A switching converter control method and system based on duty cycle extraction of square wave signals

Abstract

The present application relates to a kind of based on square wave signal duty cycle extraction switch converter control method, first extract the duty cycle of target square wave control signal PWM, and in combination with the preset reference voltage V REF It is connected to the working switch converter, and the voltage signal V PWM It is generated, and then filtering processing is carried out, in combination with the feedback voltage V FB Of switch converter, proportional addition processing and proportional amplification processing are carried out, and then the control voltage signal V PWM_FB For being used to control switch converter is obtained;And the corresponding system is designed, including switch module, low-pass filter circuit module, addition and proportional operation circuit module, for realizing each step of the designed method respectively, improve the working efficiency of switch converter, and the specific design circuit is simple, easy to practical application, low in cost, and the application effect is obvious.

Description

Technical Field

[0001] This invention relates to a switching converter control method and system based on square wave signal duty cycle extraction, belonging to the field of analog and mixed-signal integrated circuit technology. Background Technology

[0002] In circuit design, the duty cycle information contained in the square wave signal is an important signal for circuit design. During the implementation of circuit functions, this duty cycle information is directly proportional, inversely proportional, or has other quantitative relationships with the circuit's control signal. It is also closely related to the circuit's operating characteristics and essence. Therefore, the duty cycle information in the square wave signal is extracted and the control signal is processed and updated for the actual control of the circuit.

[0003] In practical applications, switching converters are often required to operate at different output voltages. This places high demands on the switching converter's ability to flexibly, conveniently, and directly adjust the output voltage. For typical switching converters, output voltage adjustment requires manual adjustment of the external circuitry, which significantly increases the difficulty of operation and reduces efficiency. Summary of the Invention

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

[0005] To solve the above-mentioned 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 executes the following steps A to C;

[0006] Step A. Based on the preset reference voltage V connected to the switching converter for operation. REF And the target square wave control signal PWM, generating a duty cycle with the same as the target square wave control signal PWM, and an amplitude equal to the reference voltage V. REF voltage signal V PWM Then proceed to step B;

[0007] Step B. For voltage signal V PWM Perform low-pass filtering based on the voltage signal V PWM The duty cycle information it carries will change the voltage signal V. PWM The DC component is converted into a DC voltage signal V. PWM_DC Then proceed to step C;

[0008] Step C. Obtain the feedback voltage V of the switching converter. FB And connect to the DC voltage signal V PWM_DC The two signals are added together according to their preset weight ratio to obtain an added voltage signal. Then, a control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB The data is then sent to the control terminal of the switching converter for controlling the operation of the switching converter.

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

[0010] Corresponding to the above, the technical problem that this invention also needs to solve is to provide a system for a switch converter control method based on square wave signal duty cycle extraction. The system adopts a modular design to realize the designed switch converter control method. For the control of the switch converter, duty cycle information and feedback voltage analysis are incorporated to improve the working efficiency of the switch converter.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention designs a system for 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 terminal of the switching module is used to receive a preset reference voltage V connected to the switching converter for operation. REF And the target square wave control signal PWM, execute step A to generate a signal with the same duty cycle as the target square wave control signal PWM, and an amplitude equal to the reference voltage V. REF voltage signal V PWM and output;

[0012] The output of the switching module is connected to the input of the low-pass filter circuit module, which receives the voltage signal V output by the switching module. PWM And perform step B, for voltage signal V PWM Perform low-pass filtering based on the voltage signal V PWM The duty cycle information it carries will change the voltage signal V. PWM The DC component is converted into a DC voltage signal V. PWM_DC and output;

[0013] The output of the low-pass filter module is connected to the input of the adder and proportional amplifier module. The output of the adder and proportional amplifier module is connected to the control terminal of the switching converter, while the input of the adder and proportional amplifier module is connected to the feedback terminal of the switching converter. The adder and proportional amplifier module receives the DC voltage signal V output from the low-pass filter module. PWM_DCand the feedback voltage V of the switching converter FB Step C is executed, and the two signals are added together according to their corresponding preset weight ratios to obtain an added voltage signal. Then, a control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB The data is then sent to the control terminal of the switching converter to control its operation.

