A fast transient response buck converter based on AOT control

Abstract

The application discloses a fast transient response Buck converter based on AOT control, compatible with the advantages of current mode control and AOT control, an error amplifier is added in a negative feedback control loop, the precision of an output voltage is improved, a current loop is stable, and there is no specific restriction on the series resistance value of an output capacitor; the improved adaptive on-time module is used to reduce the change rate of a switching frequency under heavy load, and ensure that the change of the switching frequency under different load currents is small. The transient enhancement module is used to judge the output voltage, ensure that the output voltage is rapidly stabilized when the load current suddenly changes, reduce overshoot and undershoot, and thus the overall stability and reliability are improved; the sleep detection module Sleep is used to detect the driving signal V COMP of a switching tube, so as to control the Buck converter to enter a sleep state, thereby achieving the purposes of reducing power consumption and improving efficiency.

Description

Technical Field

[0001] This invention belongs to the field of DC-DC converters, specifically relating to a fast transient response Buck converter based on AOT control. Background Technology

[0002] A DC-DC converter is a power management chip that converts electrical energy into different output voltages or currents. Smartphones, laptops, car chargers, and portable smart devices, which are now widely used, all rely on DC-DC converters. In DC / DC switching power supplies, buck converters are widely used in the electronics industry. Because electronic devices have multiple operating states such as sleep mode and active mode, the load needs to draw different and frequently changing currents from the power supply during mode switching. This requires buck converters to have a fast transient response speed; otherwise, excessive overshoot or sag voltage may cause problems such as abnormal device operation.

[0003] To enhance load transient response and operating efficiency, many control methods have been proposed. Among them, V 2 The controlled Buck converter comprises two control loops: a feedforward loop (FFL) and a regulation loop (RL). The FFL transmits a high-frequency signal of the inductor current to the PWM modulator. Therefore, V 2 The control can quickly recover undershoot / overshoot voltage when the load current changes. However, the conventional V 2 Control due to equivalent series resistance R ESR The RBCOT control has advantages such as automatic frequency reduction under light load and high efficiency. It also simplifies the design by eliminating the need for an EA and compensation network. However, this introduces DC offset problems, making it impossible to determine the DC value of the output voltage, resulting in very low accuracy. Therefore, RBCOT control requires a DC offset cancellation circuit. Furthermore, because COT is a variable frequency control, electromagnetic interference (EMI) is more severe than PWM control. Modified AOT control is typically used to adjust the on-time and maintain a constant switching frequency. CMCOT control is a current-mode constant on-time control with both voltage and current feedback loops. The current feedback control loop introduces inductor current-related information, enabling the CMCOT-controlled Buck converter to operate within an equivalent series resistance R... ESR It can operate normally even at lower voltages. The error amplifier in the feedback loop can improve output voltage accuracy. This is achieved by extending the adaptive on-time T... ON This accelerates transient response, but requires additional off-chip capacitors and resistors. Adaptive and quasi-adaptive T... ONCurrent-mode control improves transient response, but this method cannot maintain a constant switching frequency. To achieve a COT converter with a constant switching frequency and fast transient response, the LCC circuit consumes more power due to sensing inductor current, and V... SENSE It is easily affected by PVT variations. A two-stage window control circuit and a phase-locked loop (PLL) approach can achieve a fixed switching frequency. However, due to limited bandwidth, the PLL restricts the load transient response. An adaptive on-time controller with a frequency-locked loop (FLL) simplifies the system architecture and shortens the transient response, but both output voltage ripple and regulation performance are reduced.

[0004] Although various control strategies have been proposed in the industry to enhance the load transient response and efficiency of Buck converters, these methods are often accompanied by their own problems. For example, V 2 The controlled Buck converter, through the design of feedforward and regulation loops, can quickly recover voltage when the load current changes, reducing undershoot or overshoot. However, this control method suffers from a relatively large equivalent series resistance (R0). ESR This results in larger ripple, affecting the stability of the output voltage. On the other hand, while the RBCOT control strategy has advantages such as automatic frequency reduction under light load to improve efficiency and simplifying design by eliminating the need for error amplifiers and compensation networks, it also introduces DC offset problems. This makes it impossible to determine the DC value of the output voltage, significantly reducing accuracy; therefore, a DC offset cancellation circuit must be designed to compensate for this deficiency. Furthermore, since COT control is a variable frequency control, its electromagnetic interference (EMI) problem is more severe than that of PWM control. To alleviate this problem, improved AOT control is often used to adjust the conduction time to maintain a constant switching frequency; however, traditional AOT modules also change with variations in input and output conditions. Meanwhile, adaptive and quasi-adaptive T... ON While current-mode control can improve transient response, it cannot maintain a constant switching frequency, potentially impacting system stability and efficiency. In the pursuit of constant switching frequency and fast transient response, some methods, such as LCC circuits, can achieve these goals, but consume more power due to sensing inductor current, and V... SENSE Buck converters are susceptible to variations in process, voltage, and temperature (PVT). While two-stage window control circuits and phase-locked loop (PLL) methods can achieve a fixed switching frequency, the PLL limits the load transient response due to its limited bandwidth. Adaptive on-time controllers with frequency-locked loops (FLLs) simplify the system architecture and shorten the transient response, but also reduce output voltage ripple and regulation performance. Therefore, Buck converters still face many technical challenges, requiring faster transient response, higher stability, and better efficiency. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a fast transient response Buck converter based on AOT control. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a fast transient response Buck converter based on AOT control, comprising:

[0007] The system includes a signal selection module, an error amplifier (EA), a PWM comparator, an adaptive on-time module (AOT), an output module, a transient enhancement module, and a sleep detection module (Sleep).

[0008] The comparison signal selection module is used, under the control of the Sign signal output by the transient enhancement module, to select the reference voltage V. REF and soft-start voltage V SS Output the signal to be compared;

[0009] The error amplifier EA is used to convert the feedback signal V corresponding to the output voltage of the Buck converter. FB The signal is compared with the signal to be compared, and an error amplification signal V is output. EA ;

[0010] The PWM comparator is used to amplify the error signal V. EA The ripple voltage V corresponding to the inductor in the Buck converter F Compare and output the switch drive signal V. COMP ;

[0011] The adaptive on-time module (AOT) is used to determine the steady-state voltage V corresponding to the switching transistor in the output module. SW The conduction time T corresponding to the conduction signal is generated. ON ;

[0012] The output module is used to output the signal V from the switching transistor. COMP Controlling the switching transistor to turn on, based on the on-time T ON The rectifier drive signal is generated to control its own rectifier to conduct, thereby generating a periodic output voltage; the output module uses an internal adaptive dead-time circuit to prevent the rectifier and the switching transistor from conducting simultaneously.

