Feedback voltage generation circuit, control circuit and switching power supply

Abstract

The invention relates to the technical field of power electronics, and discloses a feedback voltage generation circuit, a control circuit and a switching power supply, and the feedback voltage generation circuit comprises a sampling unit which is configured to obtain a first sampling voltage and a second sampling voltage according to a current sampling signal; the proportional adjusting unit is configured to generate feedback voltage according to the first sampling voltage, the second sampling voltage and the voltage sampling signal, so that the control circuit controls the output voltage according to the feedback voltage, the difference value between the feedback voltage and the voltage sampling signal is in direct proportion to the sampling voltage drop, and the sampling voltage drop is in direct proportion to the sampling voltage drop. The sampling voltage drop is a difference between the first sampling voltage and the second sampling voltage. The feedback voltage can be accurately generated according to the current sampling signal representing the output current and the voltage sampling signal representing the output voltage, and voltage regulation in a wider range can be realized to quickly and accurately generate the feedback voltage for switching power supply control.

Description

Technical Field

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

[0002] Switching power supplies typically employ Load Line technology to meet stringent requirements for transient response. This technology is also known as Active Voltage Positioning (AVP). The key to AVP technology lies in the accurate detection of load current to achieve dynamic voltage adjustment of the switching power supply.

[0003] In related technologies, feedback voltage generation circuits typically first use a current mirror sampling method to proportionally mirror the current sampling signal corresponding to the output current of the switching power supply before generating the feedback voltage. This current mirror sampling method uses the size ratio of the output transistor and the mirror transistor to mirror the input current. However, this mirror sampling method is limited by the characteristics of the current mirror, resulting in low accuracy when sampling small-amplitude currents, leading to a very small detection range. Furthermore, the current mirror circuit structure has a significant time delay, resulting in a slow response speed for the AVP (Automated Guided Vehicle), making it difficult to meet transient response requirements. Summary of the Invention

[0004] This application provides a feedback voltage generation circuit, a control circuit, and a switching power supply, which solves the technical problems of the small detection range and slow response speed of the output current of the switching power supply in related technologies. It accurately generates feedback voltage based on the current sampling signal that can characterize the output current and the voltage sampling signal that can characterize the output voltage, and can realize a wider range of voltage regulation, so as to realize that feedback voltage can be generated quickly and accurately for switching power supply control in a wide range of output current.

[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 the control circuit of a switching power supply, wherein the output terminal of the switching power supply generates an output voltage and an output current, and the feedback voltage generating circuit includes:

[0007] A sampling unit configured to obtain a first sampling voltage and a second sampling voltage based on a current sampling signal characterizing the output current;

[0008] A proportional adjustment unit is configured to generate a feedback voltage based on a first sampling voltage, a second sampling voltage, and a voltage sampling signal characterizing the output voltage, so that the control circuit controls the output voltage based on the feedback voltage, wherein the difference between the feedback voltage and the voltage sampling signal is proportional to the sampling voltage drop, and the sampling voltage drop is the difference between the first sampling voltage and the second sampling voltage.

[0009] The feedback voltage generation circuit proposed in this application obtains a first sampling voltage and a second sampling voltage through a sampling unit. The difference between the first and second sampling voltages directly reflects the relevant information of the output current. Subsequently, a proportional adjustment unit generates a feedback voltage based on the first sampling voltage, the second sampling voltage, and the voltage sampling signal. This allows the feedback voltage to be adjusted over a wide range to precisely adapt to circuit requirements and control the output voltage. Therefore, this application embodiment can achieve accurate generation of the feedback voltage, ensuring precise generation over a wide output current range, especially for output currents with small amplitudes. It also enables multi-level adjustable feedback voltage, meeting the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit proposed in this application embodiment has a simpler structure, occupying less chip area and having lower cost. It also significantly reduces signal delay, thereby quickly and accurately generating a feedback voltage for switching power supply control.

[0010] Optionally, in some embodiments of this application, the sampling unit includes a first resistor, through which the current sampling signal flows to generate a first sampling voltage and a second sampling voltage, wherein a first end of the first resistor generates the first sampling voltage and a second end of the first resistor generates the second sampling voltage.

[0011] By allowing the current sampling signal to flow through the first resistor to generate a sampling voltage drop, the changes in the output current of the switching power supply can be reflected in real time. Furthermore, for current sampling signals of different amplitudes, the first resistor can accurately generate the corresponding sampling voltage drop, avoiding the current sampling mismatch problem. This is beneficial for generating feedback voltage quickly and accurately for switching power supply control over a wide output current range.

[0012] Optionally, in some embodiments of this application, the sampling unit further includes a clamping module configured to clamp the voltage at the first terminal of the first resistor to a preset voltage.

[0013] Optionally, in some embodiments of this application, the clamping module includes a first operational amplifier, the non-inverting input of the first operational amplifier being adapted to receive a preset voltage, the inverting input of the first operational amplifier being connected to a first terminal of the first resistor, and the output of the first operational amplifier being connected to a second terminal of the first resistor.

[0014] By forming a virtual short circuit using a clamping module, the voltage at the first end of the first resistor is clamped stably at a preset voltage. This ensures that the voltage difference across the first resistor is only related to the current sampling signal, eliminating interference from other signals, improving the accuracy of the sampling voltage drop, and further enhancing the detection accuracy of the current sampling signal. This, in turn, facilitates the rapid and accurate generation of feedback voltage.

[0015] Optionally, in some embodiments of this application, the first resistor is an adjustable resistor.

[0016] In this embodiment, the first resistor is set as an adjustable resistor, so that the sampling unit can flexibly adjust the resistance value of the first resistor to achieve precise adjustment of the sampling voltage drop in multiple ranges, which can ensure accurate detection of the current sampling signal. Thus, with a simple circuit structure, it can quickly and accurately generate feedback voltage for switching power supply control in a wide output current range, meeting the configuration requirements of AVP technology.

[0017] Optionally, in some embodiments of this application, the proportional adjustment unit includes a first proportional adjustment module, which is configured to perform differential operation on the first sampling voltage, the second sampling voltage and the voltage sampling signal to generate an output detection voltage, and generate the feedback voltage according to the output detection voltage, wherein the difference between the output detection voltage and the voltage sampling signal is proportional to the sampling voltage drop.

[0018] This application embodiment uses a first proportional adjustment module to proportionally adjust the sampling voltage drop, achieving precise scaling of the sampling voltage drop with a simple circuit structure. This not only enables flexible adjustment of the output detection signal but also effectively reduces signal delay, thereby ensuring that feedback voltage can be generated quickly and accurately for switching power supply control within a wide output current range, meeting the configuration requirements of AVP technology.

[0019] Optionally, in some embodiments of this application, the first proportional adjustment module includes a second operational amplifier, the positive input terminal of the second operational amplifier being adapted to receive the first sampling voltage and the voltage sampling signal, the negative input terminal of the second operational amplifier being adapted to receive the second sampling voltage, and the output terminal of the second operational amplifier being adapted to generate the output detection voltage.