[0014] As a preferred embodiment of the present invention: the switching module includes a first switching transistor S1 and a second switching transistor S2, wherein the drain of the first switching transistor S1 constitutes the first input terminal of the switching module, used to receive a preset reference voltage V. REF The gate of the first switching transistor S1 forms the second input terminal of the switching module, which is used to receive the inverse signal of the target square wave control signal PWM. The source of the first switching transistor S1 is connected to the drain of the second switching transistor S2, and the connection terminal forms the positive output terminal of the switching module. The gate of the second switching transistor S2 forms the third input terminal of the switching module, which is used to receive the target square wave control signal PWM. The source of the second switching transistor S2 is grounded and forms the negative output terminal of the switching module.

[0015] As a preferred embodiment of the present invention: the low-pass filter circuit module includes at least one set of filter circuits connected in series from the input end to the output end. The structures of each filter circuit are identical. 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 terminal of the filter circuit, and the other end of the resistor R is connected to one end of the capacitor C, and this connected end constitutes the positive output terminal of the filter circuit. One side of the other end of the capacitor C constitutes the negative input terminal of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output terminal of the filter circuit. In the series structure of each set of filter circuits, the positive output terminal of the adjacent preceding filter circuit is connected to the positive input terminal of the adjacent following filter circuit, and the negative output terminal of the adjacent preceding filter circuit is connected to the negative input terminal of the adjacent following filter circuit. The positive and negative input terminals of the first filter circuit in sequence constitute the positive and negative input terminals of the low-pass filter circuit module, and the positive output terminal of the last filter circuit in sequence constitutes the output terminal of the low-pass filter circuit module.

[0016] As a preferred embodiment of the present invention: the addition and scaling 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 terminal of the addition and scaling operation circuit module, 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 forms the other input terminal of the addition and proportional operation circuit module, used to receive the feedback voltage V from the switching converter. FBThe other end of the first resistor R1 is connected to the other end of the second resistor R2, and this connection point is connected to the positive input terminal of the operational amplifier AMP. The feedback voltage V is formed by the ratio of the resistance of the first resistor R1 to the resistance of the second resistor R2. FB With DC voltage signal V PWM_DC The corresponding preset weight ratio, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the two signals is used to obtain the summed voltage signal, which is then amplified and updated by the operational amplifier AMP.

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

[0018] As a preferred embodiment of the present invention, it further includes a first voltage divider resistor R. F1 Second voltage divider resistor R F2 The output of the switching converter is used to output voltage V. OUT At the same time, the first voltage divider resistor R is connected in series. F1 Second voltage divider resistor R F2 After grounding, the first voltage divider resistor R F1 With the second voltage divider resistor R F2 The connection points between them form the feedback terminal of the switching converter, used to output the feedback voltage V. FB To the input terminal of the addition and proportional operation circuit module.

[0019] The switching converter control method and system based on square wave signal duty cycle extraction described in this invention, compared with the prior art, has the following technical advantages:

[0020] (1) The switching converter control method based on square wave signal duty cycle extraction designed in this invention first extracts the duty cycle of the target square wave control signal PWM, and combines it with the preset reference voltage V connected to the switching converter for operation. REF Generate voltage signal V PWM After further filtering, combined with the feedback voltage V of the switching converter FB The process involves proportional addition and proportional amplification to obtain the control voltage signal V used to control the switching converter. PWM_FBThe corresponding system was designed, including a switching module, a low-pass filter circuit module, and an addition and proportional operation circuit module, which are used to implement each step of the designed method, improve the working efficiency of the switching converter, and the specific circuit design is simple, easy to apply in practice, low in cost, and has obvious application effect. Attached Figure Description

[0021] Figure 1 This is an application flowchart of the switching converter control method based on square wave signal duty cycle extraction designed in this invention;

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

[0023] Figure 3 This is a system circuit diagram of the switching converter control method based on square wave signal duty cycle extraction designed in this invention;

[0024] Figure 4 This is a schematic diagram of the control voltage signal of the switching converter under the target square wave control signal PWM input with different duty cycles in an embodiment of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] The switching converter control method based on square wave signal duty cycle extraction designed in this invention is used to realize the control of the switching converter by the target square wave control signal PWM. In practical applications, such as... Figure 1 As shown, the specific steps are as follows, from A to C.

