trigger module 40.

[0041] It can be understood that the reference voltage is a preset fixed voltage value, representing the desired output characteristics of the switching power supply. It is usually set according to the design requirements of the switching power supply and the needs of the load. Continuing with the above example of a 12V output power supply, the reference voltage may be set to a specific voltage division value corresponding to the 12V output, such as 1.2V.

[0042] It can be understood that the comparison module 20 will compare the feedback voltage with the reference voltage in real time. If the feedback voltage is higher than the reference voltage, it indicates that the output voltage of the switching power supply is too high; conversely, if the feedback voltage is lower than the reference voltage, it indicates that the output voltage is too low.

[0043] It can be understood that when the feedback voltage is higher than the reference voltage, the comparison module 20 will determine that the output voltage of the switching power supply exceeds the set range. At this time, the module will generate a set signal, and the logical state of this signal (such as high level) indicates that measures need to be taken to reduce the output voltage. When the feedback voltage is lower than the reference voltage, the comparison module 20 will generate a set signal with another logical state (such as low level), indicating that the output voltage needs to be increased.

[0044] It should be noted that the trigger module 40 generates a trigger signal based on the reset signal and the set signal and transmits it to the drive module 50. The drive module 50 is used to output a drive voltage to the controlled object after receiving the trigger signal.

[0045] It can be understood that the trigger module 40 undertakes a key task in the switching power supply controller. Its main function is to generate a corresponding trigger signal based on the reset signal generated by the pulse modulation module 30 and the set signal generated by the comparison module 20, and transmit this trigger signal to the drive module 50 to control the on and off of the switching transistor.

[0046] It can be understood that the reset signal is generated by the pulse modulation module 30, usually when the output voltage of the switching power supply is too high and reaches the resonance point of the quasi-resonant mode. The function of the reset signal is to notify the trigger module 40 that a reset operation needs to be performed to force the switching transistor to turn off. The set signal is generated by the comparison module 20. It is generated according to the comparison result after comparing the feedback voltage with the reference voltage. The set signal reflects the deviation between the output voltage of the switching power supply and the set value.

[0047] It can be understood that the trigger module 40 will perform logical judgments on the received reset signal and set signal. For example, when the reset signal is valid, regardless of the state of the set signal, the trigger module 40 will preferentially generate a trigger signal to turn off the switching transistor. This is because the reset signal usually indicates that a serious abnormal situation has occurred in the output voltage, and immediate measures need to be taken to protect the load and the power supply.

[0048] It can be understood that when there is no reset signal or the reset signal is invalid, the trigger module 40 will generate corresponding trigger signals according to the state of the set signal. If the set signal indicates that the output voltage is too high, the trigger module 40 will generate a trigger signal to turn off the switching transistor or reduce the conduction time; if the set signal indicates that the output voltage is too low, the trigger module 40 will generate a trigger signal to turn on the switching transistor or increase the conduction time.

[0049] Specifically, on the basis of this basic function, this embodiment provides a better implementation manner. Please refer to Figure 2 , Figure 2 which is the internal block diagram of the switching power supply controller provided in the first embodiment of this application.

[0050] In this embodiment, the comparison module 20 includes: an error amplifier 21, a comparator 22, a timer 23, and a signal generator 24.

[0051] Among them, the positive input terminal of the error amplifier 21 is connected to the reference voltage source, and the negative input terminal is connected to the feedback detection module 10. The reference voltage source provides a stable reference voltage, and the feedback detection module 10 collects the output feedback voltage of the switching power supply. The error amplifier 21 compares the feedback voltage with the reference voltage and generates an error voltage. For example, if the reference voltage is 1.2V (corresponding to an expected output of 12V) and the feedback voltage is 1.1V (the actual output is lower than the expected), the error amplifier 21 will output a positive error voltage, and the magnitude of this voltage is proportional to the difference between the feedback voltage and the reference voltage. The error voltage reflects the deviation degree between the output of the switching power supply and the set value.

[0052] Among them, the timer 23 is coupled to the signal generator 24 and provides a timing control signal for the signal generator 24. The function of the timer 23 is to control the signal generator 24 to generate a periodic ramp signal. The timer 23 can send trigger signals to the signal generator 24 at a fixed frequency and period according to the preset time parameters, so that the ramp signal generated by the signal generator 24 has a stable periodic characteristic. For example, if the timer 23 is set with a period of 12 microseconds, then the signal generator 24 will generate a complete ramp signal every 12 microseconds. The output terminal of the signal generator 24 is connected to the positive input terminal of the comparator 22.

