Flyback converter modulation chip and device

Abstract

This invention discloses a flyback converter modulation chip and device. The chip uses a state detection module to acquire the output voltage fed back from the auxiliary winding on the primary side of the flyback converter and detects the current operating state of the flyback converter based on the output voltage. When the operating state is constant voltage, the mode selection module outputs a pulse width modulation (PWM) signal to the drive module, causing the drive module to adjust the flyback converter's operating mode to PWM. When the operating state is constant current, the mode selection module outputs a pulse frequency modulation (PWM) signal to the drive module, causing the drive module to adjust the flyback converter's operating mode to PWM. This invention, by adjusting the flyback converter to PWM mode in constant voltage mode and PWM mode in constant current mode, avoids a single operating mode and effectively improves the operating efficiency of the flyback converter.

Description

Technical Field

[0001] This invention relates to the field of power management chip technology, and in particular to a flyback converter modulation chip and device. Background Technology

[0002] Power management chips are widely used in modern electronic products. They are not only used in power supply circuits, but also in other circuit applications, such as backlight circuits for LCD displays and fluorescent lamps. Compared with linear power supplies, switching power supplies have advantages such as high efficiency, good stability, and small size.

[0003] Existing flyback switching power supply chips use a single pulse width modulation (PWM) operating mode for output. Due to the single operating mode, it can only achieve one of the two operating modes: constant output voltage or constant output current. It cannot meet the requirements of constant current and constant voltage modes that are adapted to the battery in stages, resulting in low efficiency of the flyback converter.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a flyback converter modulation chip and device, which aims to solve the technical problem that existing flyback switching power supply chips use a single PWM working mode, which can only achieve one of the two working modes of constant output voltage or constant output current, and cannot meet the adaptive constant current and constant voltage modes of battery phased operation, resulting in low working efficiency of flyback converters.

[0006] To achieve the above objectives, the present invention provides a flyback converter modulation chip, which is applied to a flyback converter and includes: a state detection module, a mode selection module, and a driving module.

[0007] The mode selection module is connected to the state detection module and the drive module respectively, and the state detection module and the drive module are both connected to the flyback converter;

[0008] The state detection module is used to collect the output voltage fed back by the flyback converter on the auxiliary winding of the primary side, and detect the current working state of the flyback converter based on the output voltage.

[0009] The mode selection module is also used to output a pulse width modulation signal to the drive module when the working state is constant voltage state, so that the drive module adjusts the working mode of the flyback converter to pulse width modulation mode.

[0010] The mode selection module is further configured to output a pulse frequency modulation signal to the drive module when the operating state is constant current state, so that the drive module adjusts the operating mode of the flyback converter to pulse frequency modulation mode.

[0011] Optionally, the output voltage includes a first output voltage and a second output voltage, and the state detection module includes: a constant voltage detection unit, a constant current detection unit, and a state detection unit;

[0012] The constant voltage detection unit is connected to the flyback converter and the state detection unit respectively, and the constant current detection unit is connected to the flyback converter and the state detection unit respectively.

[0013] The constant voltage detection unit is used to collect the first output voltage of the excitation converter on the auxiliary winding feedback on the primary side, and output the first output voltage to the state detection unit.

[0014] The constant current detection unit is used to collect the second output voltage fed back from the auxiliary winding on the primary side of the excitation converter, and output the second output voltage to the state detection unit.

[0015] The state detection unit is used to determine the current operating state of the flyback converter based on the first output voltage and the second output voltage.

[0016] Optionally, the state detection unit is used to determine that the working state is a constant voltage state when the first output voltage reaches a preset reference voltage;

[0017] The state detection unit is further configured to determine that the working state is a constant voltage state when the first output voltage does not reach the preset reference voltage and the second output voltage does not reach the preset reference voltage.

[0018] The state detection unit is further configured to determine that the working state is a constant current state when the first output voltage does not reach the preset reference voltage and the second output voltage reaches the preset reference voltage.

[0019] Optionally, the chip further includes: a current detection module;

[0020] The current detection module is connected to the mode selection module and the flyback converter, respectively.

[0021] The current detection module is used to collect the operating current flowing through the primary side of the flyback converter and convert the operating current into a detection voltage;

[0022] The current detection module is also used to output a drive enable signal to the mode selection module when the detected voltage is lower than the preset reference voltage;

[0023] The mode selection module is used to output the pulse width modulation signal or the pulse frequency modulation signal according to the working state when the drive enable signal is received.

[0024] Optionally, the current detection module is further configured to stop outputting the drive enable signal to the mode selection module when the detected voltage reaches the preset reference voltage, so that the mode selection module stops outputting the pulse width modulation signal and the pulse frequency modulation signal.

[0025] Optionally, the chip further includes: a power supply module and a bandgap reference module;

[0026] The bandgap reference module is connected to the power supply module, the state detection unit, and the current detection module, respectively. The power supply module is connected to the flyback converter and the drive module, respectively.

[0027] The power module is used to acquire the power supply voltage output from the primary side of the flyback converter and output the power supply voltage to the bandgap reference module.

[0028] The bandgap reference module is used to output the preset reference voltage to the state detection unit and the current detection module respectively when the power supply voltage is received.

[0029] Optionally, the bandgap reference module includes: first to tenth MOS transistors, first to third transistors, a first resistor, and a second resistor;

[0030] The source of the first MOSFET, the source of the second MOSFET, and the source of the third MOSFET are all connected to the power module. The gate of the first MOSFET is connected to the gate of the second MOSFET, the gate of the third MOSFET, and the source of the fifth MOSFET. The drain of the first MOSFET is connected to the source of the fourth MOSFET.

[0031] The gate of the second MOS transistor is connected to the gate of the third MOS transistor, the drain of the second MOS transistor is connected to the source of the fifth MOS transistor, and the drain of the third MOS transistor is connected to the source of the sixth MOS transistor.

[0032] The gate of the fourth MOS transistor is connected to the gate of the fifth MOS transistor, the gate of the sixth MOS transistor, and the drain of the eighth MOS transistor, respectively. The drain of the fourth MOS transistor is connected to the drain of the seventh MOS transistor and the gate of the seventh MOS transistor, respectively.

[0033] The gate of the fifth MOS transistor is connected to the gate of the sixth MOS transistor, and the drain of the fifth MOS transistor is connected to the drain of the eighth MOS transistor.

