Temperature compensation circuit for primary side sampling feedback flyback converter

Abstract

The invention relates to a temperature compensation circuit for a primary side sampling feedback flyback converter, which is characterized in that a first input end of a voltage buffer module is connected with a positive temperature coefficient source of a primary side sampling feedback DCDC flyback converter system, a second input end of the voltage buffer module is connected with an external resistor, and an output end of the voltage buffer module is connected with a current mirror module; outputting current related to the temperature; the output end of the current mirror module is connected with a primary side sampling module of the primary side sampling feedback DCDC flyback converter system, and the received current related to the temperature is mirrored as the temperature compensation current of the system; the temperature compensation current is injected into the primary side sampling module to compensate the influence of the forward voltage drop of the secondary side rectifier diode on the output voltage along with the temperature change. According to the scheme provided by the invention, the reverse influence on the sampling voltage caused by the change of the forward voltage drop of the secondary side rectifier diode along with the temperature can be counteracted, so that the output voltage of the primary side sampling feedback DCDC flyback converter system tends to a zero temperature coefficient.

Description

Technical Field

[0001] This application relates to the field of switching power supply technology, and in particular to a temperature compensation circuit for a primary-side sampling feedback flyback converter. Background Technology

[0002] With the development of power electronics technology, isolated switching power supplies are widely used in various electronic devices. Among them, the primary-side sampling feedback flyback converter is highly favored because it can indirectly control the secondary-side output voltage by detecting the primary-side voltage of the transformer, eliminating the need for isolation feedback devices such as optocouplers, and significantly reducing system complexity and cost.

[0003] Primary-side sampled-feedback flyback converters typically utilize transformers for electrical isolation, while the secondary side employs diodes for rectification to protect downstream circuitry and improve efficiency. However, the diodes used for secondary-side rectification exhibit a negative temperature coefficient of forward voltage drop, meaning their voltage drop decreases with increasing temperature and increases with decreasing temperature. In traditional primary-side sampled-feedback architectures, the switching power supply control system relies on sampling the primary-side reflected voltage to infer and stabilize the secondary-side output voltage. Changes in the rectifier diode voltage drop directly alter the secondary-side output voltage, and the primary-side sampling circuit cannot directly detect this change. This leads to a deviation in the feedback signal, causing the switching power supply system's output voltage to drift with ambient temperature variations, affecting output voltage accuracy and stability. This problem is particularly pronounced in wide-temperature-range applications.

[0004] Therefore, there is an urgent need for a high-efficiency, accurate and easy-to-integrate temperature compensation circuit to eliminate the influence of the temperature characteristics of the secondary rectifier diodes on the output accuracy of the primary sampling feedback flyback converter. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a temperature compensation circuit for a primary-side sampling feedback flyback converter, aiming to solve the problem of the influence of the temperature characteristics of the secondary-side rectifier diodes of the primary-side sampling feedback flyback converter on the voltage output accuracy.

[0006] This application provides a temperature compensation circuit for a primary-side sampling feedback flyback converter, integrated within a primary-side sampling feedback DC-DC flyback converter system, comprising: Voltage buffer module and current mirror module; The first input terminal of the voltage buffer module is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system, the second input terminal of the voltage buffer module is connected to an external resistor, and the output terminal of the voltage buffer module is connected to the current mirror module. The voltage buffer module is used to receive voltage signals with positive temperature coefficients and externally adjustable voltage signals, and output temperature-dependent current. The output of the current mirror module is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system; the current mirror module is used to mirror the temperature-related current output by the voltage buffer module into a temperature-compensated current. Temperature compensation current is injected into the primary-side sampling module to compensate for the effect of temperature variation on the output voltage of the secondary-side rectifier diode in the primary-side sampling feedback DC-DC flyback converter system. By changing the resistance value of the external resistor, the temperature-dependent current output by the voltage buffer module is changed, and the temperature compensation current is also changed proportionally to adapt to the temperature compensation of different rectifier diodes.

