Overshoot voltage control method and circuit and switching converter

Abstract

The embodiment of the invention provides an overshoot voltage control method and circuit and a switching converter, the circuit comprises a conduction time detection module, a feedback voltage detection module, an overshoot voltage control module and a driving control module, the conduction time detection module is used for detecting the conduction time of a lower power tube of the switching converter in the transient change process of a load, and the feedback voltage detection module is used for detecting the feedback voltage of the overshoot voltage control module; judging whether the turn-on time is greater than a steady-state value or not; the feedback voltage detection module is used for detecting the feedback voltage of the output voltage of the switching converter in the transient change process of the load and judging whether the feedback voltage is greater than a preset reference voltage or not; the overshoot voltage control module is used for generating an overshoot voltage control signal according to a first judgment result output by the conduction time detection module and a second judgment result output by the feedback voltage detection module; and the driving control module is used for controlling the turn-off of the lower power tube according to the overshoot voltage control signal. The problem that an existing mode of reducing overshoot voltage on output voltage can cause large occupied circuit area is solved.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of integrated circuit technology, and in particular, to an overshoot voltage control method and circuit, and a switching converter. Background Art

[0002] With the update of semiconductor technology, the feature size is getting smaller and smaller, and the voltage is getting lower and lower. With the improvement of computer and AI performance, the current of CPU and some Core chips is getting larger and larger. These requirements for the output load transient response (Load Transient) of the DC-DC converter (DCDC converter) of the front-stage power supply are becoming more and more stringent. For example, taking the buck type DCDC converter as an example, Figure 1 This is an exemplary circuit diagram of a BUCK type DCDC. The transient response requirement for the VNNAON power supply in the INTEL CPU is: 0.77V+ / -50mV (0A-11.45A in 1us). Under such a fast transient change, Figure 2 As shown, it can be seen that a relatively large overshoot voltage will be generated on Vout.

[0003] As for the problem of large overshoot voltage mentioned above, due to the limitations of input and output voltage, frequency and inductance in the application, the traditional improvement method is usually to adjust the external components, such as increasing the output capacitor (COUT). However, the increase in the number of capacitors will increase the cost of the product on the one hand, and increase the area of ​​the circuit board on the other hand, which is not conducive to making small and light products. Figure 3 As shown in FIG. 1 , a schematic diagram of increasing the output capacitance to reduce the overshoot voltage on the output voltage is shown. It can be seen that increasing the capacitance will occupy a large board-level circuit area.

[0004] In summary, under fast transient conditions, the existing method of reducing the overshoot voltage on the output voltage will result in a problem of occupying a large circuit area. Summary of the invention

[0005] The embodiments described herein provide an overshoot voltage control method and circuit, and a switching converter, which are helpful in solving the problem that the existing method of reducing the overshoot voltage on the output voltage will cause a large circuit area to be occupied.

[0006] According to a first aspect of the present disclosure, an overshoot voltage control circuit is provided, the control circuit is used to control the overshoot voltage on the output voltage of a switching converter, the control circuit comprises: a conduction time detection module, a feedback voltage detection module, an overshoot voltage control module, and a drive control module, wherein the conduction time detection module is configured to detect the conduction time of the lower power tube of the switching converter during a load transient change process, and to determine whether the conduction time is greater than a steady-state value, the steady-state value being the conduction time of the lower power tube in a steady state; the feedback voltage detection module is configured to detect the conduction time of the switching converter during a load transient change process. The overshoot voltage control module is configured to generate an overshoot voltage control signal according to a first judgment result output by the conduction time detection module and a second judgment result output by the feedback voltage detection module; the drive control module is configured to control the shutdown of the lower power tube according to the overshoot voltage control signal, so as to control the shutdown of the lower power tube when the conduction time is greater than the steady-state value and the feedback voltage is greater than the preset reference voltage, so as to reduce the energy transferred from the inductance of the switching converter to the output capacitor of the switching converter.

[0007] Optionally, the conduction time detection module includes: a sampling unit and a delay unit, wherein the sampling unit is configured to collect the rising edge of the driving signal of the lower power tube; the delay unit is configured to delay the rising edge collected by the sampling unit and then output the first judgment result, and the delay time of the delay unit is greater than the steady-state value.