[0034] The drain of the sixth MOS transistor is connected to the first end of the second resistor, the state detection unit, and the current detection module, respectively. The second end of the second resistor is connected to the emitter of the third transistor. The collector and base of the third transistor are both grounded.

[0035] The gate of the seventh MOS transistor is connected to the gate of the eighth MOS transistor, and the source of the seventh MOS transistor is connected to the drain of the ninth MOS transistor and the gate of the ninth MOS transistor, respectively.

[0036] The source of the eighth MOS transistor is connected to the drain of the tenth MOS transistor;

[0037] The gate of the ninth MOS transistor is connected to the gate of the tenth MOS transistor, the source of the ninth MOS transistor is connected to the emitter of the first transistor, and the collector and base of the first transistor are both grounded.

[0038] The source of the tenth MOS transistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the emitter of the second transistor, and the collector and base of the second transistor are both grounded.

[0039] Optionally, the power module is further configured to determine whether the power supply voltage meets preset non-ideal conditions;

[0040] The power module is also configured to output an enable signal to the drive module to stop working when the power supply voltage meets the preset non-ideal conditions, so as to make the drive module stop working.

[0041] Optionally, the mode selection module is further configured to output a valley modulation drive signal to the drive module when the flyback converter is under non-heavy load operating conditions, so that the drive module adjusts the operating mode of the flyback converter to valley modulation mode.

[0042] The mode selection module is also used to output a pulse width modulation signal to the drive module when the flyback converter is under heavy load operating conditions, so that the drive module adjusts the operating mode of the flyback converter to pulse width modulation mode.

[0043] In addition, to achieve the above objectives, the present invention also proposes a flyback converter modulation device, which includes the flyback converter modulation chip as described above.

[0044] This invention provides a flyback converter modulation chip and device. The chip acquires the output voltage fed back from the auxiliary winding on the primary side of the flyback converter through a state detection module, and detects the current operating state of the flyback converter based on the output voltage. When the operating state is constant voltage, the mode selection module outputs a pulse width modulation signal to the drive module, so that the drive module adjusts the operating mode of the flyback converter to pulse width modulation mode. When the operating state is constant current, the mode selection module outputs a pulse frequency modulation signal to the drive module, so that the drive module adjusts the operating mode of the flyback converter to pulse frequency modulation mode. This invention adjusts the flyback converter's operating mode to pulse width modulation (PWM) by outputting a pulse width modulation (PWM) signal when the flyback converter is in constant voltage mode, and to pulse frequency modulation (PWM) by outputting a pulse frequency modulation (PWM) signal when the flyback converter is in constant current mode. Compared to existing flyback switching power supply chips that use a single PWM mode, the flyback converter modulation chip of this invention avoids the single operating mode of the flyback converter, achieves compatibility between constant output voltage and constant output current, meets the adaptive constant current and constant voltage modes for battery phased operation, and effectively improves the operating efficiency of the flyback converter. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of the first embodiment of the flyback converter modulation chip of the present invention;

[0046] Figure 2 This is a schematic diagram of the structure of the second embodiment of the flyback converter modulation chip of the present invention;

[0047] Figure 3 This is a schematic diagram of mode selection in the second embodiment of the flyback converter modulation chip of the present invention;

[0048] Figure 4 This is a schematic diagram of the current detection module in the second embodiment of the flyback converter modulation chip of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure of the third embodiment of the flyback converter modulation chip of the present invention;

[0050] Figure 6 This is a circuit diagram of the bandgap reference module in the third embodiment of the flyback converter modulation chip of the present invention;

[0051] Figure 7 This is a schematic diagram of the flyback converter modulation chip in the third embodiment of the present invention;

[0052] Figure 8This is a circuit diagram of the flyback converter modulation chip applied to the flyback converter in the third embodiment of the present invention.

[0053] Explanation of icon numbers:

[0054]

[0055]

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0058] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0059] It should be noted that the descriptions involving "first," "second," etc., in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0060] Reference Figure 1 1 is a schematic diagram of the structure of the first embodiment of the flyback converter modulation chip of the present invention.

[0061] like Figure 1 As shown, the flyback converter modulation chip in this embodiment is applied to the flyback converter. The chip includes: a state detection module 100, a mode selection module 200, and a drive module 300.

[0062] The mode selection module 200 is connected to the state detection module 100 and the drive module 300 respectively, and both the state detection module 100 and the drive module 300 are connected to the flyback converter 400.

[0063] The state detection module 100 is used to collect the output voltage fed back by the auxiliary winding on the primary side of the flyback converter 400, and detect the current working state of the flyback converter 400 based on the output voltage.

[0064] It should be noted that the above output voltage is the feedback voltage formed on the primary side by the voltage output from the secondary side of the flyback converter 400. When the flyback converter 400 is in different operating states, the feedback output voltage will also change accordingly. Therefore, the current operating state of the flyback converter 400 can be determined by detecting the magnitude of this output voltage.

[0065] It is understandable that the above-mentioned operating states can be the states in which the flyback converter 400 is used in applications. For example, when the flyback converter 400 is used for LED driving, it is in a constant current state, driving the LED by outputting a constant current. When the flyback converter 400 is used for power supply, it is in a constant voltage state, supplying power to the load by outputting a constant voltage.

[0066] In a specific implementation, the flyback converter 400 has an auxiliary winding on the primary side, and the state detection module 100 can be connected to the auxiliary winding. This allows the state detection module 100 to collect the voltage output on the secondary side of the flyback converter 400 through the auxiliary winding. Based on the magnitude of the collected output voltage, the current operating state of the flyback converter 400 in the application can be determined. Since the voltage output on the secondary side is monitored through the auxiliary winding on the primary side, the state detection module 100 adopts a primary-side feedback mode. There is no need for an isolation optocoupler or digital isolator. Current feedback is achieved by multiplexing the power supply winding, which reduces the number of external current devices and thus increases the circuit power density.

[0067] It should be understood that the auxiliary winding of the primary side of the flyback converter 400 can reflect the voltage output of the secondary side of the flyback converter 400. Therefore, the operating status can be determined by collecting the voltage on the auxiliary winding.

[0068] The mode selection module 200 is further configured to output a pulse width modulation signal to the drive module 300 when the operating state is constant voltage state, so that the drive module 300 adjusts the operating mode of the flyback converter 400 to pulse width modulation mode.

[0069] It should be noted that the above constant voltage state refers to the state in which the flyback converter 400 outputs a constant voltage when it is used in power supply.

