Ripple injection type DC converter and electronic equipment

Abstract

A ripple injection type DC converter and electronic equipment, the ripple injection type DC converter comprising a DC conversion circuit, a sampling circuit, a ripple generation circuit and a clamping circuit. The ripple generation circuit generates a ripple feedback signal based on a first sampling voltage, which is conducive to eliminating the ripple in the output voltage according to the ripple feedback signal. At the same time, the voltage in the ripple generation circuit is clamped by the clamping circuit, which can eliminate the problem of system instability caused by the loop gain of the ripple injection type DC converter changing with the output voltage, thereby expanding the range of the output voltage that can be output.

Description

Technical Field

[0001] The present application belongs to the technical field of voltage conversion, and in particular relates to a ripple injection type DC converter and electronic equipment. Background Art

[0002] At present, a conventional DC-DC voltage converter can usually control the on-time of a corresponding switch tube based on a pulse width modulation (PWM) signal to achieve voltage conversion.

[0003] Compared with traditional voltage mode or peak / valley current control mode systems, fixed on-time converters have simpler control circuits and faster transient response, so they are widely used in the industry. However, traditional fixed on-time converters often have restrictions on output voltage and cannot support a wide output voltage range. Summary of the invention

[0004] The purpose of the present application is to provide a ripple injection type DC converter and an electronic device, aiming to solve the problem of limited output voltage existing in traditional fixed on-time converters.

[0005] According to a first aspect of an embodiment of the present application, a ripple injection type DC converter is provided, comprising: a DC conversion circuit, the DC conversion circuit being used to generate a switch node voltage based on an input voltage according to a reference voltage and a feedback parameter, and to generate an output voltage based on the switch node voltage; the feedback parameter comprising the switch node voltage and the output voltage; a sampling circuit, the sampling circuit being connected to the DC conversion circuit, the sampling circuit being used to generate a first sampling voltage based on the switch node voltage, and being used to generate a second sampling voltage based on the output voltage; the feedback parameter comprising the second sampling voltage; a ripple generation circuit, the ripple generation circuit being connected to the sampling circuit, the ripple generation circuit being used to generate a ripple feedback signal based on the first sampling voltage; the feedback parameter comprising the ripple feedback signal; a clamping circuit, the clamping circuit being connected to the ripple generation circuit, the clamping circuit being used to clamp the voltage in the ripple generation circuit according to the reference voltage.

[0006] In one embodiment, the ripple generating circuit includes a first filtering circuit, a second filtering circuit and a subtraction circuit; a first end of the first filtering circuit is connected to the sampling circuit, a second end of the first filtering circuit is connected to a first input end of the subtraction circuit, and the first filtering circuit is used to generate a first filtering voltage based on the first sampling voltage; a first end of the second filtering circuit is connected to the sampling circuit, a second end of the second filtering circuit is connected to a second input end of the subtraction circuit, and the second filtering circuit is used to generate a second filtering voltage based on the first sampling voltage; an output end of the subtraction circuit is connected to the DC conversion circuit, and the subtraction circuit generates the ripple feedback signal according to the difference between the first filtering voltage and the second filtering voltage; wherein the time constants corresponding to the first filtering voltage and the second filtering voltage are different.

[0007] In one embodiment, the first filter circuit includes a first filter resistor and a first filter capacitor, the first end of the first filter resistor is connected to the sampling circuit, the second end of the first filter resistor is respectively connected to the first input end of the subtraction circuit and the first end of the first filter capacitor, and the second end of the first filter capacitor is grounded.

[0008] In one embodiment, the second filtering circuit includes a second filtering resistor and a second filtering capacitor, the first end of the second filtering resistor is connected to the sampling circuit, the second end of the second filtering resistor is respectively connected to the second input end of the subtraction circuit and the first end of the second filtering capacitor, and the second section of the second filtering capacitor is grounded.

[0009] In one embodiment, the clamping circuit is respectively connected to the first end of the first filter circuit and the second end of the first filter circuit, and the clamping circuit is used to adjust the voltage of the first end of the first filter circuit according to the reference voltage and the first filter voltage so that the first filter voltage is not greater than the reference voltage.

[0010] In one embodiment, the clamping circuit includes an error amplifier and a voltage regulating switch, the non-phase input terminal of the error amplifier is connected to the second end of the first filter circuit, the inverting input terminal of the error amplifier is used to access the reference voltage, the output terminal of the error amplifier is connected to the control terminal of the voltage regulating switch, the first end of the voltage regulating switch is connected to the first end of the first filter circuit, and the second end of the voltage regulating switch is grounded.

