Switching converter control method and system based on square wave signal duty ratio extraction

Abstract

The invention relates to a switching converter control method based on square wave signal duty ratio extraction, which comprises the following steps: firstly, extracting the duty ratio of a target square wave control signal PWM, generating a voltage signal VPWM in combination with a preset reference voltage VREF accessed by a switching converter during working, and then performing filtering processing and in combination with a feedback voltage VFB of the switching converter to generate a voltage signal VPWM; executing proportional addition processing and proportional amplification processing to obtain a control voltage signal VPWMFB for controlling the switching converter; a corresponding system is designed and comprises a switch module, a low-pass filter circuit module and an addition and proportion operation circuit module which are respectively used for realizing each step of the design method, the working efficiency of the switching converter is improved, and the specifically designed circuit is simple, easy to apply practically, low in cost and obvious in application effect.

Description

Technical Field

[0001] The invention relates to a switch converter control method and system based on square wave signal duty cycle extraction, belonging to the technical field of analog and digital-analog hybrid integrated circuits. Background Art

[0002] In circuit design, the duty cycle information contained in the square wave signal in the circuit is an important signal for circuit design. In the process of realizing the circuit function, this duty cycle information is directly proportional, inversely proportional, or in other quantitative relationships with the control signal of the circuit, and is closely related to the working characteristics and nature of the circuit. Therefore, the duty cycle information in the square wave signal is extracted, and the control signal is processed and updated to control the actual execution of the circuit.

[0003] In actual applications, switching converters are usually required to work at different output voltages, which places high demands on whether the switching converter can flexibly, conveniently, and directly adjust the output voltage. For general switching converters, it is necessary to manually adjust the peripheral circuits of the switching converter to adjust the output voltage, which greatly increases the difficulty of operation and has low work efficiency. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a switching converter control method based on square wave signal duty cycle extraction, which is designed with duty cycle information extraction and combined with feedback voltage to optimize and update the control signal of the switching converter to improve the working efficiency of the switching converter.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: the present invention designs a switching converter control method based on square wave signal duty cycle extraction, which is used to realize the control of the switching converter by the target square wave control signal PWM, and performs the following steps A to C;

[0006] Step A: Based on the preset reference voltage V connected to the switching converter REF , and the target square wave control signal PWM, the duty cycle generated is the same as the target square wave control signal PWM, and the amplitude is the reference voltage V REF The voltage signal V PWM , and proceed to step B;

[0007] Step B. For the voltage signal V PWM Perform low-pass filtering according to the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and proceed to step C;

[0008] Step C. Obtain the feedback voltage V of the switching converter FB , and contact the DC voltage signal V PWM_DC , according to the preset weight ratio corresponding to the two, the addition between the two is performed to obtain the added voltage signal, and then the control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

[0009] As a preferred technical solution of the present invention: the feedback voltage V FB is the output voltage of the switching converter V OUT Obtained by dividing the voltage according to the preset ratio.

[0010] Corresponding to the above, the technical problem that the present invention also needs to solve is to provide a system for a switching converter control method based on square wave signal duty cycle extraction, implement the designed switching converter control method with a modular design, integrate duty cycle information and feedback voltage analysis into the control of the switching converter, and improve the working efficiency of the switching converter.

[0011] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention designs a system of a switching converter control method based on square wave signal duty cycle extraction, including a switching module, a low-pass filter circuit module, and an addition and proportional operation circuit module, wherein the input end of the switching module is used to receive a preset reference voltage V connected to the switching converter. REF , and the target square wave control signal PWM, execute the step A to generate a duty cycle that is the same as the target square wave control signal PWM and has an amplitude of the reference voltage V REF The voltage signal V PWM , and output;

[0012] The output end of the switch module is connected to the input end of the low-pass filter circuit module, and the low-pass filter circuit module receives the voltage signal V output by the switch module. PWM , and execute step B, for the voltage signal V PWM Perform low-pass filtering according to the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and output;

