Control circuit and switching power supply using same

Abstract

The invention discloses a control circuit of a self-adaptive voltage positioning switching power supply and a switching power supply applying the control circuit, rough and quick setting of output voltage is realized by utilizing quick response of an analog current inner ring, the range of a droop resistor can be enlarged, and the number of gears can be reduced; and then, high-precision low-speed tiny correction of the output voltage is realized by utilizing the high resolution of the digital voltage outer loop, so that the droop output characteristic of the output voltage is adjusted. Therefore, the control circuit provided by the invention solves the problem that an existing simulation scheme is difficult to realize wide-range and high-resolution adjustability, greatly reduces the requirement on the high-speed sampling rate of the analog-to-digital converter (ADC) in full-digital control, and ensures the feasibility and practicability of design.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and more specifically, to a control circuit and a switching power supply using the same. Background Art

[0002] In high current switching power supplies for laptops, desktops, servers and telecommunication equipment, adaptive voltage position control (AVP control) is widely used to improve the transient response capability of the system and reduce load power consumption. Figure 1 The basic principle of AVP control is shown in FIG, where Vout represents the output voltage of the switching power supply, Iout represents the output current of the switching power supply, and Vref represents the reference voltage. Figure 1 As shown, when the output current Iout increases, the output voltage Vout decreases within the voltage tolerance range Vmax-Vmin, where Vmax represents the maximum allowable output voltage value and Vmin represents the minimum allowable output voltage value.

[0003] Figure 2 The transient response of the switching power supply with and without AVP control is compared. Figure 2 As shown in the figure, for a switching power supply without AVP control, only half of the voltage tolerance range is available due to overshoot and undershoot of the output voltage Vout when the load changes. For a switching power supply with AVP control, its output voltage Vout is adjusted to slightly above the minimum value Vmin at full load, and slightly below the maximum value Vmax at light load. Therefore, its entire tolerance range is available during load jumps, allowing the switching power supply to use a smaller output capacitor. In addition, since the output voltage Vout decreases when the output current Iout increases, the output power of the switching power supply decreases when it is fully loaded, which undoubtedly greatly reduces the difficulty of thermal design.

[0004] However, with the rapid development of electronic devices, the power of switching power supplies is getting higher and higher. Within the voltage tolerance range, traditional AVP control can no longer guarantee the safety and accurate operation of the system as well as the fast transient response capability. Summary of the invention

[0005] In view of this, the present invention provides an adaptive voltage positioning switching power supply and a control circuit thereof to balance the corresponding speed and accuracy issues.

[0006] In a first aspect, the present invention provides a control circuit of an adaptive voltage positioning switching power supply, characterized in that it comprises:

[0007] a compensation signal generating circuit, for receiving a digital voltage reference signal, a digital voltage sampling signal representing an output voltage of the switching power supply, and a digital droop voltage, and configured to perform an integration operation on an error between the digital voltage reference signal and a sum of the digital voltage sampling signal and the digital droop voltage to generate a compensation signal; and

[0008] The adaptive voltage positioning control circuit is configured to receive the compensation signal and generate a positioning signal to adjust the output voltage.

[0009] Preferably, the digital droop voltage is obtained according to the product of the digital droop resistance and a digital current sampling signal, wherein the digital current sampling signal is obtained by filtering a current sampling signal representing the inductor current of the switching power supply and then performing analog-to-digital conversion.

[0010] Preferably, the digital droop resistor corresponds to an output characteristic curve between an output voltage and an output current of the switching power supply.

[0011] Preferably, the compensation signal generating circuit comprises:

[0012] a digital integral operation module configured to perform an integral operation on an error between a digital voltage reference signal and a sum of the digital voltage sampling signal and the digital droop voltage, so as to generate a digital compensation signal at an output terminal; and

[0013] The first digital-to-analog converter is used to obtain the compensation signal after performing digital-to-analog conversion on the digital compensation signal.

[0014] Preferably, the digital integration operation module comprises a non-phase input terminal for receiving the difference between the digital voltage reference signal and the digital droop voltage, and an inverting input terminal for receiving the digital voltage sampling signal, so as to generate the digital compensation signal at the output terminal.