[0053] Among them, the positive input terminal of the comparator 22 is connected to the signal generator 24, the negative input terminal is connected to the output terminal of the error amplifier 21, and the output terminal is connected to the trigger module 40. The comparator 22 compares the error voltage with the periodic ramp signal. When the error voltage is greater than the ramp signal, the comparator 22 outputs a high level; when the error voltage is less than the ramp signal, the comparator 22 outputs a low level. Since the ramp signal is periodic, the output of the comparator 22 will form a pulse signal, that is, the set signal. The duty cycle of the set signal is dynamically adjusted by the intersection point of the error voltage and the ramp signal. For example, when the error voltage is large, the intersection point of the error voltage and the ramp signal is at a higher position on the rising edge of the ramp signal, and the duty cycle of the set signal is larger; conversely, when the error voltage is small, the intersection point position is lower, and the duty cycle of the set signal is smaller.

[0054] It can be understood that the feedback detection module 10 collects the feedback voltage and transmits it to the error amplifier 21, and the error amplifier 21 generates the error voltage. The timer 23 controls the signal generator 24 to generate a periodic ramp signal according to a preset period. The comparator 22 compares the error voltage and the ramp signal in real time and generates a set signal according to the comparison result. The duty cycle of the set signal can dynamically reflect the deviation between the output of the switching power supply and the set value. When the output deviation is large, the duty cycle of the set signal increases or decreases accordingly, so that the trigger module 40 adjusts the working state of the switching tube according to the set signal, so that the output can be restored to the set value as soon as possible. Due to the periodicity of the ramp signal, the set signal is also periodic, which makes the control of the switching power supply have a certain regularity and stability.

[0055] It should be noted that in the switching power supply controller, the feedback loop where the error amplifier 21 is located is crucial for the stability and performance of the system. Due to the presence of energy storage elements such as inductors and capacitors in the switching power supply, as well as the switching actions of the power switching tubes, the feedback loop may exhibit unstable characteristics, such as oscillation, slow response or overshoot. These unstable factors will affect the output accuracy and stability of the switching power supply, and may even cause the system to malfunction. Therefore, it is necessary to compensate the feedback loop to improve its frequency response characteristics and enhance the stability and dynamic performance of the system.

[0056] It can be understood that, due to the characteristic of a capacitor to block direct current and pass alternating current, its impedance is inversely proportional to the frequency. At low frequencies, the impedance of the capacitor is large, and the blocking effect on the signal is strong; at high frequencies, the impedance of the capacitor is small, and the blocking effect on the signal is weak. Connecting a capacitor between the output terminal of the error amplifier 21 and the ground is equivalent to introducing a low-pass filter into the feedback loop. In the low-frequency band, the impedance of the capacitor is large, and the influence on the loop gain is small, and the feedback loop can maintain a high gain to ensure the accurate detection and adjustment of the output deviation; in the high-frequency band, the impedance of the capacitor is small, which will reduce the loop gain, thereby suppressing high-frequency noise and oscillations. By reasonably selecting the capacitance value of the capacitor, the frequency response characteristic of the feedback loop can meet the stability requirements and avoid the situation of insufficient phase margin or insufficient gain margin.

[0057] The switching power supply controller further includes a power supply module 60, and the power supply module 60 is connected to the object under test and each module of the switching power supply controller. The power supply module 60 receives the current of the object under test and converts it into a startup voltage to provide the electrical energy required for the operation of each module of the switching power supply controller. At the same time, the power supply module 60 has an under-voltage protection function to ensure that power is supplied to each module only when the startup voltage exceeds a preset startup voltage threshold, avoiding abnormal operation of the module due to insufficient voltage.

[0058] Specifically, the power supply module 60 converts the current of the object under test through an internal circuit structure and outputs a stable startup voltage. For example, circuits such as rectification, filtering, and voltage regulation are used to convert alternating current or pulsating current into a stable direct-current startup voltage. At the same time, a voltage detection circuit is provided inside the power supply module 60 to monitor the magnitude of the startup voltage in real time. When the startup voltage is lower than the preset startup voltage threshold, the power supply module 60 will cut off the power supply to each module to prevent the module from operating at a low voltage and protecting the module from damage. Only when the startup voltage exceeds the threshold can the power supply be restored.

[0059] It can be understood that the power supply module 60 provides electrical energy for all modules of the switching power supply controller and is the basis for the normal operation of each module. Its stable power supply ensures that modules such as the error amplifier 21, comparator 22, timer 23, signal generator 24, trigger module 40, and drive module 50 can operate normally, thereby realizing the control function of the switching power supply.

