Feedback voltage generation circuit, control circuit, switching power supply and method

Abstract

The invention relates to the technical field of power electronics, and discloses a feedback voltage generation circuit, a control circuit, a switching power supply and a method wherein the feedback voltage generation circuit comprises: a current shunting unit configured to shunt a current sampling signal in proportion to obtain a first shunt current, and generating a drop current according to the first shunt current so as to generate a feedback voltage according to the drop current, the feedback voltage being used for performing adaptive control on an output voltage of the switching power supply. Compared with the prior art, the drop current proportional to the current sampling signal can be obtained without conversion of a multi-stage current mirror, and the drop current directly flows into a related resistor to generate the feedback voltage, so that the dynamic response speed of the AVP is greatly improved, the voltage regulation precision is improved, and the working performance of the switching power supply is improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a feedback voltage generation circuit, control circuit, switching power supply and method. Background Technology

[0002] Adaptive Voltage Position (AVP) is a technology that achieves dynamic response by adjusting the output voltage of a switching power supply. It enables the output voltage of the switching power supply to decrease as the output current increases. It is widely used in electronic devices such as laptops, desktop computers, and servers to reduce voltage spikes during transient periods and achieve better dynamic voltage regulation.

[0003] In applications where output voltage needs to be regulated independently of output current, related technologies typically employ multi-stage current mirrors to mirror and replicate the output current, thereby regulating the output voltage. However, the current signal experiences a delay during transmission through the multi-stage current mirrors, limiting the response speed of the AVP (Automated Valve Controller) and resulting in significant loss of signal accuracy, making it difficult to meet the requirements for high-response, high-precision dynamic voltage regulation. Summary of the Invention

[0004] This application provides a feedback voltage generation circuit, control circuit, switching power supply, and method, which solves the technical problems of delay and low accuracy in adaptive voltage positioning using multi-stage current mirror circuits, making it difficult to meet the requirements of high response and high precision voltage dynamic adjustment. By directly proportionally dividing and adjusting the current sampling signal, without the need for conversion through multi-stage current mirrors, a drop current proportional to the current sampling signal can be obtained, and the drop current can flow directly into the relevant resistor to generate a feedback voltage. This not only greatly improves the dynamic response speed of the AVP, but also improves the voltage regulation accuracy, which is beneficial to improving the working performance of the switching power supply.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include:

[0006] In a first aspect, embodiments of this application provide a feedback voltage generating circuit applied to a switching power supply, the feedback voltage generating circuit comprising:

[0007] A current shunt unit is configured to proportionally shunt at least one current sampling signal to obtain a first shunt current, and generate a drop current based on the first shunt current to generate a feedback voltage based on the drop current, wherein the feedback voltage is used for adaptive control of the output voltage of the switching power supply.

[0008] The feedback voltage generation circuit proposed in this application embodiment obtains a first shunt current by proportionally shunting the current sampling signal through a current shunt unit, thereby achieving proportional adjustment of the current sampling signal and accurately generating a slump current that meets the AVP control requirements. A feedback voltage is then generated based on the slump current to achieve high-response, high-precision adaptive control of the switching power supply's output voltage. Therefore, this application embodiment can directly shunt and adjust the current sampling signal through the current shunt unit. Compared to related technologies that use a current mirror for conversion, this not only simplifies the circuit structure and reduces the circuit area but also improves the transmission delay caused by the current mirror conversion, greatly enhancing the response speed of adaptive control of the switching power supply's output voltage. Simultaneously, this application embodiment can flexibly adjust the ratio between the current sampling signal and the first shunt current, enabling more precise generation of the slump current and corresponding feedback voltage, thus improving the AVP control accuracy of the switching power supply's output voltage.

[0009] Optionally, in some embodiments of this application, the current shunt unit includes at least one input terminal, each input terminal corresponds to one current sampling signal, and each input terminal is connected to a first resistor and a second resistor respectively. The current shunt unit is configured to proportionally shunt the current sampling signal according to the resistance values ​​of the first resistor and the second resistor to obtain a first shunt current.

[0010] Wherein, the first end of each first resistor and the first end of each second resistor are respectively adapted to receive the corresponding current sampling signal, the second ends of all first resistors are connected together, the second ends of all second resistors are connected to the first node, and the first shunt current is the current flowing through the first node.

[0011] The embodiments of this application perform proportional current shunting of the current sampling signal based on the resistance values ​​of the first resistor and the second resistor. Compared with related technologies, the circuit structure is more direct and simple, effectively improving the response lag problem caused by the current mirror transmission delay. This is beneficial to improving the dynamic response speed of the subsequent generated feedback voltage. Furthermore, the embodiments of this application use the resistance value to determine the current shunting ratio, which allows for flexible setting of the resistance values ​​of the first resistor and the second resistor, thereby improving the flexibility of current shunting adjustment.

[0012] Optionally, in some embodiments of this application, the current shunt unit includes an input terminal adapted to receive a current sampling signal, and the current shunt unit is further configured to proportionally shunt the current sampling signal, wherein the current sampling signal characterizes the output current of the switching power supply.

[0013] Optionally, in some embodiments of this application, the current shunt unit includes at least two input terminals, the switching power supply includes a multi-phase switching circuit, each input terminal is adapted to receive the corresponding current sampling signal, and the current shunt unit is further configured to shunt each current sampling signal in the same proportion, wherein each current sampling signal represents the current of the corresponding phase switching circuit.

[0014] Optionally, in some embodiments of this application, the current shunt unit further includes a clamping module configured to clamp the terminal voltages of the second terminal of the first resistor and the second terminal of the second resistor to be equal.

[0015] This application embodiment utilizes a clamping module to clamp the terminal voltages of the second terminals of the first resistor and the second resistor to be equal, thereby ensuring that the current shunting ratio of the current sampling signal is determined only by the resistance values ​​of the first resistor and the second resistor, avoiding interference from external factors on the current shunting, and significantly improving the accuracy of the shunting results.

[0016] Optionally, in some embodiments of this application, the current shunt unit further includes a transistor module, the clamping module includes an operational amplifier, the non-inverting input terminal of the operational amplifier is connected to the second terminal of the first resistor, the inverting input terminal of the operational amplifier is connected to the second terminal of the second resistor, and the output terminal of the operational amplifier is connected to the inverting input terminal via the transistor module.

[0017] In this embodiment, the virtual short-circuit effect of the operational amplifier is used to make the voltage at the second terminal of the first resistor and the second terminal of the second resistor equal, thereby eliminating the shunt error caused by the difference in resistor voltage.

[0018] Optionally, in some embodiments of this application, the transistor module includes a first transistor configured to generate the dropout current based on the first shunt current, such that the dropout current is equal to the first shunt current, wherein a first terminal of the first transistor is connected to the first node to receive the first shunt current, a second terminal of the first transistor is adapted to output the dropout current, and a control terminal of the first transistor is connected to the output terminal of the operational amplifier.