[0015] Preferably, the digital integration operation module comprises a non-phase input terminal for receiving the digital voltage reference signal and an inverting input terminal for receiving the sum of the digital voltage sampling signal and the digital droop voltage, so as to generate the digital compensation signal at the output terminal.

[0016] Preferably, the adaptive voltage positioning control circuit generates the positioning signal according to a voltage sampling signal representing the output voltage of the switching power supply, a current sampling signal representing the inductor current, the digital voltage reference signal and a compensation signal.

[0017] Preferably, the compensation signal generating circuit comprises:

[0018] A first analog-to-digital converter, used for converting the voltage sampling signal into a digital voltage sampling signal;

[0019] A low-pass filter, used to filter a current sampling signal representing the inductor current of the switching power supply; and

[0020] The second analog-to-digital converter is used to obtain the digital current sampling signal after analog-to-digital conversion of the filtered current sampling signal.

[0021] Preferably, the digital integration operation module is configured as a digital error amplifier circuit.

[0022] Preferably, the adaptive voltage positioning control circuit comprises:

[0023] A second digital-to-analog converter, used for converting the digital voltage reference signal into an analog voltage reference signal through digital-to-analog conversion;

[0024] The adaptive voltage positioning control circuit is used to obtain a first signal by processing the difference between the voltage sampling signal and the analog voltage reference signal with a first gain, obtain a second signal by processing the current sampling signal with a second gain, and obtain a third signal by processing the compensation signal with a third gain, and generate the positioning signal according to the first signal, the second signal and the third signal.

[0025] Preferably, the adaptive voltage positioning control circuit comprises:

[0026] A second digital-to-analog converter, used for converting the digital voltage reference signal into an analog voltage reference signal through digital-to-analog conversion;

[0027] The adaptive voltage positioning control circuit is used to obtain a first signal by subjecting the voltage sampling signal to a first gain process, obtain a second signal by subjecting the current sampling signal to a second gain process, and obtain a third signal by subjecting the sum of the compensation signal and the analog voltage reference signal to a third gain process, and generate the positioning signal according to the first signal, the second signal and the third signal.

[0028] Preferably, the adaptive voltage positioning control circuit comprises:

[0029] A superposition circuit, used for superimposing the first signal, the second signal and the inverted signal of the third signal to obtain a modulated signal;

[0030] The comparison circuit is used for comparing the modulation signal with a ramp signal to generate the positioning signal.

[0031] Preferably, the adaptive voltage positioning control circuit comprises:

[0032] A superposition circuit, used for superimposing the first signal and the second signal to obtain a modulated signal;

[0033] The comparison circuit is used for comparing the modulation signal with the third signal to generate the positioning signal.

[0034] Preferably, the adaptive voltage positioning control circuit comprises:

[0035] A superposition circuit, used for superimposing the first signal and the second signal to obtain a modulated signal;

[0036] The comparison circuit is used to compare the modulated signal with the third signal to generate the positioning signal.

[0037] Preferably, a ratio of the second gain to the first gain is determined by a first portion of a resistance value of the digital droop resistor.

[0038] Preferably, the resistance of the digital droop resistor is divided into a first part with a first unit as a unit and a second part with a second unit as a unit, and the sum of the first part and the second part is the resistance of the digital droop resistor.

[0039] Preferably, the accuracy of the compensation signal generating circuit is determined by the second part.

[0040] Preferably, the control circuit further includes:

[0041] The switch control circuit is configured to generate a switch control signal according to the positioning signal to control the switch state of the power switch in the switching power supply.

[0042] In a second aspect, the present invention provides a switching power supply, comprising:

[0043] Power stage circuit;

[0044] And, the control circuit mentioned above.