[0007] Optionally, the voltage buffer module includes: The first N-type MOSFET, the second N-type MOSFET, the third N-type MOSFET, the fourth N-type MOSFET, the fifth N-type MOSFET, the sixth N-type MOSFET, the first P-type MOSFET, the second P-type MOSFET, the third P-type MOSFET, the fourth P-type MOSFET, the fifth P-type MOSFET, and the first capacitor; The gate of the first N-type MOSFET is connected to the drain of the first N-type MOSFET and the gate of the second N-type MOSFET. The sources of the first and second N-type MOSFETs are grounded. The drain of the second N-type MOSFET is connected to the drain of the first P-type MOSFET. The gate of the third N-type MOSFET is connected to the drain of the third N-type MOSFET, the gate of the fourth N-type MOSFET, and the drain of the fourth P-type MOSFET. The sources of the third and fourth N-type MOSFETs are grounded. The drain of the fourth N-type MOSFET is connected to the gate of the fifth N-type MOSFET, the drain of the fifth P-type MOSFET, and the first capacitor. The drain of the fifth N-type MOSFET is connected to the other end of the first capacitor, the gate of the sixth N-type MOSFET, and the third P-type MOSFET. The drain of the fifth N-type MOSFET is grounded; the drain of the sixth N-type MOSFET is connected to the current mirror module, and the source of the sixth N-type MOSFET is connected to an external resistor, the drain of the fifth P-type MOSFET, the drain of the fourth P-type MOSFET, and the gate; the sources of the first, second, and third P-type MOSFETs are connected to the input voltage VIN; the gate of the first P-type MOSFET is connected to the drain of the first P-type MOSFET, the drain of the second P-type MOSFET, and the gate of the third P-type MOSFET; the sources of the fourth and fifth P-type MOSFETs are connected to the drain of the second P-type MOSFET; the gate of the fifth P-type MOSFET is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system.

[0008] Optional, the current mirror module includes: The sixth P-type MOSFET and the seventh P-type MOSFET; The gate of the sixth P-type MOSFET is connected to the drain of the sixth P-type MOSFET, the gate of the seventh P-type MOSFET, and the output of the voltage buffer module; the sources of the sixth P-type MOSFET and the seventh P-type MOSFET are connected to the input voltage VIN; the drain of the seventh P-type MOSFET is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system.

[0009] Optionally, one end of the external resistor is connected to the source of the sixth N-type MOSFET, the drain of the fifth P-type MOSFET, and the drain and gate of the fourth P-type MOSFET, while the other end of the external resistor is grounded.

[0010] Optional temperature compensation for different rectifier diodes, including: Determine the forward voltage drop deviation within the actual design temperature range of the secondary rectifier diode; calculate the voltage value that the output voltage needs to be compensated based on the forward voltage drop deviation; then calculate the resistance value of the external resistor based on the voltage value that the output voltage needs to be compensated; obtain a suitable temperature compensation current in conjunction with the temperature compensation circuit, change the output voltage, and adapt the temperature compensation of the secondary rectifier diode of different primary-side sampling feedback DC-DC flyback converter systems.

[0011] Optionally, the temperature compensation current has a positive temperature coefficient, which increases with increasing temperature and decreases with decreasing temperature.

[0012] Optionally, after the temperature compensation current is injected into the sampling voltage node of the primary-side sampling module, the voltage of the sampling voltage node is reduced. The on-time of the switching transistor in the primary-side circuit of the switching power supply is adjusted by the primary-side sampling feedback control loop of the primary-side sampling feedback DC-DC flyback converter system, thereby achieving temperature compensation for the output voltage.

[0013] Optionally, a primary-side sampled-feedback DC-DC flyback converter system includes: A transformer is used to achieve isolation between the primary and secondary sides; a secondary rectifier circuit includes rectifier diodes; and a primary sampling feedback control circuit is used to adjust the on-time of the switching transistors in the primary circuit of the transformer according to the sampled voltage.