[0060] It should be noted that the switching power supply controller further includes a temperature protection module 70; the temperature protection module 70 is connected to the trigger module 40. The temperature protection module 70 is mainly used to monitor the overall operating temperature of the switching power supply controller to prevent the performance of the module from degrading or even being damaged due to excessive temperature. When the operating temperature exceeds the preset operating temperature threshold, the temperature protection module 70 outputs a temperature cut-off signal to the trigger module 40, and the trigger module 40 stops generating the trigger signal, thereby stopping the operation of the switching transistor and protecting the switching power supply controller.

[0061] Specifically, the temperature protection module 70 is internally provided with a temperature sensor that can sense the operating temperature of the switching power supply controller in real time. The temperature sensor can adopt components such as a thermistor or a thermocouple to convert the temperature signal into an electrical signal. The temperature protection module 70 compares the detected temperature signal with the preset operating temperature threshold. When the temperature exceeds the threshold, the comparison circuit inside the module will be triggered and output a temperature cut-off signal.

[0062] It can be understood that the temperature cut-off signal output by the temperature protection module 70 is directly transmitted to the trigger module 40. After receiving this signal, the trigger module 40 immediately stops generating the trigger signal, causing the drive module 50 to stop outputting the drive voltage, turning off the switching transistor, and thus stopping the operation of the switching power supply to avoid further damage caused by excessive temperature.

[0063] It should be noted that the switching power supply controller further includes: an overcurrent protection module 80 and a blanking module 90; the overcurrent protection module 80 is respectively connected to the blanking module 90 and the trigger module 40; the blanking module 90 is also connected to the controlled object.

[0064] It should be noted that the overcurrent protection module 80 is used to monitor the operating current of the controlled object to prevent the switching power supply or the load from being damaged due to excessive current. When the operating current exceeds the preset operating current threshold, the overcurrent protection module 80 outputs an overcurrent cut-off signal to the trigger module 40, and the trigger module 40 stops generating the trigger signal to protect the switching power supply and the load.

[0065] It should be noted that the blanking module 90 is mainly used to shield the operating current when the controlled object starts up to avoid mis-triggering of the overcurrent protection module 80. When the switching power supply starts up, the controlled object may have a relatively large starting current, which is a normal phenomenon. However, if it is not shielded, the overcurrent protection module 80 may misjudge it as overcurrent and trigger the protection action.

[0066] Specifically, the overcurrent protection module 80 receives the working current signal of the controlled object through the blanking module 90. When the controlled object starts, the blanking module 90 masks the start-up current signal to prevent the overcurrent protection module 80 from malfunctioning. After the start-up process ends, the blanking module 90 resumes normal operation and transmits the actual working current signal to the overcurrent protection module 80. The overcurrent protection module 80 compares the received working current signal with a preset working current threshold. When the working current exceeds the threshold, the module outputs an overcurrent cut-off signal to the trigger module 40. After receiving the overcurrent cut-off signal, the trigger module 40 stops generating the trigger signal, turns off the switching transistor, thereby limiting the current and protecting the switching power supply and the load.

[0067] It should be noted that the trigger module 40 includes: an RS flip-flop 41 and a logic control sub-module 42; the reset terminal and the set terminal of the RS flip-flop 41 are respectively connected to the output terminals of the pulse modulation module 30 and the comparator 22; the output terminal of the RS flip-flop 41 is connected to the logic control sub-module 42; the logic control sub-module 42 is further connected to the overcurrent protection module 80, the temperature protection module 70 and the drive module 50.

[0068] It can be understood that the RS flip-flop 41 generates an initial trigger signal based on the reset signal and the set signal and outputs it to the logic control sub-module 42; the logic control sub-module 42 generates a trigger signal based on the initial trigger signal, the temperature cut-off signal and the overcurrent cut-off signal and transmits it to the drive module 50.

[0069] It can be understood that when the reset signal is valid (usually high level), regardless of the state of the set signal, the RS flip-flop 41 will set the output terminal to low level, generating an initial trigger signal of low level. This indicates that the switching transistor needs to be turned off immediately, usually used in emergency situations such as when the output voltage rises abnormally and reaches the resonance point of the quasi-resonant mode. When the reset signal is invalid (usually low level) and the set signal is valid (usually high level), the RS flip-flop 41 will set the output terminal to high level, generating an initial trigger signal of high level. This indicates that the switching transistor can be turned on, and the conduction time of the switching transistor can be adjusted according to information such as the duty cycle of the set signal, thereby controlling the output of the switching power supply. When both the reset signal and the set signal are invalid, the RS flip-flop 41 will maintain the previous output state, that is, keep the initial trigger signal unchanged.