[0045] The present invention aims to provide a control circuit of an adaptive voltage positioning switching power supply, which uses the rapid response of an analog current inner loop to achieve a rough but rapid positioning, so that the range of the droop resistance can be enlarged and the number of levels can be reduced. Then, the high resolution of the digital voltage outer loop analog-to-digital converter (ADC) is used to achieve high-precision slow and small correction, and the integral operation is performed in the digital core, and then a digital-to-analog converter (DAC) is used to convert the analog signal into an analog signal and inject it into the comparator of the analog current inner loop to adjust the droop output characteristics of the output voltage. Therefore, the control circuit of the present invention solves the problem that the existing analog solution is difficult to achieve wide range and high resolution adjustment, and greatly reduces the requirements for the high-speed sampling rate of the analog-to-digital converter (ADC) in full digital control, ensuring the feasibility and practicality of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0047] Figure 1 The basic principle of AVP control;

[0048] Figure 2 The working waveforms of the switching power supply with and without AVP control when the load changes;

[0049] Figure 3 The adaptive voltage positioning switching power supply of the first embodiment of the present invention;

[0050] Figure 4 The operating waveform diagram of the adaptive voltage positioning switching power supply according to the first embodiment of the present invention;

[0051] Figure 5 The adaptive voltage positioning switching power supply according to the second embodiment of the present invention;

[0052] Figure 6 The adaptive voltage positioning switching power supply according to the third embodiment of the present invention;

[0053] Figure 7 The adaptive voltage positioning switching power supply according to the fourth embodiment of the present invention;

[0054] Figure 8 This is an adaptive voltage positioning switching power supply according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, some specific details are described in detail. It is possible for a person skilled in the art to fully understand the present invention without the description of these details. In order to avoid confusing the essence of the present invention, known methods, processes, flows, components and circuits are not described in detail.

[0056] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0057] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0058] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0059] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0060] Figure 3 This is an adaptive voltage positioning switching power supply according to the first embodiment of the present invention. Figure 3 As shown, the power stage circuit of the adaptive voltage positioning switching power supply of this embodiment is described by taking the buck circuit as an example. It should be understood that the present invention is also applicable to other power stage circuits, and the present invention does not limit this. In this embodiment, the power stage circuit 30 includes a power switch Q1 and a power switch Q2, and an inductor L connected between the common node of the power switch Q1 and the power switch Q2 and the output terminal. s , C OUT is the output filter capacitor. The power stage circuit is used to receive the input voltage V in After power conversion, the output voltage V OUT and output current I OUT .

[0061] In this embodiment, the adaptive voltage positioning switching power supply includes a control circuit for controlling the power stage circuit 30 to realize power conversion. The control circuit includes a compensation signal generating circuit 31 and an adaptive voltage positioning control circuit 32. The compensation signal generating circuit 31 is implemented by a digital circuit for processing digital signals, and the adaptive voltage positioning control circuit 32 is implemented by an analog circuit for processing analog signals. In this embodiment, the compensation signal generating circuit 31 is used to receive a digital voltage reference signal VID[n], a digital voltage sampling signal V representing the output voltage of the switching power supply. SEN [n] and the digital drop voltage Vdrop[n], which is configured to compare the digital voltage reference signal VID[n] with the digital voltage sampling signal VSEN The error between the sum of [n] and the digital droop voltage Vdrop[n] is integrated to generate the compensation signal V COMP The digital voltage reference signal VID[n] is a digital signal used to represent the desired output voltage. SEN [n] represents the digital signal of the output voltage of the switching power supply, and the digital droop voltage Vdrop[n] represents the digital signal of the voltage on the droop resistor in the adaptive voltage positioning switching power supply. In practical applications, the designer can set the voltage reference signal and the resistance value of the droop resistor. The control circuit converts the voltage reference signal and the voltage on the droop resistor into digital signals to provide to the compensation signal generating circuit 31. The adaptive voltage positioning control circuit 32 receives the compensation signal V COMP , and generate positioning signal V VAP To adjust the output voltage V OUT In this embodiment, the adaptive voltage positioning control circuit 32 may adopt a pulse width modulation method (PWM control), a pulse frequency modulation method (PFM control), or a combination of the above methods, which is not limited here.