[0013] The transient enhancement module is used to output a Sign signal to the comparison signal selection module when the load of the Buck converter changes and the output voltage of the Buck converter overshoots or undershoots to a preset threshold.

[0014] The Sleep detection module is used to control the switching transistor drive signal V. COMP Perform detection to determine the drive signal V of the switching transistor. COMP If the preset conditions are met, a sleep signal is output to control the Buck converter to enter a sleep state.

[0015] In one embodiment of the present invention, the comparison signal selection module includes:

[0016] Reference circuit BG, soft start circuit, and selector module.

[0017] In one embodiment of the present invention, the comparison signal selection module, under the control of the Sign signal output by the transient enhancement module, selects a signal based on the reference voltage V. REF and soft-start voltage V SS Output the signal to be compared, including:

[0018] The reference circuit BG generates a reference voltage V. REF ;

[0019] The soft-start circuit generates a soft-start voltage V. SS ;

[0020] The selector module, under the control of the Sign signal output by the transient enhancement module, operates according to the reference voltage V. REF and the soft-start voltage V SS Output the signal to be compared.

[0021] In one embodiment of the present invention, the adaptive on-time module (AOT) includes:

[0022] The circuit includes a VI converter, an inverter, a MOSFET M1, a capacitor C1, resistors R1, R2, and R3, a filter circuit, a first 2-to-1 multiplexer, a second 2-to-1 multiplexer, and a first comparator COMP1; among which,

[0023] The input terminal of the VI converter is connected to a power supply voltage V. DD The first output terminal is connected to the inverting input terminal of the first comparator COMP1, and the second output terminal is connected to the first terminal of the capacitor C1.

[0024] The input terminal of the inverter is connected to the trigger signal NG1 corresponding to the switching transistor, and the output terminal is connected to the gate of the MOS transistor M1.

[0025] The source of the MOS transistor M1 is grounded, and its drain is connected to the first terminal of the capacitor C1.

[0026] The first terminal of capacitor C1 is connected to the inverting input terminal of the first comparator COMP1, and the second terminal is connected to the source of the MOS transistor M1.

[0027] The first terminal of the resistor R1 is connected to the steady-state voltage V corresponding to the switching transistor. SW The second end is connected to the first end of the capacitor C1;

[0028] The first end of resistor R2 is connected to the first end of resistor R1, and the second end is connected to the first end of resistor R3;

[0029] The first end of the resistor R3 is connected to the input end of the filter circuit, and the second end is grounded.

[0030] The output terminal of the filter circuit is connected to the first input terminal of the second 2-to-1 selector, and the ground terminal is grounded.

[0031] The first input terminal of the first 2-to-1 selector is connected to a preset first voltage V. L The second input terminal is connected to the first input terminal of the second 2-to-1 selector, the control terminal is connected to the Sign signal output by the transient enhancement module, and the output terminal is connected to the output terminal of the second 2-to-1 selector.

[0032] The second input terminal of the second 2-to-1 selector is connected to a preset second voltage V. H The output terminal is connected to the non-inverting input terminal of the first comparator COMP1;

[0033] The output of the first comparator COMP1 outputs the on-time T. ON .

[0034] In one embodiment of the present invention, the VI converter includes:

[0035] Current source I SS MOSFET M2, MOSFET M3, transistor Q1, transistor Q2, and resistor R6; among them,

[0036] Current source I SS The first end is connected to the source of the MOS transistor M3, and the second end is connected to the base of the transistor Q1;

[0037] The source of the MOS transistor M2 is connected to the source of the MOS transistor M3, the gate is connected to the gate of the MOS transistor M3, and the drain is used as the first output terminal of the VI converter.

[0038] The source of the MOSFET M3 is connected to a power supply voltage V. DD The gate is connected to its own drain, and the drain is connected to the collector of the transistor Q1.

[0039] The emitter of transistor Q1 is connected to the first end of resistor R6;

[0040] The collector of transistor Q2 is connected to the second end of resistor R6, the base serves as the second output terminal of the VI converter, and the emitter is connected to the base of transistor Q1.

[0041] The second terminal of resistor R6 is grounded.

[0042] In one embodiment of the present invention, the filter circuit includes:

[0043] Resistor R4, resistor R5, capacitor C2, and capacitor C3; among them,

[0044] The first end of resistor R4 serves as the input end of the filter circuit, and the second end is connected to the first end of resistor R5.

[0045] The first end of the resistor R5 is connected to the first end of the capacitor C2, and the second end is connected to the first end of the capacitor C3;

[0046] The second terminal of capacitor C2 serves as the ground terminal of the filter circuit;

[0047] The first end of capacitor C3 serves as the output end of the filter circuit, and the second end is connected to the second end of capacitor C2.

[0048] In one embodiment of the present invention, the on-time T generated by the adaptive on-time module AOT is... ON The expression is as follows:

[0049]

[0050] Where R2 represents the resistance value of resistor R2, R3 represents the resistance value of resistor R3, C1 represents the capacitance value of capacitor C1, R1 represents the resistance value of resistor R1, and D actual This indicates the actual duty cycle of the Buck converter.

[0051] In one embodiment of the present invention, the transient enhancement module includes:

[0052] Resistor R7, capacitor C4, second comparator COMP2, and third comparator COMP3; among which,

[0053] The first terminal of the resistor R7 is connected to the output voltage V of the Buck converter. OUT The second end is connected to the first end of the capacitor C4;

[0054] The second terminal of capacitor C4 is grounded;

[0055] The non-inverting input of the second comparator COMP2 is connected to the first terminal of the capacitor C4, the inverting input is connected to the non-inverting input of the third comparator COMP3, and the output terminal outputs the signal Sign1.

[0056] The inverting input of the third comparator COMP3 is connected to the non-inverting input of the second comparator COMP2, and the output terminal outputs the signal Sign2.

[0057] The signals Sign1 and Sign2 together form the Sign signal.

[0058] In one embodiment of the present invention, the sleep detection module Sleep includes:

[0059] First inverter, MOSFET MP1, MOSFET MP2, MOSFET MP3, MOSFET MP4, MOSFET MN1, MOSFET MN2, MOSFET MN3, MOSFET MN4, current source I SS1 and capacitor C SS ;in,

[0060] The input terminal of the first inverter is connected to the switching transistor drive signal V. COMP The output terminal is connected to the gate of the MOS transistor MP1;

[0061] The source of the MOS transistor MP1 is connected to the current source I. SS1 The output terminal is connected, and the drain is connected to the drain of the MOS transistor MN1;

[0062] The source of the MOSFET MP2 is connected to a power supply voltage V. DD The gate is connected to the gate of the MOS transistor MP3, and the drain is connected to the source of the MOS transistor MP3.