[0070] It can be understood that the logic control sub-module 42 will perform logical judgments on the initial trigger signal, overcurrent cut-off signal, and temperature cut-off signal. When the overcurrent cut-off signal or the temperature cut-off signal is valid (usually high level), regardless of the state of the initial trigger signal, the logic control sub-module 42 will set the output terminal to low level, generate a trigger signal with low level, and cause the drive module 50 to stop outputting the drive voltage and turn off the switching tube to protect the switching power supply and the load. When both the overcurrent cut-off signal and the temperature cut-off signal are invalid (usually low level), the logic control sub-module 42 will generate a corresponding trigger signal according to the state of the initial trigger signal. If the initial trigger signal is high level, a high-level trigger signal will be generated to cause the drive module 50 to output the drive voltage and turn on the switching tube; if the initial trigger signal is low level, a low-level trigger signal will be generated to turn off the switching tube.

[0071] It should be noted that after integrating all the above functions into the chip, the specific circuit design only needs to be able to implement the above functions. Therefore, the chip of the switching power supply controller has 6 ports. The port where the feedback detection module 10 is connected to the object to be measured is the FB port; the port where the power supply module 60 is connected to the object to be measured is the VDD port; the port where the drive module 50 is connected to the controlled object is the GATE port; the port where the blanking module 90 is connected is the CS port; the port where the error amplifier 21 is connected to the capacitor is the CMP port; finally, the chip is also integrated with a grounded GND port.

[0072] In this embodiment, the switching power supply controller works in cooperation with the feedback detection module, comparison module, pulse modulation module, trigger module, and drive module to achieve precise control based on the feedback voltage and generate trigger signals, without the need for complex combination schemes; each module is optimized in design, such as the cooperation of the error amplifier, comparator, timer, and signal generator in the comparison module to achieve dynamic adjustment of the duty cycle of the set signal; at the same time, the power supply module, temperature protection module, overcurrent protection module, and blanking module are integrated to provide stable power supply, multiple protection, and false trigger shielding functions; the trigger module uses an RS flip-flop and a logic control sub-module to ensure accurate generation and transmission of trigger signals. Overall, it achieves the beneficial effects of circuit simplification, cost reduction, precise control, improved stability, and perfect protection functions.

[0073] In addition, for the purpose of optimizing the rectifier circuit structure, based on Embodiment 1, this application proposes Embodiment 2 to introduce a flyback rectifier circuit. The same content as in Embodiment 1 will not be elaborated here. Please refer to Figure 3 , Figure 3 which is the structural block diagram provided for Embodiment 2 of the flyback rectifier circuit of this application.

[0074] In this embodiment, the flyback rectifier circuit includes: a switching power supply control module, a rectification module, and a flyback conversion module. Among them, the switching power supply control module includes the switching power supply controller as described above; the rectification module is respectively connected to an AC power supply, the switching power supply control module, and the flyback conversion module; the switching power supply control module is also connected to the flyback conversion module.

[0075] It should be noted that the rectification module is used to rectify alternating current into high-voltage direct current and transmit it to the flyback conversion module. The flyback conversion module performs flyback conversion on the high-voltage direct current based on the trigger signal of the switching power supply control module and outputs a direct current voltage.

[0076] Based on this, this embodiment provides a specific implementation manner of the flyback rectifier circuit. Please refer to Figure 4 , Figure 4 which is the connection diagram of the flyback rectifier circuit provided in the second embodiment of this application.

[0077] In this embodiment, the flyback conversion module includes an RCD clamp sub-module, a transformer, and an MOS transistor Q1. The transformer includes a primary winding, an auxiliary winding, and a secondary winding. In the flyback rectifier circuit, when the auxiliary winding and the primary winding are on the same side, the auxiliary winding has a tight electromagnetic coupling relationship with the primary winding, which is mainly used to provide a feedback signal or a working power supply for the switching power supply control module, and at the same time assist in realizing the winding of certain protection functions of the circuit.

[0078] It can be understood that the voltage signal output by the auxiliary winding can reflect the change of the output voltage. The switching power supply control module detects the voltage of the auxiliary winding and compares it with the internal reference voltage, thereby adjusting the on and off time of the MOS transistor Q1 to achieve stable control of the output voltage.

[0079] It can be understood that the first end of the primary winding is connected to the rectification module to receive the high-voltage direct current output by the rectification module. The second end of the primary winding is connected to the drain of the MOS transistor Q1. The MOS transistor Q1 is used as a switching element, and the on and off of it controls the on and off of the current in the primary winding.