[0062] In one implementation, the digital droop voltage Vdrop[n] is obtained based on the product of the digital droop resistor and the digital current sampling signal, wherein the control circuit filters the current sampling signal representing the inductor current of the switching power supply to generate a low-frequency component of the current sampling signal, and the low-frequency component is converted to a digital current after analog-to-digital conversion. In this embodiment, when the switching power supply is a multi-phase power stage circuit connected in parallel, the current sampling signal represents the sum of the inductor currents in each power stage circuit. The digital droop resistor is related to the output voltage V OUT and output current I OUT The output characteristic curve here refers to the characteristic that the output voltage changes with the output current. The output characteristic can be linear, piecewise linear, or nonlinear, which is not limited here.

[0063] In one embodiment, the adaptive voltage positioning control circuit 32 is used to adjust the compensation signal V COMP , current sampling signal i L , digital voltage reference signal VID[n] and voltage sampling signal V SEN Generate positioning signal V VAP , different from the compensation signal generating circuit 31 , the adaptive voltage positioning control circuit 32 is an analog control circuit.

[0064] In one embodiment, the control circuit further includes a switch control circuit 33. The switch control circuit 33 controls the positioning signal V VAPThe switch control signal PWM is generated to control the switching states of the power switch Q1 and the power switch Q2 in the power stage circuit 30 to adjust the output voltage.

[0065] In this embodiment, the compensation signal generating circuit 31 forms a digital loop to generate the compensation signal V COMP , the voltage positioning control circuit 32 forms an analog loop according to the compensation signal V COMP Adjust the output voltage V OUT . Output voltage V OUT The size of is determined by the difference between the analog voltage represented by the digital voltage reference signal VID[n] and the analog voltage represented by the digital droop voltage. This control method realizes analog and digital hybrid control by setting two parameters, the reference voltage and the droop resistance, avoiding the pain points of full analog or full digital control methods.

[0066] The main body of the control circuit of the technical solution of the present invention adopts an analog current mode architecture, on this basis, a digital loop is introduced to correct the output voltage, the rapid response of the analog current inner loop is used to achieve a rough but rapid setting of the output voltage, and the digital voltage outer loop is used to achieve high-precision and slow and small correction of the output voltage. Therefore, the control circuit of the present invention solves the problem that the existing analog solution is difficult to achieve wide range and high-resolution adjustment, and greatly reduces the requirements for sampling rate in full digital control, ensuring the feasibility and practicality of the design.

[0067] Figure 3 FIG. 2 is a schematic diagram of a specific implementation circuit of a compensation signal generating circuit 31. The compensation signal generating circuit 31 includes a digital integral operation module 311 and a first digital-to-analog converter DAC1. The digital integral operation module 311 is used to convert a digital voltage reference signal VID[n] into a digital voltage sampling signal V SEN The error between the sum of VID[n] and the digital drop voltage Vdrop[n] is integrated, that is, the equation [VID[n]-(V SEN [n]+Vdrop[n])] performs an integration operation to generate a digital compensation signal V at the output. COMP [n] A first digital-to-analog converter DAC1 is used to convert the digital compensation signal V COMP [n] After digital-to-analog conversion, the compensation signal V is obtained COMP , To provide the adaptive voltage positioning control circuit 32 for analog loop control.

[0068] In one implementation, the digital integration operation module includes a positive phase input terminal for receiving the difference between the digital voltage reference signal VID[n] and the digital drop voltage Vdrop[n], and a positive phase input terminal for receiving the digital voltage sampling signal V SENThe inverting input of [n] generates a digital compensation signal V at the output COMP [n], such as Figure 3 In another implementation, the positive input terminal of the digital integral operation module receives the digital voltage reference signal VID[n], and the negative input terminal receives the digital voltage sampling signal V SEN The sum of the digital droop voltage Vdrop[n] and the digital droop voltage Vdrop[n] is used to generate the digital compensation signal V at the output. COMP [n] It should be understood that as long as the digital integral operation module 311 can realize the operation of the above formula, its input signal and the polarity of the input terminal can be adjusted, and no limitation is made here.