[0020] Optionally, in some embodiments of this application, the first proportional adjustment module further includes:

[0021] A second resistor, the first end of which is adapted to receive the first sampled voltage, and the second end of which is connected to the non-inverting input of the second operational amplifier;

[0022] A third resistor, the first end of which is adapted to receive the second sampling voltage, and the second end of which is connected to the inverting input of the second operational amplifier;

[0023] A fourth resistor, the first end of which is connected to the non-inverting input of the second operational amplifier, and the second end of which is adapted to receive the voltage sampling signal;

[0024] The fifth resistor has a first end connected to the inverting input terminal of the second operational amplifier, and a second end connected to the output terminal of the second operational amplifier and has a first node, the first node being adapted to output the output detection voltage;

[0025] Among them, the resistance values ​​of the second resistor and the third resistor are equal, and the resistance values ​​of the fourth resistor and the fifth resistor are equal.

[0026] The first proportional adjustment module uses the resistance ratio between the second and fourth resistors to proportionally adjust the sampling voltage drop, thereby quickly and accurately generating a feedback voltage for use in switching power supply control in conjunction with the voltage sampling signal.

[0027] Optionally, in some embodiments of this application, the second resistor and the third resistor are adjustable resistors, and / or the fourth resistor and the fifth resistor are adjustable resistors.

[0028] By setting multiple sets of adjustable resistors, the flexibility of adjusting the sampling voltage drop ratio is significantly increased. The resistance value of the corresponding resistor can be flexibly adjusted to achieve high-precision adjustment of the sampling voltage drop in multiple ranges. This ensures that feedback voltage can be generated quickly and accurately for switching power supply control within a wide output current range, meeting the requirements of AVP technology for flexible circuit configuration.

[0029] Optionally, in some embodiments of this application, the second operational amplifier includes a first operational amplifier path and a second operational amplifier path.

[0030] The positive input terminal of the first operational amplifier path is connected to the positive input terminal of the second operational amplifier path and has a second node, the second node being configured as the non-inverting input terminal of the second operational amplifier. The negative input terminal of the first operational amplifier path is connected to the negative input terminal of the second operational amplifier path and has a third node, the third node being configured as the inverting input terminal of the second operational amplifier.

[0031] The first operational amplifier path is configured to perform high-frequency gain processing on the signals received at the positive and negative input terminals of the first operational amplifier path;

[0032] The second operational amplifier path is configured to perform low-frequency gain processing on the signals received at the positive and negative input terminals of the second operational amplifier path;

[0033] The second operational amplifier further includes a bias output stage, which is configured to generate the output detection voltage based on the processing result of the first operational amplifier path, the processing result of the second operational amplifier path, and the bias signal.

[0034] The signal response speed of the first operational amplifier path is greater than that of the second operational amplifier path.

[0035] By setting two operational amplifier paths with different response speeds, targeted processing can be performed on different frequency components in the sampling voltage drop. The first operational amplifier path has a faster signal response speed, which can meet the high-frequency gain requirements and ensure the operational amplifier bandwidth of the second operational amplifier. The second operational amplifier path can meet the low-frequency gain requirements to ensure that the operational amplifier offset is small. Thus, under the synergistic effect of the two, a feedback voltage is finally generated quickly and accurately for the control of the switching power supply, which meets the transient response requirements of the switching power supply.

[0036] Optionally, in some embodiments of this application, the second operational amplifier path further includes a trimming circuit configured to trim the offset voltage of the second operational amplifier path.

[0037] The tuner circuit can correct the offset voltage of the second operational amplifier path, which can effectively reduce the error caused by the offset voltage and further improve the accuracy of the second operational amplifier path in processing low-frequency signals.

[0038] Optionally, in some embodiments of this application, the proportional adjustment unit further includes a second proportional adjustment module, which is configured to generate the feedback voltage based on the voltage sampling signal and the output detection voltage, wherein the difference between the feedback voltage and the output detection voltage is proportional to the difference between the voltage sampling signal and the output detection voltage.

[0039] The second proportional adjustment module can precisely scale the output detection voltage, thereby enabling flexible adjustment of the feedback voltage. This further improves the accuracy and flexibility of the feedback voltage adjustment, ensuring that feedback voltage can be generated quickly and accurately for switching power supply control within a wide output current range.

[0040] Optionally, in some embodiments of this application, the second proportional adjustment module includes a sixth resistor and a seventh resistor. The first end of the sixth resistor is adapted to receive the output detection voltage. The second end of the sixth resistor is connected to the first end of the seventh resistor and has a fifth node. The second end of the seventh resistor is adapted to receive the voltage sampling signal. The fifth node is used to output the feedback voltage.

[0041] Optionally, in some embodiments of this application, the sixth resistor and / or the seventh resistor are adjustable resistors.

[0042] By setting multiple sets of adjustable resistors, the flexibility of proportional adjustment of the output detection voltage is significantly increased, thereby achieving high-precision adjustment of the feedback voltage at multiple levels, which meets the requirements of AVP technology for flexible circuit configuration.

[0043] Optionally, in some embodiments of this application, the proportional adjustment unit further includes a current compensation unit configured to perform error compensation on the current sampling signal and the current flowing through the first resistor.

[0044] The current compensation unit can effectively reduce the deviation between the current sampling signal and the current flowing through the first resistor, effectively improving the accuracy of the sampling voltage drop, and making the output detection voltage and feedback voltage generated based on the sampling voltage drop more accurate.

[0045] Secondly, embodiments of this application provide a control circuit, the control circuit including the feedback voltage generating circuit described in the above embodiments, wherein the feedback voltage generating circuit is used to generate a feedback voltage so that the control circuit controls the output voltage of the switching power supply according to the feedback voltage.

[0046] The control circuit proposed in this application embodiment can accurately generate the feedback voltage through the aforementioned feedback voltage generation circuit. It ensures precise feedback voltage generation over a wide output current range, especially for output currents with small amplitudes, and provides multi-level adjustable feedback voltage, meeting the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit proposed in this application embodiment has a simpler structure, occupies less chip area, is lower in cost, and significantly reduces signal delay, thereby quickly and accurately generating feedback voltage for switching power supply control.

[0047] Thirdly, embodiments of this application provide a switching power supply, the switching power supply comprising:

[0048] Power stage circuit;

[0049] And the control circuit according to 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 control the output voltage of the switching power supply.

[0050] The switching power supply proposed in this application embodiment can achieve precise generation of feedback voltage through the aforementioned control circuit. It can ensure accurate generation of feedback voltage over a wide output current range, especially for output currents with small amplitudes, and achieve multi-level adjustable feedback voltage, meeting the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit proposed in this application embodiment has a simpler structure, occupying less chip area and having lower cost, while also significantly reducing signal delay, thereby quickly and accurately generating feedback voltage for switching power supply control. Attached Figure Description

[0051] 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.