[0080] It can be understood that the RCD clamp sub-module is composed of a fifth resistor R5, a second diode D2, and a third capacitor C3. The first end of the fifth resistor R5 is respectively connected to the rectification module, the first end of the third capacitor C3, and the first end of the primary winding, which plays a role in current limiting and connecting the circuit. The second end of the fifth resistor R5 is respectively connected to the second end of the third capacitor C3 and the cathode of the second diode D2 to form a specific circuit structure to achieve the clamping function. The anode of the second diode D2 is connected to the second end of the primary winding. When the MOS transistor Q1 is turned off, it provides a discharge path for the voltage spike generated by the leakage inductance of the transformer.

[0081] It can be understood that the source electrode of the MOS transistor Q1 is grounded through a resistor, and this resistor plays a role in stabilizing the circuit and limiting the current. The gate electrode of the MOS transistor Q1 is connected to the switching power supply control module, and the switching power supply control module controls the on and off of the MOS transistor Q1 by controlling the gate voltage.

[0082] It can be understood that the first end of the auxiliary winding is connected to the switching power supply control module to provide a feedback signal or operating power supply for the switching power supply control module. The second end of the auxiliary winding is grounded to form a complete circuit loop.

[0083] It can be understood that the first end of the secondary winding is connected to the anode of the third diode D3, and the cathode of the third diode D3 is respectively connected to the first end of the fourth capacitor C4 and the load; this connection method enables the third diode D3 to conduct or cut off according to the current direction when there is an alternating current passing through the secondary winding, thereby playing a rectifying role. When the third diode D3 conducts, the current can flow to the fourth capacitor C4 and the load to provide electrical energy for the load, and at the same time, the fourth capacitor C4 can filter the current to make the voltage output to the load more stable.

[0084] It can be understood that the second end of the secondary winding is connected to the second end of the fourth capacitor C4 and grounded to provide the rectified DC voltage to the load for use. This connection forms a complete circuit loop. The fourth capacitor C4 plays a role in filtering and energy storage in this loop to further stabilize the output voltage, and grounding provides a stable reference potential for the circuit.

[0085] It can be understood that the main function of the RCD clamp sub-module is to absorb the voltage spike generated by the leakage inductance of the transformer when the MOS transistor Q1 is turned off. At the moment when the MOS transistor Q1 is turned off, the leakage inductance of the transformer will generate a relatively high induced voltage, and this voltage spike may cause breakdown damage to the MOS transistor Q1. The RCD clamp sub-module absorbs and stores the energy of the voltage spike in the capacitor through its specific circuit structure, thereby protecting the MOS transistor Q1 from being broken down and ensuring the safe and stable operation of the circuit.

[0086] In this embodiment, the rectification module includes a rectifier bridge and a π-type filter. The rectifier bridge refers to a bridge rectifier circuit composed of four diodes, which is directly connected to the AC power supply and the π-type filter to convert the alternating current into direct current and filter it.

[0087] It should be noted that the π-type filter includes: a first inductor L1, a seventh resistor R7, a sixth capacitor C6, and a seventh capacitor C7. Among them, the first inductor L1 and the seventh resistor R7 are connected in parallel. An inductor has the characteristics of passing direct current and blocking alternating current, especially the blocking effect on high-frequency alternating current signals is more obvious. The pulsating direct current output by the rectifier circuit contains many high-frequency noise components. When the current containing high-frequency noise passes through the first inductor L1, the inductor will generate a self-induced electromotive force to block the change of the current, thereby effectively suppressing the propagation of high-frequency noise and making the output current smoother.

[0088] It should be noted that an inductor can store energy when the current increases and release energy when the current decreases. In the rectifier circuit, when the rectified pulsating direct current is relatively large, the inductor L1 stores energy; when the current decreases, the inductor L1 releases energy, thereby playing a role in smoothing the current and reducing the pulsation amplitude of the current. After being connected in parallel with the resistor R7, the inductor L1 can focus on its high-frequency filtering and current smoothing functions, while the resistor R7 can play a role in other aspects, and the two cooperate with each other to improve the filtering effect.

[0089] It can be understood that the first ends of the parallel connection are respectively connected to the rectifier bridge, the first end of the sixth capacitor C6, and the switching power supply control module. This connection method enables the direct current output by the rectifier bridge to be transmitted to the inductor, capacitor, and switching power supply control module simultaneously, providing a basis for subsequent filtering and circuit control.

