Buck circuit with adjustable switching frequency and power supply

Abstract

The invention provides a Buck circuit with adjustable switching frequency and a power supply. The Buck circuit can comprise a conversion module, a first control module, a hysteresis comparison module and a second control module. The conversion module is used for outputting feedback voltage to the first control module according to the modulation signal. The first control module is used for outputting an adjustable threshold median to the hysteresis comparison module according to the feedback voltage. The second control module is used for outputting an adjustable threshold width to the hysteresis comparison module according to the modulation signal. And the hysteresis comparison module is used for outputting a modulation signal according to the adjustable threshold median and the adjustable threshold width. According to the invention, the frequency of the electromagnetic interference generated by the influence of factors such as working conditions, temperature and aging can be controlled, the controllable electromagnetic interference can be processed through the filter, and the normal operation of the load can be realized.

Description

Technical Field

[0001] The present application relates to the technical field of switching power supplies, and in particular to a Buck circuit and a power supply with adjustable switching frequency. Background Art

[0002] As the functions of the system on chip become more and more complex, the switching of the working modes of each functional module is becoming more and more frequent, which puts higher requirements on the dynamic response of the power supply. In order to meet the demand for fast dynamic response, nonlinear control such as hysteresis comparator is applied to the Buck circuit of the power supply. The Buck circuit can include a conversion module. The current flowing through the filter capacitor in the conversion module (which can be referred to as capacitor current) can intuitively reflect the dynamic changes of the output detection voltage. The hysteresis comparator is usually based on the detection voltage obtained according to the capacitor current, and theoretically can have a faster dynamic response. In the conversion circuit provided by the relevant technology, the hysteresis comparator usually compares the threshold voltage and the detection voltage according to the preset threshold width, and outputs a modulated signal. However, since the switching frequency of the hysteresis comparator will be affected by factors such as working conditions, temperature and aging, it will generate electromagnetic interference with uncontrollable frequency, resulting in the load of the conversion circuit not being able to operate normally. Summary of the invention

[0003] In order to solve the problem that the load of the conversion circuit in the prior art cannot operate normally, the present application provides a Buck circuit with adjustable switching frequency, which can include a conversion module, a first control module, a hysteresis comparison module and a second control module.

[0004] The conversion module is used to output a feedback voltage to the first control module according to the modulation signal.

[0005] The first control module is used to output an adjustable threshold median value to the hysteresis comparison module according to the feedback voltage.

[0006] The second control module is used to output an adjustable threshold width to the hysteresis comparison module according to the modulation signal.

[0007] The hysteresis comparison module is used to output a modulation signal according to an adjustable threshold median value and an adjustable threshold width.

[0008] In some possible implementations, the second control module includes a frequency divider, a frequency-to-voltage converter, a first amplifier, and a compensation unit.

[0009] Among them, the input end of the divider is connected to the output end of the hysteresis comparison module, the output end of the divider is connected to the input end of the frequency-to-voltage converter, the output end of the frequency-to-voltage converter is connected to the inverting input end of the first amplifier, the non-inverting input end of the first amplifier is used to receive a preset reference voltage, the output end of the first amplifier is connected to the input end of the compensation unit, and the output end of the compensation unit is used to output an adjustable threshold width.

[0010] Exemplarily, the frequency divider is used to adjust the frequency of the modulation signal to the input frequency of the frequency-to-voltage converter.

[0011] The frequency-to-voltage converter is used to convert the input frequency into the output voltage of the frequency-to-voltage converter.

[0012] The compensation unit is used to amplify and compensate the voltage error and output an adjustable threshold width.

[0013] The modulation signal may be a periodic square wave signal, and the voltage error is used to indicate a voltage difference between a preset reference voltage and an output voltage.

[0014] In some other possible implementations, the first control module includes an analog-to-digital conversion unit, a control unit, and a digital-to-analog conversion unit.

[0015] The analog-to-digital conversion unit is used to convert the feedback voltage into a first digital voltage.

[0016] The control unit is used to calculate the second digital voltage according to the first digital voltage.

