Loop compensation circuit and switching power supply closed loop feedback system

Abstract

The invention discloses a loop compensation circuit and a switching power supply closed-loop feedback system, and relates to the technical field of switching power supplies, the loop compensation circuit comprises a proportion conversion module and a compensation module, the proportion conversion module is connected with the compensation module and a voltage output module in the switching power supply closed-loop feedback system, and the compensation module is connected with the proportion conversion module. The compensation module is connected with a driving module in the closed-loop feedback system of the switching power supply, the voltage output module outputs a voltage signal to be compensated to the proportion conversion module, the proportion conversion module is used for carrying out equal-proportion conversion on the voltage signal to be compensated, and a generated increased current signal and a generated reduced current signal are transmitted to the compensation module. Therefore, the compensation module compensates for the increased current signal and the reduced current signal, and transmits the generated target voltage signal to the driving module.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology, and in particular to a loop compensation circuit and a closed-loop feedback system for switching power supplies. Background Technology

[0002] Loop compensation circuits are techniques used to optimize the stability and dynamic performance of closed-loop feedback systems in switching power supplies. Their purpose is to address potential issues such as system oscillation and slow response by adjusting the transmission characteristics of the feedback loop, ensuring stable power output under conditions of input voltage fluctuations and load changes.

[0003] Currently, the loop compensation in existing switching power supply closed-loop feedback systems requires large resistor and capacitor values, making it difficult to integrate them inside the chip. Even if integrated inside the chip, the large resistor and capacitor values ​​will occupy a significant amount of chip area. However, using external resistor and capacitor compensation would add extra pins, complicate the application scheme, and increase application costs. Summary of the Invention

[0004] The main objective of this invention is to provide a loop compensation circuit and a closed-loop feedback system for switching power supplies, aiming to solve the technical problem that the large resistance and capacitance values ​​required for loop compensation in existing closed-loop feedback systems for switching power supplies make it difficult to integrate them into a chip.

[0005] To achieve the above objectives, the present invention proposes a loop compensation circuit, which is applied to a closed-loop feedback system of a switching power supply. The circuit includes a proportional conversion module and a compensation module. The proportional conversion module is connected to the compensation module and the voltage output module in the closed-loop feedback system of the switching power supply, respectively. The compensation module is connected to the drive module in the closed-loop feedback system of the switching power supply. The voltage output module is used to output the voltage signal to be compensated to the proportional conversion module; The proportional conversion module is used to proportionally convert the voltage signal to be compensated and transmit the generated increased current signal and decreased current signal to the compensation module. The compensation module is used to compensate for the increased current signal and the decreased current signal, and transmit the generated target voltage signal to the drive module.

[0006] In one embodiment, the proportional conversion module includes: an auxiliary unit, a current amplification unit, and a current reduction unit; The auxiliary unit is connected to the voltage output module, the current amplification unit, and the current reduction unit, respectively. The auxiliary unit is used to receive the voltage signal to be compensated and transmit the voltage signal to be compensated to the current amplification unit and the current reduction unit respectively. The current amplification unit is used to amplify the voltage signal to be compensated by a first preset ratio and transmit the generated amplified current signal to the compensation module. The current reduction unit is used to reduce the voltage signal to be compensated by a second preset ratio and transmit the generated reduced current signal to the compensation module.

[0007] In one embodiment, the auxiliary unit includes: a reference power supply and a first MOS transistor to an eighth MOS transistor; The gate of the first MOSFET is connected to the voltage output module. The source of the first MOSFET is connected to the source of the second MOSFET and the drain of the seventh MOSFET. The drain of the first MOSFET is connected to the drain of the third MOSFET, the gate of the third MOSFET, and the gate of the sixth MOSFET. The gate of the second MOSFET is connected to the drain of the fourth MOSFET, the gate of the fourth MOSFET, the current amplification unit, and the current reduction unit. The source of the third MOSFET is grounded. The source of the fourth MOSFET is grounded. The gate of the fifth MOSFET is connected to the drain of the fifth MOSFET, the drain of the sixth MOSFET, the current amplification unit, and the current reduction unit. The source of the fifth MOSFET is connected to the source of the seventh MOSFET, the source of the eighth MOSFET, the current amplification unit, the current reduction unit, and the reference power supply. The source of the sixth MOSFET is grounded. The gate of the seventh MOSFET is connected to the gate of the eighth MOSFET and the drain of the eighth MOSFET. The gate of the seventh MOSFET is also grounded.