[0052] Figure 1 This is a schematic diagram of the feedback voltage generation circuit in related technologies;

[0053] Figure 2 This is a schematic diagram of the circuit structure of a current mirror in related technologies;

[0054] Figure 3 This is a schematic diagram of the structure of a switching power supply according to one embodiment of the present application;

[0055] Figure 4 This is a schematic diagram of the structure of a switching power supply proposed in this application in another embodiment;

[0056] Figure 5 This is a schematic diagram of the structure of a switching power supply according to another embodiment of the present application;

[0057] Figure 6 This is a schematic diagram of the circuit structure of the feedback voltage generation circuit proposed in this application in one embodiment;

[0058] Figure 7 This is a schematic diagram of the circuit structure of the feedback voltage generation circuit proposed in this application in another embodiment;

[0059] Figure 8 This is a schematic diagram of the circuit structure of the proportional adjustment unit proposed in this application in one embodiment;

[0060] Figure 9 This is a schematic diagram of the circuit structure of the second operational amplifier proposed in this application in one embodiment;

[0061] Figure 10 This is a schematic diagram of the circuit structure of the tuner circuit proposed in this application in one embodiment;

[0062] Figure 11 This is a schematic diagram of the circuit structure of the proportional adjustment unit proposed in this application in another embodiment;

[0063] Figure 12 This is a schematic diagram of the circuit structure of the proportional adjustment unit proposed in this application in yet another embodiment. Detailed Implementation

[0064] 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.

[0065] Multiphase switching power supplies typically employ load line technology to meet stringent transient response requirements; this is also known as Active Voltage Positioning (AVP) technology. The key to AVP technology lies in the accurate detection of load current to achieve dynamic adjustment of the power supply voltage. Specifically, in the feedback voltage generation circuit of related technologies, such as... Figure 1 As shown, the sampling current signal I of the output current of the switching power supply OSEN The drop current I is generated by mirror sampling through a current mirror. DROOP That is, the drop current I DROOP With current sampling signal I OSEN The proportional relationship is shown in formula (1):

[0066] I DROOP =k*I OSEN Formula (1)

[0067] In the formula, k is the above mirror ratio, and k takes the value of a positive number less than 1.

[0068] This will further reduce the drop current I DROOP Acting on the dropout resistor R DROOP The feedback voltage V is generated on the top FB , where V FB The calculation formula is shown in formula (2) below:

[0069] V FB =V OSEN +k*I OSEN *R DROOP Formula (2)

[0070] In the formula, V OSEN This is the output voltage detection voltage for a multiphase switching power supply.

[0071] Furthermore, such as Figure 2 As shown, the current mirror sampling method typically uses the size ratio of the output transistor MP to the mirror transistor MS to sample the current signal I of the power supply. OSEN The process involves mirroring, where the size ratio of the output transistor MP to the mirror transistor MS specifically refers to the ratio of the number of cells in the output transistor MP to the number of cells in the mirror transistor MS. Furthermore, an operational amplifier loop controls the drain-source voltages of the output transistor MP and the mirror transistor MS to be equal, and a buffer is used to ensure that the current sampling signal I... OSEN The input voltage is maintained at the preset voltage V. CM This generates I, which is the sum of the sampled currents. OSEN Mirror-scale drop current I DROOP .

[0072] However, this mirror sampling method is limited by the device characteristics of the current mirror. When sampling currents with small amplitudes, the mismatch is large, resulting in low accuracy and a small detection range. Furthermore, the circuit structure of the current mirror has a large time delay, which slows down the signal transmission speed and causes the AVP to have a slow response speed, making it difficult to meet the requirements of transient response.

[0073] This application provides a high-precision adjustable feedback voltage generation circuit 100, which can be used in the control circuit 10 of a switching power supply 1. The switching power supply 1 further includes a power stage circuit 20. The input terminal of the switching power supply 1 receives the input voltage Vin, and the output terminal of the switching power supply 1 generates the output voltage Vout and the output current Iout.

[0074] like Figure 3 As shown, the feedback voltage generation circuit 100 includes a sampling unit 110 and a proportional adjustment unit 120. The sampling unit 110 is configured to generate a current sampling signal I representing the output current Iout based on the current sampling signal I. OSEN The first sampling voltage V is obtained SNS P Second sampling voltage V SNS N The proportional adjustment unit 120 is configured to adjust according to the first sampled voltage V. SNS_P Second sampling voltage V SNS_N and the voltage sampling signal V that characterizes the output voltage VoutOSEN Generate feedback voltage V FB So that the control circuit 10 responds to the feedback voltage V FB The output voltage Vout is controlled, where the feedback voltage Vout is... FB With voltage sampling signal V OSEN The difference between them and the sampling voltage drop V DROOP Proportional to the sampling voltage drop V DROOP The first sampling voltage V SNS_N Second sampling voltage V SNS_N difference.

[0075] Specifically, such as Figure 3 As shown, the control circuit 10 includes the aforementioned feedback voltage generation circuit 100 and switch control sub-circuit 200, and the sampling unit 110 is used to generate the feedback voltage V. FB For example, the switch control sub-circuit 200 includes an error amplifier or comparator that receives a feedback voltage V. FB With reference voltage V REF Then, the switching control sub-circuit 200 outputs a control signal for the power transistor Q1 in the switching circuit of the power stage circuit 20 according to the signal output of the error amplifier or comparator, thereby realizing the adaptive control of the output voltage Vout of the switching power supply 1.

[0076] The sampling unit 110 is connected to the sampling port of the power stage circuit 20 and is adapted to receive the current sampling signal I from the power stage circuit 20. OSEN And based on the current sampling signal I OSEN Generate sampling voltage drop V DROOP Among them, the sampling voltage drop V DROOP Directly reflects the current sampling signal I OSEN The magnitude and other characteristics of this information provide a basis for subsequent signal processing and feedback voltage V. FB The generation of signals provides the basis for signal generation.

[0077] The proportional adjustment unit 120 is used to adjust the first sampled voltage V SNS_P Second sampling voltage V SNS_N and voltage sampling signal V OSEN Differential calculations are performed; specifically, the proportional adjustment unit 120 adjusts the sampling voltage drop V according to the proportional relationship set in the circuit. DROOP Proportional adjustment is performed to control the sampling voltage drop V. DROOP Precise scaling is achieved, ultimately based on the proportionally adjusted sampling voltage drop V. DROOP and voltage sampling signal V OSEN Generate feedback voltage V FB .

[0078] Therefore, it can be seen that the embodiments of this application use sampling unit 110 to sample the current signal I. OSEN The signal result of the first adjustment is adjusted in the first stage, and then the proportional adjustment unit 120 is used to adjust the signal result of the first adjustment in the second stage, so that the current detection result can be adjusted in small steps.