[0014] A second aspect of this application provides a method for applying a temperature compensation circuit, which utilizes the aforementioned temperature compensation circuit for a primary-side sampling feedback flyback converter, including: Determine the forward voltage drop deviation within the actual secondary-side rectifier diode design temperature range; The required compensation voltage value for the output voltage is calculated based on the positive voltage drop deviation. Then, calculate the resistance value of the external resistor based on the voltage value that needs to be compensated for the output voltage; By combining the temperature compensation circuit to obtain a suitable temperature compensation current, the output voltage is changed, and the temperature compensation of the secondary rectifier diodes of different primary-side sampling feedback DC-DC flyback converter systems is adapted.

[0015] The technical solution provided in this application may include the following beneficial effects: The voltage buffer module receives a voltage signal with a positive temperature coefficient and, in conjunction with an external resistor, generates a temperature-dependent current. This current is mirrored by a current mirror module to become a temperature-compensated current, which is then injected into the sampling node of the primary-side sampling module. This compensates for the reverse effect on the sampling voltage caused by the temperature-dependent forward voltage drop of the secondary-side rectifier diode, thus achieving temperature compensation for the secondary-side rectifier diode. Combined with the adjustment of the primary-side feedback control loop, the output voltage of the primary-side sampling feedback DC-DC flyback converter system approaches zero temperature coefficient, improving the accuracy and stability of the output voltage over a wide temperature range. By changing the externally adjustable voltage signal, i.e., changing the resistance value of the external resistor, the temperature-dependent current output by the voltage buffer module is changed, and the temperature compensation current changes proportionally, achieving temperature compensation for the rectifier diodes adapted to different systems.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0018] Figure 1 This is a schematic diagram of the temperature compensation circuit for a primary-side sampling feedback flyback converter shown in an embodiment of this application; Figure 2 This is a schematic diagram of the operation of a temperature compensation circuit for a primary-side sampling feedback flyback converter, as shown in an embodiment of this application. Figure 3 This is a circuit diagram illustrating a temperature compensation circuit for a primary-side sampling feedback flyback converter, as shown in an embodiment of this application. Figure 4 This is a schematic diagram of a primary-side sampling feedback DC-DC flyback converter system. Detailed Implementation

[0019] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0020] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the temperature compensation circuit for a primary-side sampling feedback flyback converter, as shown in an embodiment of this application.

[0023] In some implementations, the temperature compensation circuit is integrated into the primary-side sampling feedback DC-DC flyback converter system, such as... Figure 4 As shown, the primary-side sampling feedback DC-DC flyback converter system includes: a transformer for primary-secondary isolation; a secondary-side rectifier circuit including rectifier diodes; and a primary-side sampling feedback control circuit for adjusting the on-time of the switching transistor in the primary circuit of the transformer according to the sampling voltage.

[0024] See Figure 1 A temperature compensation circuit for a primary-side sampling feedback flyback converter, comprising: Voltage buffer module and current mirror module; The first input terminal of the voltage buffer module is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system, and the second input terminal of the voltage buffer module is connected to an external resistor. The output of the voltage buffer module is connected to the current mirror module; the voltage buffer module is used to receive voltage signals with positive temperature coefficients and externally adjustable voltage signals, and output temperature-dependent current.