[0008] In one embodiment, the current amplification unit includes: an amplification current output terminal, a first amplification MOSFET, and a second amplification MOSFET; The gate and source of the first increasing MOS transistor are both connected to the auxiliary unit. The drain of the first increasing MOS transistor is connected to the increasing current output terminal and the drain of the second increasing MOS transistor, respectively. The gate of the second increasing MOS transistor is connected to the auxiliary unit. The source of the second increasing MOS transistor is grounded. The increasing current output terminal is connected to the compensation module.

[0009] In one embodiment, the current reduction unit includes: a reduced current output terminal, a first increased MOS transistor, and a second increased MOS transistor; The gate and source of the first reduced MOS transistor are both connected to the auxiliary unit. The drain of the first reduced MOS transistor is connected to the reduced current output terminal and the drain of the second reduced MOS transistor, respectively. The gate of the second reduced MOS transistor is connected to the auxiliary unit. The source of the second reduced MOS transistor is grounded. The reduced current output terminal is connected to the compensation module.

[0010] In one embodiment, the compensation module includes: a compensation output terminal, a resistance unit, and a capacitance unit; The capacitance unit is connected to the proportional conversion module, the resistance unit and the compensation output terminal respectively, and the compensation output terminal is connected to the drive module; The resistance unit is used to perform resistance compensation on the increased current signal and the decreased current signal, and transmit the increased current signal and the decreased current signal after resistance compensation to the compensation output terminal through the capacitance unit. The capacitance unit is used to perform capacitance compensation on the reduced current signal and transmit the reduced current signal after capacitance compensation to the compensation output terminal. The compensation output terminal is used to transmit the generated target voltage signal to the drive module based on the increased current signal after resistor compensation, the decreased current signal after resistor compensation, and the decreased current signal after capacitor compensation.

[0011] In one embodiment, the resistance unit includes: a compensation resistor; The first end of the compensation resistor is connected to both the proportional conversion module and the capacitance unit, and the second end of the compensation resistor is grounded.

[0012] In one embodiment, the capacitance unit includes: a compensation capacitor; The first end of the compensation capacitor is connected to the proportional conversion module and the compensation output terminal, respectively, and the second end of the compensation capacitor is connected to the resistance unit and the proportional conversion module, respectively.

[0013] In one embodiment, the loop compensation circuit further includes: a first voltage divider resistor and a second voltage divider resistor; The first end of the first voltage divider resistor is connected to the voltage output module, the second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor and the proportional conversion module, and the second end of the second voltage divider resistor is grounded.

[0014] In addition, to achieve the above objectives, the present invention also proposes a closed-loop feedback system for a switching power supply, wherein the closed-loop feedback system for the switching power supply includes the loop compensation circuit as described above.

[0015] This invention proposes a loop compensation circuit and a closed-loop feedback system for a switching power supply. The circuit includes a proportional conversion module and a compensation module. The proportional conversion module is connected to both the compensation module and the voltage output module in the closed-loop feedback system. The compensation module is connected to the drive module in the closed-loop feedback system. The voltage output module outputs the voltage signal to be compensated to the proportional conversion module. This invention utilizes the proportional conversion module to proportionally convert the voltage signal to be compensated and transmits the generated increased and decreased current signals to the compensation module. This enables the compensation module to compensate for the increased and decreased current signals and transmit the generated target voltage signal to the drive module.