[0070] Understandably, the aforementioned pulse width modulation signal can be a signal that modulates the bias of the gate of the MOS transistor on the primary side of the flyback converter 400 according to the change of load. The conduction time of the MOS transistor can be changed through pulse width modulation, thereby changing the output of the flyback converter 400.

[0071] It should be noted that the above pulse width modulation mode can be a working mode driven by the above pulse width modulation signal.

[0072] In a specific implementation, the aforementioned state detection module 100 can select a pulse width modulation signal for output when it detects that the flyback converter 400 is in a constant voltage output state. The pulse width modulation signal is then output to the drive module 400. When the drive module 400 receives the pulse width modulation signal, it can control the conduction and cutoff of the MOS transistor on the primary side of the flyback converter 400 through the pulse width modulation signal, thereby adjusting the working mode of the flyback converter 400 to the pulse width modulation mode.

[0073] The mode selection module 200 is further configured to output a pulse frequency modulation signal to the drive module 300 when the working state is constant current state, so that the drive module 300 adjusts the working mode of the flyback converter 400 to pulse frequency modulation mode.

[0074] It should be noted that the constant current state described above is the state in which the flyback converter 400 outputs a constant current when applied to LED driving.

[0075] It is understandable that the above pulse frequency modulation signal can be a signal whose frequency changes with the amplitude of the above output voltage, while the duty cycle remains constant. That is, the higher the output voltage, the higher the frequency of the pulse frequency modulation signal.

[0076] It should be noted that the above pulse frequency modulation mode can be a working mode driven by the above pulse frequency modulation signal.

[0077] In a specific implementation, the aforementioned state detection module 100 can select a pulse frequency modulation signal for output when it detects that the flyback converter 400 is in a constant current output state. The pulse frequency modulation signal is then output to the drive module 400. When the drive module 400 receives the pulse frequency modulation signal, it can control the conduction and disconnection of the MOS transistor on the primary side of the flyback converter 400 through the pulse frequency modulation signal, thereby adjusting the working mode of the flyback converter 400 to the pulse frequency modulation mode.

[0078] It should be understood that the aforementioned pulse width modulation signal and pulse frequency modulation signal can be generated by the oscillator inside the flyback converter modulation chip based on the aforementioned output voltage. When the flyback converter 400 is in a constant voltage state, the pulse width modulation signal is selected for output, and when the flyback converter 400 is in a constant current state, the pulse frequency modulation signal is selected for output, thereby avoiding a single working mode.

[0079] In this embodiment, the flyback converter modulation chip acquires the output voltage fed back from the auxiliary winding on the primary side of the flyback converter through the state detection module, and detects the current operating state of the flyback converter based on the output voltage. When the operating state is constant voltage, the mode selection module outputs a pulse width modulation signal to the drive module so that the drive module adjusts the operating mode of the flyback converter to pulse width modulation mode. When the operating state is constant current, the mode selection module outputs a pulse frequency modulation signal to the drive module so that the drive module adjusts the operating mode of the flyback converter to pulse frequency modulation mode. This embodiment outputs a pulse width modulation (PWM) signal when the flyback converter is in a constant voltage state to adjust its operating mode to PWM mode, and outputs a pulse frequency modulation (PWM) signal when the flyback converter is in a constant current state to adjust its operating mode to PWM mode. Compared with existing flyback switching power supply chips that use a single PWM mode, the above-mentioned flyback converter modulation chip in this embodiment avoids the single operating mode of the flyback converter, achieves compatibility between constant output voltage and constant output current, meets the adaptive constant current and constant voltage modes for battery stages, and effectively improves the operating efficiency of the flyback converter.

[0080] refer to Figure 2 , Figure 2 This is a schematic diagram of the second embodiment of the flyback converter modulation chip of the present invention.

[0081] Based on the first embodiment described above, in this embodiment, the output voltage includes a first output voltage and a second output voltage, and the state detection module 100 includes a constant voltage detection unit 101, a constant current detection unit 102, and a state detection unit 103.

[0082] The constant voltage detection unit 101 is connected to the flyback converter 400 and the state detection unit 103 respectively, and the constant current detection unit 102 is connected to the flyback converter 400 and the state detection unit 103 respectively.

[0083] The constant voltage detection unit 101 is used to collect the first output voltage of the primary auxiliary winding feedback of the excitation converter 400, and output the first output voltage to the state detection unit 103.

[0084] It should be noted that the aforementioned first output voltage can be used to determine whether the voltage output from the secondary side of the aforementioned excitation converter 400 conforms to the constant voltage state.

[0085] In a specific implementation, the constant voltage detection unit 101 can be connected to the auxiliary winding of the primary side of the flyback converter 400 to collect the first output voltage fed back on the auxiliary winding, and output the collected first output voltage to the state detection unit for subsequent working state judgment.

[0086] The constant current detection unit 102 is used to collect the second output voltage fed back from the auxiliary winding on the primary side of the excitation converter 400, and output the second output voltage to the state detection unit 103.

[0087] It should be noted that the second output voltage mentioned above can be used to determine whether the voltage output from the secondary side of the excitation converter 400 meets the constant current condition. The magnitude of the second output voltage is different from that of the first output voltage mentioned above.

[0088] In a specific implementation, the constant current detection unit 102 can be connected to the auxiliary winding of the primary side of the flyback converter 400 to collect the feedback second output voltage on the auxiliary winding, and output the collected second output voltage to the state detection unit for subsequent working state judgment.

[0089] It should be understood that the first output voltage acquired by the constant current detection unit 101 and the second output voltage acquired by the constant current detection unit 102 are both primary-side feedback, which eliminates the need to add additional optocouplers or digital isolators to the circuit of the flyback converter 400, thereby reducing the scale of the peripheral circuit and lowering the power supply application cost and design complexity.

[0090] The state detection unit 103 is used to determine the current operating state of the flyback converter 400 based on the first output voltage and the second output voltage.

[0091] In a specific implementation, the state detection unit 103 can, after receiving the first output voltage and the second output voltage, compare the first output voltage and the second output voltage with a set reference voltage, and determine the current working state of the flyback converter 400 based on the comparison result.

[0092] Furthermore, in this embodiment, the state detection unit 103 is used to determine that the working state is a constant voltage state when the first output voltage reaches a preset reference voltage.

[0093] It should be noted that the aforementioned preset reference voltage can be used as a reference voltage to determine whether the flyback converter is in a constant voltage state or a constant current state.

