Adaptive on-time controller and voltage converter

Abstract

The application is suitable for the technical field of switching power supply, and provides a self-adaptive conduction time controller and a voltage converter.The self-adaptive conduction time controller comprises a constant current generating module, a slope voltage generating module, a modulated voltage generating module, a switching module, a duty cycle sampling module and a comparison module, the constant current generating module is electrically connected with the slope voltage generating module and the modulated voltage generating module respectively, the slope voltage generating module is electrically connected with the modulated voltage generating module, the switching module and the comparison module respectively, and the duty cycle sampling module is electrically connected with the modulated voltage generating module, the switching module and the comparison module respectively.The self-adaptive conduction time controller provided by the application can ensure that the conduction time is also related to the actual duty cycle, and realizes fixed switching frequency.This design can effectively offset the influence of non-ideal factors such as load current change, inductance parasitic effect and power tube conduction resistance, and significantly reduces the influence of electromagnetic interference.

Description

Technical Field

[0001] The present application belongs to the technical field of switching power supplies, and in particular relates to an adaptive on-time controller and a voltage converter. Background Art

[0002] With the rapid advancement of power management technology, voltage converters (such as DC-DC converters) are increasingly being used in consumer electronics, industrial control, and automotive electronics. Adaptive on-time control, due to its high output accuracy and excellent transient response, has become a key technology in switching power supply design. Ideally, conventional adaptive on-time controllers adjust the on-time inversely proportional to the input and output voltages to achieve a constant switching frequency and reduce the impact of electromagnetic interference (EMI). However, in practice, due to non-ideal factors such as load current variations, parasitic resistance of the inductor, and on-resistance of the power transistors in the voltage converter, the actual duty cycle can deviate from the ideal value, causing the switching frequency to fluctuate with load changes, exacerbating EMI issues. Summary of the Invention

[0003] The embodiments of the present application provide an adaptive on-time controller and a voltage converter, which can solve the problem in practical applications where the switching frequency fluctuates with load changes due to non-ideal factors, thereby causing electromagnetic interference problems.

[0004] In a first aspect, an embodiment of the present application provides an adaptive on-time controller, comprising a constant current generating module, a ramp voltage generating module, a modulation voltage generating module, a switch module, a duty cycle sampling module, and a comparison module, wherein the constant current generating module is electrically connected to the ramp voltage generating module and the modulation voltage generating module, respectively; the ramp voltage generating module is electrically connected to the modulation voltage generating module, the switch module, and the comparison module, respectively; and the duty cycle sampling module is electrically connected to the modulation voltage generating module, the switch module, and the comparison module, respectively;

[0005] The constant current generating module is used to generate a constant current based on a first driving voltage and a reference voltage; the ramp voltage generating module is used to output a ramp voltage to the comparison module based on the constant current; the modulation voltage generating module is used to generate a modulation voltage based on the first driving voltage, the reference voltage and the second driving voltage, and the second driving voltage is the driving signal of the main power tube in the voltage converter; the duty cycle sampling module is used to output a duty cycle voltage to the comparison module based on the modulation voltage when the switching module is turned off according to the second driving voltage; the comparison module is used to output a target voltage based on the ramp voltage and the duty cycle voltage.

[0006] In a possible implementation of the first aspect, the constant current generating module includes a constant voltage generating unit and a resistance unit, and the constant voltage generating unit is electrically connected to the resistance unit, the ramp voltage generating module, and the modulation voltage generating module respectively;

[0007] The constant voltage generating unit is used to generate a constant voltage according to the first driving voltage and the reference voltage; and the resistance unit generates the constant current according to the constant voltage.

[0008] In a possible implementation of the first aspect, the constant voltage generating unit includes a first current source, a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a fifth switching tube, a sixth switching tube, a seventh switching tube, and an eighth switching tube. The first end of the first current source, the source of the sixth switching tube, the source of the seventh switching tube, and the source of the eighth switching tube are all electrically connected to a power supply. The second end of the first current source is electrically connected to the gate of the first switching tube, the drain of the first switching tube, the gate of the second switching tube, and the modulation voltage generating module, respectively. The source of the first switching tube, the source of the second switching tube, and the source of the third switching tube are electrically connected. The gate of the fourth switching tube is electrically connected to the drain of the first switching tube. The gate of the fifth switching tube is electrically connected to the modulation voltage generating module for receiving the first driving voltage, the gate of the seventh switching tube is electrically connected to the modulation voltage generating module, the gate of the sixth switching tube, the drain of the sixth switching tube and the drain of the second switching tube, and the drain of the seventh switching tube is electrically connected to the drain of the fifth switching tube, the gate of the eighth switching tube and the ramp voltage generating module.

[0009] In a possible implementation of the first aspect, the resistance unit includes a first resistor, a first end of the first resistor is electrically connected to the source of the fourth switching tube and the drain of the eighth switching tube respectively, and a second end of the first resistor is grounded.

[0010] In a possible implementation of the first aspect, the ramp voltage generating module includes a ninth switching tube, a tenth switching tube, and a first capacitor; the gate of the ninth switching tube is electrically connected to the constant current generating module; the source of the ninth switching tube is used to be electrically connected to a power supply; the drain of the ninth switching tube is respectively electrically connected to the first end of the first capacitor, the drain of the tenth switching tube, and the modulation voltage generating module; the gate of the tenth switching tube is respectively electrically connected to the modulation voltage generating module and the switching module for receiving the second driving voltage; the source of the tenth switching tube and the second end of the first capacitor are both grounded.