[0019] In this embodiment, the drain current of the first transistor is used to generate a slump current, which in turn enables the first shunt current to participate in the generation of the subsequent feedback voltage as a slump current. This improves the generation efficiency of the feedback voltage and greatly enhances the response speed of the adaptive control of the output voltage of the switching power supply.

[0020] Optionally, in some embodiments of this application, the transistor module includes a plurality of first transistors configured to proportionally shunt the first shunt current to generate the dropout current, wherein a first terminal of each first transistor is connected to the first node to receive the first shunt current, a second terminal of the plurality of first transistors is adapted to output a plurality of second shunt currents to generate the dropout current according to the plurality of second shunt currents, and each second shunt current is proportional to the first shunt current, and a control terminal of each first transistor is connected to the output terminal of the operational amplifier.

[0021] This application embodiment sets up multiple first transistors to further adjust the gain of the current flowing through the second resistor. Based on the conduction parameters of the first transistors, the magnitude of the second shunt current can be precisely adjusted according to the actual circuit requirements, thereby achieving high-precision adjustment of the first shunt current and meeting the accuracy requirements of the adaptive control of the output voltage of the switching power supply.

[0022] Optionally, in some embodiments of this application, the current shunt unit further includes a buffer module, which is configured to clamp the terminal voltage at the second end of the first resistor to a preset voltage;

[0023] The buffer module includes a buffer, the input of which is adapted to receive the preset voltage, and the output of which is connected to the second end of the first resistor.

[0024] In this embodiment, a buffer is used to pull the voltage at the second terminal of the first resistor to a preset voltage. Combined with the virtual short effect of the operational amplifier, the voltage at the second terminal of the second resistor is pulled to the same preset voltage. This eliminates the shunt error caused by the difference in resistor terminal voltages and also clamps the terminal voltage to a specified voltage value according to actual needs.

[0025] Optionally, in some embodiments of this application, the feedback voltage generating circuit further includes a slump resistor, which is configured to generate the feedback voltage based on the slump current, an output voltage detection signal characterizing the output voltage of the switching power supply, and the resistance value of the slump resistor. The first end of the slump resistor is adapted to receive the slump current, and the second end of the slump resistor is adapted to receive the output voltage detection signal. The feedback voltage is generated through the first end of the slump resistor.

[0026] Optionally, in some embodiments of this application, the current shunt unit circuit further includes a reporting module, which is configured to generate a reporting signal based on the first shunt current, and the reporting signal characterizes the total output current of the switching power supply.

[0027] Optionally, in some embodiments of this application, the reporting module includes at least one second transistor and a third resistor. The control terminal of the second transistor is connected to the output terminal of the operational amplifier. The first terminal of the second transistor is connected to the second terminal of the second resistor. The second terminal of the second transistor is connected to the first terminal of the third resistor. The second terminal of the third resistor is connected to reference ground. The second terminal of the second transistor is adapted to output the reporting signal.

[0028] The embodiments of this application use a reporting signal generated by a second transistor and a third resistor to ensure accurate reflection of the total output current of each power stage of the switching power supply, thereby enabling real-time monitoring of the total output current. This helps to detect abnormalities in a timely manner and make adjustments, thus improving system stability.

[0029] Optionally, in some embodiments of this application, the feedback voltage generating circuit further includes a current regulating unit. When the transistor module includes a plurality of the first transistors, the current regulating unit is configured to receive a switch control command, control whether the plurality of second shunt currents flow to the reference ground according to the switch control command, and generate the drop current based on the second shunt currents that do not flow to the reference ground.

[0030] This application embodiment controls whether multiple second shunt currents flow to the reference ground, thereby flexibly and accurately adjusting the ratio between the first shunt current and the drop current, so that the generated drop current can more accurately adapt to the accuracy requirements of the adaptive control of the output voltage of the switching power supply.

[0031] Optionally, in some embodiments of this application, the feedback voltage generating circuit further includes a trimming unit configured to generate a bias current to trim the slump current.

[0032] The embodiments of this application generate a bias current through a trimming unit to trim the slump current, thereby ensuring the effective generation of the feedback voltage and expanding the applicability of the feedback voltage generation circuit.

[0033] Secondly, embodiments of this application provide a control circuit for a switching power supply, including the feedback voltage generating circuit described in the above embodiments, wherein the feedback voltage generating circuit is used to generate a feedback voltage to adaptively control the output voltage of the switching power supply.

[0034] Compared to related technologies, the control circuit proposed in this application not only simplifies the circuit structure and reduces the circuit area, but also improves the transmission delay caused by current mirror conversion, greatly enhancing the response speed of adaptive control of the switching power supply output voltage. Furthermore, the feedback voltage generation circuit in this application can flexibly adjust the shunting ratio of the current sampling signal, enabling more precise generation of slump current and corresponding feedback voltage, thus improving the AVP control accuracy of the switching power supply output voltage.

[0035] Thirdly, embodiments of this application provide a switching power supply, the switching power supply including a power stage circuit and a control circuit as described in the above embodiments, wherein the control circuit is used to generate a feedback voltage and control the power stage circuit according to the feedback voltage to adaptively control the output voltage of the switching power supply.

[0036] The switching power supply proposed in this application embodiment uses the aforementioned control circuit to proportionally shun the current sampling signal, thereby achieving high-response and high-precision adaptive control of the switching power supply output voltage. Therefore, compared to related technologies, the switching power supply proposed in this application embodiment not only simplifies the circuit structure and reduces the circuit area but also improves the transmission delay caused by current mirror conversion, significantly increasing the response speed for adaptive control of the switching power supply output voltage. Simultaneously, the feedback voltage generation circuit in this application embodiment can flexibly adjust the shunting ratio of the current sampling signal, enabling more precise generation of slump current and corresponding feedback voltage, thus improving the AVP control accuracy of the switching power supply output voltage.

[0037] Fourthly, embodiments of this application provide a feedback voltage generation method applied to a switching power supply, the method comprising:

[0038] At least one current sampling signal is proportionally shunted to obtain a first shunted current;

[0039] A dropout current is generated based on the first shunt current, and a feedback voltage is generated based on the dropout current;

[0040] The output voltage of the switching power supply is adaptively controlled based on the feedback voltage.