[0094] For ease of understanding, please refer to Figure 3 This explanation does not limit the scope of this solution. Figure 3 This is a schematic diagram of mode selection in the second embodiment of the flyback converter modulation chip of the present invention. Figure 3 In this configuration, the output voltage monitoring port DEM can be the port connecting the constant voltage detection unit 101 to the auxiliary winding in the flyback converter 400. This output voltage monitoring port DEM inputs the acquired first output voltage to the comparator of the state monitoring unit 103. The state monitoring unit 103 compares the first output voltage with the preset reference voltage V. REF Based on the comparison result, the first enable signal Enable1 is output to the selection unit when the first output voltage is greater than the preset reference voltage V. REF When the first enable signal Enable1 is output as a high-level enable signal 1, correspondingly, when the first output voltage is lower than the aforementioned preset reference voltage V... REF When the first enable signal Enable1 is output, it is a low-level enable signal 0.

[0095] like Figure 3 As shown, the feedback port INV can be the port connecting the constant current detection unit 102 to the auxiliary winding in the flyback converter 400. This feedback port INV inputs the acquired second output voltage to the comparator of the state monitoring unit 103. The state monitoring unit 103 compares the second output voltage with the preset reference voltage V. REF Based on the comparison result, the second enable signal Enable2 is output to the selection unit when the second output voltage is greater than the preset reference voltage V. REF When the output second enable signal Enable2 is a high-level enable signal 1, correspondingly, when the second output voltage is lower than the aforementioned preset reference voltage V... REF When this occurs, the output second enable signal Enable1 is a low-level enable signal 0.

[0096] It should be noted that the above-mentioned gating unit may be a unit in the above-mentioned state detection unit 103 that selects and outputs the pulse width modulation signal and the pulse frequency modulation signal according to the first enable signal Enable1 and the second enable signal Enable2.

[0097] Understandably, the aforementioned feedback port INV is connected to a voltage-controlled oscillator, which can generate a pulse width modulation (PWM) signal and a pulse frequency modulation (PFM) signal based on the second output voltage input to the feedback port INV.

[0098] In a specific implementation, when the first output voltage reaches the preset reference voltage, that is, when the first enable signal Enable1 input to the gating unit is a high-level enable signal 1, the first output voltage conforms to the voltage under constant voltage conditions, and it can be determined that the working state of the flyback converter 400 is a constant voltage state.

[0099] The state detection unit 103 is further configured to determine that the working state is a constant voltage state when the first output voltage does not reach the preset reference voltage and the second output voltage does not reach the preset reference voltage.

[0100] In a specific implementation, when the first output voltage does not reach the preset reference voltage and the second output voltage also does not reach the preset reference voltage, that is, when the first enable signal Enable1 input to the gating unit is a low-level enable signal 0 and the second enable signal Enable2 input to the gating unit is also a low-level enable signal 0, the first output voltage conforms to the voltage under constant voltage conditions, and it can be determined that the working state of the flyback converter 400 is a constant voltage state.

[0101] The state detection unit 103 is further configured to determine that the working state is a constant current state when the first output voltage does not reach the preset reference voltage and the second output voltage reaches the preset reference voltage.

[0102] In a specific implementation, when the first output voltage does not reach the preset reference voltage and the second output voltage reaches the preset reference voltage, that is, when the first enable signal Enable1 input to the gating unit is a low-level enable signal 0 and the second enable signal Enable2 input to the gating unit is a high-level enable signal 1, the second output voltage conforms to the voltage under constant current condition, and it can be determined that the working state of the flyback converter 400 is constant current voltage condition.

[0103] Furthermore, referring to Figure 4 , Figure 4 This is a schematic diagram of the current detection module in the second embodiment of the flyback converter modulation chip of the present invention. In this embodiment, the chip further includes a current detection module 500.

[0104] The current detection module 500 is connected to the mode selection module 200 and the flyback converter 400, respectively.

[0105] The current detection module 500 is used to collect the operating current flowing through the primary side of the flyback converter 400 and convert the operating current into a detection voltage.

[0106] It should be noted that the above-mentioned operating current can be the current when the primary side of the flyback converter 400 is in the on state, and correspondingly, the above-mentioned detection voltage can be the voltage corresponding to this operating current.

[0107] In a specific implementation, the current detection module 500 can collect the operating current when the primary side of the flyback converter 400 is turned on, and convert the operating current into an operating voltage through a resistor connected to the current detection module 500.

[0108] The current detection module 500 is also used to output a drive enable signal to the mode selection module 200 when the detected voltage is lower than the preset reference voltage.

[0109] It should be noted that the aforementioned drive enable signal can be a low-level enable signal that controls the mode selection module 200 to select and output the aforementioned pulse width modulation signal and pulse frequency modulation signal.

[0110] In a specific implementation, when the detection voltage is lower than the preset reference voltage, the current detection module 500 can determine that the current is within a safe range. At this time, it can output the drive enable signal to the mode selection module 200 so that the mode selection module 200 can select and output the pulse width modulation signal and the pulse frequency modulation signal.

[0111] Furthermore, in this embodiment, the current detection module 500 is also used to stop outputting the drive enable signal to the mode selection module 200 when the detected voltage reaches the preset reference voltage, so that the mode selection module 200 stops outputting the pulse width modulation signal and the pulse frequency modulation signal.

[0112] In a specific implementation, when the detected voltage is greater than the preset reference voltage, the current detection module 500 can determine that the current is too large and does not meet the safety limit, posing a safety hazard. At this time, it can output the high-level enable signal to the mode selection module 200 so that the mode selection module 200 stops selecting and outputting the pulse width modulation signal and the pulse frequency modulation signal.

[0113] The mode selection module 200 is used to output the pulse width modulation signal or the pulse frequency modulation signal according to the working state when the drive enable signal is received.

[0114] It should be noted that, referring to the above... Figure 3The aforementioned current detection module 500 can be connected to the primary side of the flyback converter 400 via a resistor through the current detection port CS to acquire the operating current of the primary side of the flyback converter 400 and the corresponding operating voltage. The current detection port CS inputs the acquired operating voltage to the comparator of the current detection module 500, comparing the operating voltage with the preset reference voltage V. REF The comparison is performed, and based on the comparison result, a third enable signal Enable3 is output to the mode selection module 200 when the operating voltage is lower than the preset reference voltage V. REF When the third enable signal input to the mode selection module 200 is a low-level enable signal 0, which is the aforementioned drive enable signal, correspondingly, when the aforementioned operating voltage is greater than the aforementioned preset reference voltage V... REF At this time, the third enable signal input to the mode selection module 200 is a high-level enable signal 1.