[0011] In one embodiment, the DC conversion circuit includes a drive control module and a power switch module; the drive control module is respectively connected to the sampling circuit, the ripple generation circuit and the power switch module, and the drive control module is used to generate a drive signal according to the switch node voltage, the output voltage, the second sampling voltage and the ripple feedback signal; the power switch module is used to generate the switch node voltage based on the input voltage according to the drive signal, and generate the output voltage based on the switch node voltage.

[0012] In one embodiment, the power switch module includes a first power switch, a second power switch and an output inductor; the first end of the first power switch is used to access the input voltage, the second end of the first power switch is respectively connected to the first end of the second power switch and the first end of the output inductor, the control end of the first power switch is connected to the drive control module, the second end of the output inductor is connected to the first end of the output capacitor, and the second end of the output capacitor is grounded; the second end of the first power switch is used to output the switch node voltage, and the second section of the output inductor is used to output the output voltage; the second end of the second power switch is grounded, and the control end of the second power switch is connected to the drive control module.

[0013] In one embodiment, the drive control module includes a fixed on-time generation unit, a comparator, a trigger and a drive unit; the fixed on-time generation unit is connected to the power switch module and the first input terminal of the trigger respectively, and the fixed on-time generation unit is used to generate and output a first control signal according to the switch node voltage and the output voltage; the non-phase input terminal of the comparator is used to access the reference voltage, the inverting input terminal of the comparator is connected to the ripple generation circuit, the output terminal of the comparator is connected to the second input terminal of the trigger, and the comparator is used to generate and output a second control signal according to the reference voltage and the ripple feedback signal; the output terminal of the trigger is connected to the input terminal of the drive unit, the trigger is used to output a PWM control signal, and configure the falling edge of the PWM control signal according to the first control signal, and configure the rising edge of the PWM control signal according to the second control signal; the first output terminal and the second output terminal of the drive unit are respectively connected to the control terminals of the two power switches of the power switch module, and the drive unit is used to control the on and off of the two power switches of the power switch module according to the PWM control signal.

[0014] A second aspect of an embodiment of the present application provides an electronic device, comprising the ripple injection type DC converter as described above.

[0015] Compared with the prior art, the embodiments of the present application have the following beneficial effects: generating a ripple feedback signal based on the first sampling voltage through a ripple generating circuit is conducive to eliminating the ripple in the output voltage according to the ripple feedback signal; at the same time, clamping the voltage in the ripple generating circuit through a clamping circuit can eliminate the problem of system instability caused by the loop gain of the ripple injection type DC converter changing with the output voltage, thereby expanding the range of the output voltage that can be output. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a ripple injection type DC converter provided in one embodiment of the present application;

[0017] Figure 2 Example circuit diagrams for ripple generation circuits and clamping circuits;

[0018] Figure 3 is the DC gain waveform;

[0019] Figure 4 is an example circuit diagram of a DC conversion circuit;

[0020] Figure 5 Schematic diagram of the waveform of the control signal;

[0021] Figure 6 A schematic diagram of an electronic device provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] It should be noted that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] Figure 1 A schematic diagram of a ripple injection type DC converter provided in an embodiment of the present application is shown. For ease of description, only the part related to the present embodiment is shown, which is described in detail as follows:

[0026] The ripple injection type DC converter 10 comprises: a DC conversion circuit 100 , a sampling circuit 200 , a ripple generation circuit 300 and a clamping circuit 400 .

[0027] The DC conversion circuit 100 is used to convert the reference voltage and feedback parameters, generates a switch node voltage SW based on the input voltage, and generates an output voltage based on the switch node voltage SW The feedback parameters include the switch node voltage SW and the output voltage The sampling circuit 200 is connected to the DC conversion circuit 100, and the sampling circuit 200 is used to generate a first sampling voltage based on the switch node voltage SW, and to generate a first sampling voltage based on the output voltage Generate a second sampling voltage FB. The feedback parameter includes the second sampling voltage FB. The ripple generation circuit 300 is connected to the sampling circuit 200, and the ripple generation circuit 300 is used to generate a ripple feedback signal based on the first sampling voltage The feedback parameters include the ripple feedback signal The clamping circuit 400 is connected to the ripple generating circuit 300 , and the clamping circuit 400 is used to clamp the voltage in the ripple generating circuit 300 according to the reference voltage.