[0069] In one embodiment, the digital integral operation module 311 is configured as a digital error amplifier circuit. It should be understood that other digital circuits capable of implementing the above integral operation can also be used in this embodiment, which is not limited here.

[0070] Figure 4 FIG. 2 shows the working waveform of the adaptive voltage positioning switching power supply according to the embodiment of the present invention. Figure 4 As shown, the output current I OUT When the output voltage V OUT is quickly reduced to the voltage V OUT 1. At voltage V OUT1 Therefore, the control circuit in the embodiment of the present invention can improve the accuracy and resolution of the output voltage.

[0071] Figure 5 The second embodiment of the present invention is an adaptive voltage positioning switching power supply. The compensation signal generating circuit 31 includes a first analog-to-digital converter ADC1, which converts the voltage sampling signal V SEN After analog-to-digital conversion, the digital voltage sampling signal V is obtained SEN [n]; filter circuit FL, used to convert the current sampling signal i L Filtering is performed to generate a low-frequency component i of the current sampling signal L(DC) The second analog-to-digital converter ADC2 is used to convert the low-frequency component i of the current sampling signal L(DC) After analog-to-digital conversion, the digital current sampling signal i is obtained L [n]; Digital integration operation module 311, used to sample the digital voltage signal V SEN [n], the digital droop voltage Vdrop[n] and the digital voltage reference signal VID[n] generate the digital compensation signal V COMP [n], where the digital drop voltage Vdrop[n] is the digital current sampling signal i L [n] and digital droop resistor R LLand a first digital-to-analog converter DAC1, for the digital compensation signal V COMP [n] After digital-to-analog conversion, the compensation signal V is obtained COMP .

[0072] More specifically, in this embodiment, the digital integration operation module 311, whose inverting input terminal receives the digital voltage sampling signal V SEN [n], the positive input terminal receives the first digital voltage reference signal VID1[n], and generates a digital compensation signal V after amplifying the error between the two. COMP [n], wherein the first digital voltage reference signal VID1[n] is the difference between the digital voltage reference signal VID[n] and the digital drop voltage Vdrop[n], that is, VID1[n]=VID[n]-Vdrop[n]. It should be understood that the error amplification compensation network can adopt any one of the existing technologies, such as PI compensation, etc., which will not be repeated here and is not limited.

[0073] Preferably, the adaptive voltage positioning control circuit 32 includes a second digital-to-analog converter DAC2, which is used to obtain an analog voltage reference signal VID after performing digital-to-analog conversion on the digital voltage reference signal VID[n]. In one implementation, the adaptive voltage positioning control circuit 32 is used to convert the voltage sampling signal V SEN The difference between the current sampling signal i L After the second gain processing, the second signal is obtained, and the compensation signal V COMP After the third gain processing, a third signal is obtained, and the positioning signal is generated according to the first signal, the second signal and the third signal. In another implementation, the adaptive voltage positioning control circuit 32 is used to convert the voltage sampling signal V SEN After the first gain processing, the first signal is obtained, and the current sampling signal i L After the second gain processing, the second signal is obtained, and the compensation signal V COMP A third signal is obtained after the sum of the first signal, the second signal and the analog voltage reference signal VID is processed by a third gain, and the positioning signal is generated according to the first signal, the second signal and the third signal.

[0074] In this embodiment, the adaptive voltage positioning control circuit 32 further includes a superposition circuit 321 for superimposing the voltage sampling signal V SEN The difference between the analog voltage reference signal VID and the first signal V1 processed by the first gain Kv, the current sampling signal i L The second signal V2 processed by the second gain Ki and the compensation signal V COMPThe inverted signal of the third signal V3 processed by the third gain Kc is superimposed to obtain a modulated signal V MOD , that is, V MOD =V1+V2-V3=(V SEN -VID)*Kv+i L *Ki-V COMP *Kc; Comparison circuit 322, used to modulate the signal V MOD After comparing with a ramp signal Vramp, a positioning signal V VAP .