[0115] In a specific implementation, the mode selection module 200 can access mode selection when it receives the low-level drive enable signal, that is, it selects the pulse width modulation signal for output in the constant voltage state and the pulse frequency modulation signal for output in the constant current state.

[0116] It should be understood that when the mode selection module 200 receives the high-level third enable signal Enable3, it stops selecting and outputting the pulse width modulation signal and the pulse frequency modulation signal to avoid excessive operating current causing damage to the flyback converter 400 and thus leading to safety hazards.

[0117] refer to Figure 5 , Figure 5 This is a schematic diagram of the third embodiment of the flyback converter modulation chip of the present invention.

[0118] Based on the above embodiments, in this embodiment, the chip further includes a power supply module 600 and a bandgap reference module 700.

[0119] The bandgap reference module 700 is connected to the power supply module 600, the state detection unit 103 and the current detection module 500 respectively. The power supply module 600 is connected to the flyback converter 400 and the drive module 300 respectively.

[0120] The power module 600 is used to acquire the power supply voltage output from the primary side of the flyback converter 400 and output the power supply voltage to the bandgap reference module 700.

[0121] It should be noted that, Figure 5The diagram shows the connection relationship between the power supply module 600 and the bandgap reference module 700. Modules and units not shown are consistent with the aforementioned embodiments and can be referred to the aforementioned figures. For ease of understanding, they will not be shown here.

[0122] It is understood that the aforementioned power supply voltage can be the supply voltage connected to the primary side of the flyback converter 400, and the flyback converter 400 operates through this power supply voltage.

[0123] In a specific implementation, the power module 600 can be connected to the primary side of the flyback converter 400 via the power port VDD, and the power supply voltage input to the primary side of the flyback converter 400 can be acquired through the power port VDD and input to the bandgap reference module 700.

[0124] The bandgap reference module 700 is used to output the preset reference voltage to the state detection unit 103 and the current detection module 500 respectively when the power supply voltage is received.

[0125] In a specific implementation, the bandgap reference module 700 can receive the power supply voltage output by the power supply module 600 and output the preset reference voltage to the state detection unit 103 according to the power supply voltage, so that the state detection unit 103 can detect the state of the flyback converter 400. At the same time, the power supply voltage is also output to the current detection module 500, so that the current detection module 500 can detect whether the operating current exceeds the safe range.

[0126] For ease of understanding, please refer to Figure 6 This explanation does not limit the scope of this solution. Figure 6 This is a circuit schematic diagram of the bandgap reference module in the third embodiment of the flyback converter modulation chip of the present invention. Figure 6 In the above, the bandgap reference module 700 includes: first to tenth MOS transistors M1 to M10, first to third transistors Q1 to Q3, first resistor R1 and second resistor R2.

[0127] The sources of the first MOSFET M1 (M1), the second MOSFET M2, and the third MOSFET N3 are all connected to the power module 600. The gate of the first MOSFET M1 is connected to the gates of the second MOSFET M2, the third MOSFET M3, and the source of the fifth MOSFET M5. The drain of the first MOSFET M1 is connected to the source of the fourth MOSFET M4. The gate of the second MOSFET M2 is connected to the gate of the third MOSFET M3, and the drain of the second MOSFET M2 is connected to the source of the fifth MOSFET M5. The drain of the third MOSFET M3 is connected to the source of the sixth MOSFET M6; the gate of the fourth MOSFET M4 is connected to the gate of the fifth MOSFET M5, the gate of the sixth MOSFET M6, and the drain of the eighth MOSFET M8; the drain of the fourth MOSFET M4 is connected to the drain of the seventh MOSFET M7 and the gate of the seventh MOSFET M7; the gate of the fifth MOSFET M5 is connected to the gate of the sixth MOSFET M6, and the drain of the fifth MOSFET M5 is connected to the drain of the eighth MOSFET M8; the sixth MOSFET M3... The drain of S-MOSFET M6 is connected to the first terminal of the second resistor R2, the state detection unit 103, and the current detection module 500, respectively. The second terminal of the second resistor R2 is connected to the emitter of the third transistor Q3. The collector and base of the third transistor Q3 are both grounded. The gate of the seventh MOSFET M7 is connected to the gate of the eighth MOSFET M8. The source of the seventh MOSFET M7 is connected to the drain of the ninth MOSFET M9 and the gate of the ninth MOSFET M9, respectively. The source of the eighth MOSFET M8... The drain of the tenth MOSFET M10 is connected to the drain of the tenth MOSFET M9; the gate of the ninth MOSFET M9 is connected to the gate of the tenth MOSFET M10, the source of the ninth MOSFET M9 is connected to the emitter of the first transistor Q1, and the collector and base of the first transistor Q1 are both grounded; the source of the tenth MOSFET M10 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the emitter of the second transistor Q2, and the collector and base of the second transistor Q2 are both grounded.

[0128] It should be noted that the first to sixth MOSFETs M1 to M6 are all PMOS transistors, the seventh to tenth MOSFETs are all NMOS transistors, and the first to third transistors Q1 to Q3 are all P-type transistors. The sources of the first MOSFET MQ, the second MOSFET M2, and the third MOSFET N3 are all connected to the power supply port VDD of the power module 600. The first to tenth MOSFETs M1 to M10, the first to third transistors Q1 to Q3, the first resistor R1, and the second resistor R2 constitute a bandgap reference. The input of this bandgap reference is the power supply voltage output from the power supply port VDD of the power module 600. The drain of the sixth MOSFET M6 is the output terminal, outputting the preset reference voltage V. REF To the aforementioned status detection unit 103 and the current detection module 500.

[0129] Furthermore, in this embodiment, the power module 600 is also used to determine whether the power supply voltage meets preset non-ideal conditions.

[0130] It should be noted that the aforementioned preset non-ideal conditions can be used to determine whether the flyback converter 400 is in a non-ideal state. Such non-ideal states may include overvoltage, undervoltage, overcurrent, overtemperature, and short-circuit states.

[0131] In the specific implementation, before the power supply voltage is input to the power port VDD of the power module 600, it is first decoupled by an external capacitor. After the power supply voltage is input to the inside of the flyback converter modulation chip through the power port VDD, a Zener diode protects the input voltage. The maximum protection voltage of the Zener diode can be selected according to the requirements, such as 10mA. A MOSFET with diode connection is used to divide the power supply voltage. Then, by comparing the divided power supply voltage with a preset reference value, it is determined whether the power supply voltage meets the preset non-ideal conditions based on the comparison result.