[0017] The digital-to-analog conversion unit is used to convert the second digital voltage into an adjustable threshold median value.

[0018] Exemplarily, the control module uses a field programmable gate array.

[0019] Optionally, the second digital voltage satisfies:

[0020] V out2 =(V ref -V out1 )Ck R / (NT s )

[0021] Among them, V out2 Represents the second digital voltage, V out1 Represents the first digital voltage, V ref represents the preset reference voltage, C represents the capacitance of the filter capacitor in the conversion module, k R represents the detection coefficient of the current flowing through the filter capacitor, N represents the preset number of switching cycles, T s Represents the switching cycle of the Buck circuit.

[0022] In some other possible implementations, the hysteresis comparison module includes a first comparator, a second comparator, a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a seventh voltage-dividing resistor, an eighth voltage-dividing resistor and a latch.

[0023] The first ends of the first and seventh voltage-dividing resistors are respectively used to receive the median value of the adjustable threshold, the first ends of the second and sixth voltage-dividing resistors are respectively used to receive the adjustable threshold width, and the first ends of the third and fifth voltage-dividing resistors are respectively used to receive the detection voltage.

[0024] The second ends of the first voltage-dividing resistor and the second voltage-dividing resistor are respectively connected to the non-inverting input terminal of the first comparator, the second ends of the fifth voltage-dividing resistor and the sixth voltage-dividing resistor are respectively connected to the non-inverting input terminal of the second comparator, the second end of the third voltage-dividing resistor and the first end of the fourth voltage-dividing resistor are both connected to the inverting input terminal of the first comparator, the second end of the seventh voltage-dividing resistor and the first end of the eighth voltage-dividing resistor are both connected to the inverting input terminal of the second comparator, and the second ends of the fourth voltage-dividing resistor and the eighth voltage-dividing resistor are respectively connected to the ground terminal.

[0025] The output end of the first comparator is connected to the reset end of the latch, the output end of the second comparator is connected to the set end of the latch, and the output end of the latch is used to output the modulation signal.

[0026] Exemplarily, the threshold signal of the hysteresis comparison module is composed of an upper threshold and a lower threshold, wherein the upper threshold is the median value of the adjustable threshold plus half of the adjustable threshold width, and the lower threshold is the median value of the adjustable threshold minus half of the adjustable threshold width.

[0027] Optionally, the ratio of the resistance of the first voltage-dividing resistor to the resistance of the second voltage-dividing resistor, the ratio of the resistance of the third voltage-dividing resistor to the resistance of the fourth voltage-dividing resistor, the ratio of the resistance of the fifth voltage-dividing resistor to the resistance of the sixth voltage-dividing resistor, and the ratio of the resistance of the seventh voltage-dividing resistor to the resistance of the eighth voltage-dividing resistor are equal.

[0028] Exemplarily, the conversion module includes a primary power supply, a driving unit, a first switching tube, a second switching tube, a filter inductor, a filter capacitor, a branch capacitor, a branch resistor, a feedback resistor, a second amplifier, a ninth voltage divider resistor and a tenth voltage divider resistor.

[0029] The input end of the driving unit is used to receive the modulation signal, and the output end of the driving unit is connected to the control electrodes of the first switch tube and the second switch tube. It can be seen that the driving unit can output a driving signal according to the modulation signal to drive the first switch tube and the second switch tube to turn on and off.

[0030] The first pole of the first switch tube is connected to the positive terminal of the primary power supply, and the second pole of the first switch tube and the first pole of the second switch tube are both connected to the first end of the filter inductor. The second end of the filter inductor, the first pole of the filter capacitor, the first end of the branch capacitor, the first end of the load and the first end of the ninth voltage-dividing resistor are connected as the output end of the Buck circuit. The second end of the branch capacitor is connected to the first end of the branch resistor, the second end of the branch resistor and the first end of the feedback resistor are both connected to the inverting input end of the second amplifier, and the second end of the feedback resistor is connected to the output end of the second amplifier for outputting the detection voltage. The second end of the ninth voltage-dividing resistor is connected to the first end of the tenth voltage-dividing resistor for outputting the feedback voltage. The second pole of the second switch tube, the second pole of the filter capacitor, the in-phase input end of the second amplifier, the second end of the load and the second end of the tenth voltage-dividing resistor are all connected to the negative terminal of the primary power supply.