[0079] Therefore, the feedback voltage generation circuit 100 proposed in this application obtains the first sampled voltage V through the sampling unit 110. SNS_P Second sampling voltage V SNS_N Through the first sampling voltage V SNS_P Second sampling voltage V SNS_N The difference directly reflects the relevant information of the output current Iout. Then, the proportional adjustment unit 120 uses the first sampled voltage V... SNS_P Second sampling voltage V SNS_N and voltage sampling signal V OSEN Generate feedback voltage V FB This makes the feedback voltage V FB It can be adjusted within a wide range to precisely adapt to circuit requirements and control the output voltage Vout. Therefore, the embodiments of this application can realize feedback voltage V FB It can accurately generate the feedback voltage V over a wide output current range, especially for output currents with small amplitudes Iout. FB To achieve the feedback voltage V FB The multi-level adjustable voltage meets the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit 100 proposed in this embodiment has a simpler structure, occupies less chip area, is lower in cost, and significantly reduces signal delay, thereby generating the feedback voltage V quickly and accurately. FB For use in switching power supply control.

[0080] exist Figure 3 In one example shown, the power stage circuit 20 includes a single-phase switching circuit, and the current sampling signal I... OSEN Specifically, to characterize the current flowing through the switching circuit 21, the sampling current I representing the current flowing through the switching circuit 21 can be used. CS1 As the current sampling signal I OSEN More specifically, the sampling current I CS1 Characterizes the current flowing through inductor L1 in switching circuit 21.

[0081] exist Figure 4 In one example shown, the power stage circuit 20 may further include a multi-phase switching circuit, and the current sampling signal I OSENSpecifically, the sum of currents flowing through switching circuits 21 to 2n can be characterized by the sampling current I, which represents the currents flowing through switching circuits 21 to 2n. CS1 I CS2 ... I CSn Obtain the current sampling signal I OSEN More specifically, the sampling current I CS1 I CS2 ... I CSn Characterize the current flowing through inductors L1 to Ln in switching circuits 21 to 2n respectively, and sample the current I. CS1 I CS2 ... I CSn The summed current is used as the current sampling signal I. OSEN .

[0082] Furthermore, the switch control sub-circuit 200 can adjust the sampling current I as described above. CS1 The control signal for power transistor Q1 in the control switching circuit 21 is generated, and the sampling current I is also used to generate the control signal. CSn Generate a control signal for the power transistor Qn in the corresponding switching circuit 2n.

[0083] It should be noted that in some embodiments of this application, the output voltage Vout of the power stage circuit 20 supplies power to the load 2 through the transmission line, and after the voltage division effect of the transmission line resistor, the actual output voltage of the switching power supply 1 is V. O+ and V O- That is, the supply voltage to load 2.

[0084] Furthermore, in Figure 5 In one example shown, the control circuit 10 further includes a differential-to-single-ended circuit 300, which receives an output voltage of V. O+ and V O- Differential sampling signal V O+SEN and V O-SEN After performing differential operations, the output voltage sampling signal V is obtained. OSEN .

[0085] It should be noted that the circuit structures of the above-mentioned switching circuits 21 to 2n are the same, and the above embodiment uses the switching circuits 21 to 2n as a step-down circuit for example, but it is not limited to this. The switching circuits 21 to 2n can also be a step-up circuit, a step-up / step-down circuit, etc.

[0086] In some embodiments of this application, such as Figure 6 As shown, the sampling unit 110 includes a first resistor R1, and the first terminal of the first resistor R1 receives the aforementioned current sampling signal I. OSEN And the current sampling signal I OSENA first sampling voltage V is generated by flowing through the first resistor R1. SNS_P Second sampling voltage V SNS_N The first terminal of the first resistor R1 generates the first sampling voltage V. SNS_P The second sampling voltage V is generated at the second terminal of the first resistor R1. SNS_N .

[0087] Specifically, the current sampling signal I OSEN The current flows directly through the first resistor R1, converting the current information into resistance voltage drop information. The voltage at the first terminal of the first resistor R1 is the first sampling voltage V. SNS_P The voltage at the second terminal of the first resistor R1 is the second sampling voltage V. SNS_N Therefore, the sampling voltage drop V DROOP As shown in the following formula (3):

[0088] V DROOP =V SNS_P -V SNS_N = R1*I OSEN Formula (3)

[0089] Therefore, compared with a current mirror, the embodiments of this application utilize the ohmic characteristics of a resistor to sample the current signal I. OSEN Converted to sampling voltage drop V DROOP It overcomes the device drawbacks of current mirrors and can operate regardless of the current sampling signal I. OSEN The magnitude of the signal does not affect the accuracy of current detection over a wide range, even if the current sampling signal I... OSEN The current value is relatively small, and it can also be obtained through the sampling voltage drop V generated by the first resistor R1. DROOP Accurately characterize the current sampling signal I OSEN .

[0090] Therefore, the embodiments of this application enable the current sampling signal I... OSEN The sampling voltage drop V is generated by flowing through the first resistor R1. DROOP This is to reflect the changes in the output current Vout in real time, and to sample current signals I of different amplitudes. OSEN All of these can accurately generate the corresponding sampling voltage drop V through the first resistor R1. DROOP This avoids the current sampling mismatch problem, thus enabling the rapid and accurate generation of feedback voltage V across a wide output current range. FB For use in switching power supply control.

[0091] Furthermore, in some embodiments of this application, such as Figure 6 As shown, the sampling unit 110 also includes a clamping module, which is configured to clamp the voltage at the first terminal of the first resistor R1 to a preset voltage V. CMThe clamping module includes a first operational amplifier 111, the non-inverting input of which is adapted to receive a preset voltage V. CM The inverting input terminal of the first operational amplifier 111 is connected to the first terminal of the first resistor R1, and the output terminal of the first operational amplifier 111 is connected to the second terminal of the first resistor R1.

[0092] Specifically, utilizing the virtual short characteristic of the first operational amplifier 111, that is, when the first operational amplifier 111 is in linear amplification mode, the voltage difference between its non-inverting input terminal and its inverting input terminal approaches zero. Since the non-inverting input terminal receives a preset voltage V... CM Based on the virtual short principle, the voltage at the inverting input terminal will be clamped to be approximately equal to the voltage at the non-inverting input terminal, that is, the voltage at the first terminal of the first resistor R1 will be clamped to the preset voltage V. CM This effectively eliminates the impact of other voltage fluctuations on the sampling voltage drop V. DROOP Interference.

[0093] Therefore, by forming a virtual short circuit using the clamping module, the voltage at the first terminal of the first resistor R1 is stably clamped at the preset voltage V. CM This ensures that the voltage difference across the first resistor R1 is only related to the current sampling signal I. OSEN Related, eliminate interference from other signals, and increase the sampling voltage drop V. DROOP The accuracy of the current sampling signal I is further improved. OSEN The detection accuracy.