[0090] It can be understood that the second ends of the parallel connection are respectively connected to the first end of the seventh capacitor C7 and the first end of the primary winding in the flyback conversion module, transmitting the filtered direct current to the flyback conversion module to provide a stable input voltage for the flyback conversion.

[0091] In this embodiment, the switching power supply control module further includes: a first resistor R1, a first capacitor C1, a first diode D1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a second capacitor C2.

[0092] Among them, the first end of the first resistor R1 is connected to the rectifier module, that is, the first end of the parallel connection mentioned above, to receive the direct current voltage output by the rectifier module. The second end of the first resistor R1 is respectively connected to the cathode of the first diode D1, the first end of the first capacitor C1, and the power supply module of the switching power supply controller, that is, the VDD terminal of the switching power supply controller chip, to provide a working power supply for the switching power supply controller; the second end of the first capacitor C1 is grounded, playing a role in filtering and energy storage to provide a stable power supply voltage for the switching power supply controller.

[0093] Among them, the anode of the first diode D1 is respectively connected to the first end of the auxiliary winding of the transformer and the first end of the second resistor, and is used for rectifying the voltage output by the auxiliary winding. The cathode of the first diode D1 is connected to the second end of the first resistor R1, and the rectified voltage is transmitted to the switching power supply controller.

[0094] Among them, the second end of the second resistor R2 is respectively connected to the feedback detection module of the switching power supply controller, that is, the FB end of the switching power supply controller chip and the first end of the third resistor R3; the second end of the third resistor R3 is grounded, and together with the second resistor R2, it forms a voltage dividing circuit, which is used for dividing the feedback voltage output by the auxiliary winding to provide a suitable feedback voltage for the feedback detection module of the switching power supply controller, so that the switching power supply controller can adjust the output according to the feedback signal.

[0095] Among them, the driving module of the switching power supply controller, that is, the GATE end of the switching power supply controller chip, is connected to the gate of the MOS transistor Q1. The blanking module of the switching power supply controller, that is, the CS end of the switching power supply controller chip, is connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is connected to the source of the MOS transistor Q1.

[0096] Among them, the output end of the error amplifier of the switching power supply controller, that is, the CMP end of the switching power supply controller chip, is grounded through the second capacitor. The second capacitor C2 is used for filtering and stabilizing the output signal of the error amplifier, and improving the stability of the controller.

[0097] Based on the above content, this embodiment gives the working process of the flyback rectifier circuit: In the startup stage, the alternating current is converted into high-voltage direct current through the rectification module (bridge rectification + π-type filter), and charges the VDD end of the switching power supply controller through the first resistor R1. When the VDD voltage rises to 17.5V (the power module startup threshold), the controller starts, and the capacitor at the CMP end of the switching power supply controller is quickly charged, and enters the closed-loop control preparation. The controller works in an open-loop mode in the initial stage of startup, and the per-cycle current limiting protection takes effect. When the auxiliary winding feedback voltage (the voltage at the FB end) reaches 2.4V, it switches to closed-loop control, and the error amplifier starts to dynamically adjust the output.

[0098] In the rectification and flyback conversion stage, the AC input is converted into pulsating DC by a rectifier bridge, and then filtered by a π-type filter, and a stable high-voltage DC is output to the primary winding of the transformer. The GATE terminal of the switching power supply controller outputs a PWM signal to drive the MOS transistor Q1: when the MOS transistor Q1 is turned on, the primary winding stores energy, and the secondary winding has no output because the third diode D3 is reverse-biased. When the MOS transistor Q1 is turned off, the energy of the transformer is released through the secondary winding, the third diode D3 is forward-conducted, and power is supplied to the load, and a stable DC voltage is output after filtering by C4.

[0099] In the feedback and dynamic regulation stage, the voltage of the auxiliary winding is divided by the second resistor R2 and the third resistor R3 and then input to the FB terminal. At the end of the turn-off of the MOS transistor Q1 (when the current passes through the zero point), the voltage of the auxiliary winding reflects the secondary output voltage: V_FB = (Vout + Vdf) * NS / NA. Among them, Vdf is the conduction voltage drop of the third diode D3. By comparing with the internal 2.5V reference voltage, the error amplifier outputs an error signal to the CMP terminal. The second capacitor C2 is externally connected to the CMP terminal to set the loop bandwidth to be less than 20Hz to suppress the power frequency ripple. The controller compares the CMP voltage with the internal sawtooth wave, dynamically adjusts the conduction time, and realizes constant voltage control.