[0063] The source of MOS transistor MP3 is connected to the source of MOS transistor MP4, the gate is connected to the drain of MOS transistor MN1, and the drain is connected to the drain of MOS transistor MN2.

[0064] The gate of the MOS transistor MP4 serves as the output terminal of the Sleep detection module, and its drain is connected to the source of the MOS transistor MN3.

[0065] The source of the MOS transistor MN1 is connected to the capacitor C. SS The second terminal is connected, the gate is connected to the gate of the MOS transistor MP1, and the drain is connected to the capacitor C. SS The first end is connected;

[0066] The source of the MOS transistor MN2 is connected to the drain of the MOS transistor MN3, and the gate is connected to the capacitor C. SSThe first end is connected, and the drain is connected to the gate of the MOS transistor MP4;

[0067] The source of the MOS transistor MN3 is grounded, and its gate is connected to the capacitor C. SS The first end is connected, and the drain is connected to the source of the MOS transistor MN4;

[0068] The gate of MOS transistor MN4 is connected to the gate of MOS transistor MP4, and the drain is connected to the source of MOS transistor MP2.

[0069] The current source I SS1 The input terminal is connected to the source of the MOS transistor MP2;

[0070] The capacitor C SS The second end is connected to the source of the MOS transistor MN3.

[0071] The beneficial effects of this invention are:

[0072] The solution provided by this invention combines the advantages of current-mode control and AOT control. By using the output voltage of the Buck converter as the negative feedback voltage and adding an error amplifier to the negative feedback control loop, the accuracy of the output voltage is improved, the current loop is stabilized, and the series resistance R of the output capacitor is reduced. ESR There are no specific limitations; an improved adaptive on-time module reduces the rate of change of switching frequency under heavy load, ensuring minimal frequency variation under different load current conditions. A transient enhancement module is used to assess the output voltage, ensuring rapid stabilization when the load current suddenly changes, reducing overshoot and undershoot, thereby improving overall stability and reliability; a sleep detection module (Sleep) is used to monitor the switching transistor drive signal V. COMP The system performs detection to control the Buck converter to enter a sleep state, thereby reducing power consumption and improving efficiency. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention;

[0074] Figure 2 This is a schematic diagram of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention;

[0075] Figure 3 This is a schematic diagram of the adaptive on-time module (AOT) in a fast transient response Buck converter based on AOT control, provided in an embodiment of the present invention.

[0076] Figure 4A schematic diagram of the transient enhancement module in a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention;

[0077] Figure 5 This is a schematic diagram of the Sleep detection module in a fast transient response Buck converter based on AOT control, provided in an embodiment of the present invention.

[0078] Figure 6 The above is a simulation diagram of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention.

[0079] Figure 7 The waveform diagram of key signals of a fast transient response Buck converter based on AOT control in steady state is provided in an embodiment of the present invention.

[0080] Figure 8 This is a comparison chart of the switching cycle of the switching transistor corresponding to the switching transistor under different load currents in a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention.

[0081] Figure 9 A comparison diagram of the output voltage and inductor current waveforms of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention, when the load current switches from heavy load to light load;

[0082] Figure 10 A comparison diagram of the output voltage and inductor current waveforms of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention, when the load current switches from light load to heavy load;

[0083] Figure 11 The waveform diagram shows the sleep module detection of a fast transient response Buck converter based on AOT control, as provided in an embodiment of the present invention. Detailed Implementation

[0084] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0085] This invention provides a fast transient response Buck converter based on AOT control, such as... Figure 1 As shown, it may include:

[0086] The system includes a signal selection module, an error amplifier (EA), a PWM comparator, an adaptive on-time module (AOT), an output module, a transient enhancement module, and a sleep detection module (Sleep).

[0087] The comparison signal selection module is used to select the reference voltage V under the control of the Sign signal output by the transient enhancement module. REF and soft-start voltage V SS Output the signal to be compared;

[0088] Error amplifier EA is used to convert the feedback signal V corresponding to the output voltage of the Buck converter. FB The signal is compared with the signal to be compared, and the output error amplification signal V is generated. EA ;

[0089] A PWM comparator is used to amplify the error signal V. EA The ripple voltage V corresponding to the inductor in the Buck converter F Compare and output the switch drive signal V. COMP ;

[0090] The Adaptive On-Time (AOT) module is used to determine the steady-state voltage V corresponding to the switching transistor in the output module. SW The conduction time T corresponding to the conduction signal is generated. ON ;

[0091] The output module is used to output the signal V from the switching transistor. COMP Controlling the switching transistor to turn on, based on the on-time T ON It generates a rectifier drive signal to control its own rectifier to conduct, thereby generating a periodic output voltage; the output module uses an internal adaptive dead-time circuit to prevent the rectifier and the switching transistor from conducting at the same time;

[0092] The transient enhancement module is used to output a Sign signal to the comparison signal selection module when the load of the Buck converter changes and the output voltage of the Buck converter overshoots or undershoots to a preset threshold.

[0093] The Sleep module is used to monitor the drive signal V of the switching transistor. COMP Perform testing to determine the switching transistor drive signal V. COMP If the preset conditions are met, a sleep signal is output to control the Buck converter to enter sleep mode.

[0094] The present invention aims to propose a high-performance Buck converter that adopts a ripple-based AOT control method to achieve fast load transient response, optimizes efficiency through an adaptive dead-time circuit, and automatically shuts down unnecessary modules under extremely light load conditions to further improve overall efficiency.

[0095] In modern electronic systems, load current changes are becoming increasingly frequent, placing higher demands on the transient response of Buck converters. Faster load transient response is required to ensure rapid output voltage stabilization when load current changes abruptly, reducing overshoot and undershoot, thereby improving the overall system stability and reliability. While the switching frequency of AOT control remains constant regardless of input and output voltage, the switching frequency varies with load current due to the on-resistance of the MOSFET and the parasitic resistance of the inductor, leading to a non-fixed system frequency and EMI issues. Under extremely light load conditions, the system's output power is very low, and the control circuit continuously consumes energy, resulting in unnecessary power consumption. By detecting the load current, the system can enter a low-power state under extremely light load conditions, thereby reducing power consumption and improving efficiency.