[0094] Furthermore, in some embodiments of this application, such as Figure 7 As shown, the first resistor R1 is an adjustable resistor, and the sampling unit 110 is also configured to adjust the resistance value of the first resistor R1 to adjust the sampling voltage drop V. DROOP Size.

[0095] In this embodiment, the first resistor R1 is set as an adjustable resistor, so that the sampling unit 110 can flexibly adjust the resistance value of the first resistor R1 to achieve the sampling voltage drop V. DROOP The system offers multiple precise adjustment levels. The larger the resistance value of the first resistor R1, the lower the sampling voltage drop V. DROOP The larger the voltage value, the better the current sampling signal I is. OSEN The accurate detection ensures that a simple circuit structure can quickly and accurately generate a feedback voltage for switching power supply control over a wide output current range, meeting the configuration requirements of AVP technology.

[0096] In some embodiments of this application, such as Figure 6 and Figure 7 As shown, the proportional adjustment unit 120 includes a first proportional adjustment module 121, which is configured to adjust the first sampled voltage V.SNS_P Second sampling voltage V SNS_N and voltage sampling signal V OSEN Perform differential operations to generate the output detection voltage V. OUT_AMP And based on the output detection voltage V OUT_AMP Generate feedback voltage V FB Among them, the output detection voltage V OUT_AMP With voltage sampling signal V OSEN The difference between them and the sampling voltage drop V DROOP Proportional.

[0097] Specifically, the first proportional adjustment module 121 constitutes a proportional amplifier circuit, capable of adjusting the sampling voltage drop V. DROOP Perform proportional adjustment to achieve the desired sampling voltage drop V DROOP Precise scaling is applied to the scaled result, and gain processing is performed on the result to combine it with the voltage sampling signal V. OSEN Generate output detection voltage V OUT_AMP .

[0098] It should be noted that the voltage sampling signal V OSEN It can be the positive output voltage VO + and negative output voltage VO - The difference can also be the difference between the positive output voltage VO and the output voltage VO. + and negative output voltage VO - The difference between the voltage sampling signals V and V is proportional, i.e. OSEN It can be determined by the following formula (4):

[0099] V OSEN =k1*(VO + - VO - ) Formula (4)

[0100] In the formula, k1 is a preset proportional coefficient.

[0101] Therefore, in this embodiment of the application, the sampling voltage drop V is adjusted by the first proportional adjustment module 121. DROOP Proportional adjustment is performed to achieve the sampling voltage drop V using a simple circuit structure. DROOP Precise scaling not only enables the output detection signal V OUT_AMP Its flexible adjustment can also effectively reduce signal delay, thereby ensuring that the feedback voltage V can be generated quickly and accurately over a wide output current range. FB It is used for switching power supply control and meets the configuration requirements of AVP technology.

[0102] Furthermore, such as Figure 6 and Figure 7As shown, the first proportional adjustment module 121 includes a second operational amplifier 1211, a second resistor R2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The positive input terminal of the second operational amplifier 1211 is adapted to receive the first sampling voltage V. SNS_P and voltage sampling signal V OSEN The negative input terminal of the second operational amplifier 1211 is adapted to receive the second sampling voltage V. SNS_N The output of the second operational amplifier 1211 is adapted to generate an output detection voltage V. OUT_AMP .

[0103] Furthermore, the first terminal of the second resistor R2 is adapted to receive the first sampling voltage V. SNS_P That is, one end of the first resistor R1 is connected, and the second end of the second resistor R2 is connected to the non-inverting input terminal VINP of the second operational amplifier 1211. The first end of the third resistor R3 is adapted to receive the second sampling voltage V. SNS_N That is, the second terminal of the first resistor R1 is connected, and the second terminal of the third resistor R3 is connected to the inverting input terminal VINN of the second operational amplifier 1211. The first terminal of the fourth resistor R4 is connected to the non-inverting input terminal VINP of the second operational amplifier 1211, and the second terminal of the fourth resistor R4 is adapted to receive the voltage sampling signal V. OSEN The first end of the fifth resistor R5 is connected to the inverting input terminal VINN of the second operational amplifier 1211, and the second end of the fifth resistor R5 is connected to the output terminal of the second operational amplifier 1211 and has a first node, which is adapted to output the aforementioned output detection voltage V. OUT_AMP and output the detected voltage V OUT_AMP Directly used as feedback voltage V FB Output.

[0104] Furthermore, the resistance values ​​of the second resistor R2 and the third resistor R3 are equal, and the resistance values ​​of the fourth resistor R4 and the fifth resistor R5 are equal.

[0105] Specifically, the aforementioned resistors and the second operational amplifier 1211 constitute a proportional amplifier circuit, wherein the output detection voltage V OUT_AMP The calculation formula is shown in the following formula (5):

[0106]

[0107] In the formula, R A R is the resistance value of the second resistor R2 or the third resistor R3. FB This refers to the resistance value of the fourth resistor R4 or the fifth resistor R5. Therefore, the first proportional adjustment module 121 can adjust the resistance value based on the proportionality R... FB / R A To achieve sampling voltage drop V DROOPThe scaling, and then the sampling voltage drop V adjusted according to the ratio. DROOP With voltage sampling signal V OSEN The sum of the results generates the output detection voltage V. OUT_AMP .

[0108] Therefore, the first proportional adjustment module 121 uses the resistance ratio between the second resistor R2 and the fourth resistor R4 to adjust the sampling voltage drop V. DROOP The proportional adjustment, combined with the voltage sampling signal V OSEN Quickly generate output detection voltage V OUT_AMP And in one example, the output detection voltage V can be... OUT_AMP Directly used as feedback voltage V FB The output improves current detection and generates feedback voltage V. FB Response speed.

[0109] Furthermore, in some embodiments of this application, the second resistor R2 and the third resistor R3 are adjustable resistors, and / or the fourth resistor R4 and the fifth resistor R5 are adjustable resistors.

[0110] The first proportional adjustment module 121 is further configured to adjust the resistance values ​​of the second resistor R2 and the third resistor R3, and / or adjust the resistance values ​​of the fourth resistor R4 and the fifth resistor R5, in order to adjust the sampling voltage drop V. DROOP Adjust the ratio.

[0111] Specifically, Figure 8 The illustration shows an embodiment where the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 are all adjustable resistors. It should be noted that this application can also be implemented in the same manner. Figure 6 and Figure 7 As shown, the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 can all be set as non-adjustable resistors. Alternatively, the second resistor R2 and the third resistor R3 can be set as adjustable resistors, and the fourth resistor R4 and the fifth resistor R5 can be set as non-adjustable resistors. Figure 8 This is merely one way to set the adjustable resistor of the first proportional adjustment module 121 and is not intended to limit this application.