[0013] The output end of the low-pass filter circuit module is connected to the input end of the addition and proportional operation circuit module, and the output end of the addition and proportional operation circuit module is connected to the control end of the switch converter. At the same time, the input end of the addition and proportional operation circuit module is connected to the feedback end of the switch converter. The addition and proportional operation circuit module receives the DC voltage signal V output by the low-pass filter circuit module. PWM_DC, and the switching converter feedback voltage V FB , execute the step C, perform the addition between the two according to the preset weight ratio corresponding to the two, obtain the added voltage signal, and then obtain the control voltage signal V under the preset amplification ratio corresponding to the added voltage signal PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

[0014] As a preferred technical solution of the present invention: the switch module includes a first switch tube S1 and a second switch tube S2, wherein the drain of the first switch tube S1 constitutes a first input end of the switch module for receiving a preset reference voltage V REF The gate of the first switch tube S1 constitutes the second input end of the switch module, which is used to receive the reverse signal of the target square wave control signal PWM. The source of the first switch tube S1 is connected to the drain of the second switch tube S2, and the connected end constitutes the positive output end of the switch module. The gate of the second switch tube S2 constitutes the third input end of the switch module, which is used to receive the target square wave control signal PWM. The source of the second switch tube S2 is grounded and constitutes the negative output end of the switch module.

[0015] As a preferred technical solution of the present invention: the low-pass filter circuit module includes at least one group of filter circuits connected in series in sequence from the input end to the output end, the structures of the filter circuits are the same, and each filter circuit includes a resistor R and a capacitor C. In the structure of each filter circuit, one end of the resistor R constitutes the positive input end of the filter circuit, the other end of the resistor R is connected to one end of the capacitor C, and the connected end constitutes the positive output end of the filter circuit, one side of the other end of the capacitor C constitutes the negative input end of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output end of the filter circuit; in the series structure of each group of filter circuits, the positive output end of the adjacent front filter circuit is connected to the positive input end of the adjacent rear filter circuit, and the negative output end of the adjacent front filter circuit is connected to the negative input end of the adjacent rear filter circuit, the positive input end and the negative input end of the first filter circuit in sequence constitute the positive input end and the negative input end of the low-pass filter circuit module, and the positive output end of the last filter circuit in sequence constitutes the output end of the low-pass filter circuit module.

[0016] As a preferred technical solution of the present invention: the addition and proportional operation circuit module includes an operational amplifier AMP, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4, wherein one end of the first resistor R1 constitutes one of the input ends of the addition and proportional operation circuit module, which is used to receive the DC voltage signal V output by the low-pass filter circuit module PWM_DC One end of the second resistor R2 constitutes another input end of the addition and proportional operation circuit module, which is used to receive the feedback voltage V FBThe other end of the first resistor R1 is connected to the other end of the second resistor R2, and the connected end is connected to the positive input end of the operational amplifier AMP. The ratio of the resistance value of the first resistor R1 to the resistance value of the second resistor R2 forms a feedback voltage V FB With DC voltage signal V PWM_DC The corresponding preset weight ratio is used, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the sum voltage signals is obtained, and then the sum voltage signal is amplified and updated by the operational amplifier AMP;

[0017] The output end of the operational amplifier AMP is connected to one end of the third resistor R3, and the connected end constitutes the output end of the addition and proportional operation circuit module. The other end of the third resistor R3, the negative input end of the operational amplifier AMP, and one end of the fourth resistor R4 are connected. The other end of the fourth resistor R4 is grounded. The ratio of the resistance value of the third resistor R3 to the resistance value of the fourth resistor R4 constitutes a preset amplification ratio, and the control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB , and output.

[0018] As a preferred technical solution of the present invention: it also includes a first voltage dividing resistor R F1 , the second voltage divider resistor R F2 , where the output terminal of the switching converter is used to output the voltage V OUT At the same time, the first voltage divider resistor R F1 , the second voltage divider resistor R F2 Then grounded, the first voltage divider resistor R F1 The second voltage divider resistor R F2 The connection position between them constitutes the feedback end of the switching converter, which is used to output the feedback voltage V FB To the input end of the addition and proportional operation circuit module.