[0096] Figure 2 This is a schematic diagram of a fast transient response Buck converter based on AOT control provided in an embodiment of the present invention. For ease of understanding, the various modules of the Buck converter proposed in this embodiment of the present invention will be described below.

[0097] Comparison signal selection module

[0098] Comparison signal selection module, such as Figure 2 As shown, it may include:

[0099] Reference circuit BG, soft start circuit, and selector module.

[0100] The comparison signal selection module, under the control of the Sign signal output by the transient enhancement module, selects the signal based on the reference voltage V. REF and soft-start voltage V SS The output signal to be compared may include:

[0101] The reference circuit BG generates a reference voltage V. REF ;

[0102] The soft start circuit generates a soft start voltage V. SS ;

[0103] Under the control of the Sign signal output by the transient enhancement module, the selector module selects the reference voltage V. REF and soft-start voltage V SS Output the signal to be compared.

[0104] Specifically, the reference circuit BG can generate a reference voltage V of 0.6V. REFThe soft-start circuit prevents inrush current and output voltage overshoot during system startup, allowing the output voltage to rise gradually. The selector module can include two stages of selectors. When the circuit first starts operating, the first-stage selector in the selector module can be used to select the voltage V generated by the soft-start circuit. SS Replacement reference voltage V REF This allows the input voltage to rise slowly. Then, the second-stage selector in the selector module selects the corresponding output voltage as the comparison signal based on the Sign signal output by the transient enhancement module; where the voltage V... REF_LH Including the preset first reference voltage V REF_L and preset second reference voltage V REF_H You can choose a voltage less than the reference voltage V. REF The voltage is used as the preset first reference voltage V REF_L Select a voltage greater than the reference voltage V. REF The voltage is used as the preset second reference voltage V REF_H When the load current of the Buck converter changes abruptly, and the Buck converter changes from a light load to a heavy load, a preset second reference voltage V is selected. REF_H As the signal to be compared, when the Buck converter changes from light load to heavy load, a preset first reference voltage V is selected. REF_L The signal to be compared is selected as the output signal of the first-stage selector during the remaining time. This is understandable. Figure 2 The diagram shown is merely an example of the structure. For the specific structure of the second-level selector in the selector module, please refer to the section below which provides a detailed introduction to the transient enhancement module.

[0105] Error amplifier EA

[0106] Error amplifier EA is used to convert the feedback signal V corresponding to the output voltage of the Buck converter. FB The signal is compared with the signal to be compared, and the output error amplification signal V is generated. EA .

[0107] Amplify the error signal V EA As a reference signal for the PWM comparator.

[0108] PWM comparator

[0109] A PWM comparator is used to amplify the error signal V. EA The ripple voltage V corresponding to the inductor in the Buck converter F Compare and output the switch drive signal V. COMP .

[0110] Understandably, the ripple voltage V corresponding to the inductor FIt is the voltage converted by the current flowing through the inductor in the Buck converter.

[0111] Adaptive On-Time Module (AOT)

[0112] Adaptive On-Time Module (AOT), such as Figure 3 As shown, it may include:

[0113] The circuit includes a VI converter, an inverter, a MOSFET M1, a capacitor C1, resistors R1, R2, and R3, a filter circuit, a first 2-to-1 multiplexer, a second 2-to-1 multiplexer, and a first comparator COMP1; among which,

[0114] The input terminal of the VI converter is connected to the power supply voltage V. DD The first output terminal is connected to the inverting input terminal of the first comparator COMP1, and the second output terminal is connected to the first terminal of capacitor C1.

[0115] The input terminal of the inverter is connected to the trigger signal NG1 corresponding to the switching transistor, and the output terminal is connected to the gate of the MOSFET M1;

[0116] The source of MOSFET M1 is grounded, and its drain is connected to the first terminal of capacitor C1.

[0117] The first terminal of capacitor C1 is connected to the inverting input terminal of the first comparator COMP1, and the second terminal is connected to the source of MOSFET M1.

[0118] The first terminal of resistor R1 is connected to the steady-state voltage V corresponding to the switching transistor. SW The second terminal is connected to the first terminal of capacitor C1;

[0119] The first end of resistor R2 is connected to the first end of resistor R1, and the second end is connected to the first end of resistor R3.

[0120] The first terminal of resistor R3 is connected to the input terminal of the filter circuit, and the second terminal is grounded.

[0121] The output of the filter circuit is connected to the first input of the second 2-to-1 selector, and the grounding terminal is grounded.

[0122] The first input terminal of the first 2-to-1 selector is connected to a preset first voltage V. L The second input terminal is connected to the first input terminal of the second 2-to-1 selector, the control terminal is connected to the Sign signal output by the transient enhancement module, and the output terminal is connected to the output terminal of the second 2-to-1 selector.

[0123] The second input terminal of the second 2-to-1 selector is connected to a preset second voltage V. H The output terminal is connected to the non-inverting input terminal of the first comparator COMP1;

[0124] The output of the first comparator COMP1 has an on-time T. ON .

[0125] Specifically, VI converters, such as Figure 3 As shown, it may include:

[0126] Current source I SS MOSFET M2, MOSFET M3, transistor Q1, transistor Q2, and resistor R6; among them,

[0127] Current source I SS The first terminal is connected to the source of MOSFET M3, and the second terminal is connected to the base of transistor Q1;

[0128] The source of MOSFET M2 is connected to the source of MOSFET M3, the gate is connected to the gate of MOSFET M3, and the drain is used as the first output terminal of the VI converter.

[0129] The source of MOSFET M3 is connected to the power supply voltage V. DD The gate is connected to its own drain, and the drain is connected to the collector of transistor Q1.

[0130] The emitter of transistor Q1 is connected to the first terminal of resistor R6;

[0131] The collector of transistor Q2 is connected to the second terminal of resistor R6, the base serves as the second output terminal of the VI converter, and the emitter is connected to the base of transistor Q1.

[0132] The second terminal of resistor R6 is grounded.

[0133] Filtering circuits, such as Figure 3 As shown, it may include:

[0134] Resistor R4, resistor R5, capacitor C2, and capacitor C3; among them,

[0135] The first terminal of resistor R4 serves as the input terminal of the filter circuit, and the second terminal is connected to the first terminal of resistor R5.

[0136] The first terminal of resistor R5 is connected to the first terminal of capacitor C2, and the second terminal is connected to the first terminal of capacitor C3.