[0112] Therefore, by setting multiple sets of adjustable resistors, the sampling voltage drop V can be controlled. DROOP Scaling R FB / R A Flexible adjustment significantly increases the control over sampling voltage drop V. DROOP The proportional adjustment offers flexibility, allowing for easy adjustment of the resistance value of the corresponding resistor to achieve the desired sampling voltage drop V. DROOPThe multi-level high-precision adjustment ensures that the feedback voltage V can be generated quickly and accurately over a wide output current range. FB It is used for switching power supply control, which meets the requirements of AVP technology for flexible circuit configuration.

[0113] Furthermore, in some embodiments of this application, such as Figure 9 As shown, the second operational amplifier 1211 includes a first operational amplifier path A1, a second operational amplifier path A2, and a bias output stage. The positive input terminal of the first operational amplifier path A1 is connected to the positive input terminal of the second operational amplifier path A2 and has a second node. The second node is configured as the non-inverting input terminal VINP of the second operational amplifier 1211. The negative input terminal of the first operational amplifier path A1 is connected to the negative input terminal of the second operational amplifier path A2 and has a third node. The third node is configured as the inverting input terminal VINN of the second operational amplifier 1211.

[0114] The first operational amplifier path A1 is configured to perform high-frequency gain processing on the signals received at the positive and negative input terminals of the first operational amplifier path A1. The second operational amplifier path A2 is configured to perform low-frequency gain processing on the signals received at the positive and negative input terminals of the second operational amplifier path A2. The bias output stage is configured to generate an output detection voltage V based on the processing results of the first operational amplifier path A1, the processing results of the second operational amplifier path A2, and the bias signal. OUT_AMP Among them, the signal response speed of the first operational amplifier path A1 is greater than the response speed of the second operational amplifier path A2.

[0115] Specifically, to improve the signal processing response speed of the second operational amplifier 1211, a first operational amplifier path A1 providing a fast path and a second operational amplifier path A2 providing a slow path are provided. The first operational amplifier path A1 is a high-speed operational amplifier, and it determines the operational amplifier bandwidth of the second operational amplifier 1211. It has a high gain-bandwidth product (GBW), thus enabling gain processing of high-frequency signals and allowing for rapid tracking of transient current changes to meet the requirements of current detection and feedback voltage V. FB The need for rapid response.

[0116] The second operational amplifier path A2 is a low-speed operational amplifier, and it can perform gain processing on low-frequency signals to adjust offset and improve gain accuracy, effectively suppressing high-frequency interference, and thus improving the output detection voltage V. OUT_AMP More accurate and effectively reduces operational amplifier misalignment.

[0117] Therefore, the second operational amplifier 1211, by setting two op-amp paths with different response speeds, can target the adjusted sampling voltage drop V. DROOPDifferent frequency components are processed in a targeted manner. The first operational amplifier path A1 has a fast signal response speed, which can meet the high-frequency gain requirements and ensure the operational amplifier bandwidth of the second operational amplifier 1211. The second operational amplifier path A2 can meet the low-frequency gain requirements to ensure that the operational amplifier offset is small. Thus, under the synergistic effect of the two, the feedback voltage V is generated quickly and accurately. FB It is used for switching power supply control and meets the transient response requirements of switching power supplies.

[0118] In some embodiments of this application, such as Figure 9 As shown, the bias output stage includes a first output transistor MP1, a second output transistor MN1, and a bias submodule 1211-1. The first output terminal of the first operational amplifier path A1 is connected to the control terminal of the first output transistor MP1, the second output terminal of the first operational amplifier path A1 is connected to the control terminal of the second output transistor MN1, and the output terminal of the second operational amplifier path A2 is connected to the control terminal of the second output transistor MN1. The control terminals of the first and second output transistors are also respectively connected to the bias submodule 1211-1 to receive the bias signal generated by the bias submodule 1211-1. The first terminal of the first output transistor MP1 is adapted to receive a reference power supply, and the first terminal of the second output transistor MN1 is adapted to connect to a reference ground. The second terminals of the first and second output transistors MP1 and MN1 are connected and have a fourth node, which is configured as the output terminal of the second operational amplifier 1211.

[0119] Specifically, the first output transistor MP1 and the second output transistor MN1 form a push-pull structure, which, together with the bias submodule 1211-1, constitutes a Class-AB push-pull output structure. The bias output stage adopts a Class-AB push-pull output structure. The bias output stage receives the result of high-frequency signal processing from the first operational amplifier path A1 and the result of low-frequency signal processing from the second operational amplifier path A2, and combines them with the bias signal to generate the output detection voltage V. OUT AMP Therefore, it can be seen that the output detection voltage V OUT_AMP The gain results, which combine high-frequency and low-frequency signals and have been optimized using a bias signal, can more accurately reflect the current sampling signal I. OSEN The characteristics of this signal provide a basis for the subsequent generation of feedback voltage V. FB This provides a reliable basis for precise adaptive control of the output voltage Vout of the switching power supply 1.

[0120] Furthermore, in some embodiments of this application, the second operational amplifier path A2 further includes a trimmer circuit 1211-2, which is configured to trim the offset voltage of the second operational amplifier path A2.

[0121] Op-amp offset refers to the phenomenon where the output of an operational amplifier is not zero when the input signal is zero. Op-amp offset will cause the output sensing voltage V to be affected. OUT_AMP There is a deviation, which affects the accuracy of the output detection voltage. Specifically, Figure 10 The circuit structure of the second operational amplifier path A2 is shown, wherein, as Figure 10 As shown, the trimming circuit 1211-2 includes a trimming resistor R0. The two ends of the trimming resistor R0 are respectively adapted to receive a first trimming current I1 and a second trimming current I2. The first trimming current I1 and the second trimming current I2 are both controlled by a 6-bit one-time programmable (OTP) trimming code, so that the sum of the first trimming current I1 and the second trimming current I2 remains a fixed value. That is, when the first trimming current I1 increases by ΔI, the second trimming current I2 decreases by ΔI. At this time, the offset voltage that can be trimmed is approximately R0*ΔI.

[0122] It should be noted that the residual offset voltage of the second operational amplifier path A2 after adjustment is only the temperature drift and time drift of the offset voltage, which greatly reduces the offset voltage.

[0123] Therefore, the tuner circuit 1211-2 proposed in this application embodiment can correct the offset voltage of the second operational amplifier path A2, effectively reduce the error caused by the offset voltage, and further improve the accuracy of the second operational amplifier path A2 in processing low-frequency signals.

[0124] In other embodiments of this application, such as Figure 11 As shown, the proportional adjustment unit 120 further includes a second proportional adjustment module 122, which is configured to adjust according to the voltage sampling signal V. OSEN and output detection voltage V OUT_AMP Generate feedback voltage V FB Among them, the feedback voltage V FB With output detection voltage V OUT_AMP The difference between them and the voltage sampling signal V OSEN With output detection voltage V OUT_AMP The difference between them is directly proportional.