[0019] The switching converter control method and system based on square wave signal duty cycle extraction of the present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0020] (1) The switching converter control method designed by the present invention based on the square wave signal duty cycle extraction first extracts the duty cycle of the target square wave control signal PWM, and combines the preset reference voltage V REF , generating a voltage signal V PWM , and then filtered and combined with the feedback voltage V FB , perform proportional addition processing and proportional amplification processing, and then obtain the control voltage signal V used to control the switching converter PWM_FB; and design a corresponding system, including a switch module, a low-pass filter circuit module, and an addition and proportional operation circuit module, which are respectively used to implement each step of the designed method to improve the working efficiency of the switching converter. The specific designed circuit is simple, easy to apply in practice, low in cost, and has obvious application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an application flow chart of the switching converter control method designed by the present invention based on the square wave signal duty cycle extraction;

[0022] Figure 2 This is an application architecture diagram of a system for a switching converter control method based on square wave signal duty cycle extraction designed by the present invention;

[0023] Figure 3 It is a system circuit structure diagram of a switching converter control method based on square wave signal duty cycle extraction designed by the present invention;

[0024] Figure 4 It is a schematic diagram of a control voltage signal of a switching converter under the input of a target square wave control signal PWM with different duty ratios according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0026] The switching converter control method designed by the present invention based on the square wave signal duty cycle extraction is used to realize the control of the switching converter by the target square wave control signal PWM. Figure 1 As shown, specifically perform the following steps A to C.

[0027] Step A: Based on the preset reference voltage V connected to the switching converter REF , and the target square wave control signal PWM, the duty cycle generated is the same as the target square wave control signal PWM, and the amplitude is the reference voltage V REF The voltage signal V PWM , and go to step B.

[0028] Step B. For the voltage signal V PWM Perform low-pass filtering according to the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and go to step C.

[0029] Step C: Output voltage V of the switching converter OUT , divide the voltage according to the preset ratio to obtain the feedback voltage V of the switching converter FB, and contact the DC voltage signal V PWM_DC , according to the preset weight ratio corresponding to the two, the addition between the two is performed to obtain the added voltage signal, and then the control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

[0030] Regarding the actual implementation of the above-mentioned design switching converter control method, the corresponding system is further designed, such as Figure 2 As shown, it specifically includes a switch module, a low-pass filter circuit module, and an addition and proportional operation circuit module, wherein the input end of the switch module is used to receive a preset reference voltage V connected to the switch converter. REF , and the target square wave control signal PWM, execute the step A to generate a duty cycle that is the same as the target square wave control signal PWM and has an amplitude of the reference voltage V REF The voltage signal V PWM , and output.

[0031] The output end of the switch module is connected to the input end of the low-pass filter circuit module, and the low-pass filter circuit module receives the voltage signal V output by the switch module. PWM , and execute step B, for the voltage signal V PWM Perform low-pass filtering according to the following formula, based on the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and output.

[0032] V PWM_DC =(1-D)*V REF

[0033] The output end of the low-pass filter circuit module is connected to the input end of the addition and proportional operation circuit module, and the output end of the addition and proportional operation circuit module is connected to the control end of the switch converter. At the same time, the input end of the addition and proportional operation circuit module is connected to the feedback end of the switch converter. The addition and proportional operation circuit module receives the DC voltage signal V output by the low-pass filter circuit module. PWM_DC , and the switching converter feedback voltage V FB , execute the step C, perform the addition between the two according to the preset weight ratio corresponding to the two, obtain the added voltage signal, and then obtain the control voltage signal V under the preset amplification ratio corresponding to the added voltage signal PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