[0008] Optionally, the overshoot voltage control module includes: a comparator, wherein the positive input terminal of the comparator is coupled to the feedback voltage, the negative input terminal of the comparator is coupled to the preset reference voltage, and the output terminal of the comparator outputs the second judgment result.

[0009] Optionally, the overshoot voltage control module includes: an AND gate and a latch, the first input of the AND gate is coupled to the first judgment result, the second input of the AND gate is coupled to the second judgment result, and the output of the AND gate is coupled to the set input of the latch; the reset input of the latch is coupled to the pulse width modulation signal of the switching converter, and the output of the latch outputs the overshoot voltage control signal.

[0010] Optionally, the drive control module includes: an upper tube drive unit and a lower tube drive unit, the upper tube drive unit being configured to generate an upper tube drive signal for controlling the upper power tube switch of the switching converter according to the pulse width modulation signal; the lower tube drive unit being configured to generate a lower tube drive signal for controlling the lower power tube switch according to the pulse width modulation signal or the overshoot voltage control signal.

[0011] Optionally, the lower tube driving unit includes: first to four NOT gates, a first NAND gate, and a first NOR gate, wherein the input end of the first NAND gate is coupled to the pulse width modulation signal, and the output end of the first NAND gate is coupled to the first input end of the first NAND gate; the second input end of the first NAND gate is coupled to the upper tube driving unit, and the output end of the first NAND gate is coupled to the first input end of the first NOR gate; the second input end of the first NOR gate is coupled to the overshoot voltage control signal, and the output end of the first NOR gate is coupled to the input end of the second NAND gate; the output end of the second NAND gate is coupled to the input end of the third NAND gate; the output end of the third NAND gate is respectively coupled to the control electrode of the lower power tube and the input end of the fourth NAND gate; the output end of the fourth NAND gate is coupled to the upper tube driving unit.

[0012] Optionally, the upper tube driving unit includes: a second NAND gate and fifth to eighth NAND gates, wherein the first input terminal of the second NAND gate is coupled to the pulse width modulation signal, the second input terminal of the second NAND gate is coupled to the output terminal of the fourth NAND gate of the lower tube driving unit, and the output terminal of the second NAND gate is coupled to the input terminal of the fifth NAND gate; the output terminal of the fifth NAND gate is coupled to the input terminal of the sixth NAND gate; the output terminal of the sixth NAND gate is coupled to the input terminal of the seventh NAND gate; the output terminal of the seventh NAND gate is respectively coupled to the control terminal of the upper power tube and the input terminal of the eighth NAND gate; the output terminal of the eighth NAND gate is coupled to the second input terminal of the first NAND gate of the lower tube driving unit.

[0013] According to a second aspect of the present disclosure, an overshoot voltage control method is provided, the method comprising: detecting the on-time of a lower power tube of a switching converter during a load transient change process, and judging whether the on-time is greater than a steady-state value, to obtain a first judgment result, wherein the steady-state value is the on-time of the lower power tube in a steady state; and, detecting a feedback voltage of an output voltage of the switching converter during a load transient change process, and judging whether the feedback voltage is greater than a preset reference voltage, to obtain a second judgment result; generating an overshoot voltage control signal according to the first judgment result and the second judgment result; and controlling the shutdown of the lower power tube according to the overshoot voltage control signal.

[0014] Optionally, generating an overshoot voltage control signal based on the first judgment result and the second judgment result includes: if the first judgment result indicates that the conduction time is greater than the steady-state value, and the second judgment result indicates that the feedback voltage is greater than the preset reference voltage, then controlling the overshoot voltage control signal to be a first level signal, and the first level signal is an effective signal that can shut down the lower power tube.

[0015] According to a third aspect of the present disclosure, a switching converter is provided, wherein the switching converter at least includes the overshoot voltage control circuit described in the first aspect.