[0100] Finally, it is realized that when the load increases, the output voltage Vout decreases, the feedback voltage V_FB decreases, the CMP voltage increases, the conduction time increases, the energy transfer increases, and the output voltage Vout rises. When the load decreases, the output voltage Vout rises, the feedback voltage V_FB rises, the voltage at the CMP terminal decreases, the conduction time decreases, the energy transfer decreases, and the output voltage Vout decreases.

[0101] For the quasi-resonant mode, after the MOS transistor Q1 is turned off, the leakage inductance of the transformer resonates with the parasitic capacitance, and the voltage at the FB terminal drops with the resonant valley. When the voltage at the FB terminal is lower than the 0V threshold, the controller triggers the next switching cycle to achieve zero-voltage switching and reduce the switching loss. For frequency control, the highest frequency is clamped at 100kHz to prevent magnetic saturation; the lowest frequency is limited to 500Hz to avoid audio noise; the maximum turn-off time is 77 microseconds to ensure complete energy release.

[0102] For the protection mechanism, the CS terminal detects the source current of the MOS transistor Q1 through the fourth resistor R4, and shields the current spike through front-edge blanking (300ns) during the normal conduction period. When the current exceeds the threshold, the output of the GATE terminal is immediately turned off, and cycle-by-cycle current limiting is entered. For over-temperature protection, when the junction temperature is greater than 150°C, the drive output is stopped, and it automatically resumes after the temperature drops to the hysteresis threshold. For over-voltage or under-voltage protection of the VDD terminal, when the voltage at the VDD terminal is greater than 32V, over-voltage locking is triggered; when the voltage at the VDD terminal is less than 6.5V, under-voltage protection is entered and the operation stops until the voltage recovers. For short-circuit protection, when the voltage at the FB terminal is continuously less than 0.4V, it is determined that the output is short-circuited, and the drive signal is turned off.

[0103] During steady-state operation, the voltage on the CMP terminal changes slowly because a large external capacitor is connected to the CMP terminal, so the on-time is constant. In a flyback topology, the constant turn-on time and quasi-resonant operation can provide a high power factor and low total harmonic distortion. By fixing the on-time, which is determined by the intersection of the CMP voltage and the sawtooth wave, the input current waveform follows the input voltage, achieving a power factor greater than 0.9 and a total harmonic distortion less than 10%.

[0104] In this embodiment, a single-stage output low-cost control system that can complete control through the primary side. With a unique and highly accurate CV system design scheme, no secondary-side feedback components, optocouplers, and TL431 are required, and a high power factor can be achieved under a constant real-time control scheme.

[0105] The above are only some embodiments of the present application, and thus do not limit the patent scope of the present application. Any equivalent structural transformation made under the technical concept of the present application by using the content of the specification and drawings of the present application, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A switching power supply controller, characterized in that, The switching power supply controller includes: a feedback detection module, a comparison module, a pulse modulation module, a trigger module, and a drive module; The feedback detection module is respectively connected to the pulse modulation module, the comparison module, and the object to be measured; the trigger module is respectively connected to the pulse modulation module, the comparison module, and the drive module; the drive module is further connected to the controlled object; The feedback detection module is configured to collect the feedback voltage of the object to be measured and transmit the feedback voltage to the pulse modulation module and the comparison module through the quasi-resonant mode; The pulse modulation module is configured to convert the feedback voltage into a reset signal and transmit it to the trigger module; The comparison module compares the feedback voltage with a reference voltage and generates a set signal based on the comparison result and transmits it to the trigger module; The trigger module generates a trigger signal based on the reset signal and the set signal and transmits it to the drive module; The drive module is configured to output a drive voltage to the controlled object after receiving the trigger signal.

2. The switching power supply controller according to claim 1, wherein The comparison module includes: an error amplifier, a comparator, a timer, and a signal generator; The positive input terminal and the negative input terminal of the error amplifier are respectively connected to a reference voltage source and the feedback detection module; The positive input terminal and the negative input terminal of the comparator are respectively connected to the signal generator and the output terminal of the error amplifier; The output terminal of the comparator is connected to the trigger module; the timer is coupled to the signal generator; The timer is configured to control the signal generator to generate a periodic ramp signal; The error amplifier generates an error voltage by comparing the feedback voltage with the reference voltage; The comparator generates a set signal by comparing the error voltage with the periodic ramp signal and transmits it to the trigger module, and the duty cycle of the set signal is dynamically adjusted by the intersection point of the error voltage and the ramp signal.

3. The switching power supply controller according to claim 2, wherein, The output terminal of the error amplifier is grounded through a capacitor to achieve loop compensation.