[0041] The feedback voltage generation method proposed in this application obtains a first shunt current by proportionally shunting the current sampling signal, thereby achieving proportional adjustment of the current sampling signal and accurately generating a slump current that meets the AVP control requirements. A feedback voltage is then generated based on the slump current to achieve high-response, high-precision adaptive control of the switching power supply's output voltage. Therefore, this application embodiment can directly shunt the current sampling signal. Compared to related technologies that use a current mirror for conversion, this not only simplifies the circuit structure and reduces the circuit area but also improves the transmission delay caused by the current mirror conversion, significantly increasing the response speed of adaptive control of the switching power supply's output voltage. Simultaneously, this application embodiment can flexibly adjust the ratio between the current sampling signal and the first shunt current, enabling more precise generation of the slump current and the corresponding feedback voltage, thus improving the AVP control accuracy of the switching power supply's output voltage. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of a switching power supply in related technologies;

[0044] Figure 2 This is a schematic diagram of the circuit structure of a multi-stage current mirror in related technologies;

[0045] Figure 3 This is a schematic diagram of the feedback voltage generation circuit proposed in this application in one embodiment;

[0046] Figure 4 This is a schematic diagram of the circuit structure of the feedback voltage generation circuit proposed in this application in another embodiment;

[0047] Figure 5 This is a schematic diagram of the circuit structure of the current shunt unit proposed in this application in one embodiment;

[0048] Figure 6 This is a schematic diagram of the circuit structure of the current shunt unit proposed in this application in another embodiment;

[0049] Figure 7 This is a schematic diagram of the circuit structure of the current shunt unit proposed in this application in yet another embodiment;

[0050] Figure 8This is a schematic diagram of the circuit structure of the current shunt unit proposed in this application in another embodiment;

[0051] Figure 9 This is a schematic diagram of the reporting module proposed in this application in one embodiment;

[0052] Figure 10 This is a schematic diagram of the circuit structure of the current regulation unit proposed in one embodiment of this application;

[0053] Figure 11 This is a schematic diagram of the reporting module proposed in this application in another embodiment;

[0054] Figure 12 This is a schematic diagram of the structure of the adjustment unit proposed in one embodiment of the present application;

[0055] Figure 13 This is a schematic flowchart of a feedback voltage generation method proposed in an embodiment of this application. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] AVP control is a technology that achieves dynamic response by adjusting the output voltage of a switching power supply. It enables the output voltage Vout of the switching power supply to decrease as the output current Iout increases. It is widely used in electronic devices such as laptops, desktop computers, and servers to reduce voltage spikes during transient periods and achieve better dynamic voltage regulation. Specifically, such as... Figure 1 As shown, in related technologies, a switching power supply includes a power stage circuit and a control circuit. The power stage circuit generates an output voltage Vout and an output current Iout. The feedback signal generation circuit in the control circuit acquires the detection signal Vosen of the output voltage Vout and mirrors the output current Iout to obtain a proportional sag current Idroop. The mirrored sag current Idroop flows through the sag resistor Rdroop, thereby generating a feedback voltage VFB based on the sag current Idroop and the output voltage detection signal Vosen. The calculation formula for the sag current Idroop is shown in the following formula (1):

[0058] Idroop=K0*Iout formula (1)

[0059] In the formula, K0 is the scaling factor for mirror processing.

[0060] The switching control circuit in the control circuit includes an error amplifier U2, which sends the feedback voltage VFB to the inverting input terminal of the error amplifier U2 and the reference voltage Vref to the non-inverting input terminal of the error amplifier U2. The switching control circuit outputs control signals to control the power transistors Q1 of each switching circuit in the power stage circuit according to the signal from the error amplifier U2, so as to adjust the output voltage Vout of the switching power supply.

[0061] In some applications, the output voltage needs to be adjusted independently of the output current. Related technologies typically employ multi-stage current mirrors to mirror and replicate the output current, thereby achieving output voltage regulation. Specifically, for example... Figure 2 As shown, the current mirror circuit U1, composed of switching transistors M1 to M5, clamps the source voltage of switching transistor M5 to a preset voltage VCM and mirrors the output current Iout of the power stage circuit, causing the drain of switching transistor M4 to generate a drop current Idroop proportional to the output current Iout of the power stage circuit. The drop current Idroop flows through the drop resistor Rdroop, thereby generating the feedback signal VFB.

[0062] The drop current Idroop flows through the drop resistor Rdroop, and the resulting feedback signal is shown in formula (2):

[0063] VFB=Vosen+K0*Iout*Rdroop formula (2)

[0064] Finally, VFB adjusts the output voltage Vout of the switching power supply through the feedback signal VFB to achieve AVP control.

[0065] However, during the transmission process of multi-stage current mirrors, the multi-stage mirroring of the current signal leads to a significant extension of the signal propagation path, making it difficult to quickly track the transient changes in the output current of the switching power supply, which seriously affects the dynamic response speed of the AVP.

[0066] Meanwhile, due to process deviations, temperature fluctuations, and non-ideal device parameters of the switching transistors, each current mirror stage introduces image error, and the error accumulates as the number of stages increases, eventually causing the drop current to deviate too much from the expected value, resulting in a significant loss of signal accuracy. This will directly affect the regulation accuracy of the switching power supply output voltage.

[0067] Furthermore, the redundant structure of multi-stage current mirrors results in a larger circuit layout area, which not only increases manufacturing costs but also introduces parasitic capacitance and inductance due to complex wiring, increasing the risk of signal interference. Therefore, using multi-stage current mirrors is insufficient to meet the requirements for high-response, high-precision dynamic voltage regulation.

[0068] To address the aforementioned technical problems, this application proposes a feedback voltage generation circuit 100, which can be applied to the control circuit 10 of a switching power supply 1. The control circuit 10 further includes a switch control sub-circuit 200. The switching power supply 1 also includes a power stage circuit 20. The input terminal of the switching power supply 1 receives an input voltage Vin, and the output terminal of the switching power supply 1 generates an output voltage Vout and an output current Iout.

[0069] like Figure 3 As shown, the feedback voltage generation circuit 100 includes a current shunt unit 110, wherein the current shunt unit 110 is configured to proportionally shunt at least one current sampling signal to obtain a first shunt current, and generate a drop current based on the first shunt current to generate a feedback voltage based on the drop current, wherein the feedback voltage is used for adaptive control of the output voltage Vout of the switching power supply.

[0070] Specifically, the current sampling signal I is sampled through the current shunt unit 110. CS The first shunt current I0 is obtained by proportionally dividing the current, thereby enabling the sampling of the current signal I. CS The proportional adjustment. Wherein, the first shunt current I0 and the current sampling signal I... CS There is a proportional relationship between them, providing a suitable current basis for the subsequent generation of the slump current Idroop that meets the AVP control requirements. Then, the slump current Idroop is generated based on the first shunt current I0, and a feedback voltage VFB is generated based on the slump current Idroop. The error amplifier or comparator U2 in the switching control sub-circuit 200 receives the feedback voltage VFB and the reference voltage Vref, and outputs a control signal to the power transistor Q1 in the switching circuit of the power stage circuit 20 based on the signal from the error amplifier or comparator U2, thereby adaptively controlling the output voltage Vout of the switching power supply 1. The output voltage Vout is input to the load 2 through a transmission line to power the load 2.

[0071] In summary, the embodiments of this application can directly sample the current signal I through the current shunt unit 110. CS Compared to related technologies that use current mirrors for conversion, this method of current shunting and regulation simplifies the circuit structure, reduces the circuit area, and improves the transmission delay caused by current mirror conversion, significantly increasing the response speed to adaptive control of the switching power supply output voltage. Furthermore, this embodiment directly samples the current signal I... CS By performing proportional current shunting, the slump current Idroop and the corresponding feedback voltage VFB can be generated more accurately, thus improving the control accuracy of AVP of the switching power supply output voltage.