[0028] The ripple generating circuit 300 generates a ripple feedback signal based on the first sampling voltage It is helpful to feedback the signal according to the ripple Eliminate output voltage At the same time, the voltage in the ripple generating circuit 300 is clamped by the clamping circuit 400, so that the loop gain of the ripple injection type DC converter 10 can be eliminated along with the output voltage. The output voltage can be increased by range.

[0029] The ripple injection type DC converter 10 may be a ripple injection type buck converter with a fixed on-time.

[0030] In one embodiment, if Figure 2As shown, the ripple generating circuit 300 includes a first filtering circuit 310, a second filtering circuit 320 and a subtraction circuit 330. The first end of the first filtering circuit 310 is connected to the sampling circuit 200, the second end of the first filtering circuit 310 is connected to the first input end of the subtraction circuit 330, and the first filtering circuit 310 is used to generate a first filtering voltage V1 based on the first sampling voltage. The first end of the second filtering circuit 320 is connected to the sampling circuit 200, the second end of the second filtering circuit 320 is connected to the second input end of the subtraction circuit 330, and the second filtering circuit 320 is used to generate a second filtering voltage V2 based on the first sampling voltage. The output end of the subtraction circuit 330 is connected to the DC conversion circuit 100, and the subtraction circuit 330 generates a ripple feedback signal according to the difference between the first filtering voltage V1 and the second filtering voltage V2. The first filtered voltage V1 and the second filtered voltage V2 have different corresponding time constants.

[0031] Since the first filtered voltage V1 and the second filtered voltage V2 are both obtained by filtering the first sampled voltage, the average voltages of the first filtered voltage V1 and the second filtered voltage V2 are the same. Then, a subtraction circuit 330 is used to subtract the first filtered voltage V1 and the second filtered voltage V2. When the time constants corresponding to the first filtered voltage V1 and the second filtered voltage V2 are different, a ripple feedback signal with a DC value of 0V can be generated. .

[0032] Ripple feedback signal It reflects the ripple of the first sampling voltage, that is, it reflects the ripple of the switch node voltage SW, so it can be fed back according to the ripple signal The DC conversion circuit 100 is adjusted to improve the transient response performance of the ripple injection type DC converter 10 .

[0033] In one embodiment, if Figure 2 As shown, the first filter circuit 310 includes a first filter resistor R3 and a first filter capacitor C1, the first end of the first filter resistor R3 is connected to the sampling circuit 200, the second end of the first filter resistor R3 is respectively connected to the first input end of the subtraction circuit 330 and the first end of the first filter capacitor C1, and the second end of the first filter capacitor C1 is grounded.

[0034] It should be noted that, since the switch node voltage SW switches between the input voltage and 0V, the first sampling voltage switches back and forth between the high level voltage and the low level voltage. When the first sampling voltage is a high level voltage, the first sampling voltage can charge the first filter capacitor C1 through the first filter resistor R3. When the first sampling voltage is a low level voltage, the charge on the first filter capacitor C1 will discharge to the ground, thereby generating a first filter voltage V1 with ripples.

[0035] In one embodiment, if Figure 2 As shown, the second filter circuit 320 includes a second filter resistor R4 and a second filter capacitor C2, the first end of the second filter resistor R4 is connected to the sampling circuit 200, the second end of the second filter resistor R4 is respectively connected to the second input end of the subtraction circuit 330 and the first end of the second filter capacitor C2, and the second end of the second filter capacitor C2 is grounded.

[0036] Similarly, when the first sampling voltage is a high level voltage, the first sampling voltage can charge the second filter capacitor C2 through the second filter resistor R4. When the first sampling voltage is a low level voltage, the charge on the second filter capacitor C2 will discharge to the ground, thereby generating a second filter voltage V2 with ripples.

[0037] It should be noted that by reasonably configuring the parameters of the first filter resistor R3, the first filter capacitor C1, the second filter resistor R4 and the second filter capacitor C2, the first filter voltage V1 and the second filter voltage V2 can have different time constants. After the first filter voltage V1 and the second filter voltage V2 are subtracted by a subtraction circuit 330, a ripple feedback signal with a DC value of 0V can be generated. .

[0038] In one embodiment, if Figure 2 As shown, the clamp circuit 400 is respectively connected to the first end of the first filter circuit 310 and the second end of the first filter circuit 310, and the clamp circuit 400 is used to The voltage at the first end of the first filter circuit 310 is adjusted by the first filter voltage V1 so that the first filter voltage V1 is not greater than the reference voltage .