[0132] It should be understood that the aforementioned preset reference value can be used to determine whether the power supply voltage meets the preset non-ideal conditions. Different values ​​can be selected according to different states, such as the reference value for overvoltage, the reference value for undervoltage, and the reference value for overcurrent.

[0133] The power module 600 is also configured to output an enable signal for a stop working state to the drive module 300 when the power supply voltage meets the preset non-ideal conditions, so as to stop the drive module 300 from working.

[0134] In a specific implementation, when the power supply module 600 detects that the power supply voltage after voltage division exceeds the preset reference value corresponding to the preset non-ideal condition, it outputs the enable signal of the stop working state to the drive module 300. For example, when the preset non-ideal condition is the condition corresponding to the overvoltage state, and the power supply voltage after voltage division exceeds the preset reference value, the enable signal is output to the drive module 300 to stop the drive module 300 from working, thereby protecting the flyback converter 400.

[0135] For ease of understanding, please refer to Figure 7 This explanation does not limit the scope of this solution. Figure 7 This is a schematic diagram of the flyback converter modulation chip in the third embodiment of the present invention. Figure 7 In this embodiment, the external ports of the flyback converter modulation chip include: power supply port VDD, feedback port INV, output voltage monitoring port DEM, power MOSFET drive port GATE, current monitoring port CS, and common ground port.

[0136] It should be noted that the aforementioned power port VDD is used for overvoltage detection, undervoltage detection, input voltage clamping, and output of various reference sources for the primary side power supply voltage of the flyback converter 400. This power port VDD is the port of the aforementioned power module 600, which can be referred to in the description of the aforementioned power module 600, and will not be repeated here.

[0137] Understandably, the aforementioned feedback port INV can be used to monitor the voltage signal fed back from the output of the flyback converter 400 on the primary auxiliary winding, including the feedback output voltage and possibly the feedback phase signal. The corresponding modules are the current control module, the sample-and-hold module, and the supplementary module, which can work with the aforementioned mode selection module to select the output of the PWM signal (pulse width modulation signal) and the PFM signal (pulse frequency modulation signal). The feedback port INV is the port of the aforementioned constant current detection unit 102 and also includes the functions of the aforementioned constant current monitoring unit 102. Please refer to the description of the aforementioned constant current detection unit 102, which will not be repeated here.

[0138] It should be noted that the aforementioned common ground port GND is used to connect the reference ground of the flyback converter modulation chip to the external ground to achieve potential matching.

[0139] Understandably, the aforementioned power MOSFET drive port GATE is used to output the drive signal of the flyback converter modulation chip to the gate of the external power MOSFET to control the switching of the external power MOSFET, realize the topology function, and adjust the operating mode of the flyback converter 400. The drive signal may include the aforementioned pulse width modulation signal and the aforementioned pulse frequency modulation signal. This functional MOSFET port GATE is the port of the aforementioned drive module 300, which can be referred to in the description of the aforementioned drive module 300, and will not be repeated here.

[0140] It should be noted that the aforementioned output voltage detection port DEM is used to monitor the voltage output from the secondary side of the flyback converter 400 through the auxiliary winding of the primary side of the flyback converter 400, and together with the aforementioned feedback port INV, forms a detection of the output state to realize output voltage feedback, thereby determining whether the output state is constant current or constant voltage, and adjusting the corresponding drive mode to pulse width modulation mode or pulse frequency modulation mode. This output voltage port DEM is the port of the aforementioned constant voltage detection unit 101, which can be referred to in the description of the aforementioned constant voltage detection unit 101, and will not be repeated here.

[0141] Understandably, the aforementioned current detection port CS can be a port for detecting the operating current on the primary side of the flyback converter 400 to achieve current detection protection. It can be the port corresponding to the aforementioned current detection module 500, which can be referred to in the description of the aforementioned current detection module 500, and will not be repeated here.

[0142] Understandably, the aforementioned flyback converter modulation chip also includes a logic control module and a soft starter. The logic control module is used to control the priority of each control logic in the flyback converter modulation chip and to judge the output signal. The soft starter is used to adjust the duty cycle of the output drive signal step by step during the startup process of the flyback converter modulation chip, so that the output voltage is stable and thus the output voltage does not overshoot.

[0143] For ease of understanding, please refer to Figure 8 This explanation does not limit the scope of this solution. Figure 8 The circuit diagram of the flyback converter modulation chip applied to the flyback converter in the third embodiment of the present invention is shown. Figure 8 The flyback converter circuit using the aforementioned flyback converter modulation chip includes: a flyback converter modulation chip U1, resistors R3 to R16 (third to sixteenth), a first NMOS transistor Q01, capacitors C1 to C7 (first to seventh), capacitors EC1 to EC3 (first to third), diodes D1 to D3 (first to third), an inductor L1, an inductor L2, a power supply winding T1, and a primary winding N. PR1 Secondary winding N SEC Auxiliary winding NAUX The circuit consists of: first fuse F1, live wire L, neutral wire N, negative temperature coefficient thermistor NTC, rectifier bridge BD1, positive output terminal V+, and negative output terminal V-.