[0125] Specifically, in this embodiment, the third-level adjustment is achieved through the second proportional adjustment module 122, which also uses the proportional relationship of components such as resistors in the circuit to realize the output detection voltage V. OUT_AMP The proportional adjustment is used to achieve control over the output detection voltage V. OUT_AMP Precise scaling, thereby further regulating the feedback voltage V FB Size.

[0126] Therefore, the second proportional adjustment module 122 proposed in this application embodiment can adjust the output detection voltage V. OUT_AMP Precise scaling is performed to achieve control over the feedback voltage V. FB The flexible adjustment further enhances the control over the feedback voltage V. FB The precision and flexibility of adjustment ensure that the feedback voltage V can be generated quickly and accurately over a wide output current range. FB For use in switching power supply control.

[0127] Furthermore, in some embodiments of this application, such as Figure 11 As shown, the second proportional adjustment module 122 includes a sixth resistor R6 and a seventh resistor R7. The first terminal of the sixth resistor R6 is adapted to receive the output detection voltage V. OUT_AMP The second terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7 are connected and have a fifth node. The second terminal of the seventh resistor R7 is adapted to receive the voltage sampling signal V. OSEN The fifth node is used to output the feedback voltage V. FB .

[0128] Wherein, the sixth resistor R6 and / or the seventh resistor R7 are adjustable resistors, and the second proportional adjustment module 122 is further configured to adjust the resistance values ​​of the sixth resistor R6 and / or the seventh resistor R7 to adjust the feedback voltage V. FB Adjust the ratio.

[0129] Specifically, in this embodiment, the feedback voltage V is controlled by the voltage divider effect of the sixth resistor R6 and the seventh resistor R7. FB With output detection voltage V OUT_AMP The difference between them and the voltage sampling signal V OSEN With output detection voltage V OUT_AMP The difference between them is adjusted proportionally to further increase the feedback voltage V. FB The adjustment accuracy. Feedback voltage V FB The calculation formula is shown in the following formula (6):

[0130]

[0131] In the formula, R OA R is the resistance value of the sixth resistor. OB This is the resistance value of the seventh resistor.

[0132] Due to V DROOP＝ R DROOP *I OSEN It can be achieved by adjusting R DROOP R FB With R A Ratio and R OA With R OBAt least one of the proportions is used to achieve the feedback voltage V. FB Small step size adjustment.

[0133] Figure 11 This illustration shows an embodiment where both the sixth resistor R6 and the seventh resistor R7 are adjustable resistors. It should be noted that when adjusting R... OA With R OB In the proportional case, this application can also set the sixth resistor R6 to be an adjustable resistor and the seventh resistor R7 to be a non-adjustable resistor, or it can set the sixth resistor R6 to be a non-adjustable resistor and the seventh resistor R7 to be an adjustable resistor. Figure 11 This is merely one way to set the adjustable resistor of the second proportional adjustment module 122, and is not intended to limit this application.

[0134] Therefore, by setting multiple sets of adjustable resistors, the embodiments of this application significantly increase the control over the output detection voltage V. OUT_AMP The flexibility of proportional adjustment enables the feedback voltage V. FB The multi-level high-precision adjustment meets the requirements of AVP technology for flexible circuit configuration.

[0135] Therefore, in this embodiment, the current sampling signal I is determined solely by the resistance matching property. OSEN Compared to a current mirror, the adjustment ratio overcomes the mismatch problem when sampling small-amplitude currents, and its influence from trace resistance is negligible. Furthermore, the feedback voltage generation circuit proposed in this application allows for flexible adjustment of the resistance values ​​of the first to seventh resistors, enabling adjustment of R... DROOP R FB With R A Ratio and R OA With R OB At least one of the proportions is used, thereby improving the accuracy of current detection while also enabling the feedback voltage V. FB Adjustment of the small step size and width range.

[0136] Furthermore, in the feedback voltage generation circuit proposed in this application embodiment, the response speed of current detection is only affected by the proportional adjustment unit 120. The proportional adjustment unit 120 optimizes the circuit's response bandwidth and offset voltage through the first proportional adjustment module 121, thereby achieving wide-range current detection while significantly improving the current detection and feedback voltage generation efficiency. FB Response speed.

[0137] In some embodiments of this application, such as Figure 12 As shown, the proportional adjustment unit 120 further includes a current compensation unit 1212, which is configured to process the current sampling signal I. OSEN Error compensation is performed on the current flowing through the first resistor R1.

[0138] Specifically, because the positive input terminal of the second operational amplifier 1211 shunts the leakage current I from the sampling port... Leakage The current flows into the second resistor R2, and the current sampling signal I... OSEN Not all of the current flows through the first resistor R1, therefore the resulting sampling voltage drop V DROOP This will cause deviation. In this embodiment, a compensation current I is generated through a current compensation unit 1212. COMP and will compensate current I COMP Refill the first terminal of the first resistor R1 to compensate for the above deviation.

[0139] Among them, the current compensation unit 1212 realizes the leakage current I through the third operational amplifier. Leakage The replication causes the output signal of the third operational amplifier to flow through the eighth resistor R8, generating a replication current I. COPY The resistance value of the eighth resistor, R8, is R. FB That is, the resistance value is equal to that of the fourth resistor R4 or the fifth resistor R5. The current compensation unit 1212 also utilizes the first sampling mirror transistor MP2 and the second sampling mirror transistor MN2 to replicate the current I. COPY Perform mirroring to obtain the compensation current I COMP And I COMP =I COPY .

[0140] Therefore, the current compensation unit 1212 proposed in this application embodiment can effectively reduce the current sampling signal I. OSEN The deviation between the current flowing through the first resistor R1 and the sampling voltage drop V effectively increases the sampling voltage drop. DROOP The accuracy makes it possible to base the sampling voltage drop V DROOP The generated output detection voltage V OUT_AMP and feedback voltage V FB More accurate.

[0141] Accordingly, please refer to Figures 3 to 5 This application embodiment also provides a control circuit 10, which includes the feedback voltage generating circuit 100 described in the above embodiments, and further includes a switch control sub-circuit 200, wherein the feedback voltage generating circuit 100 is used to generate a feedback voltage V. FB So that the control circuit 10 responds to the feedback voltage V FB The output voltage Vout of switching power supply 1 is controlled.

[0142] The specific configurations and further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0143] The control circuit 10 proposed in this embodiment can realize feedback voltage V through the feedback voltage generation circuit 100. FB It generates precise current and can operate over a wide output current range, especially for current sampling signals with small amplitudes I. OSEN Both can ensure accurate generation of feedback voltage, achieving feedback voltage V. FB The multi-level adjustable voltage meets the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit 100 proposed in this embodiment has a simpler structure, occupies less chip area, is lower in cost, and significantly reduces signal delay, thereby generating the feedback voltage V quickly and accurately. FB For use in switching power supply control.