[0137] The second terminal of capacitor C2 serves as the ground terminal of the filter circuit;

[0138] The first terminal of capacitor C3 serves as the output terminal of the filter circuit, and the second terminal is connected to the second terminal of capacitor C2.

[0139] The Adaptive On-Time (AOT) module is used to determine the steady-state voltage V corresponding to the switching transistor in the output module. SW The conduction time T corresponding to the conduction signal is generated. ONDuring the corresponding conduction time T ON During the process, when the Sign signal output by the transient enhancement module indicates that the Buck converter has switched from heavy load to light load, the first 2-to-1 selector selects the preset first voltage V. L Replace V C1 To shorten the conduction time T ON When the Sign signal output by the transient enhancement module indicates that the Buck converter is switching from light load to heavy load, the second 2-to-1 selector selects the preset second voltage V. H Replace V C1 To extend the conduction time T ON .

[0140] Understandably, the adaptive on-time module (AOT) uses a DC steady-state voltage V. SW and includes input voltage V IN The current charges the capacitor to generate the corresponding on-time T. ON This reduces the degree of switching frequency fluctuations caused by non-ideal factors, thus stabilizing the operating frequency of the Buck converter.

[0141] Specifically, V SW V is the voltage between the switching transistor and the inductor in the Buck converter. When the switching transistor is on, V... SW =V IN -I L ·R ON1 When the rectifier tube is turned on, V SW =I L ·R ON2 Among them, R ON1 R represents the on-resistance of the switching transistor. ON2 I represents the on-resistance of the rectifier diode. L Indicates the load current. From Figure 3 As can be seen from V SW After being divided by resistors R2 and R3, the voltage V is obtained at the output of the filter circuit. C1 Voltage V C1 The expression is as follows:

[0142]

[0143] Where R2 represents the resistance value of resistor R2, R3 represents the resistance value of resistor R3, and D actual This indicates the actual duty cycle of the Buck converter.

[0144] NG1 is the trigger signal corresponding to the switching transistor. When NG1 is high, MOSFET M1 is turned off, capacitor C1 begins to charge, and the charging current I... C1 for:

[0145]

[0146] Among them, I1 follows V C2 I2 decreases with increasing V C2 The current source I increases with the increase of [something]. SS MOSFETs M2 and M3, transistors Q1 and Q2, and resistor R6 form a VI converter. When the width-to-length ratio of MOSFETs M2 and M3 is equal and the resistance values ​​of resistors R1 and R6 are equal, i.e. (W / L) M2 =(W / L) M3 And when R1 = R6, the charging current I C1 It can be represented as:

[0147]

[0148] The first comparator COMP1 compares V. C1 and V C2 The size of V C1 Greater than V C2 When T is high, the first comparator COMP1 outputs a high level. ON Start timing. As C1 gradually increases, when V... C1 Less than V C2 When the comparator outputs a low level, the switching transistor is turned off, and T... ON When the timing ends, NG1 goes low, and the on-time T generated by the adaptive on-time module AOT... ON The expression is as follows:

[0149]

[0150] Where R2 represents the resistance value of resistor R2, R3 represents the resistance value of resistor R3, C1 represents the capacitance value of capacitor C1, R1 represents the resistance value of resistor R1, and D actual This indicates the actual duty cycle of the Buck converter.

[0151] As can be seen from the above formula, the constant conduction time generated by this circuit is independent of the load current, input and output voltage, and the on-resistance of the switching transistor and rectifier transistor, thus reducing the variation of the switching frequency.

[0152] Transient enhancement module

[0153] Transient enhancement modules, such as Figure 4 As shown, it may include:

[0154] Resistor R7, capacitor C4, second comparator COMP2, and third comparator COMP3; among which,

[0155] The first terminal of resistor R7 is connected to the output voltage V of the Buck converter. OUTThe second terminal is connected to the first terminal of capacitor C4;

[0156] The second terminal of capacitor C4 is grounded;

[0157] The non-inverting input of the second comparator COMP2 is connected to the first terminal of capacitor C4, and the inverting input is connected to the non-inverting input of the third comparator COMP3. The output terminal outputs the signal Sign1.

[0158] The inverting input of the third comparator COMP3 is connected to the non-inverting input of the second comparator COMP2, and the output terminal outputs the signal Sign2.

[0159] Signal Sign1 and signal Sign2 together form the Sign signal.

[0160] The transient enhancement module is used to output a Sign signal to the comparison signal selection module when the load of the Buck converter changes and the output voltage of the Buck converter overshoots or undershoots to a preset threshold.

[0161] Specifically, the circuit structure of the transient enhancement module is as follows: Figure 4 As shown, resistor R7 and capacitor C4 form a voltage regulator to stabilize the output voltage. When the load current changes abruptly, the output voltage V... OUT Upward or downward, V OUT_S The signal is still in steady state, so when the output voltage drops to the preset threshold, the comparator outputs a Sign signal, and the positive input of the error amplifier EA is changed by V. REF Switch to V REF_HL This signal accelerates the output speed of the error amplifier EA and improves the transient overshoot voltage of the Buck converter. Understandably, from... Figure 4 As can be seen, the second-stage selector in the selector module can include a first sub-selector and a second sub-selector. The control terminal of the first sub-selector is connected to the signal Sign1. When the load current of the Buck converter changes abruptly, and the Buck converter changes from a light load to a heavy load, it selects a preset second reference voltage V. REF_H As the signal to be compared; the control terminal of the second sub-selector is connected to the signal Sign2, which selects the preset first reference voltage V when the Buck converter changes from light load to heavy load. REF_L The signal to be compared is used as the signal to be compared during the rest of the time; the signal output by the first-stage selector is used as the signal to be compared during the rest of the time.

[0162] Sleep detection module

[0163] Sleep detection module, such as Figure 5 As shown, it may include:

[0164] First inverter, MOSFET MP1, MOSFET MP2, MOSFET MP3, MOSFET MP4, MOSFET MN1, MOSFET MN2, MOSFET MN3, MOSFET MN4, current source I SS and capacitor C SS ;in,

[0165] The input terminal of the first inverter is connected to the switching transistor drive signal V. COMP The output terminal is connected to the gate of MOSFET MP1;

[0166] The source and current source I of MOSFET MP1 SS The output terminal is connected, and the drain is connected to the drain of MOSFET MN1;

[0167] The source of MOSFET MP2 is connected to the power supply voltage V. DD The gate is connected to the gate of MOSFET MP3, and the drain is connected to the source of MOSFET MP3.