[0016] In the overshoot voltage control method and circuit of the embodiment of the present disclosure, the conduction time of the lower power tube of the switching converter is detected during the Load Transient process, and it is determined whether the conduction time is greater than the steady-state value. At the same time, the feedback voltage of the output voltage of the switching converter is detected during the load transient change process, and it is determined whether the feedback voltage is greater than the preset reference voltage. An overshoot voltage control signal is generated according to the two judgment results, so that when the conduction time is greater than the steady-state value and the feedback voltage of the output voltage is greater than the preset reference voltage, the shutdown of the lower power tube is controlled by the generated overshoot voltage control signal. Through the above design, the falling slope of the inductor current can be increased, which reduces the energy transferred from the inductor to the output capacitor, so that the overshoot voltage of the system is reduced, and the overshoot voltage during transient response is reduced without adding external components and changing the system application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described below. It should be noted that the drawings described below only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure, wherein:

[0018] Figure 1 An exemplary circuit diagram of an existing BUCK type DCDC is shown;

[0019] Figure 2 Shows Figure 1 Schematic diagram of the waveform of the corresponding signal;

[0020] Figure 3 A schematic diagram showing an existing method of reducing overshoot voltage by increasing output capacitance is shown;

[0021] Figure 4 A schematic block diagram of an overshoot voltage control circuit according to an embodiment of the present disclosure is shown;

[0022] Figure 5 An exemplary circuit diagram of an overshoot voltage control circuit according to an embodiment of the present disclosure is shown;

[0023] Figure 6 A waveform diagram of a key signal corresponding to an overshoot voltage control circuit according to an embodiment of the present disclosure is shown;

[0024] Figure 7 A schematic diagram showing waveforms of the inductor current and the output voltage corresponding to the prior art and the embodiment of the present disclosure is shown;

[0025] Figure 8 A flow chart of an overshoot voltage control method according to an embodiment of the present disclosure is shown;

[0026] Elements in the drawings are schematic and not drawn to scale. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work also fall within the scope of protection of the present disclosure.

[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, a statement that two or more parts are "connected" or "coupled" together shall mean that the parts are joined together directly or through one or more intermediate components.

[0029] In all embodiments of the present disclosure, since the source and drain of a metal oxide semiconductor (MOS) transistor are symmetrical, and the conduction current directions between the source and drain of an N-type transistor and a P-type transistor are opposite, in the embodiments of the present disclosure, the controlled middle terminal (gate or gate terminal) of the MOS transistor is referred to as a control terminal, and the remaining two terminals of the MOS transistor are referred to as a first terminal and a second terminal, respectively. In addition, terms such as "first" and "second" are only used to distinguish one component (or a portion of a component) from another component (or another portion of a component).

[0030] In order to solve the problem that the existing method of reducing the overshoot voltage on the output voltage will cause a large circuit area to be occupied, an overshoot voltage control method is proposed that can reduce the overshoot voltage during transient response without changing the system application and without adding external components. The overshoot voltage control method in the embodiment of the present disclosure detects the output voltage during the Load Transient process, and at the same time detects the conduction time of the lower power tube. If the conduction time of the lower power tube is longer than the steady-state value, and the feedback voltage of the output voltage exceeds the preset reference voltage, the lower power tube is turned off, so that the falling slope of the inductor current changes from Vout / L to (Vout+Vdiode) / L, where Vdiode is the conduction voltage of the body diode of the lower power tube, that is, the falling slope of the inductor current is increased, and the energy transferred from the inductor to the output capacitor is reduced, so that the overshoot voltage on the output voltage is reduced. The overshoot voltage control circuit 100 of the present disclosure is first described in detail below.

[0031] Figure 4 FIG. 1 is a schematic block diagram of an overshoot voltage control circuit 100 according to an embodiment of the present disclosure. Figure 4 As shown, the overshoot voltage control circuit 100 includes: a conduction time detection module 110, a feedback voltage detection module 120, an overshoot voltage control module 130, and a drive control module 140.

[0032] The on-time detection module 110 is coupled to the overshoot voltage control module 130, and is configured to detect the on-time of the lower power tube LSF of the switching converter during the transient change of the load, and determine whether the on-time is greater than the steady-state value, and the steady-state value is the on-time of the lower power tube LSF in the steady state. The on-time detection module 110 can output a first judgment result A1, if the on-time is greater than the steady-state value, then the first judgment result A1 is a first level signal, such as a high level signal, if the on-time is not greater than the steady-state value, then the first judgment result A1 is a second level signal, such as a low level signal.