[0027] Step A. Based on the preset reference voltage V connected to the switching converter for operation. REF And the target square wave control signal PWM, generating a duty cycle with the same as the target square wave control signal PWM, and an amplitude equal to the reference voltage V. REF voltage signal V PWM Then proceed to step B.

[0028] Step B. For voltage signal V PWM Perform low-pass filtering based on the voltage signal V PWM The duty cycle information it carries will change the voltage signal V. PWM The DC component is converted into a DC voltage signal V. PWM_DC Then proceed to step C.

[0029] Step C. For the output voltage V of the switching converter OUT The feedback voltage V of the switching converter is obtained by dividing the voltage according to a preset ratio. FBAnd connect to the DC voltage signal V PWM_DC The two signals are added together according to their preset weight ratio to obtain an added voltage signal. Then, a control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB The data is then sent to the control terminal of the switching converter for controlling the operation of the switching converter.

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

[0031] The output of the switching module is connected to the input of the low-pass filter circuit module, which receives the voltage signal V output by the switching module. PWM And perform step B, for voltage signal V PWM Low-pass filtering is performed according to the following formula, based on the voltage signal V. PWM The duty cycle information it carries will change 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 of the low-pass filter module is connected to the input of the adder and proportional amplifier module. The output of the adder and proportional amplifier module is connected to the control terminal of the switching converter, while the input of the adder and proportional amplifier module is connected to the feedback terminal of the switching converter. The adder and proportional amplifier module receives the DC voltage signal V output from the low-pass filter module. PWM_DC and the feedback voltage V of the switching converter FB Step C is executed, and the two signals are added together according to their corresponding preset weight ratios to obtain an added voltage signal. Then, a control voltage signal V corresponding to the preset amplification ratio of the added voltage signal is obtained. PWM_FB The data is then sent to the control terminal of the switching converter to control its operation.

[0034] Regarding the aforementioned switch module, low-pass filter circuit module, and addition and proportional operation circuit module, specific circuit implementations are carried out in practical applications, such as... Figure 3 As shown, the design of the switching module includes a first switching transistor S1 and a second switching transistor S2. The drain of the first switching transistor S1 forms the first input terminal of the switching module, used to receive a preset reference voltage V. REF The gate of the first switching transistor S1 forms the second input terminal of the switching module, which is used to receive the inverse signal of the target square wave control signal PWM. The source of the first switching transistor S1 is connected to the drain of the second switching transistor S2, and the connection terminal forms the positive output terminal of the switching module. The gate of the second switching transistor S2 forms the third input terminal of the switching module, which is used to receive the target square wave control signal PWM. The source of the second switching transistor S2 is grounded and forms the negative output terminal of the switching module.

[0035] For the low-pass filter circuit module, the specific circuit structure design includes at least one set of filter circuits connected in series from the input terminal to the output terminal. The structures of each filter circuit are identical. 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 terminal of the filter circuit, and the other end of the resistor R is connected to one end of the capacitor C, and this connected end constitutes the positive output terminal of the filter circuit. One side of the other end of the capacitor C constitutes the negative input terminal of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output terminal of the filter circuit. In the series structure of each set of filter circuits, the positive output terminal of the adjacent preceding filter circuit is connected to the positive input terminal of the adjacent following filter circuit, and the negative output terminal of the adjacent preceding filter circuit is connected to the negative input terminal of the adjacent following filter circuit. The positive and negative input terminals of the first filter circuit in sequence constitute the positive and negative input terminals of the low-pass filter circuit module, and the positive output terminal of the last filter circuit in sequence constitutes the output terminal of the low-pass filter circuit module.