[0011] In a possible implementation of the first aspect, the modulation voltage generation module includes an eleventh switching tube, a twelfth switching tube, a thirteenth switching tube, a fourteenth switching tube, a fifteenth switching tube, a sixteenth switching tube, and a second resistor. The gate of the eleventh switching tube is electrically connected to the constant current generation module, the source of the eleventh switching tube and the source of the twelfth switching tube are both used to be electrically connected to a power supply, the drain of the eleventh switching tube is respectively electrically connected to the gate of the twelfth switching tube and the drain of the thirteenth switching tube, the gate of the thirteenth switching tube is electrically connected to the constant current generation module for receiving the first driving voltage, and the source of the thirteenth switching tube is respectively electrically connected to the drain of the fourteenth switching tube. The drain of the 15th switching tube is electrically connected to the drain of the 15th switching tube, the gate of the 14th switching tube is electrically connected to the constant current generating module for receiving the reference voltage, the source of the 14th switching tube is electrically connected to the drain of the 12th switching tube, the source of the 16th switching tube and the first end of the second resistor, the gate of the 15th switching tube is electrically connected to the constant current generating module, the source of the 15th switching tube is electrically connected to the second end of the second resistor, the gate of the 16th switching tube is electrically connected to the switching module and the ramp voltage generating module for receiving the second driving voltage, and the drain of the 16th switching tube is electrically connected to the switching module and the duty cycle sampling module.

[0012] In a possible implementation of the first aspect, the switching module includes a seventeenth switching tube, the gate of the seventeenth switching tube is electrically connected to the ramp voltage generating module and the modulation voltage generating module, respectively, for receiving the second driving voltage, the source of the seventeenth switching tube is grounded, and the drain of the seventeenth switching tube is electrically connected to the modulation voltage generating module.

[0013] In a possible implementation of the first aspect, the duty cycle sampling module includes a third resistor and a second capacitor, the first end of the third resistor is electrically connected to the modulation voltage generating module and the switching module, respectively, the second end of the third resistor is electrically connected to the first end of the second capacitor and the comparison module, and the second end of the second capacitor is grounded.

[0014] In a possible implementation of the first aspect, the comparison module includes a comparator, a first input end of the comparator is electrically connected to the ramp voltage generating module, a second input end of the comparator is electrically connected to the duty cycle sampling module, and an output end of the comparator is used to output the target voltage.

[0015] In a second aspect, an embodiment of the present application provides a voltage converter, comprising the adaptive on-time controller described in any one of the first aspects.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0017] An adaptive on-time controller provided in an embodiment of the present application includes a constant current generation module, a ramp voltage generation module, a modulation voltage generation module, a switch module, a duty cycle sampling module, and a comparison module. The constant current generation module receives a first driving voltage and a reference voltage and generates a constant current based on the first driving voltage and the reference voltage. The ramp voltage generation module generates a ramp voltage based on the constant current and transmits the ramp voltage to the comparison module. The modulation voltage generation module generates a modulation voltage based on the first driving voltage, the reference voltage, and the second driving voltage. When the switch module is turned off in response to the second driving voltage, the modulation voltage can be transmitted to the duty cycle sampling module, which outputs a duty cycle voltage to the comparison module based on the modulation voltage. The comparison module outputs a target voltage based on the ramp voltage and the duty cycle voltage, thereby determining the on-time. Since the second driving voltage is the drive signal for the main power transistor in the voltage converter, the on-time of the main power transistor (i.e., the time when the switch module is turned off in response to the second driving signal) corresponds to the actual duty cycle of the voltage converter. Therefore, the adaptive on-time controller provided in the embodiment of the present application accurately controls the transmission timing of the modulation voltage to the duty cycle sampling module through the second drive voltage, so that the duty cycle voltage output by the duty cycle sampling module is proportional to the second drive voltage, and then the target voltage output by the comparison module based on the ramp voltage and the duty cycle voltage is also related to the actual duty cycle. Therefore, it can be ensured that the on-time is also related to the actual duty cycle, achieving a fixed switching frequency. This design can effectively offset the influence of non-ideal factors such as load current changes, inductor parasitic effects, and power tube on-resistance, and significantly reduce the impact of electromagnetic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0019] Figure 1 is a circuit schematic diagram of an existing adaptive on-time controller;

[0020] Figure 2 is a principle block diagram of an adaptive on-time controller provided by an embodiment of the present application;

[0021] Figure 3 is a circuit connection schematic diagram of an adaptive on-time controller provided by an embodiment of the present application;

[0022] Figure 4 is a principle simplified schematic diagram of an adaptive on-time controller provided by an embodiment of the present application.

[0023] In the figure, 10, adaptive on-time controller; 101, constant current generation module; 1011, constant voltage generation unit; 1012, resistance unit; 102, ramp voltage generation module; 103, modulation voltage generation module; 104, switch module; 105, duty cycle sampling module; 106, comparison module. DETAILED DESCRIPTION

[0024] In the following description, specific details are set forth in order to provide a thorough understanding of embodiments of the present application. However, persons of ordinary skill in the art will readily recognize that embodiments of the present application can be practiced without these specific details, in other instances, well-known structures, devices, circuits, and methods have not been described in detail in order to avoid obscuring the present application.