[0031] Optionally, the detection voltage satisfies:

[0032] V C =I C k R

[0033] Among them, V C Represents the detection voltage, I C Represents the current flowing through the filter capacitor, k R Indicates the detection coefficient of the current flowing through the filter capacitor.

[0034] On the other hand, the present application also provides a power supply, which may include a circuit board and the above-mentioned Buck circuit. The Buck circuit is arranged on the circuit board.

[0035] Compared with the prior art, the beneficial effects of this application are:

[0036] In the Buck circuit with adjustable switching frequency provided in the present application, the first control module outputs an adjustable threshold median value according to the feedback voltage, that is, the threshold median value output by the first control module is adjustable; the second control module can be used to output an adjustable threshold width according to the modulation signal, that is, the threshold width output by the second control module is adjustable; according to the adjustable threshold median value and the adjustable threshold width, the frequency of electromagnetic interference generated by factors such as working conditions, temperature and aging can be controlled, and the controllable electromagnetic interference can be processed by a filter, thereby achieving normal operation of the load.

[0037] In the present application, the adjustable threshold median value and the adjustable threshold width can make the switching frequency of the buck circuit reach the target frequency, that is, the switching frequency of the buck circuit is adjustable, and the frequency offset problem of the hysteresis comparison control is solved.

[0038] In the present application, the control unit calculates the second digital voltage based on the preset reference voltage and the first digital voltage, and outputs an adjustable threshold voltage through the digital-to-analog conversion unit, so that the feedback voltage can quickly return to the vicinity of the reference voltage after several adjustment cycles, thereby achieving adjustable output voltage of the Buck circuit and being able to power different types of loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 A schematic structural diagram of a Buck circuit in an embodiment of the present application;

[0041] Figure 2 Another schematic structural diagram of the Buck circuit in the embodiment of the present application;

[0042] Figure 3 is a schematic structural diagram of a hysteresis comparison module in an embodiment of the present application;

[0043] Figure 4 is a schematic waveform diagram of the second digital voltage in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0045] The terms "first", "second", etc. in the specification embodiments, claims, and drawings of the present application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, including a series of steps or units. The method, system, product, or device is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0046] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0047] The present application provides a Buck circuit with adjustable switching frequency, such as Figure 1 The Buck circuit 10 includes a transformation module 1 , a first control module 2 , a hysteresis comparison module 3 and a second control module 4 .

[0048] Optionally, the conversion module 1 is used to: output a feedback voltage (which can be V fb (represented) to the first control module 2.

[0049] The first control module 2 is used to: fb Output adjustable threshold value (can be used with V mid Indicates) to the hysteresis comparison module 4.

[0050] The second control module 3 is used to output an adjustable threshold width (which can be V wid Indicates) to the hysteresis comparison module 4.

[0051] The hysteresis comparison module 4 is used to: mid and adjustable threshold width V wid Output modulated signal.

[0052] In some possible implementations, such as Figure 2 As shown, the second control module 3 includes a frequency divider 31 , a frequency-to-voltage converter 32 , a first amplifier 33 (which may be an operational amplifier) ​​and a compensation unit 34 .

[0053] The input end of the frequency divider 31 is connected to the output end of the hysteresis comparison module 4, the output end of the frequency divider 31 is connected to the input end of the frequency-to-voltage converter 32, the output end of the frequency-to-voltage converter 32 is connected to the inverting input end of the first amplifier 33, and the non-inverting input end of the first amplifier 33 is used to receive a preset reference voltage (which can be V cr The output end of the first amplifier 33 is connected to the input end of the compensation unit 34, and the output end of the compensation unit 34 is used to output the adjustable threshold width V wid .

[0054] Exemplarily, the frequency divider 31 is used to: divide the frequency of the modulation signal (which can be expressed as f sw ) is adjusted to the input frequency of the frequency-to-voltage converter 32 (which can be expressed as f d denoted). Satisfies, f d =f sw / K FD . K FD Indicates the frequency division coefficient.