[0036] In practical applications, the addition and scaling 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. One end of the first resistor R1 forms one input terminal of the addition and scaling operation circuit module, used to receive the DC voltage signal V output from the low-pass filter circuit module. PWM_DC One end of the second resistor R2 forms the other input terminal of the addition and proportional operation circuit module, used to receive the feedback voltage V from the switching converter. FB The other end of the first resistor R1 is connected to the other end of the second resistor R2, and this connection point is connected to the positive input terminal of the operational amplifier AMP. The feedback voltage V is formed by the ratio of the resistance of the first resistor R1 to the resistance of the second resistor R2. FB With DC voltage signal V PWM_DCThe corresponding preset weight ratio, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the two values ​​yields an added voltage signal, which is then amplified and updated by an operational amplifier (AMP). The output of the AMP is connected to one end of the third resistor R3, forming the output of the addition and proportional operation circuit module. The other end of the third resistor R3, the negative input of the AMP, and one end of the fourth resistor R4 are connected together, with the other end of the fourth resistor R4 grounded. The ratio of the resistance values ​​of the third resistor R3 and the fourth resistor R4 constitutes a preset amplification ratio, resulting in a control voltage signal V corresponding to the preset amplification ratio of the added voltage signal. PWM_FB And output, specifically, 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] Furthermore, the above formula can be transformed into: V FB =V REF *((R1*R4-R2*R3) / (R1*(R3+R4))+D*(R2 / R1)).

[0039] In practical applications, the feedback voltage V of the switching converter FB Its specific design incorporates a first voltage divider resistor R. F1 With the second voltage divider resistor R F2 In practice, the output of the switching converter is used to output voltage V. OUT At the same time, the first voltage divider resistor R is connected in series. F1 Second voltage divider resistor R F2 After grounding, the first voltage divider resistor R F1 With the second voltage divider resistor R F2 The connection points between them form the feedback terminal of the switching converter, used to output the feedback voltage V. FB To the input terminal of the addition and proportional operation circuit module.

[0040] Therefore, the control voltage signal V obtained by executing the above design is... PWM_FB The signal is sent to the switching converter for control, and the switching converter outputs voltage V. OUT This 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 cycles is as follows: Figure 4 As shown, the control voltage signal V for the switching converter can be seen. PWM_FB It decreases as the duty cycle of the target square wave control signal PWM increases, thereby enabling the adjustment 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 based on square wave signal duty cycle extraction designed in the above technical solution first extracts the duty cycle of the target square wave control signal PWM, and combines it with the preset reference voltage V connected to the switching converter for operation. REF Generate voltage signal V PWM After further filtering, combined with the feedback voltage V of the switching converter FB The process involves proportional addition and proportional amplification to obtain the control voltage signal V used to control the switching converter. PWM_FB The corresponding system was designed, including a switching module, a low-pass filter circuit module, and an addition and proportional operation circuit module, which are used to implement each step of the designed method, improve the working efficiency of the switching converter, and the specific circuit design is simple, easy to apply in practice, low in cost, and has obvious application effect.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A system for controlling a switching converter based on square wave signal duty cycle extraction, characterized in that: The system includes a switching module, a low-pass filter circuit module, and an adder and proportional operation circuit module. The output of the switching module is connected to the input of the low-pass filter circuit module, the output of the low-pass filter circuit module is connected to the input of the adder and proportional operation circuit module, and the output of the adder and proportional operation circuit module is connected to the control terminal of the switching converter. Simultaneously, the input of the adder and proportional operation circuit module is connected to the feedback terminal of the switching converter. The switching module includes a first switching transistor S1 and a second switching transistor S2. The drain of the first switching transistor S1 forms the first input terminal of the switching module, used to receive a preset reference voltage V. REF The gate of the first switch S1 forms the second input terminal of the switch module, which is used to receive the inverse signal of the target square wave control signal PWM. The source of the first switch S1 is connected to the drain of the second switch S2, and the connection terminal forms the positive output terminal of the switch module. The gate of the second switch S2 forms the third input terminal of the switch module, which is used to receive the target square wave control signal PWM. The source of the second switch S2 is grounded and forms the negative output terminal of the switch module. The system executes steps A to C to achieve the control of the switching converter by the target square wave control signal PWM; Step A. The input terminal of the switching module is used to receive the preset reference voltage V connected to the switching converter for operation. REF And the target square wave control signal PWM, generating a duty cycle with the same as the target square wave control signal PWM, and an amplitude equal to the reference voltage V. REF voltage signal V PWM , and output, then proceed to step B; Step B. The low-pass filter circuit module receives the voltage signal V output from the switching module. PWM For voltage signal V PWM Perform low-pass filtering based on the voltage signal V PWM The duty cycle information it carries will change the voltage signal V. PWM The DC component is converted into a DC voltage signal V. PWM_DC , and output, then proceed to step C; Step C. The addition and proportional operation circuit module receives the DC voltage signal V output from the low-pass filter circuit module. PWM_DC and the feedback voltage V of the switching converter FB The two voltage signals are added together according to their preset weight ratio to obtain an added voltage signal. Then, a control voltage signal V corresponding to the preset voltage division ratio is obtained from the added voltage signal. PWM_FB The data is then sent to the control terminal of the switching converter for controlling the operation of the switching converter.