[0025] Specifically, such as Figure 3As shown, the voltage buffer module includes a first N-type MOSFET MN1, a second N-type MOSFET MN2, a third N-type MOSFET MN3, a fourth N-type MOSFET MN4, a fifth N-type MOSFET MN5, a sixth N-type MOSFET MN6, a first P-type MOSFET MP1, a second P-type MOSFET MP2, a third P-type MOSFET MP3, a fourth P-type MOSFET MP4, a fifth P-type MOSFET MP5, and a first capacitor C1. The gate of the first N-type MOSFET MN1 is connected to the drain of the first N-type MOSFET MN1 and the gate of the second N-type MOSFET MN2. The sources of the first N-type MOSFET MN1 and the second N-type MOSFET MN2 are grounded. The drain of the second N-type MOSFET MN2 is connected to the drain of the first P-type MOSFET MP1. The gate of the third N-type MOSFET MN3 is connected to the drain of the third N-type MOSFET MN3, the gate of the fourth N-type MOSFET MN4, and the drain of the fourth P-type MOSFET MP4. The sources of the third N-type MOSFET MN3 and the fourth N-type MOSFET MN4 are grounded. The drain of the fourth N-type MOSFET MN4 is connected to the gate of the fifth N-type MOSFET MN5, the drain of the fifth P-type MOSFET MP5, and the first capacitor C1. The drain of the fifth N-type MOSFET MN5 is connected to the other end of the first capacitor C1, the gate of the sixth N-type MOSFET MN6, and the drain of the third P-type MOSFET MP3. The source of the fifth N-type MOSFET MN5 is grounded. The drain of the sixth N-type MOSFET MN6 is connected to the current mirror module, and the source of the sixth N-type MOSFET MN6 is connected to an external resistor. The drain of the fifth P-type MOSFET MP5 and the drain and gate of the fourth P-type MOSFET MP4, and the external resistor. The other end is grounded. The sources of the first P-type MOSFET MP1, the second P-type MOSFET MP2, and the third P-type MOSFET MP3 are connected to the input voltage VIN; the gate of the first P-type MOSFET MP1 is connected to the drain of the first P-type MOSFET MP1, the drain of the second P-type MOSFET MP2, and the gate of the third P-type MOSFET MP3; the sources of the fourth P-type MOSFET MP4 and the fifth P-type MOSFET MP5 are connected to the drain of the second P-type MOSFET MP2; the gate of the fifth P-type MOSFET MP5 is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system.

[0026] The output of the current mirror module is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system; the current mirror module is used to mirror the temperature-dependent current output by the voltage buffer module into a temperature-compensated current.

[0027] Specifically, the current mirror module includes a sixth P-type MOSFET MP6 and a seventh P-type MOSFET MP7; the gate of the sixth P-type MOSFET MP6 is connected to the drain of the sixth P-type MOSFET MP6, the gate of the seventh P-type MOSFET MP7, and the output terminal of the voltage buffer module; the sources of the sixth P-type MOSFET MP6 and the seventh P-type MOSFET MP7 are connected to the input voltage VIN; the drain of the seventh P-type MOSFET MP7 is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system.

[0028] After the temperature compensation current is injected into the sampling voltage node of the primary-side sampling module, the voltage of the sampling voltage node is reduced. The primary-side sampling feedback control loop of the primary-side DC-DC flyback converter system adjusts the on-time of the switching transistor in the primary-side circuit of the switching power supply, thereby achieving temperature compensation for the output voltage. The temperature compensation current has a positive temperature coefficient, increasing with increasing temperature and decreasing with decreasing temperature.

[0029] The temperature compensation circuit works as follows: when the first input terminal of the voltage buffer module receives a voltage with a positive temperature coefficient from the positive temperature coefficient source... When the external resistor connected to the external pin VTC of the chip When grounded, the voltage buffer module forms a closed loop. = The output current has a positive temperature coefficient. : (1) Current Temperature-compensated current is generated by mirroring the image using a current mirror module. : (2) In the formula, k is the mirror ratio of the current mirror.

[0030] As the temperature decreases, the voltage drop across the secondary rectifier diode decreases, reducing its impact on the sampling voltage. At this time, the temperature compensation current... The temperature compensation current decreases as temperature decreases, thus reducing its effect on the sampling voltage. As temperature increases, the voltage drop across the secondary rectifier diode increases, having a greater impact on the sampling voltage; at this point, the temperature compensation current... The effect of reducing the sampling voltage increases with increasing temperature, thus achieving temperature compensation for the primary-side sampling feedback DC-DC flyback converter system. Specifically, Injected into the sampling voltage Vs node, the voltage at the sampling voltage node is reduced. The on-time of the switching transistor in the primary-side circuit of the switching power supply is adjusted through the primary-side sampling feedback control loop to achieve temperature compensation of the output voltage, thus offsetting the influence of the secondary-side rectifier diode on the sampling voltage. Ultimately, the output voltage of the primary-side sampling feedback DC-DC flyback converter system is... for: (3) In the formula, For internal reference current, For the primary-side sampling feedback DC-DC flyback converter system, Forward voltage drop of the secondary rectifier diode, This represents the turns ratio of the transformer.