[0039] It should be noted that the ripple injection type DC converter 10 has a DC gain , DC gain The calculation formula is:

[0040] (1)

[0041] In formula (1), is the gain factor determined by the circuit of the ripple injection type DC converter 10, is the reference voltage, is the output voltage. Among them, the gain factor and reference voltage When all parameters are fixed, as the output voltage Boost, DC gain In order to maintain system stability, the DC gain is usually Crossing the 0dB plane at a -10dB / dec slope.

[0042] like Figure 3 As shown, the waveform in the figure is the output voltage The DC gain at VO1, VO2 and VO3 respectively The waveform diagram shows that VO1 is greater than VO2, VO2 is greater than VO3, and when the output voltage When the voltage is VO1, the DC gain The curve crosses the 0dB plane at -40dbB / dec. At this time, the phase is close to 0 degrees and the system is at risk of oscillation. Figure 3 It can be seen that as the output voltage The increase of the conjugate pole f dp , compensation zero pole f Z and the high frequency pole f bw The phase is deteriorating.

[0043] It is understandable that as the output voltage The first filtered voltage V1 will also increase gradually. When the first filtered voltage V1 is higher than the reference voltage When the clamping circuit 400 can clamp the first filtered voltage V1 at the reference voltage .

[0044] At this time, the DC gain The calculation formula is:

[0045] (2)

[0046] At the same time, due to , therefore, the first filtered voltage V1 is clamped at the reference voltage When the DC gain Always 1, as shown in the figure, regardless of the output voltage What is the DC gain? The phase and bandwidth remain unchanged, so that the ripple injection type DC converter 10 can output a larger voltage and has a wide output voltage range.

[0047] In one embodiment, the clamp circuit 400 includes an error amplifier U1 and a voltage regulating switch Q1. The non-inverting input terminal of the error amplifier U1 is connected to the second terminal of the first filter circuit 310. The inverting input terminal of the error amplifier U1 is used to access the reference voltage. The output end of the error amplifier U1 is connected to the control end of the voltage regulating switch Q1, the first end of the voltage regulating switch Q1 is connected to the first end of the first filter circuit 310, and the second end of the voltage regulating switch Q1 is grounded.

[0048] It should be noted that when the first filtered voltage V1 is less than the reference voltage When the error amplifier U1 can control the voltage regulating switch to turn off, the first filtered voltage V1 is output normally. When the error amplifier U1 controls the voltage regulating switch to conduct, the first filtered voltage V1 is reduced so that the first filtered voltage V1 does not exceed the reference voltage. .

[0049] In some embodiments, the voltage regulating switch Q1 includes an N-type MOS transistor.

[0050] In one embodiment, if Figure 4 As shown, the DC conversion circuit 100 includes a drive control module 110 and a power switch module 120. The drive control module 110 is connected to the sampling circuit 200, the ripple generation circuit 300 and the power switch module 120 respectively. The drive control module 110 is used to generate a ripple signal according to the switch node voltage SW and the output voltage , the second sampling voltage FB and the ripple feedback signal The power switch module 120 is used to generate a switch node voltage SW based on the input voltage according to the drive signal, and to generate an output voltage based on the switch node voltage SW. .

[0051] The drive control module 110 is used to process the signal according to the switch node voltage SW and the output voltage , the second sampling voltage FB and the ripple feedback signal The real-time change generates a corresponding driving signal to adjust the output voltage of the power switch module 120 .

[0052] In one embodiment, if Figure 4 As shown, the power switch module 120 includes a first power switch Q2, a second power switch Q3, an output inductor L1, and an output capacitor C3. The first end of the first power switch Q2 is used to access the input voltage, the second end of the first power switch Q2 is connected to the first end of the second power switch Q3 and the first end of the output inductor L1 respectively, the control end of the first power switch Q2 is connected to the drive control module 110, the second end of the output inductor L1 is connected to the first end of the output capacitor C3, and the second end of the output capacitor C3 is grounded. The second end of the first power switch Q2 is used to output the switch node voltage SW, and the second end of the output inductor L1 is used to output the output voltage The second terminal of the second power switch Q3 is grounded, and the control terminal of the second power switch Q3 is connected to the driving control module 110 .

[0053] The first power switch Q2 is the upper switch, and the second power switch Q3 is the lower switch.