[0034] Regarding the switch module, low-pass filter circuit module, addition and proportional operation circuit module designed above, specific circuit implementation is carried out in actual application, such as Figure 3 As shown, the switch module is designed to include a first switch tube S1 and a second switch tube S2, wherein the drain of the first switch tube S1 constitutes a first input terminal of the switch module for receiving a preset reference voltage V REF The gate of the first switch tube S1 constitutes the second input end of the switch module, which is used to receive the reverse signal of the target square wave control signal PWM. The source of the first switch tube S1 is connected to the drain of the second switch tube S2, and the connected end constitutes the positive output end of the switch module. The gate of the second switch tube S2 constitutes the third input end of the switch module, which is used to receive the target square wave control signal PWM. The source of the second switch tube S2 is grounded and constitutes the negative output end of the switch module.

[0035] For the low-pass filter circuit module, the specifically designed circuit structure includes at least one group of filter circuits connected in series in a direction from the input end to the output end, the structures of the filter circuits are the same, and the filter circuits respectively include a resistor R and a capacitor C. In the structure of each filter circuit, one end of the resistor R constitutes the positive input end of the filter circuit, the other end of the resistor R is connected to one end of the capacitor C, and the connected end constitutes the positive output end of the filter circuit, one side of the other end of the capacitor C constitutes the negative input end of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output end of the filter circuit; in the series structure of each group of filter circuits, the positive output end of the adjacent front filter circuit is connected to the positive input end of the adjacent rear filter circuit, and the negative output end of the adjacent front filter circuit is connected to the negative input end of the adjacent rear filter circuit, the positive input end and the negative input end of the first filter circuit in sequence constitute the positive input end and the negative input end of the low-pass filter circuit module, and the positive output end of the last filter circuit in sequence constitutes the output end of the low-pass filter circuit module.

[0036] Regarding the addition and proportional operation circuit module, in actual application, the specific design includes an operational amplifier AMP, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4, wherein one end of the first resistor R1 constitutes one of the input ends of the addition and proportional operation circuit module, which is used to receive the DC voltage signal V output by the low-pass filter circuit module. PWM_DC One end of the second resistor R2 constitutes another input end of the addition and proportional operation circuit module, which is used to receive the feedback voltage V FB The other end of the first resistor R1 is connected to the other end of the second resistor R2, and the connected end is connected to the positive input end of the operational amplifier AMP. The ratio of the resistance value of the first resistor R1 to the resistance value of the second resistor R2 forms a feedback voltage V FB With DC voltage signal V PWM_DCThe corresponding preset weight ratio is used, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the three resistors R3 and R4 is added to obtain a sum voltage signal, and then the sum voltage signal is amplified and updated by the operational amplifier AMP; the output end of the operational amplifier AMP is connected to one end of the third resistor R3, and the connected end constitutes the output end of the addition and proportional operation circuit module, the other end of the third resistor R3, the negative input end of the operational amplifier AMP, and one end of the fourth resistor R4 are connected, and the other end of the fourth resistor R4 is grounded. The ratio of the resistance value of the third resistor R3 to the resistance value of the fourth resistor R4 constitutes a preset amplification ratio, and the control voltage signal V corresponding to the preset amplification ratio of the sum voltage signal is obtained. PWM_FB , and output, that is, execute according to the following formula to obtain the control voltage signal V PWM_FB .

[0037] V PWM_FB =((R1 / (R1+R2))*V FB +(R2 / (R1+R2))*V PWM_DC )*((R3+R4) / R4)

[0038] Further, the above formula can be converted to: V FB =V REF *((R1*R4-R2*R3) / (R1*(R3+R4))+D*(R2 / R1)).

[0039] About the feedback voltage V of the switching converter in practical applications FB The specific design introduces the first voltage divider resistor R F1 The second voltage divider resistor R F2 In the specific implementation, the output terminal of the switching converter is used to output the voltage V OUT At the same time, the first voltage divider resistor R F1 , the second voltage divider resistor R F2 Then grounded, the first voltage divider resistor R F1 The second voltage divider resistor R F2 The connection position between them constitutes the feedback end of the switching converter, which is used to output the feedback voltage V FB To the input end of the addition and proportional operation circuit module.