[0055] The frequency-to-voltage converter 32 is used to convert the input frequency f d Converted to the output voltage of the frequency-to-voltage converter 32 (can be V sf express).

[0056] The compensation unit 34 is used to: error (indicated) for amplification and compensation, and output adjustable threshold width.

[0057] The modulation signal can be a periodic square wave signal, and the voltage error V error Used to indicate the preset reference voltage (V cr Indicates) and output voltage V sf voltage difference.

[0058] When the above process is stable, the output voltage V sf With the preset reference voltage V cr By adjusting the preset reference voltage V cr Change the adjustable threshold width V wid , so that the frequency of the modulation signal output by the hysteresis comparison module 4 reaches the preset target frequency.

[0059] In other embodiments, Figure 2 As shown, the first control module 2 includes an analog-to-digital conversion unit (ADC for short) 21 , a control unit 22 and a digital-to-analog conversion unit (DAC for short) 23 .

[0060] The analog-to-digital conversion unit 21 is used to convert the feedback voltage V fb Converted to a first digital voltage (can be used with Vout1 express).

[0061] The control unit 22 is used to: out1 Calculate the second digital voltage (you can use V out2 express).

[0062] The digital-to-analog conversion unit 23 is used to convert the second digital voltage V out2 Convert to adjustable threshold value V mid .

[0063] Exemplarily, the control module adopts a Field Programmable Gate Array (FPGA).

[0064] Optionally, the second digital voltage V out2 satisfy:

[0065] V out2 =(V ref -V out1 )Ck R / (NT s )

[0066] Among them, V out2 Represents the second digital voltage, V out1 Represents the first digital voltage, V ref represents the preset reference voltage, C represents the capacitance of the filter capacitor C in the conversion module 1, k R represents the detection coefficient of the current flowing through the filter capacitor C, N represents the preset number of switching cycles, and N should be greater than the value calculated by the analog-to-digital conversion unit 21, the control unit 22 and the digital-to-analog conversion unit 23 from V out1 To the adjustable threshold value V mid The number of switching cycles experienced. s represents the switching cycle of the Buck circuit 10.

[0067] Adjustable threshold median V mid The generation method is based on: In order to make the feedback voltage V fb In the next few cycles, the reference voltage V ref , by calculating the reference voltage V ref With the feedback voltage V fb The difference is multiplied by the capacitance of the filter capacitor to determine the amount of charge required by the output filter capacitor. The amount of charge required by the filter capacitor is divided by the time experienced in the next several cycles (i.e., NT s ), that is, the current flowing through the filter capacitor C (which can be expressed as I C Indicates) the reference current during this period, multiplied by the detection coefficient k R The adjustable threshold value V mid .

[0068] In the nth sampling cycle, as time t changes, the second digital voltage V out2 The schematic waveform diagram of (n) is as follows Figure 4 shown. Figure 4 In, V e Indicates the reference voltage V ref With the first digital voltage V out1 The difference, V e =V ref -V out1 . V out2 (n-1) represents the second digital voltage in the n-1th sampling period.

[0069] Continue to refer Figure 2 The conversion module 1 includes a primary power supply 11, a driving unit 12, a first switch tube Q1, a second switch tube Q2, a filter inductor L, a filter capacitor C, a branch capacitor Cs, a branch resistor Rs, a feedback resistor R, a second amplifier Amp2, a ninth voltage-dividing resistor R9 and a tenth voltage-dividing resistor R10.

[0070] The input end of the driving unit 12 is used to receive the modulation signal, and the output end of the driving unit 12 is connected to the control electrode of each of the first switch tube Q1 and the second switch tube Q2. It can be seen that the driving unit 12 can output a driving signal according to the modulation signal to drive the first switch tube Q1 and the second switch tube Q2 to be turned on and off. In the embodiment of the present application, the first switch tube Q1 and the second switch tube Q2 can be N-type metal oxide semiconductor transistors (Metal-Oxide-Semiconductor), which can be referred to as NMOS tubes. Of course, the first switch tube Q1 and the second switch tube Q2 can also be other types of semiconductor devices, which are not limited in the embodiment of the present application.