[0168] The source of MOSFET MP3 is connected to the source of MOSFET MP4, the gate is connected to the drain of MOSFET MN1, and the drain is connected to the drain of MOSFET MN2.

[0169] The gate of MOSFET MP4 serves as the output terminal of the Sleep detection module, and its drain is connected to the source of MOSFET MN3.

[0170] The source of MOSFET MN1 and capacitor C SS The second terminal is connected, with the gate connected to the gate of MOSFET MP1, and the drain connected to capacitor C. SS The first end is connected;

[0171] The source of MOSFET MN2 is connected to the drain of MOSFET MN3, and the gate is connected to capacitor C. SS The first terminal is connected, and the drain is connected to the gate of the MOSFET MP4;

[0172] The source of MOSFET MN3 is grounded, and the gate is connected to capacitor C. SS The first terminal is connected, and the drain is connected to the source of MOSFET MN4;

[0173] The gate of MOSFET MN4 is connected to the gate of MOSFET MP4, and the drain is connected to the source of MOSFET MP2.

[0174] Current source I SS The input terminal is connected to the source of MOSFET MP2;

[0175] Capacitor C SS The second terminal is connected to the source of MOS transistor MN3.

[0176] The Sleep module is used to monitor the drive signal V of the switching transistor. COMP The system performs a test to determine whether the switching transistor drive signal meets the preset conditions. If it does, it outputs a sleep signal to control the Buck converter to enter a sleep state.

[0177] Specifically, the sleep detection module, such as Figure 5 As shown, V COMP The signal is the switching transistor drive signal output by the PWM comparator. When the Buck converter is under extremely light load, the switching transistor has a constant on-time, the inductor charges, the rectifier transistor turns off after the current crosses zero, and the load discharges slowly. COMP The high level is maintained for a longer period of time, V COMP When high, MP1 is on, I SS Give C SS Charging, when V COMP When C is at a high level for a duration exceeding the set time, SS The voltage continued to increase, exceeding MN. 2～4 and MP 2～4 When the hysteresis comparator is positively charged, it outputs a sleep signal to shut down unnecessary modules, thereby reducing power consumption in extremely light load conditions.

[0178] Output module

[0179] The output module is used to output the signal V from the switching transistor. COMP Controlling the switching transistor to turn on, based on the on-time T ON A rectifier drive signal is generated to control the conduction of its own rectifier to generate a periodic output voltage; the adaptive dead time circuit in the output module prevents the rectifier and the switching transistor from conducting simultaneously.

[0180] The output module consists of a bootstrap circuit, a logic circuit (LOGIC), an adaptive dead-time circuit (DEAD TIME), and a driver circuit (DRIVER). The bootstrap circuit outputs a high voltage to the switching transistor during the initial stage. The logic circuit (LOGIC) outputs corresponding logic control signals based on received signals to control the operating state of the switching transistor or rectifier. The adaptive dead-time circuit (DEAD TIME) can add a dead time period where neither transistor conducts simultaneously, depending on the load current, to prevent losses caused by simultaneous conduction. The driver circuit controls the corresponding switching transistor or rectifier based on the logic control signals and the output of the adaptive dead-time circuit (DEAD TIME).

[0181] It is understandable that the fast transient response Buck converter proposed in the embodiments of the present invention, such as Figure 2 As shown, it may also include:

[0182] The circuit includes a zero-current shutdown (ZCD) circuit, an overcurrent protection circuit (OCP) circuit, an overtemperature protection circuit (OTP) circuit, an overvoltage protection circuit (OVP) circuit, a minimum opening time circuit, a minimum shutdown time circuit, and a mode selector; among these,

[0183] The Zero Current Turn-Off (ZCD) circuit can be used to turn off the lower rectifier diode when the inductor current crosses zero, preventing reverse current from increasing system power consumption. When the Buck converter needs to transition from CCM mode to DCM mode, the fixed mode remains unchanged. CCM (Continuous Conduction Mode) operates as follows: within one switching cycle, the inductor current never reaches 0, and the inductor is never "reset," meaning the inductor flux never returns to zero during the switching cycle, and current still flows through the coil when the power transistor is closed. DCM (Discontinuous Conduction Mode) operates as follows: within one switching cycle, the inductor current always reaches 0, meaning the inductor is properly "reset," i.e., the inductor current is zero when the power switch is closed.

[0184] Overcurrent protection circuits (OCPs) can be used to prevent excessive current in Buck converters from damaging the circuitry.

[0185] Over-temperature protection circuits (OTPs) can be used to prevent excessive temperature in Buck converters from damaging the circuitry.

[0186] Overvoltage protection circuits (OVP) can be used to prevent excessive voltage in Buck converters from damaging the circuitry.

[0187] The minimum opening time circuit and the minimum shut-down time circuit can be used to ensure the shortest time that the switching transistor is always on in each switching cycle and the shortest time that the switching transistor is always off in each switching cycle, respectively, thus ensuring the stable operation of the Buck converter.

[0188] The Mode Select option can be used to select the operating mode of the Buck converter.

[0189] The working principle of the fast transient response Buck converter proposed in this embodiment of the invention is as follows: In the initial stage, the voltage V output by the soft-start circuit is selected. SS As the input voltage to the non-inverting input of the error amplifier EA, V becomes the input voltage after the EN enable terminal is activated. REF The output voltage is established, and a feedback signal V is output through a resistor divider network.FB V FB With V REF The signal is fed into error amplifier EA for comparison, and the output is an amplified error signal V. EA V EA and V F The comparison is performed using a PWM comparator. When V F Descending to V EA When the PWM comparator flips, the upper switch turns on and the lower rectifier turns off. The inductor current and output voltage rise, and the adaptive on-time module (AOT) starts timing. The on-time is controlled and adjusted based on the input and output voltages, ensuring a nearly stable switching frequency for the Buck converter in CCM mode. After timing ends, the switch turns off, the rectifier turns on, and the inductor current and output voltage decrease, starting a new cycle.

[0190] The following simulation experiment is conducted on the fast transient response Buck converter proposed in the embodiments of the present invention to verify the beneficial effects of the fast transient response Buck converter.

[0191] In this embodiment of the invention, based on TSMC's 180nm BCD process, after completing the circuit design, a comprehensive simulation of the Buck converter is performed. The overall simulation diagram of the fast transient response Buck converter is shown below. Figure 6 As shown, the Buck converter has an input voltage of 3.3V and an output voltage of 0.9V. When the load current is 1.5A, the Buck converter operates in CCM mode, with an output voltage ripple of 1.15mV and a switching frequency of 4MHz. When the load current is 10mA, the Buck converter automatically adjusts its frequency and operates in DCM mode, with an output voltage ripple of 4.3mV and a switching frequency of 104.4KHz. The output voltage ripple and inductor current ripple increase, and the switching cycle becomes longer.