[0016] Because this invention incorporates a loop compensation circuit in the closed-loop feedback system of the switching power supply, when the voltage signal to be compensated output by the voltage output module reaches the proportional conversion module, the proportional conversion module performs a proportional current conversion on the voltage to be compensated and simultaneously outputs an increased current signal and a decreased current signal to the compensation module. The compensation module then compensates for the increased and decreased current signals respectively to obtain the desired target voltage signal, which is then transmitted to the drive module. Compared to existing conversion modules, this invention, by adding a proportional conversion, allows the compensation module to also be proportionally reduced, resulting in a smaller size of the compensation module within the entire loop compensation circuit, thereby achieving compatibility of the compensation module within the loop compensation circuit. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the first embodiment of the loop compensation circuit proposed in this invention. Figure 2 This is a circuit diagram of the loop compensation circuit in the first embodiment of the loop compensation circuit proposed in this invention. Figure 3 This is a circuit diagram of a traditional loop compensation circuit; Figure 4 This is a circuit diagram of the proportional conversion module in the second embodiment of the loop compensation circuit proposed in this invention. Figure 5This is a schematic diagram of the third embodiment of the loop compensation circuit proposed in this invention. Figure 6 This is a circuit diagram of the loop compensation circuit in the third embodiment of the loop compensation circuit proposed in this invention.

[0020] Explanation of icon numbers:

[0021] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0026] It should be noted that loop compensation circuits are a technique used to optimize the stability and dynamic performance of closed-loop feedback systems in switching power supplies. Their purpose is to address potential issues such as system oscillation and slow response by adjusting the transmission characteristics of the feedback loop, ensuring stable power output even under input voltage fluctuations and load changes.

[0027] Currently, the loop compensation in existing switching power supply closed-loop feedback systems requires large resistor and capacitor values, making it difficult to integrate them inside the chip. Even if integrated inside the chip, the large resistor and capacitor values ​​will occupy a significant amount of chip area. However, using external resistor and capacitor compensation would add extra pins, complicate the application scheme, and increase application costs.

[0028] To address the aforementioned technical problems, this embodiment provides a loop compensation circuit. In this invention, a loop compensation circuit is incorporated into the closed-loop feedback system of the switching power supply. When the voltage signal to be compensated output by the voltage output module 3 reaches the proportional conversion module 1, the proportional conversion module 1 performs a proportional current conversion on the voltage to be compensated and simultaneously outputs an increased current signal and a decreased current signal to the compensation module 2. The compensation module 2 then compensates for the increased and decreased current signals to obtain the desired target voltage signal, which is then transmitted to the drive module 4. Compared to existing conversion modules, this invention, by incorporating a proportional conversion, allows the compensation module 2 to also be proportionally reduced in size, resulting in a smaller overall size of the compensation module 2 within the loop compensation circuit. This achieves compatibility of the compensation module 2 within the loop compensation circuit.

[0029] For ease of understanding, the following is combined with Figures 1 to 6 The loop compensation circuit provided in the embodiments of the present invention will be described in detail.

[0030] Reference Figure 1 , Figure 2 as well as Figure 3 , Figure 1 This is a schematic diagram of the first embodiment of the loop compensation circuit proposed in this invention. Figure 2 This is a circuit diagram of the loop compensation circuit in the first embodiment of the loop compensation circuit proposed in this invention. Figure 3 This is a circuit diagram of a traditional loop compensation circuit.