[0025] It should be understood that, when used in the specification and the appended claims of the present application, the term "comprising" indicates the presence of described features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0026] It should also be understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0027] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0028] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0030] With the rapid development of power management technology, voltage converters (such as DC-DC converters) are increasingly used in consumer electronics, industrial control, and automotive electronics. Adaptive on-time control has become a key technology in switching power supply design due to its high output accuracy and excellent transient response characteristics. Ideally, a traditional adaptive on-time controller adjusts the on-time so that it is inversely proportional to the input voltage and output voltage, thereby achieving a constant switching frequency and reducing the impact of electromagnetic interference. Specifically, under ideal conditions, the relationship between the switching frequency fsw, on-time Ton, ideal duty cycle D, input voltage Vin, and output voltage Vout in continuous conduction mode can be expressed as:

[0031]

[0032] like Figure 1 As shown, the prior art generally uses a traditional adaptive on-time module to generate an on-time Ton proportional to Vout / Vin, which is expressed as:

[0033]

[0034] Offset the effects of input voltage and output voltage to achieve a fixed switching frequency fsw:

[0035]

[0036] However, in practical application, the on-resistance and the parasitic resistance of the inductor will cause power loss, so more energy must be obtained from the power supply, thus the actual duty ratio D1 will be greater than the ideal duty ratio D, and the relationship between the actual duty ratio D1 and the on-resistance of the upper power transistor R ON , the on-resistance of the lower power transistor R ON , the current resistance of the inductor R DCR , and the load current I L may be expressed as:

[0037]

[0038] The actual switching frequency is D1 / Ton, thus the conventional adaptive on-time module cannot offset the influence of the non-ideal effects such as the change of the load current, the parasitic resistance of the inductor, and the on-resistance of the power transistor, and the switching frequency cannot be constant in the continuous conduction mode, but varies with the load current, thus causing the problems of efficiency reduction and electromagnetic interference.

[0039] To address the above-mentioned issues, an adaptive on-time controller provided in an embodiment of the present application includes a constant current generation module, a ramp voltage generation module, a modulation voltage generation module, a switch module, a duty cycle sampling module, and a comparison module. The constant current generation module receives a first driving voltage and a reference voltage and generates a constant current based on the first driving voltage and the reference voltage. The ramp voltage generation module generates a ramp voltage based on the constant current and transmits the ramp voltage to the comparison module. The modulation voltage generation module generates a modulation voltage based on the first driving voltage, the reference voltage, and the second driving voltage. When the switch module is turned off in response to the second driving voltage, the modulation voltage can be transmitted to the duty cycle sampling module, which outputs a duty cycle voltage to the comparison module based on the modulation voltage. The comparison module outputs a target voltage based on the ramp voltage and the duty cycle voltage, thereby determining the on-time. Since the second driving voltage is the drive signal for the main power transistor in the voltage converter, the on-time of the main power transistor (i.e., the time when the switch module is turned off in response to the second driving signal) corresponds to the actual duty cycle of the voltage converter. Therefore, the adaptive on-time controller provided in the embodiment of the present application accurately controls the transmission timing of the modulation voltage to the duty cycle sampling module through the second drive voltage, so that the duty cycle voltage output by the duty cycle sampling module is proportional to the second drive voltage, and then the target voltage output by the comparison module based on the ramp voltage and the duty cycle voltage is also related to the actual duty cycle. Therefore, it can be ensured that the on-time is also related to the actual duty cycle, achieving a fixed switching frequency. This design can effectively offset the influence of non-ideal factors such as load current changes, inductor parasitic effects, and power tube on-resistance, and significantly reduce the impact of electromagnetic interference.

[0040] In order to illustrate the technical solution described in this application, specific embodiments are provided below.

[0041] Figure 2 FIG1 shows a block diagram of the principle of an adaptive on-time controller 10 provided in an embodiment of the present application. Figure 2 As shown, the adaptive on-time controller 10 includes a constant current generating module 101, a ramp voltage generating module 102, a modulation voltage generating module 103, a switch module 104, a duty cycle sampling module 105 and a comparison module 106. The constant current generating module 101 is electrically connected to the ramp voltage generating module 102 and the modulation voltage generating module 103, respectively. The ramp voltage generating module 102 is electrically connected to the modulation voltage generating module 103, the switch module 104 and the comparison module 106, respectively. The duty cycle sampling module 105 is electrically connected to the modulation voltage generating module 103, the switch module 104 and the comparison module 106, respectively.

[0042] Specifically, the constant current generation module 101 receives a first driving voltage VB and a reference voltage VREF and generates a constant current based on the first driving voltage VB and the reference voltage VREF. The ramp voltage generation module 102 generates a ramp voltage VRAMP based on the constant current and transmits the ramp voltage VRAMP to the comparison module 106. The modulation voltage generation module 103 generates a modulation voltage VR2 based on the first driving voltage VB, the reference voltage VREF, and the second driving voltage VG. When the switch module 104 is turned off in response to the second driving voltage VG, the modulation voltage VR2 can be transmitted to the duty cycle sampling module 105. The duty cycle sampling module 105 outputs a duty cycle voltage VDUTY based on the modulation voltage VR2 to the comparison module 106. The comparison module 106 outputs a target voltage VDRI based on the ramp voltage VRAMP and the duty cycle voltage VDUTY, thereby determining the on-time. Since the second driving voltage VG is the drive signal for the main power transistor in the voltage converter, the on-time of the main power transistor (i.e., the time when the switch module 104 is turned off in response to the second driving signal) corresponds to the actual duty cycle of the voltage converter. Therefore, the adaptive on-time controller 10 provided in the embodiment of the present application accurately controls the transmission timing of the modulation voltage VR2 to the duty cycle sampling module 105 through the second drive voltage VG, so that the duty cycle voltage VDUTY output by the duty cycle sampling module 105 is proportional to the second drive voltage VG, and thus the target voltage VDRI output by the comparison module 106 based on the ramp voltage VRAMP and the duty cycle voltage VDUTY is also related to the actual duty cycle. Therefore, it can be ensured that the on-time is also related to the actual duty cycle, achieving a fixed switching frequency. This design can effectively offset the influence of non-ideal factors such as load current changes, inductor parasitic effects, and power tube on-resistance, significantly reducing the impact of electromagnetic interference.