[0072] In the embodiments of this application, such as Figure 3 As shown, the feedback voltage generation circuit 100 further includes a dropout resistor Rdroop, which is configured to generate a feedback voltage VFB based on the dropout current Idroop, the output voltage detection signal Vosen representing the output voltage Vout of the switching power supply 1, and the resistance value of the dropout resistor Rdroop. The first end of the dropout resistor Rdroop is adapted to receive the dropout current Idroop, and the second end of the dropout resistor Rdroop is adapted to receive the output voltage detection signal Vosen. The feedback voltage VFB is generated through the first end of the dropout resistor Rdroop, as shown in formula (3):

[0073] VFB=Idroop*Rdroop+Vosen formula (3)

[0074] In some embodiments of this application, the current shunt unit 110 includes at least one input terminal, each input terminal corresponding to a current sampling signal, and each input terminal is connected to a first resistor and a second resistor respectively, so that the current shunt unit 110 is configured to proportionally shunt the current sampling signal according to the resistance values ​​of the first resistor and the second resistor to obtain a first shunt current I0.

[0075] Specifically, the first end of each first resistor and the first end of each second resistor are respectively adapted to receive the corresponding current sampling signal, the second ends of all first resistors are connected together, the second ends of all second resistors are connected to the first node, and the first shunt current I0 is the current flowing through the first node.

[0076] It should be noted that the resistance values ​​of the first resistors can be the same or different. Similarly, the resistance values ​​of the second resistors can be the same or different. However, the ratio of the resistance values ​​of the first and second resistors corresponding to each input terminal must be the same to ensure the accuracy of the current shunting result.

[0077] In some embodiments of this application, the current shunt unit 110 includes an input terminal adapted to receive a current sampling signal. In this embodiment, the power stage circuit 20 may include a single-phase switching circuit 21, or it may include multi-phase switching circuits 21, 22, ..., 2n. The current shunt unit 110 is also configured to proportionally shunt the current sampling signal, wherein the current sampling signal characterizes the output current Iout of the switching power supply.

[0078] Specifically, such as Figure 3 As shown, taking the power stage circuit 20 as an example including a single-phase switching circuit 21, the current shunt unit 110 includes an input terminal for receiving a current sampling signal I. CS Current sampling signal I CSSpecifically, it represents the current flowing through the switching circuit 21; more specifically, the current sampling signal I... CS Characterizes the current flowing through inductor L1 in switching circuit 21.

[0079] Taking the power stage circuit 20, which includes multi-phase switching circuits 21, 22, ..., 2n, as an example, the current shunt unit 110 may include an input terminal for receiving a current sampling signal I. CS1 I CS2 ... I CSn The total current. Current sampling signal I. CS1 I CS2 ... I CSn Specifically, it represents the current flowing through the switching circuits 21, 22, ..., 2n; more specifically, the current sampling signal I... CS1 I CS2 ... I CSn Characterizes the current flowing through the inductors in the switching circuits 21, 22, ..., 2n.

[0080] In other embodiments of this application, the current shunt unit 110 includes at least two input terminals. In this embodiment, the power stage circuit 20 includes multiphase switching circuits 21, 22, ..., 2n, each input terminal being adapted to receive a corresponding current sampling signal I. CS1 I CS2 ... I CSn The current shunt unit 110 is also configured to sample each current signal I separately. CS1 I CS2 ... I CSn The current is split in the same proportion, where each current sampling signal I... CS1 I CS2 ... I CSn Characterizes the current of the corresponding phase switching circuits 21, 22, ..., 2n.

[0081] Specifically, such as Figure 4 As shown, the power stage circuit 20 includes multi-phase switching circuits 21, 22, ..., 2n as an example. The current shunt unit 110 includes n input terminals, each of which receives a corresponding current sampling signal I. CS1 I CS2 ... I CSn Similarly, the current sampling signal I CS1 I CS2 ... I CSn Specifically, it represents the current flowing through the switching circuits 21, 22, ..., 2n; more specifically, the current sampling signal I... CS1 I CS2 ... I CSnThis represents the current flowing through the inductors in the switching circuits 21, 22, ..., 2n. In some other embodiments of this application, the total current of the multiphase switching circuits 21, 22, ..., 2n can also be directly sampled to obtain the current sampling signal I. CS .

[0082] Furthermore, such as Figure 5 As shown, the current shunt unit 110 includes an input terminal as an example. This input terminal is connected to a first resistor R1 and a second resistor R2, respectively. The first terminal of the first resistor R1 and the first terminal of the second resistor R2 are adapted to receive the current sampling signal I. CS The current shunt unit 110 is also configured to sample the current signal I. CS The current is proportionally divided, and the current flowing through the second resistor R2 is used as the first shunt current I0.

[0083] Specifically, in this embodiment, the current sampling signal I is based on the resistance values ​​of the first resistor R1 and the second resistor R2. CS The current is proportionally divided, wherein the current flowing through the second resistor R2 is I0, and the value of the current I0 is as shown in formula (4):

[0084] I0 = I CS *R1 / (R1+R2) Formula (4)

[0085] Therefore, I0 is used as the first shunt current.

[0086] Furthermore, in this embodiment, the switch control sub-circuit 200 is also adapted to receive the voltage V at the input terminal. CS Therefore, based on the signal output of the error amplifier or comparator U2 and the voltage V at the input terminal... CS This enables control of the power transistor in the switching circuit 21.

[0087] like Figure 6 As shown, the current shunt unit 110 includes n input terminals as an example. The n input terminals correspond one-to-one with the multi-phase switching circuits 21, 22, ..., 2n, and each input terminal is connected to the corresponding first resistor R11 to R1. n One of them, and each input terminal is also connected to a corresponding second resistor R21 to R2. n One of the resistors, R11, R12, ..., R1 n The first terminal and the second resistors R21, R22, ..., R2 n The first end is adapted to receive the current sampling signal I CS1 to I CSn .

[0088] Among them, each of the first resistors R11, R12, ..., R1 nThe first terminal and the corresponding second resistors R21, R22, ..., R2 n The first end is connected, and at the same time, the first resistors R11, R12, ..., R1 n The second ends are connected together, and the second resistors R21, R22, ..., R2 n The second end is connected together.

[0089] In this embodiment, based on the resistance values ​​of the first and second resistors in each group, the corresponding current sampling signal I is obtained. CSn The current is proportionally divided, with the current flowing through the second resistor R2 corresponding to the nth phase switching circuit 2n. n The current is I0 n And I0 n The current value is shown in formula (5):

[0090] I0 n =I CSn *R1 n / (R1 n +R2 n ) Formula (5)

[0091] In the formula, n is a positive integer greater than or equal to 2.