[0040] Therefore, the control voltage signal V PWM_FB , sent to the switching converter for control, the switching converter output voltage V OUT It corresponds to the following formula.

[0041] V OUT =((R F1 +R F2) / R F2 )*V FB =V REF *((R F1 +R F2 ) / R F2 )*((R1*R4-R2*R3) / (R1*(R3+R4))+D*(R2 / R1))

[0042] In practical applications, the control voltage signal of the switching converter under the target square wave control signal PWM input with different duty ratios is as follows: Figure 4 As shown, it can be seen that the control voltage signal V PWM_FB It will decrease as the duty cycle of the target square wave control signal PWM increases, thereby achieving the regulation of the output voltage of the switching converter by the target square wave control signal PWM input with different duty cycles.

[0043] The switching converter control method designed by the above technical solution based on the square wave signal duty cycle extraction first extracts the duty cycle of the target square wave control signal PWM, and combines the preset reference voltage V connected to the switching converter to work REF , generating a voltage signal V PWM , and then filtered and combined with the feedback voltage V FB , perform proportional addition processing and proportional amplification processing, and then obtain the control voltage signal V used to control the switching converter PWM_FB ; and design a corresponding system, including a switch module, a low-pass filter circuit module, and an addition and proportional operation circuit module, which are respectively used to implement each step of the designed method to improve the working efficiency of the switching converter. The specific designed circuit is simple, easy to apply in practice, low in cost, and has obvious application effect.

[0044] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A switching converter control method based on square wave signal duty cycle extraction, used to achieve the control of the switching converter by the target square wave control signal PWM, characterized in that: Perform steps A to C as follows; Step A: Based on the preset reference voltage V connected to the switching converter REF , and the target square wave control signal PWM, the duty cycle generated is the same as the target square wave control signal PWM, and the amplitude is the reference voltage V REF The voltage signal V PWM , and proceed to step B; Step B. For the voltage signal V PWM Perform low-pass filtering according to the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and proceed to step C; Step C. Obtain the feedback voltage V of the switching converter FB , and contact the DC voltage signal V PWM_DC , according to the preset weight ratio corresponding to the two, the two are added to obtain the added voltage signal, and then the control voltage signal V corresponding to the preset voltage division ratio of the added voltage signal is obtained. PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

2. The switching converter control method based on square wave signal duty cycle extraction according to claim 1, characterized in that: The feedback voltage V of the switching converter FB is the output voltage of the switching converter V OUT Obtained by dividing the voltage according to the preset ratio.

3. A system for implementing the switching converter control method based on square wave signal duty cycle extraction according to claim 1 or 2, characterized in that: It includes a switch module, a low-pass filter circuit module, and an addition and proportional operation circuit module, wherein the input end of the switch module is used to receive a preset reference voltage V connected to the switch converter. REF , and the target square wave control signal PWM, execute the step A to generate a duty cycle that is the same as the target square wave control signal PWM and has an amplitude of the reference voltage V REF The voltage signal V PWM , and output; The output end of the switch module is connected to the input end of the low-pass filter circuit module, and the low-pass filter circuit module receives the voltage signal V output by the switch module. PWM , and execute step B, for the voltage signal V PWM Perform low-pass filtering according to the voltage signal V PWM The duty cycle information carried by the voltage signal V PWM The DC component is converted into a DC voltage signal V PWM_DC , and output; The output end of the low-pass filter circuit module is connected to the input end of the addition and proportional operation circuit module, and the output end of the addition and proportional operation circuit module is connected to the control end of the switch converter. At the same time, the input end of the addition and proportional operation circuit module is connected to the feedback end of the switch converter. The addition and proportional operation circuit module receives the DC voltage signal V output by the low-pass filter circuit module. PWM_DC , and the switching converter feedback voltage V FB , execute the step C, perform the addition between the two according to the preset weight ratio corresponding to the two, obtain the added voltage signal, and then obtain the control voltage signal V under the preset voltage division ratio corresponding to the added voltage signal PWM_FB , and sent to the control end of the switching converter to control the operation of the switching converter.