[0043] It should be noted that when the switch module 104 is turned on according to the second driving voltage VG, it can discharge the current transmitted by the modulation voltage generating module 103.

[0044] In one embodiment of the present application, Figure 3 As shown, the constant current generating module 101 includes a constant voltage generating unit 1011 and a resistance unit 1012 , and the constant voltage generating unit 1011 is electrically connected to the resistance unit 1012 , the ramp voltage generating module 102 and the modulation voltage generating module 103 respectively.

[0045] Specifically, the constant voltage generating unit 1011 and the resistance unit 1012 in the constant current generating module 101 cooperate with each other to provide a stable current basis for the whole adaptive on-time controller 10. The core role of the constant voltage generating unit 1011 is to generate a constant voltage VR1 that is not disturbed by external factors according to the input first driving voltage VB and the reference voltage VREF, thereby laying a stable voltage basis for the subsequent generation of constant current. The resistance unit 1012 generates constant current through its own resistance characteristics based on the constant voltage VR1, and transmits the constant current to the slope voltage generating module 102 to provide a stable current source for the generation of the slope voltage VRAMP, thereby ensuring the linearity and stability of the slope voltage VRAMP, and further providing key support for the whole controller to realize accurate time control and stable switching frequency.

[0046] In an embodiment of the present application, as shown in Figure 3 The constant voltage generating unit 1011 includes a first current source I, a first switch tube MN1, a second switch tube MN2, a third switch tube MN3, a fourth switch tube MN4, a fifth switch tube MN5, a sixth switch tube MP1, a seventh switch tube MP2, and an eighth switch tube MP3. The first end of the first current source I, the source of the sixth switch tube MP1, the source of the seventh switch tube MP2, and the source of the eighth switch tube MP3 are electrically connected to the power supply VDD. The second end of the first current source I is electrically connected to the gate of the first switch tube MN1, the drain of the first switch tube MN1, the gate of the second switch tube MN2, and the modulation voltage generating module 103. The source of the first switch tube MN1, the source of the second switch tube MN2, and the source of the third switch tube MN3 are electrically connected. The gate of the fourth switch tube MN4 is electrically connected to the modulation voltage generating module 103 for receiving the reference voltage VREF. The source of the fourth switch tube MN4 is electrically connected to the drain of the eighth switch tube MP3 and the resistance unit 1012. The drain of the fourth switch tube MN4 is electrically connected to the drain of the third switch tube MN3 and the source of the fifth switch tube MN5. The gate of the fifth switch tube MN5 is electrically connected to the modulation voltage generating module 103 for receiving the first driving voltage VB. The gate of the seventh switch tube MP2 is electrically connected to the modulation voltage generating module 103, the gate of the sixth switch tube MP1, the drain of the sixth switch tube MP1, and the drain of the second switch tube MN2. The drain of the seventh switch tube MP2 is electrically connected to the drain of the fifth switch tube MN5, the gate of the eighth switch tube MP3, and the slope voltage generating module 102.

[0047] Specifically, the first current source I is configured to provide a fixed first current, which is the current flowing through the first switch MN1. Because the first, second, and third switches MN1 form a current mirror, the currents flowing through the first, second, and third switches MN3 are proportional to each other. Therefore, the currents flowing through the second and third switches MN2 and MN3 are both fixed. Because the current flowing through the second switch MN2 is equal to the current flowing through the sixth switch MP1, the current flowing through the sixth switch MP1 is also fixed. Because the sixth and seventh switches MP1 form a current mirror, the currents flowing through the sixth and seventh switches MP2 are proportional to each other. Therefore, the current flowing through the seventh switch MP2 is also fixed. The current flowing through the seventh switch MP2 is equal to the current flowing through the fifth switch MN5, indicating that the current flowing through the fifth switch MN5 is also fixed. Since the current flowing through the third switch MN3 is equal to the sum of the current flowing through the fifth switch MN5 and the current flowing through the fourth switch MN4, and the current flowing through the fifth switch MN5 is a fixed value, the current flowing through the fourth switch MN4 is also a fixed value. Since the current flowing through the fourth switch MN4 is fixed, the gate-source voltage of the fourth switch MN4 is also fixed. Furthermore, the fourth switch MN4 functions as a voltage follower. Therefore, the source voltage of the fourth switch MN4 (constant voltage VR1) is:

[0048]

[0049] Among them, V GS,MN4 is the gate-source voltage of the fourth switch tube MN4.

[0050] It should be noted that the first driving voltage VB is the bias voltage of the fifth switch tube MN5.

[0051] It should be noted that, since the current flowing through the eighth switch tube MP3 is equal to the sum of the current flowing through the fourth switch tube MN4 and the current flowing through the resistor unit 1012, wherein the current flowing through the fourth switch tube MN4 can be ignored when the fourth switch tube MN4 is turned on, the current flowing through the eighth switch tube MP3 is equal to the current flowing through the resistor unit 1012, that is, the above-mentioned constant current.