[0033] The feedback voltage detection module 120 is also coupled to the overshoot voltage control module 130 and is configured to detect the feedback voltage V of the output voltage Vout of the switching converter during a load transient change. FB , and determine the feedback voltage V FB Is it greater than the preset reference voltage Vref? The feedback voltage V of the output voltage Vout FB It reflects the change of the output voltage Vout, by detecting the feedback voltage V FBIt is to detect the change of the output voltage Vout. In the embodiment of the present disclosure, it is to reduce the overshoot voltage on the output voltage Vout. In practical applications, an overshoot voltage allowable range is usually set, such as less than 50mV. Reducing the overshoot voltage is to reduce the overshoot voltage to within the allowable range. Therefore, when setting the preset reference voltage Vref, it is set according to the steady-state voltage value of the output voltage Vout and the allowable range of the overshoot voltage. For example, if the steady-state voltage value of the output voltage Vout is 1V, and the allowable range of the overshoot voltage is 5% of the steady-state value of the output voltage Vout, then the preset reference voltage Vref can be set to a value less than 1V*(1+5%), such as 1V*(1+2.5%) or 1V*(1+3%), etc. When setting, it is also necessary to set the reference voltage Vref according to the steady-state voltage value of the output voltage Vout and the feedback voltage V FB The feedback voltage detection module 120 can output a second judgment result A2 if the feedback voltage V FB is greater than the preset reference voltage Vref, the second judgment result A2 is a first level signal, such as a high level signal. If the feedback voltage V FB is not greater than the preset reference voltage Vref, the second judgment result A2 is a second level signal, such as a low level signal.

[0034] The overshoot voltage control module 130 is configured to generate an overshoot voltage control signal B according to the first judgment result A1 output by the conduction time detection module 110 and the second judgment result A2 output by the feedback voltage detection module 120. Specifically, the overshoot voltage control module 130 needs to realize that when the first judgment result A1 indicates that the conduction time of the lower power tube LSF is greater than the steady-state value, and the second judgment result A2 indicates that the feedback voltage V FB When the overcharge voltage control signal is greater than the preset reference voltage Vref, the overcharge voltage control signal is a first level signal capable of shutting down the lower power tube LSF through the driving control module 140 , for example, it can be a high level signal.

[0035] The drive control module 140 is configured to control the shutdown of the lower power tube LSF according to the overshoot voltage control signal B. The drive control module 140 is a circuit that can generate a drive signal that directly controls the switch of the power tube (the lower power tube LSF and the upper power tube HSF). Usually, in a switching converter, a pulse width modulation signal (PWM signal) needs to be input into the drive control module 140 to generate a drive signal for the power tube to control the switch of the power tube and realize the regulation of the input voltage Vin to the output voltage Vout. In the embodiment of the present disclosure, the drive control module 140 is an improvement on the usual drive control module 140. On the basis of not affecting the switch control of the power tube by the PWM signal, an overshoot voltage control signal B is added that can also indirectly control the shutdown of the lower power tube LSF. This overshoot voltage control signal B is to reduce the overshoot voltage on the output voltage Vout when the load changes transiently. Because when the lower power tube LSF is turned off by the overshoot voltage control signal B, the falling slope of the inductor current can be increased from Vout / L to (Vout+Vdiode) / L, which reduces the energy transferred from the inductor to the output capacitor, thereby reducing the overshoot voltage on the output voltage Vout. Figure 4 Where Vdiode is the conduction voltage of the body diode D1.

[0036] According to the above description, it can be seen that the overshoot voltage control circuit 100 of the embodiment of the present disclosure detects the on-time of the lower power tube LSF of the switching converter during the load transient change process, and determines whether the on-time is greater than the steady-state value, and at the same time detects the feedback voltage V of the output voltage Vout of the switching converter during the load transient change process. FB , and determine the feedback voltage V FB Is it greater than the preset reference voltage Vref? Based on the two judgment results, an overshoot voltage control signal B is generated to make the on-time greater than the steady-state value and the feedback voltage V of the output voltage Vout FB When it is greater than the preset reference voltage Vref, the shutdown of the lower power tube LSF is controlled by the generated overshoot voltage control signal B. Through the above design, the falling slope of the inductor current can be increased from Vout / L to (Vout+Vdiode) / L, which reduces the energy transferred from the inductor to the output capacitor, reduces the overshoot voltage of the system, and reduces the overshoot voltage during transient response without adding external components or changing the system application.