4. The system of the switching converter control method based on square wave signal duty cycle extraction according to claim 3, characterized in that: The switch module includes a first switch tube S1 and a second switch tube S2, wherein the drain of the first switch tube S1 constitutes a first input terminal of the switch module for receiving a preset reference voltage V REF The gate of the first switch tube S1 constitutes the second input end of the switch module, which is used to receive the reverse signal of the target square wave control signal PWM. The source of the first switch tube S1 is connected to the drain of the second switch tube S2, and the connected end constitutes the positive output end of the switch module. The gate of the second switch tube S2 constitutes the third input end of the switch module, which is used to receive the target square wave control signal PWM. The source of the second switch tube S2 is grounded and constitutes the negative output end of the switch module.

5. A system for a switching converter control method based on square wave signal duty cycle extraction according to claim 3 or 4, characterized in that: The low-pass filter circuit module includes at least one group of filter circuits connected in series in a direction from the input end to the output end, the structures of the filter circuits are the same, and each filter circuit includes a resistor R and a capacitor C. In the structure of each filter circuit, one end of the resistor R constitutes the positive input end of the filter circuit, the other end of the resistor R is connected to one end of the capacitor C, and the connected end constitutes the positive output end of the filter circuit, one side of the other end of the capacitor C constitutes the negative input end of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output end of the filter circuit; in the series structure of each group of filter circuits, the positive output end of the adjacent front filter circuit is connected to the positive input end of the adjacent rear filter circuit, and the negative output end of the adjacent front filter circuit is connected to the negative input end of the adjacent rear filter circuit, the positive input end and the negative input end of the first filter circuit in sequence constitute the positive input end and the negative input end of the low-pass filter circuit module, and the positive output end of the last filter circuit in sequence constitutes the output end of the low-pass filter circuit module.

6. A system for a switching converter control method based on square wave signal duty cycle extraction according to claim 3, characterized in that: The addition and proportional operation circuit module includes an operational amplifier AMP, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4, wherein one end of the first resistor R1 constitutes one input end of the addition and proportional operation circuit module, and is used to receive a DC voltage signal V output by the low-pass filter circuit module. PWM_DC One end of the second resistor R2 constitutes another input end of the addition and proportional operation circuit module, which is used to receive the feedback voltage V FB The other end of the first resistor R1 is connected to the other end of the second resistor R2, and the connected end is connected to the positive input end of the operational amplifier AMP. The ratio of the resistance value of the first resistor R1 to the resistance value of the second resistor R2 forms a feedback voltage V FB With DC voltage signal V PWM_DC The corresponding preset weight ratio is used, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the sum voltage signals is obtained, and then the sum voltage signal is amplified and updated by the operational amplifier AMP; The output end of the operational amplifier AMP is connected to one end of the third resistor R3, and the connected end constitutes the output end of the addition and proportional operation circuit module. The other end of the third resistor R3, the negative input end of the operational amplifier AMP, and one end of the fourth resistor R4 are connected. The other end of the fourth resistor R4 is grounded. The ratio of the resistance value of the third resistor R3 to the resistance value of the fourth resistor R4 constitutes a preset voltage division ratio, and the control voltage signal V corresponding to the preset voltage division ratio of the added voltage signal is obtained. PWM_FB , and output.

7. A system for a switching converter control method based on square wave signal duty cycle extraction according to claim 3, characterized in that: Also includes a first voltage dividing resistor R F1 , the second voltage divider resistor R F2 , where the output terminal of the switching converter is used to output the voltage V OUT At the same time, the first voltage divider resistor R F1 , the second voltage divider resistor R F2 Then grounded, the first voltage divider resistor R F1 The second voltage divider resistor R F2 The connection position between them constitutes the feedback end of the switching converter, which is used to output the feedback voltage V FB To the input end of the addition and proportional operation circuit module.

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