[0052] For example, designers can select the types of the first switch MN1, the second switch MN2, the third switch MN3, the fourth switch MN4, the fifth switch MN5, the sixth switch MP1, the seventh switch MP2, and the eighth switch MP3 based on actual conditions. Specifically, fully controllable power devices such as metal oxide field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs) can be used. For example, the first switch MN1, the second switch MN2, the third switch MN3, the fourth switch MN4, and the fifth switch MN5 can all be NMOS transistors, and the sixth switch MP1, the seventh switch MP2, and the eighth switch MP3 can all be PMOS transistors.

[0053] In one embodiment of the present application, Figure 3 As shown, the resistance unit 1012 includes a first resistor R1 , a first end of the first resistor R1 is electrically connected to the source of the fourth switch transistor MN4 and the drain of the eighth switch transistor MP3 , and a second end of the first resistor R1 is grounded.

[0054] Specifically, the first resistor R1, as the core component of the resistor unit 1012, converts the constant voltage VR1 output by the constant voltage generating unit 1011 into a precisely controllable constant current according to Ohm's law (I=V / R). This provides a stable current for the ramp voltage generating module 102. Furthermore, by precisely selecting the resistance value of the first resistor R1, the current magnitude can be calibrated to match the system timing requirements, ensuring that the duty cycle voltage VDUTY output by the duty cycle sampling module 105 is strictly proportional to the actual duty cycle. Furthermore, the physical properties of the first resistor R1 naturally provide resistance to power supply fluctuations and load variations, effectively isolating the current from interference caused by non-ideal factors, thereby improving the anti-interference performance and frequency stability of the entire adaptive on-time controller 10.

[0055] It should be noted that the constant current is:

[0056]

[0057] Here, R is the resistance of the resistor unit 1012 , ie, the resistance of the first resistor R1 . It can be seen that the constant current has nothing to do with the input / output voltage and the load current, but is only related to the constant voltage VR1 and the resistance of the resistor unit 1012 .

[0058] It should be noted that the present application does not limit the number of resistors in the resistor unit 1012 and the series-parallel relationship. Other numbers of resistors can be selected for series-parallel connection to achieve the function of converting the constant voltage VR1 into a constant current.

[0059] It should be noted that the embodiments provided in this application only show one circuit structure as the constant current generating module 101, which does not mean that only this circuit structure can realize the function of the constant current generating module 101. Other circuit structures that can realize this function can also be replaced, and the present invention is not limited to this.

[0060] In one embodiment of the present application, Figure 3 As shown, the ramp voltage generating module 102 includes a ninth switching tube MP4, a tenth switching tube MN6, and a first capacitor CON. The gate of the ninth switching tube MP4 is electrically connected to the constant current generating module 101, the source of the ninth switching tube MP4 is used to be electrically connected to the power supply VDD, the drain of the ninth switching tube MP4 is electrically connected to the first end of the first capacitor CON, the drain of the tenth switching tube MN6, and the modulation voltage generating module 103, respectively. The gate of the tenth switching tube MN6 is electrically connected to the modulation voltage generating module 103 and the switching module 104, respectively, for receiving the second driving voltage VG. The source of the tenth switching tube MN6 and the second end of the first capacitor CON are both grounded.

[0061] Specifically, because the ninth switch MP4 and the eighth switch MP3 form a current mirror, that is, the current flowing through the ninth switch MP4 and the current flowing through the eighth switch MP3 are proportional (e.g., the ratio is 1:1), the current flowing through the ninth switch MP4 is equal to the current flowing through the eighth switch MP3, that is, equal to a constant current. The first capacitor CON can be charged according to the constant current, thereby obtaining a ramp voltage VRAMP:

[0062]

[0063] CON is the capacitance of the first capacitor CON. Since the tenth switch MN6 is connected in parallel across the first capacitor CON, when the tenth switch MN6 is turned on in response to the second drive voltage VG (the second drive voltage VG is a high-level signal), it can discharge current flowing through the first capacitor CON. When the tenth switch MN6 is turned off in response to the second drive voltage VG, a constant current can charge the first capacitor CON, thereby generating a ramp voltage VRAMP, which is then transmitted to the comparison module 106.

[0064] For example, designers can select the types of the ninth switch MP4 and the tenth switch MN6 based on actual conditions. Specifically, both can use fully controllable power devices such as metal oxide field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs). For example, the ninth switch MP4 can be a PMOS transistor, and the tenth switch MN6 can be an NMOS transistor.

[0065] It should be noted that the embodiments provided herein only illustrate one circuit structure as the ramp voltage generating module 102, and this does not mean that only this circuit structure can implement the function of the ramp voltage generating module 102. Other circuit structures that can implement this function can also be substituted, and the present invention is not limited thereto.

[0066] In one embodiment of the present application, Figure 3 As shown, the modulation voltage generating module 103 includes an eleventh switching transistor MP5, a twelfth switching transistor MP6, a thirteenth switching transistor MN9, a fourteenth switching transistor MN8, a fifteenth switching transistor MN7, a sixteenth switching transistor MP7 and a second resistor R2. The gate of the eleventh switching transistor MP5 is electrically connected to the constant current generating module 101. The source of the eleventh switching transistor MP5 and the source of the twelfth switching transistor MP6 are both electrically connected to the power supply VDD. The drain of the eleventh switching transistor MP5 is respectively electrically connected to the gate of the twelfth switching transistor MP6 and the drain of the thirteenth switching transistor MN9. The gate of the thirteenth switching transistor MN9 is electrically connected to the constant current generating module 101 for receiving the first driving voltage VB. The source of the thirteenth switching transistor MN9 is respectively electrically connected to the fourteenth switching transistor MN8. The drain of the switching transistor MN8 is electrically connected to the drain of the fifteenth switching transistor MN7, the gate of the fourteenth switching transistor MN8 is electrically connected to the constant current generating module 101 for receiving the reference voltage VREF, the source of the fourteenth switching transistor MN8 is electrically connected to the drain of the twelfth switching transistor MP6, the source of the sixteenth switching transistor MP7, and the first end of the second resistor R2, respectively, the gate of the fifteenth switching transistor MN7 is electrically connected to the constant current generating module 101, the source of the fifteenth switching transistor MN7 is electrically connected to the second end of the second resistor R2, the gate of the sixteenth switching transistor MP7 is electrically connected to the switching module 104 and the ramp voltage generating module 102, respectively, for receiving the second driving voltage VG, and the drain of the sixteenth switching transistor MP7 is electrically connected to the switching module 104 and the duty cycle sampling module 105, respectively.