[0092] The total current flowing through each of the second resistors is taken as the first shunt current I0, which is shown in the following formula (6):

[0093] I0 = I01 + I02 + ... + I0 n Formula (6)

[0094] In addition, in such Figure 5 In the illustrated embodiment, the current shunt unit 110 is provided with an input terminal, making it suitable not only for single-phase switching circuits but also for multi-phase switching circuits. Figure 6 In the illustrated embodiment, the current shunt unit 110 is provided with n input terminals, and is a preferred embodiment suitable for multi-phase switching circuits, wherein the switch control sub-circuit 200 is adapted to receive the voltage V from each input terminal. CS1 V CS2 ... V CSn Therefore, based on the signal output of the error amplifier or comparator U2 and the voltage V at the input terminal... CS1 V CS2 ... V CSn This enables the separate control of the power transistors in the switching circuits 21, 22, ..., 2n.

[0095] Therefore, in this embodiment of the application, the first shunt current I0 and the current sampling signal I CS1 to I CSnThere is a first ratio between them. The embodiments of this application divide the current sampling signal proportionally based on the resistance values ​​of the first resistor and the second resistor. Compared with related technologies, the circuit structure is more direct and simple, effectively improving the response lag problem caused by the current mirror transmission delay, which is conducive to improving the dynamic response speed of the subsequent generated feedback voltage. Furthermore, the embodiments of this application use the resistance value to determine the current division ratio, which allows for flexible setting of the resistance values ​​of the first resistor and the second resistor, thereby improving the flexibility of current division adjustment.

[0096] It should be noted that in some embodiments of this application, the resistance values ​​of the first resistor R1 and the second resistor R2 can be adjusted according to the actual circuit requirements. For example, the resistance value of the first resistor R1 can be set to be greater than the resistance value of the second resistor R2, or the first resistor R1 and the second resistor R2 can be set to be adjustable resistors, thereby flexibly adjusting the current sampling signal shunting ratio.

[0097] like Figure 5 and Figure 6 As shown, the current shunt unit 110 also includes a clamping module 111, which is configured to clamp the terminal voltages of the second terminal of the first resistor and the second terminal of the second resistor to be equal.

[0098] In this embodiment, the clamping module 111 clamps the voltage at the second terminal of the first resistor and the second terminal of the second resistor to be equal, thereby ensuring that the current shunting ratio of the current sampling signal is determined only by the resistance values ​​of the first resistor and the second resistor, avoiding interference from external factors on the current shunting, and significantly improving the accuracy of the shunting result.

[0099] Specifically, such as Figure 5 As shown, the current shunt unit 110 further includes a transistor module 112, and the clamping module 111 includes an operational amplifier. The non-inverting input terminal of the operational amplifier is connected to the second terminal of the first resistor R1, the inverting input terminal of the operational amplifier is connected to the second terminal of the second resistor R2, and the output terminal of the operational amplifier is connected to the inverting input terminal of the operational amplifier via the transistor module 112.

[0100] like Figure 6 As shown, taking a multiphase switching circuit as an example, the non-inverting input terminal of the operational amplifier is connected to the first resistor R11 to R1. n The second terminal, the inverting input terminal of the operational amplifier, is connected to the second resistor R21 to R2. n The second terminal of the operational amplifier is connected to the inverting input terminal of the operational amplifier via the transistor module 112.

[0101] In this embodiment, the virtual short-circuit effect of the operational amplifier is used to make the voltage at the second terminal of the first resistor and the second terminal of the second resistor equal, thereby eliminating the shunt error caused by the difference in resistor voltage.

[0102] It should be noted that, as Figure 5 The transistor module 112 shown includes at least one first transistor. Figure 6 Taking transistor module 112 as an example, which includes a first transistor Q1, transistor module 112 may also include multiple first transistors in other examples, which is not intended to limit this application.

[0103] Furthermore, when the transistor module 112 includes a plurality of first transistors, the drain of a portion of the first transistors can be selectively connected to the first end of the dropout resistor Rdroop, and the drain of another portion of the first transistors can be connected to the reference ground, thereby generating a dropout current Idroop according to the first shunt current I0.

[0104] Furthermore, in some embodiments of this application, such as Figure 6 As shown, transistor module 112 includes a first transistor Q1, which is configured to generate a drop current Idroop based on a first shunt current I0, such that the drop current Idroop is equal to the first shunt current I0, i.e., the first shunt current I0 is used as the drop current Idroop. The first terminal of the first transistor Q1 is connected to a first node to receive the first shunt current I0, the second terminal of the first transistor is adapted to output the drop current Idroop, and the control terminal of the first transistor Q1 is connected to the output terminal of an operational amplifier.

[0105] It should be noted that, in Figure 5 and Figure 6 In the illustrated embodiment, the first transistor Q1 is taken as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). However, the first transistor Q1 can also be a switching device such as an Insulated Gate Bipolar Transistor (IGBT), and this is not intended to limit the scope of this application. Specifically, the source of the first transistor Q1 is connected to the second terminals of each of the second resistors, driving the first transistor Q1 to conduct. This causes the first shunt current I0 to flow into the source of the first transistor Q1 and out through its drain. Therefore, the drain output drop current Idroop of the first transistor Q1 is equal to the first shunt current I0. In this embodiment, the first shunt current I0 is used as the drop current Idroop.

[0106] Therefore, in this embodiment, the second terminal of the first transistor Q1 outputs a dropout current Idroop, which makes the first shunt current I0 participate in the generation of the subsequent feedback voltage VFB as a dropout current Idroop, thereby improving the generation efficiency of the feedback voltage VFB and greatly improving the response speed of the adaptive control of the output voltage of the switching power supply.

[0107] In some embodiments of this application, the transistor module 112 includes a plurality of first transistors configured to proportionally shunt a first shunt current I0 to generate a drop current Idroop. Each first transistor has a first terminal connected to a first node to receive the first shunt current I0, and its second terminals are adapted to output a plurality of second shunt currents I1 to generate the drop current Idroop based on the plurality of second shunt currents I1. Each second shunt current I1 is proportional to the first shunt current I0, and the control terminal of each first transistor is connected to the output terminal of an operational amplifier.

[0108] Specifically, such as Figure 7 As shown, transistor module 112 includes first transistors Q1 to Q4. The sources of first transistors Q1 to Q4 are all connected to the second terminal of the second resistor R2. The drains of first transistors Q1 to Q4 serve as independent shunt branches, outputting corresponding second shunt currents I1. The gates of all first transistors Q1 to Q4 are connected together, thus the gate drive conditions of multiple transistors are the same. First transistors Q1 to Q4 can be four transistors with identical device specifications. Based on their consistent conduction characteristics, these four transistors can divide the first shunt current I0 flowing through the second resistor R2 into four equal parts of the second shunt current I1, i.e., I1 = I0 / 4, facilitating finer adjustment of the drop current Idroop. Alternatively, first transistors Q1 to Q4 can be transistors with different device specifications, utilizing different conduction characteristics to divide the first shunt current I0 flowing through the second resistor R2 into multiple second shunt currents of different magnitudes, making the adjustment of the drop current Idroop more flexible.