[0031] because It has a positive temperature coefficient. It has a negative temperature coefficient, so appropriate adjustments are needed. It can achieve With a zero temperature coefficient, it achieves better temperature compensation.

[0032] Different secondary rectifier diodes with different parameters are typically selected for different system applications, and their forward voltage drop varies at different temperatures. This application provides a method for adapting to different system applications, since the temperature compensation circuit is connected to an external resistor R. TC Therefore, change the external resistor R TC The resistance value, temperature compensation current I TC The voltage will also change proportionally, which will in turn change the system output voltage.

[0033] First, determine the forward voltage drop deviation Δ within the required temperature range for the actual secondary-side rectifier diode design based on the device datasheet or actual measurements. The calculation formula is: (4) In the formula, To design the secondary rectifier diode voltage drop at the highest required temperature, To determine the voltage drop of the secondary rectifier diode at the lowest required temperature in the design.

[0034] According to Δ Calculate the value that the output voltage needs to be compensated for. The calculation formula is: (5) Then, based on the required compensation value of the output voltage... Calculate the external resistance R of the chip TC The resistance value is calculated using the following formula: (6) In the formula, This is the voltage drop of the secondary-side rectifier diode at room temperature.

[0035] Finally, by combining this with a temperature compensation circuit, a suitable temperature compensation current I can be obtained. TC This changes the output voltage, thus adapting it to different system applications.

[0036] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A temperature compensation circuit for a primary-side sampling feedback flyback converter, integrated within a primary-side sampling feedback DC-DC flyback converter system, characterized in that, include: Voltage buffer module and current mirror module; The first input terminal of the voltage buffer module is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system, the second input terminal of the voltage buffer module is connected to an external resistor, and the output terminal of the voltage buffer module is connected to the current mirror module; the voltage buffer module is used to receive a voltage signal with a positive temperature coefficient and an externally adjustable voltage signal, and output a temperature-dependent current. The output of the current mirror module is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system. The current mirror module is used to mirror the temperature-related current output by the voltage buffer module into a temperature-compensated current. The temperature compensation current is injected into the primary-side sampling module to compensate for the effect of temperature variation on the output voltage of the secondary-side rectifier diode of the primary-side sampling feedback DC-DC flyback converter system. By changing the resistance value of the external resistor, the temperature-dependent current output by the voltage buffer module is changed, and the temperature compensation current is also changed proportionally to adapt to the temperature compensation of different rectifier diodes.

2. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that, The voltage buffer module includes: The first N-type MOSFET, the second N-type MOSFET, the third N-type MOSFET, the fourth N-type MOSFET, the fifth N-type MOSFET, the sixth N-type MOSFET, the first P-type MOSFET, the second P-type MOSFET, the third P-type MOSFET, the fourth P-type MOSFET, the fifth P-type MOSFET, and the first capacitor; The gate of the first N-type MOS transistor is connected to the drain of the first N-type MOS transistor and the gate of the second N-type MOS transistor. The sources of the first N-type MOS transistor and the second N-type MOS transistor are grounded. The drain of the second N-type MOS transistor is connected to the drain of the first P-type MOS transistor. The gate of the third N-type MOS transistor is connected to the drain of the third N-type MOS transistor, the gate of the fourth N-type MOS transistor, and the drain of the fourth P-type MOS transistor. The sources of the third N-type MOS transistor and the fourth N-type MOS transistor are grounded. The drain of the fourth N-type MOS transistor is connected to the gate of the fifth N-type MOS transistor, the drain of the fifth P-type MOS transistor, and the first capacitor. The drain of the fifth N-type MOS transistor is connected to the other end of the first capacitor, the gate of the sixth N-type MOS transistor, and the drain of the third P-type MOS transistor, and the source of the fifth N-type MOS transistor is grounded. The drain of the sixth N-type MOS transistor is connected to the current mirror module, and the source of the sixth N-type MOS transistor is connected to the external resistor, the drain of the fifth P-type MOS transistor, and the drain and gate of the fourth P-type MOS transistor. The sources of the first P-type MOS transistor, the second P-type MOS transistor, and the third P-type MOS transistor are connected to the input voltage VIN; the gate of the first P-type MOS transistor is connected to the drain of the first P-type MOS transistor, the drain of the second P-type MOS transistor, and the gate of the third P-type MOS transistor. The sources of the fourth and fifth P-type MOS transistors are connected to the drain of the second P-type MOS transistor. The gate of the fifth P-type MOS transistor is connected to the positive temperature coefficient source of the primary-side sampling feedback DC-DC flyback converter system.

3. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that, The current mirror module includes: The sixth P-type MOSFET and the seventh P-type MOSFET; The gate of the sixth P-type MOS transistor is connected to the drain of the sixth P-type MOS transistor, the gate of the seventh P-type MOS transistor, and the output terminal of the voltage buffer module. The source terminals of the sixth P-type MOS transistor and the seventh P-type MOS transistor are connected to the input voltage VIN. The drain of the seventh P-type MOS transistor is connected to the primary-side sampling module of the primary-side sampling feedback DC-DC flyback converter system.

4. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 2, characterized in that: One end of the external resistor is connected to the source of the sixth N-type MOS transistor, the drain of the fifth P-type MOS transistor, and the drain and gate of the fourth P-type MOS transistor, while the other end of the external resistor is grounded.

5. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that, The temperature compensation for adapting to different rectifier diodes includes: Determine the forward voltage drop deviation within the actual secondary-side rectifier diode design temperature range; The required compensation voltage value for the output voltage is calculated based on the positive voltage drop deviation. Then, calculate the resistance value of the external resistor based on the voltage value that needs to be compensated for the output voltage; By combining the temperature compensation circuit to obtain a suitable temperature compensation current, the output voltage is changed to adapt to the temperature compensation of the secondary rectifier diodes of different primary-side sampling feedback DC-DC flyback converter systems.

6. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that: The temperature compensation current has a positive temperature coefficient, which increases with increasing temperature and decreases with decreasing temperature.

7. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that: After the temperature compensation current is injected into the sampling voltage node of the primary-side sampling module, the voltage of the sampling voltage node is reduced. The primary-side sampling feedback control loop of the primary-side DC-DC flyback converter system adjusts the on-time of the switching transistor in the primary-side circuit of the switching power supply, thereby achieving temperature compensation for the output voltage.

8. The temperature compensation circuit for a primary-side sampling feedback flyback converter according to claim 1, characterized in that, The primary-side sampling feedback DC-DC flyback converter system includes: Transformers are used to achieve isolation between the primary and secondary sides. Secondary-side rectifier circuit, including rectifier diodes; The primary-side sampling feedback control circuit is used to adjust the conduction time of the switching transistor in the primary circuit of the transformer according to the sampling voltage.

9. A method for applying a temperature compensation circuit, used in the temperature compensation circuit for a primary-side sampling feedback flyback converter as described in any one of claims 1-8, characterized in that, include: Determine the forward voltage drop deviation within the actual secondary-side rectifier diode design temperature range; The required compensation voltage value for the output voltage is calculated based on the positive voltage drop deviation. Then, calculate the resistance value of the external resistor based on the voltage value that needs to be compensated for the output voltage; By combining the temperature compensation circuit to obtain a suitable temperature compensation current, the output voltage is changed to adapt to the temperature compensation of the secondary rectifier diodes of different primary-side sampling feedback DC-DC flyback converter systems.

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