[0075] The switch control circuit 33 is used to control the positioning signal V VAP A switch control signal PWM is generated to control the power switch Q1 and the power switch Q2 in the switch power supply. The power switch Q1 and the power switch Q2 are turned on and off by the switch control signal, so that the output voltage generated by the power stage circuit 30 meets the characteristics of the adaptive voltage positioning curve.

[0076] Furthermore, the ratio of the second gain Ki to the first gain Kv is determined by the digital droop resistor R LL The compensation signal generating circuit 31 also determines the resistance value of the digital droop resistor R LL The resistance value is divided into the first part R LL _1 and the second part R with the second unit as the unit LL _2, and the first part R LL _1 and the second part R LL _2 is the digital droop resistor R LL The resistance value of the second gain Ki and the first gain Kv is determined by the first part, and the accuracy of the compensation signal generating circuit 31 is determined by the second part.

[0077] It should be noted that the digital droop resistor R LL The resistance value represents the size of the AVP virtual droop resistor required by the system, which can be a high-resolution value with multiple decimal places. Assume that the digital droop resistor R LL The required target range is 0-3mΩ, with a resolution of up to 1uΩ, so there are 3000 adjustable gears to choose from. The specific implementation algorithm is as follows:

[0078] Assuming the digital droop resistor R LL The resistance value is 0.42mΩ. After decomposition, the digital droop resistor R LL The resistance value is divided into a first part R with a first unit (such as 0.1m) as a unit LL _1=4*0.1mΩ, and the second part R in the second unit (e.g. 1u) LL_2=20*0.001mΩ, when splitting into two parts, both can be rounded down directly. After splitting, the value of the first part is handed over to the analog current inner loop, that is, the adaptive voltage positioning control circuit 32 to complete. More specifically, the second gain Ki and the first gain Kv of the analog inner loop need to be configured to satisfy the following formula: Ki / Kv=R LL _1=0.4m; the value of the second part is handed over to the digital voltage outer loop for adjustment, that is, it is completed by the compensation signal generating circuit 31.

[0079] It should be noted that the embodiment of the present invention processes the AVP virtual droop resistor R LL When splitting, the principle of large number processing of rounding down is adopted. If other large number processing principles are adopted, such as rounding, etc., it is still the same as the essence of the idea of ​​the present invention and is not limited here.

[0080] Since the response speeds of the analog inner loop and the digital outer loop differ, the load dynamic response process of the output voltage can be roughly divided into a part dominated by the analog inner loop, which is fast but inaccurate, and another part dominated by the digital outer loop, which is slow but accurate.

[0081] The present invention provides a digital-analog hybrid control scheme that combines the advantages of analog and digital control and avoids their respective shortcomings. The main body of the control loop of the technical solution of the present invention adopts an analog current mode architecture, on which a digital loop containing an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) is introduced to correct the output voltage. A rough but fast setting is achieved by using the fast response of the analog current inner loop, which can increase the range of the droop resistance and reduce the number of gears. Then, the high resolution of the digital voltage outer loop analog-to-digital converter (ADC) is used to achieve high-precision slow and small correction, and the integral operation is performed in the digital core, and then converted into an analog signal by a digital-to-analog converter (DAC) and injected into the comparator of the analog current inner loop to adjust the droop output characteristics of the output voltage. Therefore, the control circuit of the present invention solves the problem that the existing analog solution is difficult to achieve wide range and high resolution adjustment, and greatly reduces the requirements for the high-speed sampling rate of the analog-to-digital converter (ADC) in full digital control, ensuring the feasibility and practicality of the design.

[0082] Figure 6 The adaptive voltage positioning switching power supply of the third embodiment of the present invention is different from the second embodiment only in that the compensation signal generating circuit 41 superimposes the digital droop voltage Vdrop[n] on the digital voltage sampling signal V SEN After the digital voltage reference signal VID[n] is amplified, the compensation signal V COMP The composition and working principle of other circuit modules are the same as those of the first embodiment, and will not be described in detail here.