[0109] It should be noted that, in Figure 7 In the illustrated embodiment, the aforementioned plurality of first transistors are exemplified by Q1 to Q4. Different numbers of first transistors can be used depending on actual needs, and this is not intended to limit the scope of this application. Furthermore, the more first transistors are used, the higher the adjustment accuracy of the subsequent droop current Idroop, which is beneficial for accurately generating a droop current Idroop that meets the requirements of voltage adaptive control.

[0110] Furthermore, in the embodiments of this application, such as Figure 8As shown, in the case of a switching power supply including a multi-phase switching circuit, multiple first transistors are provided. The specific configuration and further functional description of each module are the same as those in the corresponding embodiment described above, and will not be repeated here.

[0111] This application embodiment sets up multiple first transistors to further adjust the gain of the current flowing through the second resistor. Based on the conduction parameters of the first transistors, the magnitude of the second shunt current I1 can be precisely adjusted according to the actual circuit requirements, thereby achieving high-precision adjustment of the first shunt current I0, meeting the requirements of adaptive control of the output voltage of the switching power supply, and significantly improving the control accuracy of the output voltage of the switching power supply.

[0112] Furthermore, such as Figures 5 to 8 As shown, in some embodiments of this application, the current shunt unit 110 further includes a buffer module configured to clamp the terminal voltage of the second end of the first resistor to a preset voltage VCM. The buffer module includes a buffer 113, the input of which is adapted to receive the preset voltage VCM, the output of which is connected to the second end of the first resistor, the non-inverting input of an operational amplifier connected to the output of the buffer 113, and the inverting input of the operational amplifier connected to the second end of the second resistor, so that the current sampling signal is proportionally shunt according to the resistance values ​​of the first and second resistors.

[0113] Specifically, the input terminal of buffer 113 is adapted to receive a preset voltage VCM, which is a fixed voltage value generated on-chip. In this embodiment, VCM can be set to 1.8V. Under the action of buffer 113, the voltage at the second terminal of the first resistor is pulled to the preset voltage VCM. At the same time, the first terminal of the first transistor is connected to the inverting input terminal of the operational amplifier, thereby creating a virtual short between the non-inverting and inverting input terminals of the operational amplifier. Since the non-inverting input terminal of the operational amplifier is connected to the second terminal of the first resistor, and the voltage at the second terminal of the first resistor has been pulled to the preset voltage VCM under the action of buffer 113, the voltages at both the non-inverting and inverting input terminals of the operational amplifier are the preset voltage VCM. Furthermore, the inverting input terminal of the operational amplifier is connected to the second terminal of the second resistor, thereby pulling the voltage at the second terminal of the second resistor to the preset voltage VCM as well.

[0114] Therefore, under the synergistic effect of the buffer 113, the operational amplifier and the first transistor, the voltage at the second end of the first resistor and the second resistor are the same, eliminating the shunting error caused by the difference in resistor voltage. This ensures that the shunting ratio of the current sampling signal is determined only by the resistance values ​​of the first resistor and the second resistor, avoiding interference from external factors on the current shunting and significantly improving the accuracy of the shunting result.

[0115] like Figure 9 As shown, in some embodiments of this application, the current shunt unit 110 further includes a reporting module 114, which is configured to generate a reporting signal Simon based on the first shunt current I0, wherein the reporting signal Simon characterizes the output current Iout of the switching power supply.

[0116] Furthermore, the reporting module 114 includes at least one second transistor Q5 and a third resistor Rimon. The control terminal of the second transistor Q5 is connected to the gate of the first transistor Q1. The first terminal of the second transistor Q5 is connected to the second terminal of the second resistor R2. The second terminal of the second transistor Q5 is connected to the first terminal of the third resistor Rimon. The second terminal of the third resistor Rimon is connected to reference ground. The second terminal of the second transistor Q5 is adapted to output the reporting signal Simon.

[0117] Specifically, in Figure 9 In the illustrated embodiment, taking the second transistor Q5 as a MOSFET as an example, the gate of the second transistor Q5 is connected to the gates of the first transistors Q1 to Q4. Therefore, the conduction drive conditions of the second transistor Q5 and the first transistors Q1 to Q4 are the same. When the second transistor Q5 is turned on, the drain of the second transistor Q5 is connected to the first terminal of the third resistor Rimon. Therefore, the first shunt current I0 flowing through the second resistor R2 flows into the third resistor Rimon through the second transistor Q5, generating a voltage drop across the third resistor Rimon. This generates the reporting signal Simon through the connection node between the third resistor Rimon and the drain of the second transistor Q5.

[0118] The ratio between the reporting signal Simon and the first shunt current I0 can be adjusted according to the different device specifications of the first transistors Q1 to Q4 and the second transistor Q5. Since the first shunt current I0 can characterize the output current Iout, the reporting signal Simon can be used to characterize the output current Iout.

[0119] In this embodiment, the reporting signal generated by the second transistor Q5 and the third resistor Rimon ensures accurate reflection of the total output current of each switching circuit in the power stage circuit, realizing real-time monitoring of the output current of the switching power supply. This helps to detect abnormalities in a timely manner and make adjustments, thereby improving system stability.

[0120] like Figure 4 As shown, in some embodiments of this application, the feedback voltage generation circuit 100 further includes a current regulation unit 120. It should be noted that... Figure 4The example uses a power stage circuit 20 that includes a multi-phase switching circuit. However, a current regulation unit 120 can also be provided in the case of a single-phase switching circuit. Furthermore, when the power stage circuit 20 includes a multi-phase switching circuit, the current regulation unit 120 may not be provided. Therefore, the current regulation unit 120 is a preferred embodiment in this application and is not intended to limit the scope of this application.

[0121] Furthermore, such as Figure 7 and Figure 8 As shown, when the transistor module 112 includes a plurality of first transistors, the current regulation unit 120 is configured to receive a switch control command, control whether a plurality of second shunt currents I1 flow to the reference ground according to the switch control command, and generate a drop current Idroop according to the second shunt currents I1 that do not flow to the reference ground.

[0122] Therefore, in this embodiment, the current regulation unit 120 controls whether multiple second shunt currents I1 flow to the reference ground, thereby flexibly and accurately adjusting the ratio of the first shunt current I0 to the drop current Idroop, so that the generated drop current Idroop can more accurately adapt to the requirements of adaptive control of the output voltage of the switching power supply, thereby improving the regulation accuracy of the output voltage of the switching power supply.

[0123] Specifically, such as Figure 10 As shown in the embodiment of this application, the current adjustment unit 120 controls the flow path of multiple second shunt currents I1, wherein a portion of the second shunt currents I1 are controlled to flow to the reference ground, the sum of the second shunt currents I1 flowing to the reference ground is Iredundancy, and the remaining second shunt currents I1 that do not flow to the reference ground are summed up as drop current Idroop.