[0192] The waveforms of key signals when the Buck converter is in steady state are shown below. Figure 7 As shown, V C1 The signal is V SW When the DC steady-state voltage is high, and the trigger signal (NG1) corresponding to the switching transistor is high, V C2 The voltage gradually increases, when V C2 Greater than V C1 At that time, T ON A high output signal indicates the end of the timing. Under the control of the Adaptive On-Time (AOT) module, the switching transistor turns off after the adaptive on-time. After the switching transistor turns off, the rectifier diode turns back on after a dead time, and the Buck converter enters a new switching cycle.

[0193] To verify the frequency stability of the adaptive on-time circuit in this embodiment of the invention, the switching period was compared under different load currents. A comparison graph of the switching period for the on-signal corresponding to the switching transistor under different load currents is shown below. Figure 8 As shown, when the load current is 1A, the switching period of the Buck converter is 500.6ns; when the load current is 3A, the switching period of the Buck converter is 496.6ns, with a period change rate of only 0.8%. It can be seen that this adaptive on-time circuit is effective and the switching frequency is stable.

[0194] A comparison of the output voltage and inductor current waveforms of a Buck converter when the load current switches from heavy load to light load, with and without a transient boost module, is shown in the figure. Figure 9 As shown in the figure, when the load current changes from 3A to 10mA at a rate of 1.5A / μs, without the transient enhancement circuit, the output voltage overshoot is 43.6mV. After adding the transient enhancement circuit, the output voltage overshoot is reduced to 18.5mV, an improvement of 58%, demonstrating a significant effect. (The last sentence appears to be incomplete and possibly refers to a technical indicator.) L As can be seen from the waveform, when the output voltage surges, the adaptive conduction time becomes longer and the load current rises faster.

[0195] A comparison of the output voltage and inductor current waveforms of a Buck converter with and without a transient boost module when the load current changes from light load to heavy load, as shown in the figure. Figure 10 As shown, when the load current changes from 10mA to 3A at a rate of 1.5A / μs, without the transient enhancement circuit, the output voltage undershoot is 43.6mV. After adding the transient enhancement circuit, the output voltage undershoot becomes 20.3mV, an improvement of 53%, demonstrating a significant effect. (Through I...) L As can be seen from the waveform, when the output voltage surges, the adaptive conduction time becomes shorter and the load current decreases faster.

[0196] The waveform diagram detected by the sleep module of the Buck converter, as shown below. Figure 11 As shown, it can be seen that when the load is very small, V COMP When the voltage is high for an extended period, V is detected. COMP The duration of the high-level signal determines whether the Buck converter has entered sleep mode. When the Sleep signal is low, the Buck converter enters sleep mode.

[0197] In summary, this invention presents a Buck converter with fast transient response, stable switching frequency, and extremely light load sleep mode. The transient enhancement module improves load overshoot by 58%, and the adaptive on-time (AOT) module exhibits a switching frequency variation rate of only 0.8% under different load currents. The sleep detection module detects whether the Buck converter is in an extremely light load state, thus improving system efficiency.

[0198] The fast transient response Buck converter proposed in this invention combines the advantages of current-mode control and AOT control. By using the output voltage of the Buck converter as the negative feedback voltage and adding an error amplifier to the negative feedback control loop, the accuracy of the output voltage is improved, the current loop is stabilized, and the series resistance R of the output capacitor is reduced. ESR There are no specific limitations; a transient voltage enhancement module is used to judge the output voltage, ensuring that the output voltage can quickly stabilize when the load current changes suddenly, reducing overshoot and undershoot, thereby improving overall stability and reliability; a sleep detection module is used to monitor the switching transistor drive signal V. COMP The system performs detection to control the Buck converter to enter a sleep state, thereby reducing power consumption and improving efficiency.

[0199] It should be noted that, in the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0200] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An AOT control based fast transient response Buck converter characterized by, The application relates to a Buck converter control circuit, which comprises a comparison signal selection module, an error amplifier EA, a PWM comparator, an adaptive on-time module AOT, an output module, a transient enhancement module and a sleep detection module Sleep; wherein, The transient enhancement module is used for outputting a Sign signal to the comparison signal selection module when the output voltage of the Buck converter surges or drops to a preset threshold when the load of the Buck converter jumps. The comparison signal selection module is configured to output a to-be-compared signal under the control of a Sign signal output by the transient enhancement module according to a reference voltage V REF and a soft start voltage V SS ​ The error amplifier EA is configured to compare a feedback signal V FB with the to-be-compared signal, and output an error amplification signal V EA ; The PWM comparator is used for comparing the error amplification signal V EA The ripple voltage V corresponding to the inductor in the Buck converter F The PWM comparator is used for comparing the error amplification signal V COMP ; The adaptive on-time module AOT is configured to determine a steady-state voltage V SW corresponding to the switch tube in the output module according to the steady-state voltage V ON and the on signal generates a corresponding on time T The output module is configured to control the switch tube to be turned on according to the switch tube driving signal V COMP The switch tube is turned on according to the turn-on time T ON The rectifier tube driving signal is generated to control the rectifier tube to be turned on to generate a periodic output voltage; the output module utilizes an internal adaptive dead time circuit to prevent the rectifier tube and the switch tube from being turned on simultaneously. The comparison signal selection module comprises a reference circuit BG, a soft start circuit Soft Start and a selector module. The sleep detection module Sleep is configured to detect the switch tube driving signal V COMP and determine whether the switch tube driving signal V COMP satisfies a preset condition. If the preset condition is satisfied, a sleep signal is output to control the Buck converter to enter a sleep state.