[0144] This application embodiment also provides a switching power supply 1, including a power stage circuit 20 and a control circuit 10 according to the above embodiment, wherein the control circuit 10 is connected to the sampling port of the power stage circuit 20, the output terminal of the power stage circuit 20 is connected to the load 2, and the control circuit 10 is used to generate a feedback voltage V. FB And based on the feedback voltage V FB The power stage circuit 20 controls the output voltage Vout of the switching power supply 1.

[0145] The specific configurations and further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0146] The switching power supply 1 proposed in this application embodiment can realize the sampling of current signal I through the above-mentioned control circuit 10. OSEN Wide-range, high-precision detection, especially for current sampling signals I with small amplitude. OSEN It can also ensure high-precision detection and directly adjust the corresponding signal proportionally to achieve control over the output detection voltage V. OUT_AMP and the corresponding feedback voltage V FB The multi-level adjustable voltage meets the flexible configuration requirements of AVP technology. Furthermore, compared to a current mirror, the feedback voltage generation circuit 100 proposed in this embodiment has a simpler structure, occupies less chip area, is lower in cost, and significantly reduces signal delay, thereby generating the feedback voltage V quickly and accurately. FB For use in switching power supply control.

[0147] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0148] 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.

[0149] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0150] 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.

[0151] 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 control circuit used in the switching power supply generates output voltage and output current at the output terminal of the switching power supply. The feedback voltage generation circuit includes: A sampling unit configured to obtain a first sampling voltage and a second sampling voltage based on a current sampling signal characterizing the output current; A proportional adjustment unit is configured to generate a feedback voltage based on a first sampling voltage, a second sampling voltage, and a voltage sampling signal characterizing the output voltage, so that the control circuit controls the output voltage based on the feedback voltage, wherein the difference between the feedback voltage and the voltage sampling signal is proportional to the sampling voltage drop, and the sampling voltage drop is the difference between the first sampling voltage and the second sampling voltage.

2. The feedback voltage generating circuit according to claim 1, characterized in that, The sampling unit includes a first resistor, through which the current sampling signal flows to generate a first sampling voltage and a second sampling voltage, wherein the first end of the first resistor generates the first sampling voltage and the second end of the first resistor generates the second sampling voltage.

3. The feedback voltage generating circuit according to claim 2, characterized in that, The sampling unit further includes a clamping module, which is configured to clamp the voltage at the first end of the first resistor to a preset voltage.

4. The feedback voltage generating circuit according to claim 3, characterized in that, The clamping module includes a first operational amplifier, the non-inverting input of which is adapted to receive a preset voltage, the inverting input of which is connected to the first end of the first resistor, and the output of which is connected to the second end of the first resistor.

5. The feedback voltage generating circuit according to claim 2 or 3, characterized in that, The first resistor is an adjustable resistor.

6. The feedback voltage generating circuit according to claim 1, characterized in that, The proportional adjustment unit includes a first proportional adjustment module, which is configured to perform differential operation on the first sampling voltage, the second sampling voltage and the voltage sampling signal to generate an output detection voltage, and generate the feedback voltage based on the output detection voltage, wherein the difference between the output detection voltage and the voltage sampling signal is proportional to the sampling voltage drop.

7. The feedback voltage generating circuit according to claim 6, characterized in that, The first proportional adjustment module includes a second operational amplifier. The positive input terminal of the second operational amplifier is adapted to receive the first sampling voltage and the voltage sampling signal, the negative input terminal of the second operational amplifier is adapted to receive the second sampling voltage, and the output terminal of the second operational amplifier is adapted to generate the output detection voltage.

8. The feedback voltage generating circuit according to claim 7, characterized in that, The first proportional adjustment module further includes: A second resistor, the first end of which is adapted to receive the first sampled voltage, and the second end of which is connected to the non-inverting input of the second operational amplifier; A third resistor, the first end of which is adapted to receive the second sampling voltage, and the second end of which is connected to the inverting input of the second operational amplifier; A fourth resistor, the first end of which is connected to the non-inverting input of the second operational amplifier, and the second end of which is adapted to receive the voltage sampling signal; The fifth resistor has a first end connected to the inverting input terminal of the second operational amplifier, and a second end connected to the output terminal of the second operational amplifier and has a first node, the first node being adapted to output the output detection voltage; Among them, the resistance values ​​of the second resistor and the third resistor are equal, and the resistance values ​​of the fourth resistor and the fifth resistor are equal.

9. The feedback voltage generating circuit according to claim 8, characterized in that, The second resistor and the third resistor are adjustable resistors, and / or the fourth resistor and the fifth resistor are adjustable resistors.

10. The feedback voltage generating circuit according to any one of claims 7 to 9, characterized in that, The second operational amplifier includes a first operational amplifier path and a second operational amplifier path. The positive input terminal of the first operational amplifier path is connected to the positive input terminal of the second operational amplifier path and has a second node, the second node being configured as the non-inverting input terminal of the second operational amplifier. The negative input terminal of the first operational amplifier path is connected to the negative input terminal of the second operational amplifier path and has a third node, the third node being configured as the inverting input terminal of the second operational amplifier. The first operational amplifier path is configured to perform high-frequency gain processing on the signals received at the positive and negative input terminals of the first operational amplifier path; The second operational amplifier path is configured to perform low-frequency gain processing on the signals received at the positive and negative input terminals of the second operational amplifier path; The second operational amplifier further includes a bias output stage, which is configured to generate the output detection voltage based on the processing result of the first operational amplifier path, the processing result of the second operational amplifier path, and the bias signal. The signal response speed of the first operational amplifier path is greater than that of the second operational amplifier path.

11. The feedback voltage generating circuit according to claim 10, characterized in that, The second operational amplifier path further includes a trimmer circuit configured to trim the offset voltage of the second operational amplifier path.

12. The feedback voltage generating circuit according to claim 6, characterized in that, The proportional adjustment unit further includes a second proportional adjustment module, which is configured to generate the feedback voltage based on the voltage sampling signal and the output detection voltage, wherein the difference between the feedback voltage and the output detection voltage is proportional to the difference between the voltage sampling signal and the output detection voltage.

13. The feedback voltage generating circuit according to claim 12, characterized in that, The second proportional adjustment module includes a sixth resistor and a seventh resistor. The first end of the sixth resistor is adapted to receive the output detection voltage. The second end of the sixth resistor is connected to the first end of the seventh resistor and has a fifth node. The second end of the seventh resistor is adapted to receive the voltage sampling signal. The fifth node is used to output the feedback voltage.

14. The feedback voltage generating circuit according to claim 13, characterized in that, The sixth resistor and / or the seventh resistor are adjustable resistors.

15. The feedback voltage generating circuit according to claim 2, characterized in that, The proportional adjustment unit further includes a current compensation unit, which is configured to perform error compensation on the current sampling signal and the current flowing through the first resistor.

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

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

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