[0124] Furthermore, the current regulating unit 120 includes multiple switching branches, each including first controllable switches K11 to K41 and second controllable switches K12 to K42. The first terminal of each first controllable switch in each branch is connected to the first terminal of each second controllable switch, and the first terminals of the first and second controllable switches are adapted to receive corresponding second shunt currents I1. The second terminal of each first controllable switch is connected to a reference ground. The second terminals of all second controllable switches are connected and have a second node adapted to generate a drop current Idroop. Specifically, as... Figure 10As shown, the aforementioned switch branches correspond one-to-one with the first transistors Q1 to Q4. Specifically, the switch branch corresponding to the first transistor Q1 includes the first controllable switch K11 and the second controllable switch K12; the switch branch corresponding to the first transistor Q2 includes the first controllable switch K21 and the second controllable switch K22; the switch branch corresponding to the first transistor Q3 includes the first controllable switch K31 and the second controllable switch K32; and the switch branch corresponding to the first transistor Q4 includes the first controllable switch K41 and the second controllable switch K42. If the first controllable switch is closed, the corresponding second shunt current I1 flows to the reference ground; if the second controllable switch is closed, the corresponding second shunt current I1 flows to the fourth resistor Rdroop.

[0125] Therefore, the current adjustment unit 120 can control a portion of the second shunt current I1 to flow to the reference ground, so that the generated drop current Idroop has a second ratio with the first shunt current I0. The more second shunt currents I1 flowing to the reference ground, the smaller this second ratio, and the smaller the generated drop current Idroop. Taking the current shunt unit 110 with first transistors Q1 to Q4 as an example, if the first transistors Q1 to Q4 have the same device specifications, and each first transistor outputs a second shunt current I1 at its drain, then the process of generating the drop current Idroop can be adjusted in steps of each second shunt current I1. Therefore, the drop current Idroop can be 1 to 4 times the second shunt current I1, that is, it is possible to flexibly adjust one-quarter to all of the first shunt current I0 as the drop current Idroop.

[0126] Furthermore, in some embodiments of this application, the current regulating unit 120 is also configured to receive a switching control command Idroop Code, which can be issued by a controller or a computer device including a controller. The current regulating unit 120 controls the closing and opening of the first and second controllable switches according to the switching control command Idroop Code to control whether the plurality of second shunt currents I1 flow to the reference ground. In addition, if the switching power supply 1 does not require adaptive output voltage regulation, all first controllable switches can be closed to improve system flexibility.

[0127] In this embodiment, the switching control command Idroop Code controls the opening and closing of the first and second controllable switches, so that the second shunt current I1 on the corresponding switch branch flows into the reference ground when the first controllable switch is closed, and participates in the generation of the drop current Idroop when the second controllable switch is closed. Therefore, under the control of the switching control command Idroop Code, multiple second shunt currents I1 can be adjusted according to various ratios, which greatly improves the flexibility and accuracy of the output voltage regulation of the switching power supply.

[0128] Furthermore, such as Figure 11 As shown, in some embodiments of this application, the reporting module 114 may further include a third controllable switch K51 and a fourth controllable switch K52, which have the same structure as the switch branch in the current regulation unit 120. The first terminals of the third controllable switch K51 and the fourth controllable switch K52 are respectively connected to the second terminal of the second transistor Q5. The second terminal of the third controllable switch K51 is connected to the first terminal of the third resistor Rimon, and a reporting signal Simon is generated at the connection node. The second terminal of the fourth controllable switch K52 is connected to the reference ground. In addition, the on / off state of the third controllable switch K51 and the fourth controllable switch K52 is controlled by the switch control instruction Imon Code. If the third controllable switch K51 is closed, a reporting signal Simon is generated; if the fourth controllable switch K52 is closed, the current reporting function is disabled.

[0129] like Figure 12 As shown, in some embodiments of this application, the circuit further includes a trimming unit configured to generate a bias current Ioffset to trim the drop current Idroop.

[0130] Specifically, the adjustment unit includes a bias current source 130, which is connected to the first terminals of multiple first transistors Q1 to Q4. The function of the bias current source 130 is to superimpose the first shunt current I0 with the bias current Ioffset to ensure that the drop current Idroop can maintain a reasonable current direction under different operating conditions. The bias current Ioffset flows from the bias current source 130 to the first terminal of the first transistor. As long as the magnitude of the bias current Ioffset is set reasonably, regardless of the current sampling signal I... CS Whether the direction is positive or negative, it can ensure the effective generation of the drop current Idroop, thereby generating an effective feedback voltage VFB.

[0131] Therefore, the embodiments of this application generate a bias current Ioffset through a trimming unit, thereby ensuring the generation of an effective feedback voltage VFB and expanding the applicability of the feedback voltage generation circuit.

[0132] Accordingly, such as Figure 3 As shown, this application embodiment also provides a control circuit 10, including the feedback voltage generation circuit 100 described in the above embodiment, wherein the feedback voltage generation circuit 100 is used to generate a feedback voltage VFB to adaptively control the output voltage Vout of the switching power supply 1.

[0133] Compared to related technologies, the control circuit proposed in this application not only simplifies the circuit structure and reduces the circuit area, but also improves the transmission delay caused by current mirror conversion, greatly enhancing the response speed of adaptive control of the switching power supply output voltage. Furthermore, the feedback voltage generation circuit in this application can flexibly adjust the shunting ratio of the current sampling signal, enabling more precise generation of slump current and corresponding feedback voltage, thus improving the AVP control accuracy of the switching power supply output voltage.

[0134] Accordingly, this application also provides a switching power supply 1, which includes a power stage circuit 20 and a control circuit 10 as described in the above embodiments. The control circuit 10 is used to generate a feedback voltage VFB and control the power stage circuit 20 according to the feedback voltage VFB to adaptively control the output voltage Vout of the switching power supply 1.

[0135] The specific configurations and further functional descriptions of each of the above modules are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0136] Compared to related technologies, the switching power supply 1 proposed in this application not only simplifies the circuit structure and reduces the circuit area, but also improves the transmission delay caused by current mirror conversion, greatly enhancing the response speed of adaptive control of the switching power supply output voltage. Furthermore, by directly proportionally dividing and adjusting the current sampling signal, this application can more accurately generate the slump current and corresponding feedback voltage, improving the AVP control accuracy of the switching power supply output voltage.

[0137] Accordingly, please refer to Figure 13 This application also provides a feedback voltage generation method for a switching power supply 1, comprising the following steps:

[0138] Step S1: Proportional shunting of at least one current sampling signal to obtain a first shunted current;

[0139] Step S3: Generate a dropout current based on the first shunt current, and generate a feedback voltage based on the dropout current;

[0140] Step S5: Adaptively control the output voltage of the switching power supply based on the feedback voltage.