[0067] Specifically, similar to the fourth switch tube MN4 in the constant current generating module 101, the fourteenth switch tube MN8 is a voltage follower, and thus the modulation voltage VR2 can be obtained as:

[0068]

[0069] Among them, V GS,MN8 is the gate-source voltage of the fourteenth switch tube MN8.

[0070] The twelfth switch MP6, the fifteenth resistor, the fourteenth switch MN8, and the thirteenth switch MN9 form a negative feedback network for adjusting the modulation voltage VR2. Specifically, if the current flowing through the eleventh switch MP5 suddenly increases, the drain voltage of the eleventh switch MP5 decreases, which in turn increases the gate-source voltage of the twelfth switch MP6, increasing the current flowing through the twelfth switch MP6 and thus causing the modulation voltage VR2 to decrease. However, at this time, the gate-source voltage of the fourteenth switch MN8 increases, increasing the current flowing through the fourteenth switch MN8. Since the sum of the current flowing through the fourteenth switch MN8 and the current flowing through the eleventh switch MP5 equals the current flowing through the fifteenth switch MN7, and the fifteenth switch MN7 forms a current mirror with the third switch MN3, i.e., the current flowing through the fifteenth switch MN7 remains constant, the current flowing through the eleventh switch MP5 decreases, thereby adjusting the modulation voltage VR2 to increase.

[0071] The sixteenth switch MP7 functions as a switching device and can be turned on or off based on the second drive voltage VG. When the second drive voltage VG is a high-level signal, the sixteenth switch MP7 is turned off, and when the second drive voltage VG is a low-level signal, the sixteenth switch MP7 is turned on. When the sixteenth switch MP7 is turned on, the switch module 104 is turned off, and the modulation voltage VR2 can be transmitted to the duty cycle sampling module 105. Furthermore, the second resistor R2 is configured to generate a current based on the modulation voltage VR2.

[0072] For example, designers can select the types of the eleventh switch MP5, the twelfth switch MP6, the thirteenth switch MN9, the fourteenth switch MN8, the fifteenth switch MN7, and the sixteenth switch MP7 based on actual conditions. That is, they can all be fully controllable power devices such as metal oxide field effect transistors or insulated gate bipolar transistors. For example, the eleventh switch MP5, the twelfth switch MP6, and the sixteenth switch MP7 can all be PMOS transistors, and the thirteenth switch MN9, the fourteenth switch MN8, and the fifteenth switch MN7 can all be NMOS transistors.

[0073] It should be noted that the embodiments provided herein only illustrate one circuit structure as the modulation voltage generating module 103, and this does not mean that this is the only circuit structure that can implement the function of the modulation voltage generating module 103. Other circuit structures that can implement this function may also be substituted, and the present invention is not limited thereto.

[0074] In one embodiment of the present application, Figure 3As shown, the switch module 104 includes a seventeenth switch tube MN10, the gate of the seventeenth switch tube MN10 is electrically connected to the ramp voltage generating module 102 and the modulation voltage generating module 103 respectively, and is used to receive the second driving voltage VG, the source of the seventeenth switch tube MN10 is grounded, and the drain of the seventeenth switch tube MN10 is electrically connected to the modulation voltage generating module 103.

[0075] Specifically, the seventeenth switch MN10, as a switching device, can be turned on or off based on the second drive voltage VG. When the second drive voltage VG is a high-level signal, the seventeenth switch MN10 is turned on, and when the second drive voltage VG is a low-level signal, the seventeenth switch MN10 is turned off. When the seventeenth switch MN10 is turned on, it can discharge the current on the transmission line. When the seventeenth switch MN10 is turned off, the sixteenth switch MP7 is turned on, and the modulation voltage VR2 can be transmitted to the duty cycle sampling module 105.

[0076] For example, designers can select the type of the seventeenth switch MN10 according to actual conditions, that is, a fully controlled power device such as a metal oxide field effect transistor or an insulated gate bipolar transistor can be used. For example, the seventeenth switch MN10 can be selected as an NMOS transistor.

[0077] It should be noted that the embodiment provided in this application only shows one circuit structure as the switch module 104, which does not mean that only this circuit structure can realize the function of the switch module 104. Other circuit structures that can realize this function can also be replaced, and are not limited to this.

[0078] In one embodiment of the present application, Figure 3 As shown, the duty cycle sampling module 105 includes a third resistor RF and a second capacitor CF, the first end of the third resistor RF is electrically connected to the modulation voltage generating module 103 and the switching module 104 respectively, the second end of the third resistor RF is electrically connected to the first end of the second capacitor CF and the comparison module 106 respectively, and the second end of the second capacitor CF is grounded.