2. The system of the switching converter control method based on square wave signal duty cycle extraction according to claim 1, characterized in that: The low-pass filter circuit module includes at least one set of filter circuits connected in series from the input terminal to the output terminal. Each filter circuit has the same structure. 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 terminal of the filter circuit, and the other end of the resistor R is connected to one end of the capacitor C, and this connected end constitutes the positive output terminal of the filter circuit. One side of the other end of the capacitor C constitutes the negative input terminal of the filter circuit, and the other side of the other end of the capacitor C constitutes the negative output terminal of the filter circuit. In the series structure of each set of filter circuits, the positive output terminal of the adjacent preceding filter circuit is connected to the positive input terminal of the adjacent following filter circuit, and the negative output terminal of the adjacent preceding filter circuit is connected to the negative input terminal of the adjacent following filter circuit. The positive and negative input terminals of the first filter circuit in sequence constitute the positive and negative input terminals of the low-pass filter circuit module, and the positive output terminal of the last filter circuit in sequence constitutes the output terminal of the low-pass filter circuit module.

3. The system of the switching converter control method based on square wave signal duty cycle extraction according to claim 1, characterized in that: The addition and scaling 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. One end of the first resistor R1 constitutes one input terminal of the addition and scaling operation circuit module, used to receive the DC voltage signal V output from the low-pass filter circuit module. PWM_DC One end of the second resistor R2 forms the other input terminal of the addition and proportional operation circuit module, used to receive the feedback voltage V from the switching converter. FB The other end of the first resistor R1 is connected to the other end of the second resistor R2, and this connection point is connected to the positive input terminal of the operational amplifier AMP. The feedback voltage V is formed by the ratio of the resistance of the first resistor R1 to the resistance of the second resistor R2. FB With DC voltage signal V PWM_DC The corresponding preset weight ratio, and the feedback voltage V is executed according to the weight ratio. FB With DC voltage signal V PWM_DC The sum of the two signals is used to obtain the summed voltage signal, which is then amplified and updated by the operational amplifier AMP. The output of the operational amplifier AMP is connected to one end of the third resistor R3, and this connection constitutes the output of the adder and proportional operation circuit module. The other end of the third resistor R3, the negative input of the operational amplifier AMP, and one end of the fourth resistor R4 are connected together, with the other end of the fourth resistor R4 grounded. The ratio of the resistance of the third resistor R3 to the resistance of the fourth resistor R4 forms a preset voltage division ratio, thereby obtaining the control voltage signal V corresponding to the preset voltage division ratio of the added voltage signal. PWM_FB , and output.

4. The system of the switching converter control method based on square wave signal duty cycle extraction according to claim 1, characterized in that: It also includes the first voltage divider resistor R F1 Second voltage divider resistor R F2 The output of the switching converter is used to output voltage V. OUT At the same time, the first voltage divider resistor R is connected in series. F1 Second voltage divider resistor R F2 After grounding, the first voltage divider resistor R F1 With the second voltage divider resistor R F2 The connection points between them form the feedback terminal of the switching converter, used to output the feedback voltage V. FB To the input terminal of the addition and proportional operation circuit module.

5. The system of a 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 The output voltage V of the switching converter OUT The voltage is obtained by dividing the voltage according to a preset ratio.

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