[0037] Further, such as Figure 5As shown, the conduction time detection module 110 includes: a sampling unit 111, a delay unit 112, wherein the sampling unit 111 is configured to collect the rising edge of the driving signal DRVL of the lower power tube LSF; the delay unit 112 is configured to delay the rising edge collected by the sampling unit 111 and then output a first judgment result A1, and the delay time of the delay unit 112 is greater than the steady-state value (i.e., the steady-state value of the conduction time of LSF in the steady state). The working principle of the delay unit 112 is: receiving the rising edge signal of the lower power tube LSF, after the delay time, if the output A1 is a high level, it means that the conduction time of the lower power tube LSF is greater than the steady-state value, if the output A1 is a low level, it means that the conduction time of the lower power tube LSF is not greater than the steady-state value, so it can be judged by the state of A1 whether the conduction time of the lower power tube LSF is greater than the steady-state value.

[0038] Optionally, the overshoot voltage control module 130 includes: a comparator comp, wherein a positive input terminal of the comparator comp is coupled to a feedback voltage V FB , the negative input terminal of the comparator comp is coupled to the preset reference voltage Vref, and the output terminal of the comparator comp outputs the second judgment result A2. If A2 is high level, it means that the feedback voltage V FB is greater than the preset reference voltage Vref. If A2 is low, it means that the feedback voltage V FB is not greater than the preset reference voltage Vref.

[0039] Optionally, the overshoot voltage control module 130 includes: an AND gate G1 and a latch RS-latch, wherein the first input terminal of the AND gate G1 is coupled to the first judgment result A1, the second input terminal of the AND gate G1 is coupled to the second judgment result A2, and the output terminal of the AND gate G1 is coupled to the set input terminal S of the latch RS-latch; the reset input terminal R of the latch RS-latch is coupled to the pulse width modulation signal PWM of the switching converter, and the output terminal Q of the latch RS-latch outputs the overshoot voltage control signal B. The working principle of the overshoot voltage control module 130 is as follows: when the first judgment result A1 and the second judgment result A2 are both high level, the set input terminal S of the latch RS-latch is high level, and the PWM signal is also low level (when PWM is low level, the lower power tube LSF is turned on), then the output overshoot voltage control signal B is a first level signal (high level signal); when at least one of A1 or A2 is low level, the set input terminal S of the latch RS-latch changes from high level to low level, at this time the output overshoot voltage control signal B maintains the original state or is still the first level signal, when PWM becomes high level (upper power tube HSF is turned on), the latch RS-latch is reset, and the output overshoot voltage control signal B becomes a second level signal (low level signal).

[0040] Optionally, the drive control module 140 includes: an upper tube drive unit 142 and a lower tube drive unit 141, wherein the upper tube drive unit 142 is configured to generate an upper tube drive signal DRVH for controlling the upper power tube HSF switch of the switching converter according to the pulse width modulation signal PWM; and the lower tube drive unit 141 is configured to generate a lower tube drive signal DRVL for controlling the lower power tube LSF switch according to the pulse width modulation signal PWM or the overshoot voltage control signal B. Further, as Figure 5 As shown, the lower tube driving unit 141 includes: first to four NOT gates (G2, G5, G6, G7), a first NAND gate G3, and a first NOR gate G4, wherein the input end of the first NOT gate G2 is coupled to the pulse width modulation signal PWM, and the output end of the first NOT gate G2 is coupled to the first input end of the first NAND gate G3; the second input end of the first NAND gate G3 is coupled to the upper tube driving unit 142, and the output end of the first NAND gate G3 is coupled to the first input end of the first NOR gate G4; the second input end of the first NOR gate G4 is coupled to the overshoot voltage control signal B, and the output end of the first NOR gate G4 is coupled to the input end of the second NOT gate G5; the output end of the second NOT gate G5 is coupled to the input end of the third NOT gate G6; the output end of the third NOT gate G6 is respectively coupled to the control electrode (i.e., the output DRVL signal) of the lower power tube LSF and the input end of the fourth NOT gate G7; the output end of the fourth NOT gate G7 is coupled to the upper tube driving unit 142. The upper tube driving unit 142 includes: a second NAND gate G8, and fifth to eighth NAND gates (G9-G12), wherein a first input terminal of the second NAND gate G8 is coupled to a pulse width modulation signal PWM, a second input terminal of the second NAND gate G8 is coupled to an output terminal of a fourth NAND gate G7 of the lower tube driving unit 141, and an output terminal of the second NAND gate G8 is coupled to an input terminal of a fifth NAND gate G9; an output terminal of the fifth NAND gate G9 is coupled to an input terminal of a sixth NAND gate G10; an output terminal of the sixth NAND gate G10 is coupled to an input terminal of a seventh NAND gate G11; an output terminal of the seventh NAND gate G11 is respectively coupled to a control terminal (i.e., outputting a DRVH signal) of the upper power tube HSF and an input terminal of an eighth NAND gate G12; and an output terminal of the eighth NAND gate G12 is coupled to a second input terminal of the first NAND gate G3 of the lower tube driving unit 141.