[0054] When the second power switch Q3 is turned off and the first power switch Q2 is turned on, the input voltage charges the output inductor L1. When the first power switch Q2 is turned off and the second power switch Q3 is turned on, the energy stored in the output inductor L1 is discharged to the output capacitor C3 and the load. During the entire switching process, the energy stored in the output inductor L1 is balanced with the energy released. The formula for calculating the output voltage is:

[0055] (3)

[0056] In formula (3), D is the proportion of the conduction time of the first power switch Q2 in a switching cycle, is the input voltage.

[0057] In some embodiments, the first power switch Q2 and the second power switch Q3 both include N-type MOS tubes.

[0058] In one embodiment, if Figure 4 As shown, the driving control module 110 includes a fixed on-time generating unit 111, an adding circuit 112, a comparator 113, a trigger 114 and a driving unit 115. The fixed on-time generating unit 111, the adding circuit 112, the comparator 113, the trigger 114 and the driving unit 115 can adopt corresponding electronic devices or integrated circuits, which are not limited in this embodiment.

[0059] The fixed on-time generating unit 111 is connected to the power switch module 120 and the first input terminal of the trigger 114 respectively. The fixed on-time generating unit 111 is used to generate a fixed on-time according to the switch node voltage SW and the output voltage The adding circuit 112 is connected to the sampling circuit 200, the ripple generating circuit 300 and the inverting input terminal of the comparator 113 respectively, and is used to add the second sampling voltage FB to the ripple feedback signal The positive input terminal of the comparator 113 is used to access the reference voltage The output terminal of the comparator 113 is connected to the second input terminal of the trigger 114. The comparator 113 is used to generate a reference voltage according to the reference voltage. and feedback voltage to generate and output the second control signal TH. The output end of the trigger 114 is connected to the input end of the driving unit 115. The trigger 114 is used to output the PWM control signal, and configure the falling edge of the PWM control signal according to the first control signal TL, and configure the rising edge of the PWM control signal according to the second control signal TH. The first output end and the second output end of the driving unit 115 are respectively connected to the control ends of the two power switches of the power switch module 120. The driving unit 115 is used to control the conduction and shutdown of the two power switches of the power switch module 120 according to the PWM control signal. Among them, the driving unit 115 may include a control unit such as a driving chip.

[0060] It should be noted that the first control signal TL is a control signal for controlling the first power switch Q2 to be turned off and the second power switch Q3 to be turned on, and the second control signal TH is a control signal for controlling the first power switch Q2 to be turned on and the second power switch Q3 to be turned off.

[0061] For example, each signal waveform is as follows: Figure 5 As shown. When the feedback voltage drops to the reference voltage When the fixed on-time ends, the first control signal TL changes from low level to high level, the first power switch Q2 turns on, and the second power switch Q3 turns off. This cycle is repeated to achieve the final output voltage of the input voltage. To output voltage conversion.

[0062] It should be noted that the fixed on-time generating unit 111 , the adding circuit 112 , the comparator 113 , the trigger 114 and the driving unit 115 may adopt a conventional fixed on-time DC voltage regulation scheme, which is not limited in this embodiment.

[0063] Figure 6 A schematic diagram of an electronic device provided by an embodiment of the present application is shown. For ease of description, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0064] The electronic device 20 includes the ripple injection type DC converter 10 according to any one of the above embodiments.

[0065] The electronic device 20 may be a chip, a power supply device, etc.

[0066] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0067] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0068] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A ripple injection type DC converter, characterized in that: include: A DC conversion circuit, the DC conversion circuit is used to generate a switch node voltage based on an input voltage and generate an output voltage based on the switch node voltage according to a reference voltage and a feedback parameter; the feedback parameter includes the switch node voltage and the output voltage; a sampling circuit, the sampling circuit being connected to the DC conversion circuit, the sampling circuit being used to generate a first sampling voltage based on the switch node voltage, and being used to generate a second sampling voltage based on the output voltage; the feedback parameter including the second sampling voltage; a ripple generating circuit, the ripple generating circuit being connected to the sampling circuit, the ripple generating circuit being used to generate a ripple feedback signal based on the first sampling voltage; the feedback parameter comprising the ripple feedback signal; A clamping circuit, wherein the clamping circuit is connected to the ripple generating circuit, and the clamping circuit is used to clamp the voltage in the ripple generating circuit according to the reference voltage.