[0083] Specifically, the compensation signal generating circuit 41 includes a digital integration operation module 411, whose inverting input terminal receives the first digital voltage sampling signal V SEN1 The positive input terminal receives the digital voltage reference signal VID[n] and amplifies the error between them to generate a digital compensation signal V COMP [n], wherein the first digital voltage sampling signal V SEN1 [n] is the digital voltage sampling signal V SEN The sum of the digital droop voltage Vdrop[n] and the digital droop voltage Vdrop[n].

[0084] Figure 7 The adaptive voltage positioning switching power supply of the fourth embodiment of the present invention differs from the second embodiment only in that the connection method of the signals in the adaptive voltage positioning control circuit 52 is different, and the composition and working principle of other circuit modules are the same as those of the second embodiment, which will not be described in detail here.

[0085] Specifically, the adaptive voltage positioning control circuit 52 includes a second digital-to-analog converter DAC2, which is used to obtain an analog voltage reference signal VID after digital-to-analog conversion of the digital voltage reference signal VID[n]; a superposition circuit 521, which is used to convert the voltage sampling signal V SEN The difference between the analog voltage reference signal VID and the first signal V1 processed by the first gain Kv, the current sampling signal i L The second signal V2 processed by the second gain Ki is superimposed to obtain a modulated signal V MOD , that is, V MOD =V1+V2=(V SEN -VID)*Kv+i L *Ki; Comparison circuit 522, used to modulate the signal V MOD and compensation signal V COMP The third signal V3 processed by the third gain Kc is compared to generate a positioning signal V VAP .

[0086] Figure 8 The adaptive voltage positioning switching power supply of the fifth embodiment of the present invention differs from the second embodiment only in that the connection method of the signals in the adaptive voltage positioning control circuit 62 is different, and the composition and working principle of other circuit modules are the same as those of the second embodiment, which will not be repeated here.

[0087] Specifically, the adaptive voltage positioning control circuit 62 includes a second digital-to-analog converter DAC2, which is used to obtain an analog voltage reference signal VID after digital-to-analog conversion of the digital voltage reference signal VID[n]; a superposition circuit 621, which is used to convert the voltage sampling signal V SENThe first signal V1 after the first gain Kv processing, the current sampling signal i L The second signal V2 processed by the second gain Ki is superimposed to obtain a modulated signal V MOD , that is, V MOD =V1+V2=V SEN *Kv+i L *Ki; Comparison circuit 622, used to modulate the signal V MOD and compensation signal V COMP The positioning signal V is generated by comparing the sum of the analog voltage reference signal VID with the third signal V3 processed by the third gain Kc. VAP , that is, V3=(V COMP +VID)*K C The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control circuit for an adaptive voltage positioning switching power supply, characterized in that: include: a compensation signal generating circuit, for receiving a digital voltage reference signal, a digital voltage sampling signal representing the output voltage of the switching power supply, and a digital droop voltage, and configured to perform an integration operation on an error between the digital voltage reference signal and a sum of the digital voltage sampling signal and the digital droop voltage to generate a compensation signal; as well as The adaptive voltage positioning control circuit is configured to receive the compensation signal and generate a positioning signal to adjust the output voltage.

2. The control circuit according to claim 1, characterized in that: The digital droop voltage is obtained according to the product of the digital droop resistance and the digital current sampling signal, wherein the digital current sampling signal is obtained by filtering the current sampling signal representing the inductor current of the switching power supply and then performing analog-to-digital conversion.

3. The control circuit according to claim 2, characterized in that: The digital droop resistor corresponds to an output characteristic curve between an output voltage and an output current of the switching power supply.

4. The control circuit according to claim 1, characterized in that: The compensation signal generating circuit comprises: a digital integral operation module configured to perform an integral operation on an error between a digital voltage reference signal and a sum of the digital voltage sampling signal and the digital droop voltage, so as to generate a digital compensation signal at an output terminal; and The first digital-to-analog converter is used to obtain the compensation signal after performing digital-to-analog conversion on the digital compensation signal.