4. The switching power supply controller according to claim 1, wherein The switching power supply controller further includes: a power supply module; The power supply module is connected to the object to be measured and each module of the switching power supply controller; The power supply module receives the current of the object to be measured and converts it into a startup voltage, and supplies power to each module of the switching power supply controller when the startup voltage exceeds a preset startup voltage threshold.

5. The switching power supply controller according to claim 4, wherein The switching power supply controller further includes: a temperature protection module; The temperature protection module is connected to the trigger module; The temperature protection module is further configured to detect the overall operating temperature of the switching power supply controller, and when the operating temperature exceeds a preset operating temperature threshold, output a temperature cut-off signal to the trigger module; The trigger module stops generating the trigger signal when receiving the temperature cut-off signal.

6. The switching power supply controller according to claim 5, characterized in that, The switching power supply controller further includes: an overcurrent protection module and a blanking module; The overcurrent protection module is respectively connected to the blanking module and the trigger module; The blanking module is further connected to the controlled object; The overcurrent protection module receives the operating current of the controlled object through the blanking module; The overcurrent protection module is further configured to output an overcurrent cut-off signal to the trigger module when the operating current exceeds a preset operating current threshold; The trigger module stops generating a trigger signal when receiving the overcurrent cut-off signal; The blanking module is configured to shield the operating current when the controlled object starts, to prevent the overcurrent protection module from being wrongly triggered.

7. The switching power supply controller according to claim 6, characterized in that, The trigger module includes: an RS flip-flop and a logic control sub-module; The reset terminal and the set terminal of the RS flip-flop are respectively connected to the pulse modulation module and the comparison module; The output terminal of the RS flip-flop is connected to the logic control sub-module; The logic control sub-module is further connected to the overcurrent protection module, the temperature protection module and the drive module; The RS flip-flop generates an initial trigger signal based on the reset signal and the set signal and outputs it to the logic control sub-module; The logic control sub-module generates a trigger signal based on the initial trigger signal, the temperature cut-off signal and the overcurrent cut-off signal and transmits it to the drive module.

8. A flyback rectifier circuit, characterized in that, The flyback rectifier circuit includes: a switch power control module, a rectification module and a flyback conversion module; The switch power control module includes the switch power controller according to any one of claims 1 to 7; The rectification module is respectively connected to an AC power supply, the switch power control module and the flyback conversion module; The switch power control module is further connected to the flyback conversion module; The rectification module is configured to rectify the alternating current into high-voltage direct current and transmit it to the flyback conversion module; The flyback conversion module performs flyback conversion on the high-voltage direct current based on the trigger signal of the switch power control module and outputs a direct current voltage.

9. The flyback rectifier circuit according to claim 8, characterized in that, The flyback conversion module includes an RCD clamp sub-module, a transformer and a MOS tube; The transformer includes a primary winding, an auxiliary winding and a secondary winding; The first end of the primary winding of the transformer is connected to the rectification module, and the second end of the primary winding of the transformer is connected to the drain of the MOS tube; The RCD clamp sub-module is respectively connected to the first end and the second end of the primary winding; The source of the MOS tube is grounded through a resistor; The gate of the MOS tube is connected to the switch power control module; The first end of the auxiliary winding of the transformer is connected to the switch power control module, and the second end of the auxiliary winding is grounded; the secondary winding of the transformer is connected to a load; The RCD clamp sub-module is configured to absorb the voltage spike generated by the leakage inductance of the transformer when the MOS tube is turned off to protect the MOS tube from being broken down.

10. The flyback rectifier circuit according to claim 9, wherein, The switch power control module further includes: a first resistor, a first capacitor, a first diode, a second resistor, a third resistor, a fourth resistor and a second capacitor; The first end of the first resistor is connected to the rectification module, and the second end of the first resistor is respectively connected to the cathode of the first diode, the first end of the first capacitor and the power supply module of the switch power controller; the second end of the first capacitor is grounded; The anode of the first diode is respectively connected to the first end of the auxiliary winding of the transformer and the first end of the second resistor; The second terminal of the second resistor is respectively connected to the feedback detection module of the switching power supply controller and the first terminal of the third resistor; the second terminal of the third resistor is grounded; The driving module of the switching power supply controller is connected to the gate of the MOS transistor; The blanking module of the switching power supply controller is connected to the first terminal of the fourth resistor; The second terminal of the fourth resistor is connected to the source of the MOS transistor; The output terminal of the error amplifier of the switching power supply controller is grounded through the second capacitor.

Images