2. The ripple injection type DC converter according to claim 1, characterized in that: The ripple generating circuit comprises a first filtering circuit, a second filtering circuit and a subtraction circuit; A first end of the first filtering circuit is connected to the sampling circuit, a second end of the first filtering circuit is connected to a first input end of the subtraction circuit, and the first filtering circuit is used to generate a first filtering voltage based on the first sampling voltage; A first end of the second filtering circuit is connected to the sampling circuit, a second end of the second filtering circuit is connected to a second input end of the subtraction circuit, and the second filtering circuit is used to generate a second filtering voltage based on the first sampling voltage; The output end of the subtraction circuit is connected to the DC conversion circuit, and the subtraction circuit generates the ripple feedback signal according to the difference between the first filter voltage and the second filter voltage; wherein the time constants corresponding to the first filter voltage and the second filter voltage are different.

3. The ripple injection type DC converter according to claim 2, characterized in that: The first filter circuit includes a first filter resistor and a first filter capacitor, the first end of the first filter resistor is connected to the sampling circuit, the second end of the first filter resistor is respectively connected to the first input end of the subtraction circuit and the first end of the first filter capacitor, and the second end of the first filter capacitor is grounded.

4. The ripple injection type DC converter according to claim 2, characterized in that: The second filtering circuit includes a second filtering resistor and a second filtering capacitor, the first end of the second filtering resistor is connected to the sampling circuit, the second end of the second filtering resistor is respectively connected to the second input end of the subtraction circuit and the first end of the second filtering capacitor, and the second section of the second filtering capacitor is grounded.

5. The ripple injection type DC converter according to claim 2, characterized in that: The clamping circuit is respectively connected to the first end of the first filter circuit and the second end of the first filter circuit, and is used to adjust the voltage of the first end of the first filter circuit according to the reference voltage and the first filter voltage so that the first filter voltage is not greater than the reference voltage.

6. The ripple injection type DC converter according to claim 5, characterized in that: The clamping circuit includes an error amplifier and a voltage regulating switch, the non-phase input terminal of the error amplifier is connected to the second end of the first filter circuit, the inverting input terminal of the error amplifier is used to access the reference voltage, the output terminal of the error amplifier is connected to the control terminal of the voltage regulating switch, the first end of the voltage regulating switch is connected to the first end of the first filter circuit, and the second end of the voltage regulating switch is grounded.

7. The ripple injection type DC converter according to any one of claims 1 to 6, characterized in that: The DC conversion circuit includes a drive control module and a power switch module; The drive control module is connected to the sampling circuit, the ripple generation circuit and the power switch module respectively, and the drive control module is used to generate a drive signal according to the switch node voltage, the output voltage, the second sampled voltage and the ripple feedback signal; The power switch module is configured to generate the switch node voltage based on the input voltage according to the drive signal, and to generate the output voltage based on the switch node voltage.

8. The ripple injection type DC converter according to claim 7, characterized in that: The power switch module includes a first power switch, a second power switch, an output inductor and an output capacitor; The first end of the first power switch is used to access the input voltage, the second end of the first power switch is respectively connected to the first end of the second power switch and the first end of the output inductor, the control end of the first power switch is connected to the drive control module, the second end of the output inductor is connected to the first end of the output capacitor, and the second end of the output capacitor is grounded; the second end of the first power switch is used to output the switch node voltage, and the second section of the output inductor is used to output the output voltage; The second end of the second power switch is grounded, and the control end of the second power switch is connected to the drive control module.

9. The ripple injection type DC converter according to claim 7, characterized in that: The drive control module includes a fixed on-time generation unit, an adding circuit, a comparator, a trigger and a drive unit; The fixed on-time generation unit is connected to the power switch module and the first input terminal of the trigger respectively, and the fixed on-time generation unit is used to generate and output a first control signal according to the switch node voltage and the output voltage; The adding circuit is connected to the sampling circuit, the ripple generating circuit and the inverting input terminal of the comparator respectively, and the adding circuit is used to add the second sampling voltage and the ripple feedback signal to obtain a feedback voltage; The non-inverting input terminal of the comparator is used to access the reference voltage, the output terminal of the comparator is connected to the second input terminal of the trigger, and the comparator is used to generate and output a second control signal according to the reference voltage and the feedback voltage; The output end of the trigger is connected to the input end of the driving unit, and the trigger is used to output a PWM control signal, and configure the falling edge of the PWM control signal according to the first control signal, and configure the rising edge of the PWM control signal according to the second control signal; The first output terminal and the second output terminal of the driving unit are respectively connected to the control terminals of the two power switches of the power switch module, and the driving unit is used to control the on and off of the two power switches of the power switch module according to the PWM control signal.

10. An electronic device, characterized in that: It comprises the ripple injection type DC converter as claimed in any one of claims 1 to 9.

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