[0079] Specifically, the third resistor RF and the second capacitor CF form an RC filter for outputting a duty cycle voltage VDUTY based on the received modulation voltage VR2. Specifically, the filter integrates the modulation voltage VR2, converting the high-frequency pulse signal into a DC signal proportional to the average voltage within the switching cycle, thereby generating a duty cycle voltage VDUTY related to the actual duty cycle. The duty cycle voltage VDUTY is:

[0080]

[0081] Where Dt is the actual duty cycle of the system. In addition, the filtering characteristics of the RC network are used to effectively filter out the switching ripple and high-frequency noise in the modulation voltage VR2, ensuring that the output duty cycle voltage VDUTY is pure and stable.

[0082] It should be noted that because the second drive voltage VG serves as the drive signal for the main power transistor, the present invention's design ensures that only when the tenth switch MN6 is turned off in response to the second drive voltage VG (the second drive voltage VG is a low-level signal), the seventeenth switch MN10 is turned off in response to the second drive voltage VG (the second drive voltage VG is a low-level signal), and the sixteenth switch MP7 is turned on in response to the second drive voltage VG (the second drive voltage VG is a low-level signal), a constant current charges the first capacitor CON to generate a ramp voltage VRAMP. Simultaneously, the modulation voltage VR2 is transmitted to the third resistor RF and the second capacitor CF to generate a duty cycle voltage VDUTY related to the actual duty cycle. This enables the adaptive on-time controller 10 of the present invention to achieve a fixed switching frequency.

[0083] It should be noted that the embodiments provided herein only illustrate one circuit structure for the duty cycle sampling module 105, and this does not mean that this is the only circuit structure that can implement the functions of the duty cycle sampling module 105. Other circuit structures that can implement this function may also be substituted, and the present invention is not limited thereto.

[0084] In one embodiment of the present application, Figure 3 As shown, the comparison module 106 includes a comparator CMP, a first input terminal of the comparator CMP is electrically connected to the ramp voltage generating module 102, a second input terminal of the comparator CMP is electrically connected to the duty cycle sampling module 105, and an output terminal of the comparator CMP is used to output the target voltage VDRI.

[0085] Specifically, the negative input terminal of the comparator CMP serves as the first input terminal of the comparator CMP and is used to receive the ramp voltage VRAMP. The positive input terminal of the comparator CMP serves as the second input terminal of the comparator CMP and is used to receive the duty cycle voltage VDUTY. The comparator CMP performs a logical operation on the received ramp voltage VRAMP and the duty cycle voltage VDUTY to obtain the target voltage VDRI and know the on-time:

[0086]

[0087] At this time, the switching frequency can be expressed as:

[0088]

[0089] Since VREF, R, V GS,MN4 and V GS,MN8and CON are constants, so we can get an adaptive on-time generator that is not affected by non-ideal effects and can achieve a constant switching frequency. By properly designing the ratio of MN4, MN8 and the current mirror size, we can get V GS,MN4 =V GS,MN8 , the switching frequency can be further expressed as:

[0090]

[0091] In this case, the switching frequency depends solely on the values ​​of R and CON, resulting in greater robustness and immunity to non-ideal factors. Therefore, a converter implementing COT control maintains a constant frequency under heavy load, reducing the impact of electromagnetic interference (EMI) and improving system stability and transient response. This makes it ideal for products with strict EMI requirements. Furthermore, a constant switching frequency ensures more stable inductor ripple current, extending the service life of power inductors and capacitors. It also optimizes power device stress and mitigates saturation risks.

[0092] It should be noted that if Figure 4 As shown, the present application directly uses the actual duty cycle instead of Vin and Vout to design Ton, so that the frequency variation can be compensated. VDUTY is obtained from the second driving voltage VG and can be expressed as:

[0093]

[0094] in,

[0095]

[0096] I1 is a constant current and will not be affected by Vin, Vout, load current I L The on-time Ton generated by this structure can be expressed as:

[0097]

[0098] The present application also discloses a voltage converter, including the aforementioned adaptive on-time controller 10. The voltage converter employs the aforementioned adaptive on-time controller 10, which enables the voltage converter to maintain a fixed switching frequency in the face of non-ideal factors such as load current changes, inductor parasitic resistance, and power tube on-resistance, thereby effectively reducing electromagnetic interference. At the same time, by accurately tracking and adjusting the actual duty cycle, it achieves a fast transient response, operates stably over a wide load range, and achieves both low power consumption and high reliability without the need for a complex circuit structure. This significantly improves the overall performance and application flexibility of the voltage converter, making it better suited for various electronic equipment scenarios with high requirements for power supply stability and electromagnetic compatibility.

[0099] Since the processing and functions implemented by the voltage converter in this embodiment basically correspond to the embodiments, principles and examples of the aforementioned adaptive on-time controller, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0100] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. An adaptive on-time controller, characterized in that: The invention comprises a constant current generating module, a ramp voltage generating module, a modulation voltage generating module, a switch module, a duty cycle sampling module and a comparison module, wherein the constant current generating module is electrically connected to the ramp voltage generating module and the modulation voltage generating module respectively, the ramp voltage generating module is electrically connected to the modulation voltage generating module, the switch module and the comparison module respectively, and the duty cycle sampling module is electrically connected to the modulation voltage generating module, the switch module and the comparison module respectively; The constant current generating module is used to generate a constant current according to the first driving voltage and the reference voltage; the ramp voltage generating module is used to output a ramp voltage to the comparison module according to the constant current; The modulation voltage generating module is used to generate a modulation voltage according to the first driving voltage, the reference voltage and the second driving voltage, wherein the second driving voltage is a driving signal of the main power tube in the voltage converter; The duty cycle sampling module is configured to output a duty cycle voltage to the comparison module according to the modulation voltage when the switch module is turned off according to the second driving voltage; The comparison module is configured to output a target voltage according to the ramp voltage and the duty cycle voltage.