[0041] Combine the following Figure 4-5 The circuit principle of the overshoot voltage control circuit 100 in the embodiment of the present disclosure is described as follows: the overshoot control in the embodiment of the present disclosure occurs during a transient change in the load. When PWM is at a low level, DRVL becomes a high level, and the lower power tube LSF is controlled to be turned on. At the same time, the sampling unit 111 can collect the rising edge of DRVL. If the on time of the lower power tube LSF is greater than the steady-state value, then after the delay unit 112, the output A1 is a high level. At this time, if the feedback voltage V FBIf it is also greater than the preset reference voltage Vref, then A2 is also high, and the S end of the latch RS-latch is high. When PWM is still low, the Q end of the latch RS-latch is high, that is, B is high. After B is high, DRVL becomes low through G4, G5, and G6, so that the lower power tube LSF is turned off, and then the downward slope of the inductor current increases from Vout / L to (Vout+Vdiode) / L, which reduces the energy transferred from the inductor to the output capacitor, reducing the overshoot voltage of the system. Figure 6 , which shows a waveform diagram corresponding to a key signal in an embodiment of the present disclosure, Figure 6 From top to bottom, the preset reference voltage Vref, the feedback voltage V FB , the second judgment result A2, the first judgment result A1, and the waveform diagram of the overshoot voltage control signal B, from Figure 6 It can also be seen that after A1 and A2 are both high, B is also high, thereby controlling the shutdown of the lower power tube LSF. In addition, it should be noted that for application systems with a smaller output voltage Vout, such as the INTEL CPU platform with a Vout of 0.77V, by using the overshoot control circuit 100 in the embodiment of the present disclosure, the inductor current slope can be increased from 0.77 / L to (0.77+0.7) / L, almost twice, so the overshoot voltage can be significantly reduced. For application systems with a larger output voltage Vout, the overshoot can also be reduced, but it is not as significant as with a smaller output voltage Vout, that is, the embodiment of the present disclosure is more suitable for application systems with a smaller output voltage Vout. .

[0042] In order to further illustrate the effect of the embodiment of the present disclosure, the embodiment of the present disclosure is simulated and analyzed with a specific example to compare with the prior art. The simulation adopts an application with an input voltage Vin of 15V, an output voltage Vout of 0.77V, a frequency of 1MHz, an inductance of 0.47uH, a load from 11.45A to 0A within 1us, and an overvoltage requirement standard of 50mV. The output overshoot voltage in the worst case is simulated. Figure 7As shown, a schematic diagram of the waveforms of the inductor current IL and the output voltage Vout corresponding to the prior art and the embodiment of the present disclosure is shown, wherein a1 and c1 are the waveforms of the inductor current IL and the output voltage Vout corresponding to the prior art using a 300uF output capacitor, a2 and c2 are the waveforms of the inductor current IL and the output voltage Vout corresponding to the prior art using a 360uF output capacitor, and b and d are the waveforms of the inductor current IL and the output voltage Vout corresponding to the embodiment of the present disclosure using a 300uF output capacitor. Through comparative analysis of the waveforms, it can be seen that compared with the prior art, the falling slope of the inductor current IL of the embodiment of the present disclosure is significantly increased, and under the same size of output capacitance (300uF), the embodiment of the present disclosure can control the overshoot voltage of the output voltage Vout within 50mV, meeting the overshoot voltage standard of the application, while the overshoot voltage of the output voltage Vout of the prior art is 58mV when the output capacitance is 300uF, which cannot meet the overshoot voltage standard of the application. The prior art controls the overshoot voltage within 50mV when the output capacitance is 360uF, but 360uF is 20% higher than 300uF, and the volume, area and cost will all increase. Therefore, it can be seen that the embodiment of the present disclosure can achieve a smaller output capacitance, and can also reduce the overshoot voltage to meet the application standard, reducing the circuit area and cost.