[0144] like Figure 8 As shown, the power supply port VDD of the flyback converter modulation chip U1 is connected to the first terminal of the fifth resistor R5, the first terminal of the second capacitor C2, the first terminal of the third capacitor C3, and the first terminal of the fourteenth resistor R14, respectively. The second terminals of the second capacitor C2 and the third capacitor C3 are both grounded. The second terminal of the fifth resistor R5 is connected to the cathode of the second diode D2. The anode of the second diode D2 is connected to the first terminal of the seventh resistor R7, the first terminal of the ninth resistor R9, and the auxiliary winding N, respectively. AUX The first terminal is connected, the second terminal of the seventh resistor R7 is connected to the first terminal of the eighth resistor R8, the second terminal of the ninth resistor R9 is connected to the first terminal of the tenth resistor R10, and the second terminals of the eighth resistor R8, the tenth resistor R10, and the auxiliary winding N are connected together. AUX The second terminals of all components are grounded; the output voltage monitoring port DEM of the flyback converter modulation chip U1 is connected to the first terminal of the tenth resistor R10 and the first terminal of the fourth capacitor C4, respectively, and the second terminal of the fourth capacitor C4 is grounded; the feedback port INV of the flyback converter modulation chip U1 is connected to the first terminal of the eighth resistor R8 and the first terminal of the fifth capacitor C5, respectively, and the second terminal of the fifth capacitor C5 is grounded; the common ground port GND of the flyback converter modulation chip U1 is grounded; the power MOSFET drive port of the flyback converter modulation chip U1 is connected to the first terminal of the thirteenth resistor R13; the second terminal of the thirteenth resistor R13 is connected to the gate of the first NMOS transistor Q01; the source of the first NMOS transistor Q01 is connected to the first terminal of the twelfth resistor R12, the first terminal of the sixth resistor R6, and the first terminal of the fifteenth resistor R15, respectively; the second terminals of the sixth resistor R6 and the second terminals of the fifteenth resistor R15 are both grounded; the drain of the first NMOS transistor Q01 is connected to the anode of the first diode D1 and the primary winding N1, respectively. PR1 The first terminal of the first diode D1 is connected to the first terminal of the fourth resistor R4. The second terminal of the fourth resistor R4 is connected to the first terminal of the third resistor R3 and the first terminal of the first capacitor C1. The second terminal of the first capacitor C1 is connected to the second terminal of the third resistor R3 and the primary winding N. PR1The second terminal of the first inductor is connected to the first terminal of the sixteenth resistor R16, the first terminal of the first inductor L1, and the eighteenth resistor R18. The second terminal of the sixteenth resistor R16 is connected to the second terminal of the fourteenth resistor R14. The second terminal of the first inductor L1 is connected to the second terminal of the eighteenth resistor R18, the positive terminal of the rectifier bridge BD1, and the positive terminal of the first polarized capacitor EC1. The negative terminal of the first polarized capacitor EC1 is connected to the negative terminal of the rectifier bridge and the first terminal of the second inductor L2. The first input terminal of the rectifier bridge is connected to the first terminal of the first fuse. The second terminal of the first fuse is connected to the live wire L; the second input terminal of the rectifier bridge is connected to the first terminal of the negative temperature coefficient thermistor NTC; the second terminal of the negative temperature coefficient thermistor NTC is connected to the neutral wire N; the second terminal of the second inductor L2 is connected to the negative terminal of the second polarized capacitor EC2; the positive terminal of the second polarized capacitor EC2 is connected to the first terminal of the eighteenth resistor R18D; the current detection port CS of the flyback converter modulation chip U1 is connected to the second terminal of the twelfth resistor R12 and the first terminal of the seventh capacitor C7, respectively; the second terminal of the seventh capacitor C7 is grounded; the aforementioned secondary winding N... SEC The first terminal is connected to the first terminal of the sixth capacitor C6 and the anode of the third diode D3. The second terminal of the sixth capacitor C6 is connected to the first terminal of the seventeenth resistor R17. The second terminal of the seventeenth resistor R17 is connected to the cathode of the third diode D3, the positive terminal of the third polarized capacitor EC3, and the first terminal of the eleventh resistor R11. The negative terminal of the third polarized capacitor EC3, the second terminal of the eleventh resistor R11, and the secondary winding N are connected to the second terminal of the third polarized capacitor EC3. SEC The second terminal of the eleventh resistor R11 is grounded. The first terminal of the eleventh resistor R11 is connected to the load as the positive output terminal V+, and the second terminal of the eleventh resistor R11 is connected to the output load as the negative output terminal V-. The primary winding N PR1 Secondary winding N SEC and auxiliary winding N AUX All are power supply windings T1.

[0145] It should be noted that the flyback converter 400 is connected to the load through the aforementioned positive output terminal V+ and negative output terminal V-. The output voltage is the voltage across the eleventh resistor R11, and the auxiliary winding N... AUX When the primary side of the flyback converter 400 is turned on, the output voltage can be fed back. The flyback converter modulation chip U1 can acquire the auxiliary winding N through the output voltage monitoring port DEM and the feedback port INV. AUX The output voltage is fed back to achieve primary-side feedback. Compared with conventional flyback converters, which require optocouplers or digital isolators for electrical isolation between the primary and secondary sides, the flyback converter 400 in this embodiment does not require additional optocouplers or digital isolators, reducing the size of the peripheral circuit and lowering the cost and design complexity of power supply applications.

[0146] Furthermore, in this embodiment, the mode selection module 200 is also used to output a valley modulation drive signal to the drive module 300 when the flyback converter 400 is under non-heavy load operating conditions, so that the drive module 300 adjusts the operating mode of the flyback converter 400 to valley modulation mode.

[0147] In a specific implementation, when the mode selection module 200 detects that the flyback converter 400 is under non-heavy load operating conditions, if the current detection port CS detects the current signal output from the primary side of the flyback converter 400, it can generate a pulse width modulation signal and output the pulse width modulation signal to the drive module 300. Conversely, if the current detection port CS does not detect the current output from the primary side of the flyback converter 400, it cannot generate a pulse width modulation signal. In this case, it generates an intermittent pulse signal to the drive module 300. By selecting between the pulse width modulation signal and the intermittent pulse signal, the drive module 300 adjusts the operating mode of the flyback converter 400 to the trough modulation mode, thereby achieving better operating efficiency under light load or no-load operating conditions.

[0148] It should be understood that the above-mentioned valley modulation mode can be a mode for selecting and outputting intermittent pulse signals and pulse width modulation signals. Correspondingly, the intermittent pulse signals and pulse width modulation signals in the valley modulation mode can both be the above-mentioned valley modulation driving signals.

[0149] It should be noted that the above-mentioned intermittent pulse signal can be a drive signal with the same operating frequency as the pulse width modulation signal, but with a different duty cycle. The duty cycle can be set by the technician according to the requirements. For example, the duty cycle can be 30%, and every 3 to 6 pulses are output, the low level is maintained for 64 cycles to achieve the valley modulation mode with the above-mentioned pulse width modulation signal.

[0150] The mode selection module 200 is further configured to output a pulse width modulation signal to the drive module 300 when the flyback converter 400 is under heavy load operating conditions, so that the drive module 300 adjusts the operating mode of the flyback converter 400 to pulse width modulation mode.

[0151] In a specific implementation, when the mode selection module 200 detects that the flyback converter 400 is under heavy load operating conditions, it outputs a pulse width modulation signal to the drive module 300, so that the drive module 300 adjusts the operating mode of the flyback converter 400 to pulse width modulation mode, thereby achieving better working efficiency under heavy load operating conditions.

[0152] In addition, to achieve the above objectives, the present invention also proposes a flyback converter modulation device, which includes the flyback converter modulation chip as described above.