2. The adaptive on-time controller according to claim 1, wherein: The constant current generating module includes a constant voltage generating unit and a resistance unit, and the constant voltage generating unit is electrically connected to the resistance unit, the ramp voltage generating module and the modulation voltage generating module respectively; The constant voltage generating unit is used to generate a constant voltage according to the first driving voltage and the reference voltage; and the resistance unit generates the constant current according to the constant voltage.

3. The adaptive on-time controller according to claim 2, wherein: The constant voltage generating unit includes a first current source, a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a fifth switching tube, a sixth switching tube, a seventh switching tube and an eighth switching tube. The first end of the first current source, the source of the sixth switching tube, the source of the seventh switching tube and the source of the eighth switching tube are all used to be electrically connected to a power supply. The second end of the first current source is electrically connected to the gate of the first switching tube, the drain of the first switching tube, the gate of the second switching tube and the modulation voltage generating module respectively. The source of the first switching tube, the source of the second switching tube and the source of the third switching tube are electrically connected. The gate of the fourth switching tube is electrically connected to the modulation voltage generating module. The modulation voltage generating module is electrically connected to the modulation voltage generating module for receiving the reference voltage, the source of the fourth switching tube is electrically connected to the drain of the eighth switching tube and the resistance unit, respectively, the drain of the fourth switching tube is electrically connected to the drain of the third switching tube and the source of the fifth switching tube, the gate of the fifth switching tube is electrically connected to the modulation voltage generating module for receiving the first driving voltage, the gate of the seventh switching tube is electrically connected to the modulation voltage generating module, the gate of the sixth switching tube, the drain of the sixth switching tube and the drain of the second switching tube, respectively, and the drain of the seventh switching tube is electrically connected to the drain of the fifth switching tube, the gate of the eighth switching tube and the ramp voltage generating module.

4. The adaptive on-time controller according to claim 3, wherein: The resistance unit includes a first resistor, a first end of the first resistor is electrically connected to the source of the fourth switching transistor and the drain of the eighth switching transistor respectively, and a second end of the first resistor is grounded.

5. The adaptive on-time controller according to claim 1, wherein: The ramp voltage generating module includes a ninth switching tube, a tenth switching tube and a first capacitor. The gate of the ninth switching tube is electrically connected to the constant current generating module, the source of the ninth switching tube is used to be electrically connected to the power supply, the drain of the ninth switching tube is respectively electrically connected to the first end of the first capacitor, the drain of the tenth switching tube and the modulation voltage generating module, the gate of the tenth switching tube is respectively electrically connected to the modulation voltage generating module and the switching module, and is used to receive the second driving voltage. The source of the tenth switching tube and the second end of the first capacitor are both grounded.

6. The adaptive on-time controller according to claim 1, wherein: The modulation voltage generating module includes an eleventh switching tube, a twelfth switching tube, a thirteenth switching tube, a fourteenth switching tube, a fifteenth switching tube, a sixteenth switching tube and a second resistor. The gate of the eleventh switching tube is electrically connected to the constant current generating module. The source of the eleventh switching tube and the source of the twelfth switching tube are both used to be electrically connected to a power supply. The drain of the eleventh switching tube is respectively electrically connected to the gate of the twelfth switching tube and the drain of the thirteenth switching tube. The gate of the thirteenth switching tube is electrically connected to the constant current generating module for receiving the first driving voltage. The source of the thirteenth switching tube is respectively electrically connected to the drain of the fourteenth switching tube and the drain of the fifteenth switching tube. The drain of the 12th switching tube is electrically connected to the gate of the 14th switching tube, the gate of the 14th switching tube is electrically connected to the constant current generating module for receiving the reference voltage, the source of the 14th switching tube is electrically connected to the drain of the 12th switching tube, the source of the 16th switching tube and the first end of the second resistor, the gate of the 15th switching tube is electrically connected to the constant current generating module, the source of the 15th switching tube is electrically connected to the second end of the second resistor, the gate of the 16th switching tube is electrically connected to the switching module and the ramp voltage generating module for receiving the second driving voltage, and the drain of the 16th switching tube is electrically connected to the switching module and the duty cycle sampling module.

7. The adaptive on-time controller according to claim 1, wherein: The switching module includes a seventeenth switching tube, the gate of the seventeenth switching tube is electrically connected to the ramp voltage generating module and the modulation voltage generating module respectively, and is used to receive the second driving voltage, the source of the seventeenth switching tube is grounded, and the drain of the seventeenth switching tube is electrically connected to the modulation voltage generating module.

8. The adaptive on-time controller according to claim 1, wherein: The duty cycle sampling module includes a third resistor and a second capacitor, the first end of the third resistor is electrically connected to the modulation voltage generating module and the switching module respectively, the second end of the third resistor is electrically connected to the first end of the second capacitor and the comparison module respectively, and the second end of the second capacitor is grounded.

9. The adaptive on-time controller according to claim 1, wherein: The comparison module includes a comparator, a first input terminal of the comparator is electrically connected to the ramp voltage generating module, a second input terminal of the comparator is electrically connected to the duty cycle sampling module, and an output terminal of the comparator is used to output the target voltage.

10. A voltage converter, characterized in that: The adaptive on-time controller comprises the adaptive on-time controller according to any one of claims 1 to 9.

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