[0141] The specific configurations and further functional descriptions of each of the above steps are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0142] The feedback voltage generation method proposed in this application obtains a first shunt current by proportionally shunting the current sampling signal of the switching power supply, thereby achieving proportional adjustment of the current sampling signal and accurately generating a slump current that meets the AVP control requirements. A feedback voltage is then generated based on the slump current to achieve high-response, high-precision adaptive control of the switching power supply output voltage. Therefore, this application embodiment can directly shunt the current sampling signal. Compared with related technologies that use a current mirror for conversion, this not only simplifies the circuit structure and reduces the circuit area but also improves the transmission delay caused by the current mirror conversion, greatly increasing the response speed of adaptive control of the switching power supply output voltage. Furthermore, the direct proportional shunting of the current sampling signal in this application embodiment can more accurately generate the slump current and the corresponding feedback voltage, improving the control accuracy of AVP of the switching power supply output voltage.

[0143] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0144] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0145] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

[0146] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A feedback voltage generating circuit, characterized in that, The feedback voltage generation circuit, used in the control circuit of a switching power supply, includes: A current shunt unit is configured to proportionally shunt at least one current sampling signal to obtain a first shunt current, and generate a drop current based on the first shunt current to generate a feedback voltage based on the drop current, wherein the feedback voltage is used for adaptive control of the output voltage of the switching power supply.

2. The feedback voltage generating circuit according to claim 1, characterized in that, The current shunting unit includes at least one input terminal, each input terminal corresponds to a current sampling signal, and each input terminal is connected to a first resistor and a second resistor respectively. The current shunting unit is configured to proportionally shun the current sampling signal according to the resistance values ​​of the first resistor and the second resistor to obtain a first shunting current. Wherein, the first end of each first resistor and the first end of each second resistor are respectively adapted to receive the corresponding current sampling signal, the second ends of all first resistors are connected together, the second ends of all second resistors are connected to the first node, and the first shunt current is the current flowing through the first node.

3. The feedback voltage generating circuit according to claim 2, characterized in that, The current shunt unit includes an input terminal adapted to receive a current sampling signal, and the current shunt unit is further configured to proportionally shunt the current sampling signal, wherein the current sampling signal characterizes the output current of the switching power supply.

4. The feedback voltage generating circuit according to claim 2, characterized in that, The current shunt unit includes at least two input terminals, the switching power supply includes a multi-phase switching circuit, each input terminal is adapted to receive the corresponding current sampling signal, and the current shunt unit is further configured to shunt each current sampling signal in the same proportion, wherein each current sampling signal represents the current of the corresponding phase switching circuit.

5. The feedback voltage generating circuit according to claim 2, characterized in that, The current shunt unit further includes a clamping module configured to clamp the terminal voltages of the second terminal of the first resistor and the second terminal of the second resistor to be equal.

6. The feedback voltage generating circuit according to claim 5, characterized in that, The current shunt unit further includes a transistor module, and the clamping module includes an operational amplifier. The non-inverting input terminal of the operational amplifier is connected to the second terminal of the first resistor, the inverting input terminal of the operational amplifier is connected to the second terminal of the second resistor, and the output terminal of the operational amplifier is connected to the inverting input terminal via the transistor module.

7. The feedback voltage generating circuit according to claim 6, characterized in that, The transistor module includes a first transistor configured to generate the dropout current based on the first shunt current, such that the dropout current is equal to the first shunt current. A first terminal of the first transistor is connected to the first node to receive the first shunt current, a second terminal of the first transistor is adapted to output the dropout current, and a control terminal of the first transistor is connected to the output terminal of the operational amplifier.

8. The feedback voltage generating circuit according to claim 6, characterized in that, The transistor module includes a plurality of first transistors configured to proportionally shunt the first shunt current to generate the dropout current. Each first transistor has a first terminal connected to the first node to receive the first shunt current, and a second terminal of the plurality of first transistors adapted to output a plurality of second shunt currents to generate the dropout current based on the plurality of second shunt currents. Each second shunt current is proportional to the first shunt current, and a control terminal of each first transistor is connected to the output terminal of the operational amplifier.

9. The feedback voltage generating circuit according to claim 2, characterized in that, The current shunt unit further includes a buffer module, which is configured to clamp the terminal voltage at the second end of the first resistor to a preset voltage. The buffer module includes a buffer, the input of which is adapted to receive the preset voltage, and the output of which is connected to the second end of the first resistor.

10. The feedback voltage generating circuit according to any one of claims 1 to 9, characterized in that, The feedback voltage generation circuit further includes a slump resistor, which is configured to generate the feedback voltage based on the slump current, an output voltage detection signal characterizing the output voltage of the switching power supply, and the resistance value of the slump resistor. The first end of the slump resistor is adapted to receive the slump current, and the second end of the slump resistor is adapted to receive the output voltage detection signal. The feedback voltage is generated through the first end of the slump resistor.

11. The feedback voltage generating circuit according to claim 6, characterized in that, The current shunt unit further includes a reporting module, which is configured to generate a reporting signal based on the first shunt current, and the reporting signal characterizes the output current of the switching power supply.

12. The feedback voltage generating circuit according to claim 11, characterized in that, The reporting module includes at least one second transistor and a third resistor. The control terminal of the second transistor is connected to the output terminal of the operational amplifier. The first terminal of the second transistor is connected to the second terminal of the second resistor. The second terminal of the second transistor is connected to the first terminal of the third resistor. The second terminal of the third resistor is connected to a reference ground. The second terminal of the second transistor is adapted to output the reporting signal.

13. The feedback voltage generating circuit according to claim 8, characterized in that, The feedback voltage generation circuit further includes a current regulation unit. In the case that the transistor module includes a plurality of first transistors, the current regulation unit is configured to receive a switch control command, control whether the plurality of second shunt currents flow to the reference ground according to the switch control command, and generate the drop current based on the second shunt currents that do not flow to the reference ground.

14. The feedback voltage generating circuit according to claim 1, characterized in that, The feedback voltage generation circuit further includes a trimming unit configured to generate a bias current to trim the slump current.

15. A control circuit for a switching power supply, characterized in that, The system includes a feedback voltage generating circuit according to any one of claims 1-14, wherein the feedback voltage generating circuit is used to generate a feedback voltage for adaptive control of the output voltage of the switching power supply.

16. A switching power supply, characterized in that, The switching power supply includes: Power stage circuit; And the control circuit according to claim 15, wherein the control circuit is configured to generate a feedback voltage and control the power stage circuit according to the feedback voltage to adaptively control the output voltage of the switching power supply.

17. A method for generating a feedback voltage, characterized in that, The method, applied to a control circuit of a switching power supply, includes: At least one current sampling signal is proportionally shunted to obtain a first shunted current; A slump current is generated based on the first shunt current, and a feedback voltage is generated based on the slump current; the output voltage of the switching power supply is adaptively controlled based on the feedback voltage.

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