[0071] The first electrode (which may be the drain electrode) of the first switch tube Q1 is connected to the positive terminal of the primary power supply 11, and the second electrode (which may be the source electrode) of the first switch tube Q1 and the first electrode (which may be the drain electrode) of the second switch tube Q2 are both connected to the first end of the filter inductor L. The second end of the filter inductor L, the first electrode of the filter capacitor C, the first end of the branch capacitor Cs, and the load R LOAD The first end of the ninth voltage-dividing resistor R9 is connected to the first end of the ninth voltage-dividing resistor R9, serving as the output end of the Buck circuit 10 (i.e. Figure 2 The second end of the branch capacitor Cs is connected to the first end of the branch resistor Rs, the second end of the branch resistor Rs and the first end of the feedback resistor R are both connected to the inverting input end of the second amplifier Amp2, and the second end of the feedback resistor R is connected to the output end of the second amplifier Amp2 for outputting the detection voltage V CThe second end of the feedback resistor R is connected to the output end of the second amplifier Amp2 and the hysteresis comparison module 4. The second end of the ninth voltage-dividing resistor R9 is connected to the first end of the tenth voltage-dividing resistor R10 for outputting the feedback voltage V fb The second electrode of the second switch tube Q2, the second electrode of the filter capacitor C, the in-phase input terminal of the second amplifier Amp2, the load R LOAD The second end of and the second end of the tenth voltage resistor R10 are both connected to the negative terminal of the primary power supply 11.

[0072] For example, the load R LOAD It can be a portable device or a communication system, etc.

[0073] Optionally, the detection voltage satisfies:

[0074] V C =I C k R

[0075] Among them, V C Represents the detection voltage, I C represents the current flowing through the filter capacitor C, k R Indicates the detection coefficient of the current flowing through the filter capacitor C, i.e. k R Indicates I C The detection coefficient.

[0076] from Figure 2 It can be seen that by connecting the branch capacitor Cs in parallel next to the filter capacitor C, the current flowing through the filter capacitor C is copied to the branch capacitor Cs in equal proportion, and the current is converted into a detection voltage by the second amplifier Amp2 connected by negative feedback. Due to the existence of non-ideal effects, there is an equivalent series inductance and an equivalent series resistance in the filter capacitor C, so the impedance characteristics of the parallel branch (composed of the branch capacitor Cs and the branch resistor R in series) are proportional to the filter capacitor C. The second amplifier Amp2 is equivalent to an inductor within the bandwidth, and the equivalent inductance matches the equivalent series inductance of the filter capacitor C. To ensure accurate replication of the capacitive current, the resistance value of the branch resistor R matches the filter capacitor C and the equivalent series resistance.

[0077] refer to Figure 3 The hysteresis comparison module 4 includes a first comparator 41, a second comparator 42, a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, a third voltage-dividing resistor R3, a fourth voltage-dividing resistor R4, a fifth voltage-dividing resistor R5, a sixth voltage-dividing resistor R6, a seventh voltage-dividing resistor R7, an eighth voltage-dividing resistor R8 and a latch 43 (which can be an RS latch).

[0078] The first end of the first voltage-dividing resistor R1 and the first end of the seventh voltage-dividing resistor R7 are respectively used to receive the adjustable threshold median value V midThe first ends of the second voltage-dividing resistor R3 and the sixth voltage-dividing resistor R6 are each used to receive the adjustable threshold width V wid The first ends of the third voltage-dividing resistor R3 and the fifth voltage-dividing resistor R5 are each used to receive the detection voltage V C .