2. The fast transient response Buck converter based on AOT control according to claim 1, wherein, The adaptive on-time module AOT comprises a V-I converter, an inverter, a MOS tube M1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a filter circuit, a first two-select selector, a second two-select selector and a first comparator COMP1; wherein, The input end of the inverter is connected with a trigger signal NG1 corresponding to the switching tube, and the output end is connected with the gate of the MOS tube M1; 3. The fast transient response Buck converter based on AOT control according to claim 2, characterized in that, The comparison signal selection module outputs a signal to be compared under the control of the Sign signal outputted by the transient enhancement module, according to the reference voltage V REF and the soft start voltage V SS comprises: The reference circuit BG generates a reference voltage V REF ; The soft start circuit Soft Start generates a soft start voltage V SS ; The selector module outputs the signal to be compared under the control of the sign signal outputted by the transient enhancement module according to the reference voltage V REF and the soft start voltage V SS ​ 4. The fast transient response Buck converter based on AOT control according to claim 1, wherein, The source of the MOS tube M1 is grounded, and the drain is connected with the first end of the capacitor C1; The first end of the capacitor C1 is connected with the inverting input end of the first comparator COMP1, and the second end is connected with the source of the MOS tube M1; The input of the V-I converter is connected to a supply voltage V DD The first output is connected to the inverting input of the first comparator COMP1 and the second output is connected to the first terminal of the capacitor C1. The first end of the resistor R2 is connected with the first end of the resistor R1, and the second end is connected with the first end of the resistor R3; The first end of the resistor R3 is connected with the input end of the filter circuit, and the second end is grounded; The output end of the filter circuit is connected with the first input end of the second two-select selector, and the grounding end is grounded; The first end of the resistor R1 is connected to the steady-state voltage V corresponding to the switch tube SW , and the second end is connected to the first end of the capacitor C1. The V-I converter comprises a MOS tube M2, a MOS tube M3, a transistor Q1 and a transistor Q2; wherein, The source of the MOS tube M2 is connected with the source of the MOS tube M3, the gate is connected with the gate of the MOS tube M3, and the drain is used as the first output end of the V-I converter; The first end of the resistor R6 is connected with the emitter of the transistor Q1; The first input end of the first two-select selector is connected with a preset first voltage V L The second input end of the first two-select selector is connected with the first input end of the second two-select selector, the control end is connected with the Sign signal output by the transient enhancement module, and the output end is connected with the output end of the second two-select selector. The second input terminal of the second selection selector is connected to a preset second voltage V H , and the output terminal is connected to the non-inverting input terminal of the first comparator COMP1. The output of the first comparator COMP1 outputs the on-time T ON .

5. The fast transient response Buck converter based on AOT control according to claim 4, characterized in that, The second end of the resistor R6 is grounded. Current source I SS MOS transistor M2, MOS transistor M3, transistor Q1, transistor Q2 and resistor R6; wherein, Current source I SS a first end connected to a source of the MOS transistor M3 and a second end connected to a base of the transistor Q1; The filter circuit comprises a resistor R4, a resistor R5, a capacitor C2 and a capacitor C3; wherein, The source of the MOS transistor M3 is connected to a power supply voltage V DD The gate is connected to the drain, and the drain is connected to the collector of the transistor Q1. The first end of the resistor R4 is used as the input end of the filter circuit, and the second end is connected with the first end of the resistor R5; The first end of the resistor R5 is connected with the first end of the capacitor C2, and the second end is connected with the first end of the capacitor C3; The second end of the capacitor C2 is used as the grounding end of the filter circuit; 6. The fast transient response Buck converter based on AOT control according to claim 4, characterized in that, The first end of the capacitor C3 is used as the output end of the filter circuit, and the second end is connected with the second end of the capacitor C2. The transient enhancement module comprises a resistor R7, a capacitor C4, a second comparator COMP2 and a third comparator COMP3; wherein, The second end of the capacitor C4 is grounded; The non-inverting input end of the second comparator COMP2 is connected with the first end of the capacitor C4, the inverting input end is connected with the non-inverting input end of the third comparator COMP3, and the output end outputs a signal Sign1; ​ ​ 7. The fast transient response Buck converter based on AOT control according to claim 4, characterized in that, The adaptive on-time module AOT generates an on-time T ON The expression of T is as follows: where R2 represents a resistance value of the resistance R2, R3 represents a resistance value of the resistance R3, C1 represents a capacitance value of the capacitance C1, R1 represents a resistance value of the resistance R1, D actual denotes the actual duty cycle of the Buck converter.

8. The fast transient response Buck converter based on AOT control according to claim 1, wherein, ​ ​ The first end of the resistor R7 is connected to the output voltage V of the Buck converter OUT , and the second end is connected to the first end of the capacitor C4. ​ ​ The inverting input end of the third comparator COMP3 is connected with the non-inverting input end of the second comparator COMP2, and the output end outputs a signal Sign2; The signal Sign1 and the signal Sign2 constitute a Sign signal.

9. The fast transient response Buck converter based on AOT control according to claim 1, wherein, The sleep detection module Sleep includes: a first inverter, a MOS transistor MP1, a MOS transistor MP2, a MOS transistor MP3, a MOS transistor MP4, a MOS transistor MN1, a MOS transistor MN2, a MOS transistor MN3, a MOS transistor MN4, a current source I SS1 and a capacitor C SS ; wherein, An input end of the first inverter is connected to a switch tube driving signal V COMP , and an output end is connected to a gate of the MOS tube MP1. The source of the MOS transistor MP1 is connected to the output of the current source I SS1 and the drain is connected to the drain of the MOS transistor MN1. The source of the MOS transistor MP2 is connected to a power supply voltage V DD The gate of the MOS transistor MP3 is connected to the gate of the MOS transistor MP2, and the source of the MOS transistor MP3 is connected to the drain of the MOS transistor MP2. The source of the MOS transistor MP3 is connected with the source of the MOS transistor MP4, the gate is connected with the drain of the MOS transistor MN1, and the drain is connected with the drain of the MOS transistor MN2; The gate of the MOS transistor MP4 serves as the output end of the sleep detection module Sleep, and the drain is connected with the source of the MOS transistor MN3; The source of the MOS transistor MN1 is connected to the capacitor C. SS The second terminal is connected, the gate is connected to the gate of the MOS transistor MP1, and the drain is connected to the capacitor C. SS The first end is connected; The source of the MOS transistor MN2 is connected to the drain of the MOS transistor MN3, the gate is connected to the first end of the capacitor C SS and the drain is connected to the gate of the MOS transistor MP4. The source of the MOS transistor MN3 is connected to ground, the gate is connected to the first terminal of the capacitor C SS and the drain is connected to the source of the MOS transistor MN4. The gate of the MOS transistor MN4 is connected with the gate of the MOS transistor MP4, and the drain is connected with the source of the MOS transistor MP2; The gate of the MOS transistor MN4 is connected with the gate of the MOS transistor MP4, and the drain is connected with the source of the MOS transistor MP2; The current source I SS1 The input end of the MOS transistor MP2 is connected with the source of the MOS transistor MP1. The capacitor C SS The second end of the capacitor C is connected to the source of the MOS transistor MN3.

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