[0153] Other embodiments or specific implementations of the flyback converter modulation device of the present invention can be referred to the embodiments of the flyback converter modulation chip described above, and will not be repeated here.

[0154] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0155] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0156] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A flyback converter modulation chip, characterized in that, The chip is used in a flyback converter, and the chip includes: a state detection module, a mode selection module, and a drive module; The mode selection module is connected to the state detection module and the driving module respectively, and both the state detection module and the driving module are connected to the primary side of the flyback converter. The state detection module is used to collect the output voltage fed back by the flyback converter on the auxiliary winding of the primary side, and detect the current working state of the flyback converter based on the output voltage. The mode selection module is also used to output a pulse width modulation signal to the drive module when the working state is constant voltage state, so that the drive module adjusts the working mode of the flyback converter to pulse width modulation mode. The mode selection module is also used to output a pulse frequency modulation signal to the drive module when the working state is constant current state, so that the drive module adjusts the working mode of the flyback converter to pulse frequency modulation mode. The output voltage includes a first output voltage and a second output voltage, and the state detection module includes: a constant voltage detection unit, a constant current detection unit, and a state detection unit. The constant voltage detection unit is connected to the flyback converter and the state detection unit respectively, and the constant current detection unit is connected to the flyback converter and the state detection unit respectively. The constant voltage detection unit is used to acquire the first output voltage fed back from the auxiliary winding on the primary side of the excitation converter through the output voltage monitoring port, and output the first output voltage to the state detection unit. The constant current detection unit is used to acquire the second output voltage fed back from the auxiliary winding on the primary side of the excitation converter through the feedback port, and output the second output voltage to the state detection unit. The state detection unit is used to determine the current operating state of the flyback converter based on the first output voltage and the second output voltage.

2. The flyback converter modulation chip as described in claim 1, characterized in that, The state detection unit is used to determine that the working state is a constant voltage state when the first output voltage reaches a preset reference voltage. The state detection unit is further configured to determine that the working state is a constant voltage state when the first output voltage does not reach the preset reference voltage and the second output voltage does not reach the preset reference voltage. The state detection unit is further configured to determine that the working state is a constant current state when the first output voltage does not reach the preset reference voltage and the second output voltage reaches the preset reference voltage.

3. The flyback converter modulation chip as described in claim 2, characterized in that, The chip also includes: a current detection module; The current detection module is connected to the mode selection module and the primary side of the flyback converter, respectively. The current detection module is used to collect the operating current flowing through the primary side of the flyback converter and convert the operating current into a detection voltage; The current detection module is also used to output a drive enable signal to the mode selection module when the detected voltage is lower than the preset reference voltage; The mode selection module is used to output the pulse width modulation signal or the pulse frequency modulation signal according to the working state when the drive enable signal is received.

4. The flyback converter modulation chip as described in claim 3, characterized in that, The current detection module is further configured to stop outputting the drive enable signal to the mode selection module when the detected voltage reaches the preset reference voltage, so that the mode selection module stops outputting the pulse width modulation signal and the pulse frequency modulation signal.

5. The flyback converter modulation chip as described in claim 4, characterized in that, The chip also includes: a power module and a bandgap reference module; The bandgap reference module is connected to the power supply module, the state detection unit, and the current detection module, respectively. The power supply module is connected to the flyback converter and the drive module, respectively. The power module is used to acquire the power supply voltage output from the primary side of the flyback converter and output the power supply voltage to the bandgap reference module. The bandgap reference module is used to output the preset reference voltage to the state detection unit and the current detection module respectively when the power supply voltage is received.

6. The flyback converter modulation chip as described in claim 5, characterized in that, The bandgap reference module includes: first to tenth MOS transistors, first to third transistors, a first resistor, and a second resistor; The source of the first MOSFET, the source of the second MOSFET, and the source of the third MOSFET are all connected to the power module. The gate of the first MOSFET is connected to the gate of the second MOSFET, the gate of the third MOSFET, and the source of the fifth MOSFET. The drain of the first MOSFET is connected to the source of the fourth MOSFET. The gate of the second MOS transistor is connected to the gate of the third MOS transistor, the drain of the second MOS transistor is connected to the source of the fifth MOS transistor, and the drain of the third MOS transistor is connected to the source of the sixth MOS transistor. The gate of the fourth MOS transistor is connected to the gate of the fifth MOS transistor, the gate of the sixth MOS transistor, and the drain of the eighth MOS transistor, respectively. The drain of the fourth MOS transistor is connected to the drain of the seventh MOS transistor and the gate of the seventh MOS transistor, respectively. The gate of the fifth MOS transistor is connected to the gate of the sixth MOS transistor, and the drain of the fifth MOS transistor is connected to the drain of the eighth MOS transistor. The drain of the sixth MOS transistor is connected to the first end of the second resistor, the state detection unit, and the current detection module, respectively. The second end of the second resistor is connected to the emitter of the third transistor. The collector and base of the third transistor are both grounded. The gate of the seventh MOS transistor is connected to the gate of the eighth MOS transistor, and the source of the seventh MOS transistor is connected to the drain of the ninth MOS transistor and the gate of the ninth MOS transistor, respectively. The source of the eighth MOS transistor is connected to the drain of the tenth MOS transistor; The gate of the ninth MOS transistor is connected to the gate of the tenth MOS transistor, the source of the ninth MOS transistor is connected to the emitter of the first transistor, and the collector and base of the first transistor are both grounded. The source of the tenth MOS transistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the emitter of the second transistor, and the collector and base of the second transistor are both grounded.

7. The flyback converter modulation chip as described in claim 6, characterized in that, The power module is also used to determine whether the power supply voltage meets preset non-ideal conditions; The power module is also configured to output an enable signal to the drive module to stop working when the power supply voltage meets the preset non-ideal conditions, so as to make the drive module stop working.

8. The flyback converter modulation chip according to any one of claims 1 to 7, characterized in that, The mode selection module is also used to output a valley modulation drive signal to the drive module when the flyback converter is under non-heavy load operating conditions, so that the drive module adjusts the operating mode of the flyback converter to valley modulation mode. The mode selection module is also used to output a pulse width modulation signal to the drive module when the flyback converter is under heavy load operating conditions, so that the drive module adjusts the operating mode of the flyback converter to pulse width modulation mode.

9. A flyback converter modulation device, characterized in that, The flyback converter modulation device includes the flyback converter modulation chip as described in any one of claims 1 to 8.

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