[0079] The second end of each of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 is connected to the non-inverting input end of the first comparator 41, the second end of each of the fifth voltage-dividing resistor R5 and the sixth voltage-dividing resistor R6 is connected to the non-inverting input end of the second comparator 42, the second end of the third voltage-dividing resistor R3 and the first end of the fourth voltage-dividing resistor R4 are both connected to the inverting input end of the first comparator 41, the second end of the seventh voltage-dividing resistor R7 and the first end of the eighth voltage-dividing resistor R8 are both connected to the inverting input end of the second comparator 42, and the second end of each of the fourth voltage-dividing resistor R4 and the eighth voltage-dividing resistor R8 is connected to the ground end. The output end of the first comparator 41 (for outputting the first comparison signal) is connected to the reset end (i.e., the R end) of the latch 43, and the output end of the second comparator 42 (for outputting the second comparison signal) is connected to the set end (i.e., the S end) of the latch 43. The output end (i.e., the Q end) of the latch 43 is used to output the modulation signal. That is, the latch 43 outputs the modulation signal according to the first comparison signal and the first comparison signal.

[0080] Exemplarily, the threshold signal of the hysteresis comparison module 4 is composed of an upper threshold and a lower threshold. The upper threshold is the median value of the adjustable threshold V mid Add adjustable threshold width V wid The lower threshold is the median value of the adjustable threshold V mid Minus the adjustable threshold width V wid half.

[0081] Optionally, the ratio of the resistance value of the first voltage-dividing resistor R1 to the resistance value of the second voltage-dividing resistor R2, the ratio of the resistance value of the third voltage-dividing resistor R3 to the resistance value of the fourth voltage-dividing resistor R4, the ratio of the resistance value of the fifth voltage-dividing resistor R5 to the resistance value of the sixth voltage-dividing resistor R6, and the ratio of the resistance value of the seventh voltage-dividing resistor R7 to the resistance value of the eighth voltage-dividing resistor R8 are equal. That is, R 1 / R 2 =R 3 / R 4 =R 5 / R 6 =R 7 / R 8 .

[0082] The embodiment of the present application further provides a power supply, which may include a circuit board and the above-mentioned Buck circuit. The Buck circuit is arranged on the circuit board.

[0083] Optionally, the power supply can supply power to one or more loads, which will not be described in detail in the embodiments of the present application.

[0084] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A Buck circuit with adjustable switching frequency, characterized in that: It includes a transformation module, a first control module, a hysteresis comparison module and a second control module; The conversion module is used to: output a feedback voltage to the first control module according to the modulation signal; The first control module is used to: output an adjustable threshold median value to the hysteresis comparison module according to the feedback voltage; The second control module is used to: output an adjustable threshold width to the hysteresis comparison module according to the modulation signal; The hysteresis comparison module is used to output the modulation signal according to the adjustable threshold median value and the adjustable threshold width.

2. The Buck circuit according to claim 1, characterized in that: The second control module includes a frequency divider, a frequency-to-voltage converter, a first amplifier and a compensation unit; Among them, the input end of the frequency divider is connected to the output end of the hysteresis comparison module, the output end of the frequency divider is connected to the input end of the frequency-to-voltage converter, the output end of the frequency-to-voltage converter is connected to the inverting input end of the first amplifier, the non-inverting input end of the first amplifier is used to receive a preset reference voltage, the output end of the first amplifier is connected to the input end of the compensation unit, and the output end of the compensation unit is used to output the adjustable threshold width.

3. The Buck circuit according to claim 2, characterized in that: The frequency divider is used to: adjust the frequency of the modulation signal to the input frequency of the frequency-to-voltage converter; The frequency-to-voltage converter is used to: convert the input frequency into an output voltage of the frequency-to-voltage converter; The compensation unit is used to: amplify and compensate the voltage error and output the adjustable threshold width; The voltage error is used to indicate a voltage difference between the preset reference voltage and the output voltage.

4. The Buck circuit according to claim 1, characterized in that: The first control module includes an analog-to-digital conversion unit, a control unit and a digital-to-analog conversion unit; The analog-to-digital conversion unit is used to: convert the feedback voltage into a first digital voltage; The control unit is used to: calculate a second digital voltage according to the first digital voltage; The digital-to-analog conversion unit is used to convert the second digital voltage into the median value of the adjustable threshold.