[0043] Furthermore, the embodiment of the present disclosure also provides an overshoot voltage control method 300, which is applied to the overshoot control circuit 100 in the above embodiment. Specifically, Figure 8 As shown, the method includes the following steps S201-S204: S201. Detect the conduction time of the lower power tube of the switching converter during the load transient change process, and determine whether the conduction time is greater than the steady-state value, and obtain a first judgment result; wherein the steady-state value is the conduction time of the lower power tube in the steady state; and, execute step S202. Detect the feedback voltage of the output voltage Vout of the switching converter during the load transient change process, and determine whether the feedback voltage is greater than the preset reference voltage, and obtain a second judgment result; S203. Generate an overshoot voltage control signal according to the first judgment result and the second judgment result. S204. Control the shutdown of the lower power tube according to the overshoot voltage control signal.

[0044] Further, in step S203, generating an overshoot voltage control signal according to the first judgment result and the second judgment result includes: if the first judgment result indicates that the conduction time is greater than the steady-state value, and the second judgment result indicates that the feedback voltage is greater than the preset reference voltage, then the overshoot voltage control signal is controlled to be a first level signal. The first level signal is a valid signal that can control the lower power to be turned off. Specifically, in the embodiment of the present disclosure, the first level signal is a high level signal. If the first judgment result indicates that the conduction time is not greater than the steady-state value, and / or the second judgment result indicates that the feedback voltage is not greater than the preset reference voltage, then the overshoot voltage control signal is controlled to be a second level signal, and the second level signal is a low level signal, and the lower power tube cannot be turned off at this time.

[0045] According to a third aspect of the present disclosure, a switching converter is provided, the switching converter at least comprising the overshoot voltage control circuit 100 in the first aspect. The switching converter of the embodiment of the present disclosure may be a DCDC converter, including a BUCK type, a Boost type, etc. The switching converter using the overshoot voltage control circuit 100 of the embodiment of the present disclosure may also reduce the overshoot voltage during transient response while ensuring a smaller circuit area, lower circuit cost, and without changing the system.

[0046] In summary, the overshoot voltage control method in the embodiment of the present disclosure can reduce the overshoot voltage even with a smaller output capacitor, thereby saving circuit area and cost.

[0047] Unless the context clearly indicates otherwise, the singular form of the words used herein and in the appended claims includes the plural and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the words "comprise" and "include" are to be interpreted as inclusive rather than exclusive. Likewise, the terms "include" and "or" should be interpreted as inclusive unless such interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it is placed after a group of terms, "example" is merely exemplary and illustrative and should not be considered exclusive or comprehensive.

[0048] Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present disclosure can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0049] Several embodiments of the present disclosure are described in detail above, but it is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the attached claims.

Claims

1. An overshoot voltage control circuit, characterized in that: The control circuit is used to control the overshoot voltage on the output voltage of the switching converter, and the control circuit includes: a conduction time detection module, a feedback voltage detection module, an overshoot voltage control module, and a drive control module. The on-time detection module is configured to detect the on-time of the lower power tube of the switching converter during a transient load change, and determine whether the on-time is greater than a steady-state value, wherein the steady-state value is the on-time of the lower power tube in a steady state; The feedback voltage detection module is configured to detect a feedback voltage of the output voltage of the switching converter during a load transient change process, and determine whether the feedback voltage is greater than a preset reference voltage; The overshoot voltage control module is configured to generate an overshoot voltage control signal according to a first judgment result output by the conduction time detection module and a second judgment result output by the feedback voltage detection module; The drive control module is configured to control the shutdown of the lower power tube according to the overshoot voltage control signal, so as to control the shutdown of the lower power tube when the conduction time is greater than the steady-state value and the feedback voltage is greater than the preset reference voltage, so as to reduce the energy transferred from the inductance of the switching converter to the output capacitor of the switching converter.

2. The overshoot voltage control circuit according to claim 1, characterized in that: The conduction time detection module includes: a sampling unit and a delay unit. Wherein, the sampling unit is configured to collect the rising edge of the driving signal of the lower power tube; The delay unit is configured to delay the rising edge collected by the sampling unit and then output the first judgment result, and the delay time of the delay unit is greater than the steady-state value.