5. The control circuit according to claim 4, characterized in that: The digital integration operation module includes a non-phase input terminal for receiving the difference between the digital voltage reference signal and the digital droop voltage, and an inverting input terminal for receiving the digital voltage sampling signal, so as to generate the digital compensation signal at the output terminal.

6. The control circuit according to claim 4, characterized in that: The digital integration operation module includes a non-phase input terminal for receiving the digital voltage reference signal and an inverting input terminal for receiving the sum of the digital voltage sampling signal and the digital droop voltage, so as to generate the digital compensation signal at the output terminal.

7. The control circuit according to claim 1, characterized in that: The adaptive voltage positioning control circuit generates the positioning signal according to a voltage sampling signal representing the output voltage of the switching power supply, a current sampling signal representing the inductor current, the digital voltage reference signal and a compensation signal.

8. The control circuit according to claim 4, characterized in that: The compensation signal generating circuit comprises: A first analog-to-digital converter, used for converting the voltage sampling signal into a digital voltage sampling signal; A low-pass filter, used to filter a current sampling signal representing the inductor current of the switching power supply; and The second analog-to-digital converter is used to obtain the digital current sampling signal after analog-to-digital conversion of the filtered current sampling signal.

9. The control circuit according to claim 4, characterized in that: The digital integration operation module is configured as a digital error amplifier circuit.

10. The control circuit according to claim 1, characterized in that: The adaptive voltage positioning control circuit comprises: A second digital-to-analog converter, used for converting the digital voltage reference signal into an analog voltage reference signal through digital-to-analog conversion; The adaptive voltage positioning control circuit is used to obtain a first signal by processing the difference between the voltage sampling signal and the analog voltage reference signal with a first gain, obtain a second signal by processing the current sampling signal with a second gain, and obtain a third signal by processing the compensation signal with a third gain, and generate the positioning signal according to the first signal, the second signal and the third signal.

11. The control circuit according to claim 1, characterized in that: The adaptive voltage positioning control circuit comprises: A second digital-to-analog converter, used for converting the digital voltage reference signal into an analog voltage reference signal through digital-to-analog conversion; The adaptive voltage positioning control circuit is used to obtain a first signal by subjecting the voltage sampling signal to a first gain process, obtain a second signal by subjecting the current sampling signal to a second gain process, and obtain a third signal by subjecting the sum of the compensation signal and the analog voltage reference signal to a third gain process, and generate the positioning signal according to the first signal, the second signal and the third signal.

12. The control circuit according to claim 10, characterized in that: The adaptive voltage positioning control circuit comprises: A superposition circuit, used for superimposing the first signal, the second signal and the inverted signal of the third signal to obtain a modulated signal; The comparison circuit is used for comparing the modulation signal with a ramp signal to generate the positioning signal.

13. The control circuit according to claim 10, characterized in that: The adaptive voltage positioning control circuit comprises: A superposition circuit, used for superimposing the first signal and the second signal to obtain a modulated signal; The comparison circuit is used for comparing the modulation signal with the third signal to generate the positioning signal.

14. The control circuit according to claim 11, characterized in that: The adaptive voltage positioning control circuit comprises: A superposition circuit, used for superimposing the first signal and the second signal to obtain a modulated signal; The comparison circuit is used to compare the modulated signal with the third signal to generate the positioning signal.

15. The control circuit according to claim 10 or 11, characterized in that: A ratio of the second gain to the first gain is determined by a first portion of a resistance value of the digital droop resistor.

16. The control circuit according to claim 2, characterized in that: The resistance of the digital droop resistor is divided into a first part with a first unit as a unit and a second part with a second unit as a unit, and the sum of the first part and the second part is the resistance of the digital droop resistor.

17. The control circuit according to claim 16, characterized in that: The accuracy of the compensation signal generating circuit is determined by the second part.

18. The control circuit according to claim 1, characterized in that: Also includes: The switch control circuit is configured to generate a switch control signal according to the positioning signal to control the switch state of the power switch in the switching power supply.

19. A switching power supply comprising: Power stage circuit; And, the control circuit according to any one of claims 1-18.

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