5. The Buck circuit according to claim 4, characterized in that: The second digital voltage satisfies: V out2 =(V ref -V out1 )Ck R / (NT s ) Among them, V out2 Represents the second digital voltage, V out1 Represents the first digital voltage, V ref represents the preset reference voltage, C represents the capacitance of the filter capacitor in the conversion module, k R represents the detection coefficient of the current flowing through the filter capacitor, N represents the preset number of switching cycles, T s Represents the switching period of the Buck circuit.

6. The Buck circuit according to claim 1, characterized in that: The hysteresis comparison module includes a first comparator, a second comparator, a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a seventh voltage-dividing resistor, an eighth voltage-dividing resistor and a latch; The first ends of the first voltage-dividing resistor and the seventh voltage-dividing resistor are respectively used to receive the median value of the adjustable threshold, the first ends of the second voltage-dividing resistor and the sixth voltage-dividing resistor are respectively used to receive the adjustable threshold width, and the first ends of the third voltage-dividing resistor and the fifth voltage-dividing resistor are respectively used to receive the detection voltage; The second end of each of the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the non-inverting input end of the first comparator, the second end of each of the fifth voltage-dividing resistor and the sixth voltage-dividing resistor is connected to the non-inverting input end of the second comparator, the second end of the third voltage-dividing resistor and the first end of the fourth voltage-dividing resistor are both connected to the inverting input end of the first comparator, the second end of the seventh voltage-dividing resistor and the first end of the eighth voltage-dividing resistor are both connected to the inverting input end of the second comparator, and the second end of each of the fourth voltage-dividing resistor and the eighth voltage-dividing resistor is connected to the ground end; The output end of the first comparator is connected to the reset end of the latch, the output end of the second comparator is connected to the set end of the latch, and the output end of the latch is used to output the modulation signal.

7. The Buck circuit according to claim 1, characterized in that: The ratio of the resistance value of the first voltage-dividing resistor to the resistance value of the second voltage-dividing resistor, the ratio of the resistance value of the third voltage-dividing resistor to the resistance value of the fourth voltage-dividing resistor, the ratio of the resistance value of the fifth voltage-dividing resistor to the resistance value of the sixth voltage-dividing resistor, and the ratio of the resistance value of the seventh voltage-dividing resistor to the resistance value of the eighth voltage-dividing resistor are equal.

8. The Buck circuit according to claim 1, characterized in that: The conversion module includes a primary power supply, a driving unit, a first switch tube, a second switch tube, a filter inductor, a filter capacitor, a branch capacitor, a branch resistor, a feedback resistor, a second amplifier, a ninth voltage divider resistor and a tenth voltage divider resistor; The input end of the driving unit is used to receive the modulation signal, and the output end of the driving unit is connected to the control electrodes of the first switch tube and the second switch tube respectively; the first electrode of the first switch tube is connected to the positive terminal of the primary power supply, and the second electrode of the first switch tube and the first electrode of the second switch tube are both connected to the first end of the filter inductor; the second end of the filter inductor, the first electrode of the filter capacitor, the first end of the branch capacitor, the first end of the load and the first end of the ninth voltage-dividing resistor are connected as the output end of the Buck circuit; the second end of the branch capacitor is connected to the first end of the branch resistor, the second end of the branch resistor and the first end of the feedback resistor are both connected to the inverting input end of the second amplifier, and the second end of the feedback resistor is connected to the output end of the second amplifier for outputting the detection voltage; the second end of the ninth voltage-dividing resistor is connected to the first end of the tenth voltage-dividing resistor for outputting the feedback voltage; the second electrode of the second switch tube, the second electrode of the filter capacitor, the in-phase input end of the second amplifier, the second end of the load and the second end of the tenth voltage-dividing resistor are all connected to the negative terminal of the primary power supply.

9. The Buck circuit according to claim 8, characterized in that: The detection voltage satisfies: V C =I C k R Among them, V C represents the detection voltage, I C represents the current flowing through the filter capacitor, k R A detection coefficient representing the current flowing through the filter capacitor.

10. A power supply, characterized in that: It comprises a circuit board and the Buck circuit according to any one of claims 1 to 9; the Buck circuit is arranged on the circuit board.

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