3. The overshoot voltage control circuit according to claim 1, characterized in that: The overshoot voltage control module includes: a comparator, The positive input terminal of the comparator is coupled to the feedback voltage, the negative input terminal of the comparator is coupled to the preset reference voltage, and the output terminal of the comparator outputs the second determination result.

4. The overshoot voltage control circuit according to claim 1, characterized in that: The overshoot voltage control module includes: an AND gate, a latch, The first input terminal of the AND gate is coupled to the first judgment result, the second input terminal of the AND gate is coupled to the second judgment result, and the output terminal of the AND gate is coupled to the set input terminal of the latch; A reset input terminal of the latch is coupled to a pulse width modulation signal of the switching converter, and an output terminal of the latch outputs the overshoot voltage control signal.

5. The overshoot voltage control circuit according to claim 4, characterized in that: The driving control module includes: an upper tube driving unit and a lower tube driving unit. The upper tube driving unit is configured to generate an upper tube driving signal for controlling an upper power tube switch of the switching converter according to the pulse width modulation signal; The lower tube driving unit is configured to generate a lower tube driving signal for controlling the lower power tube switch according to the pulse width modulation signal or the overshoot voltage control signal.

6. The overshoot voltage control circuit according to claim 5, characterized in that: The lower tube driving unit includes: first to fourth NOT gates, a first NAND gate, and a first NOR gate. Wherein, an input terminal of the first NOT gate is coupled to the pulse width modulation signal, and an output terminal of the first NOT gate is coupled to a first input terminal of the first NAND gate; The second input terminal of the first NAND gate is coupled to the upper tube driving unit, and the output terminal of the first NAND gate is coupled to the first input terminal of the first NOR gate; The second input terminal of the first NOR gate is coupled to the overshoot voltage control signal, and the output terminal of the first NOR gate is coupled to the input terminal of the second NOR gate; The output terminal of the second NOT gate is coupled to the input terminal of the third NOT gate; The output end of the third NOT gate is respectively coupled to the control electrode of the lower power tube and the input end of the fourth NOT gate; An output terminal of the fourth NOT gate is coupled to the upper tube driving unit.

7. The overshoot voltage control circuit according to claim 6, characterized in that: The upper tube driving unit includes: a second NAND gate, fifth to eighth NAND gates, Wherein, the first input terminal of the second NAND gate is coupled to the pulse width modulation signal, the second input terminal of the second NAND gate is coupled to the output terminal of the fourth NAND gate of the lower tube driving unit, and the output terminal of the second NAND gate is coupled to the input terminal of the fifth NAND gate; The output terminal of the fifth NOT gate is coupled to the input terminal of the sixth NOT gate; The output terminal of the sixth NOT gate is coupled to the input terminal of the seventh NOT gate; The output end of the seventh NOT gate is respectively coupled to the control electrode of the upper power tube and the input end of the eighth NOT gate; The output terminal of the eighth NOT gate is coupled to the second input terminal of the first NAND gate of the lower tube driving unit.

8. An overshoot voltage control method, applied to a switching converter, characterized in that: The method comprises: During a load transient change process, the conduction time of the lower power tube of the switching converter is detected, and it is determined whether the conduction time is greater than a steady-state value to obtain a first determination result, wherein the steady-state value is the conduction time of the lower power tube in a steady state; and, Detecting a feedback voltage of the output voltage of the switching converter during a load transient change process, and determining whether the feedback voltage is greater than a preset reference voltage to obtain a second determination result; generating an overshoot voltage control signal according to the first judgment result and the second judgment result; The shutdown of the lower power tube is controlled according to the overshoot voltage control signal, so that when the conduction time is greater than the steady-state value and the feedback voltage is greater than the preset reference voltage, the lower power tube is controlled to be shut down to reduce the energy transferred from the inductance of the switching converter to the output capacitor of the switching converter.

9. The overshoot voltage control method according to claim 8, characterized in that: Generating an overshoot voltage control signal according to the first judgment result and the second judgment result includes: If the first judgment result indicates that the conduction time is greater than the steady-state value, and the second judgment result indicates that the feedback voltage is greater than the preset reference voltage, the overshoot voltage control signal is controlled to be a first level signal, which is an effective signal that can shut down the lower power tube.

10. A switching converter, characterized in that: The switching converter at least comprises the overshoot voltage control circuit as described in claims 1-7.

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