[0031] like Figure 1 As shown, in this embodiment, the above-mentioned loop compensation circuit is applied to the closed-loop feedback system of the switching power supply. The circuit includes: a proportional conversion module 1 and a compensation module 2. The aforementioned proportional conversion module 1 is connected to the aforementioned compensation module 2 and the voltage output module 3 in the aforementioned switching power supply closed-loop feedback system, respectively. The aforementioned compensation module 2 is connected to the aforementioned drive module 4 in the aforementioned switching power supply closed-loop feedback system. The voltage output module 3 is used to output the voltage signal to be compensated to the proportional conversion module 1. The aforementioned proportional conversion module 1 is used to perform proportional conversion on the aforementioned voltage signal to be compensated, and transmit the generated increased current signal and decreased current signal to the aforementioned compensation module 2; The aforementioned compensation module 2 is used to compensate for the aforementioned increased current signal and the aforementioned decreased current signal, and to transmit the generated target voltage signal to the aforementioned drive module 4.

[0032] It should be noted that the aforementioned closed-loop feedback system for the switching power supply can be a system capable of compensating for and stabilizing the input voltage and performing dynamic error correction. The aforementioned proportional conversion module 1 can be a module capable of converting a voltage signal into a current signal amplified by a preset ratio and a current signal reduced by a preset ratio, such as an operational transconductance amplifier (OTA). The aforementioned compensation module 2 can be a module capable of compensating for the current signal and converting it into a voltage signal. The aforementioned voltage output module 3 can be any module with voltage signal output functionality. The aforementioned drive module 4 can be any module with both voltage receiving and driving functions.

[0033] It is understood that the voltage signal to be compensated can be a voltage signal whose dynamic performance does not meet the target requirements of the circuit, such as a voltage signal with large fluctuations and oscillations. The above proportional conversion can be 3 or 5. In order to meet the actual circuit integration requirements, this embodiment uses a ratio of 3 to 5.

[0034] It should also be noted that the aforementioned increased current signal can be a current signal increased by a multiple of 3 to 5, and the aforementioned decreased current signal can be a current signal decreased by a multiple of 3 to 5. The aforementioned target voltage signal can be a voltage signal that meets the target requirements of the circuit after compensation, for example, a voltage signal that eliminates problems such as large fluctuations and large oscillations, i.e., a more stable voltage signal.

[0035] In specific implementations, such as Figure 2 As shown, when the aforementioned switching voltage closed-loop feedback system operates to the aforementioned voltage output module 3, the aforementioned voltage output module 3 outputs the aforementioned voltage signal to be compensated (i.e., Figure 2 The voltage signal to be compensated (k*Vout) is sent to the proportional conversion module 1, and then the proportional conversion module 1 performs a proportional conversion on the voltage signal to be compensated. The conversion formula for increasing the current signal is: ; The conversion formula for the reduced current signal is as follows: ; Where, k*Vout is the voltage signal to be compensated, Iota is the increased current signal, Inew is the decreased current signal, gm is the conversion coefficient, which is related to the specific structure of the proportional conversion module 1, and Vref is the reference voltage (i.e., Figure 2In the above, Vref), m and n are proportional multiples. In this embodiment, m and n are usually taken as 3 to 5.

[0036] After completing the proportional conversion, the proportional conversion module 1 transmits the increased current signal and the decreased current signal to the compensation module 2. The compensation module 2 then compensates for the increased current signal and the decreased current signal respectively, and after compensation, transmits the generated target voltage signal to the drive module 4. The formula for generating the target voltage signal is: ; This can be represented by the following transformation: ; Wherein, Vcomp is the target voltage signal, Rc is the resistance value of the compensation resistor in the compensation module 2, Cc is the capacitance value of the compensation capacitor in the compensation module 2, and s is the complex frequency.

[0037] It should be noted that if this condition is not met: ; This leads to another formula for generating a voltage signal: ; It should also be emphasized that in this embodiment, m and n are set to 3~5, indicating a minimum difference of 9 times. In this case, the error caused by the gm / m part can be ignored. In addition, even if it is less than 9 times, only 2 or 3 times, it is theoretically valid, but the error caused by the neglected terms in the derived formula will be slightly increased when the difference is 2 or 3 times.

[0038] like Figure 3 As shown, the traditional formula for generating the target voltage signal is: ; Where V is the traditional target voltage signal, R is the resistance value of the traditional compensation resistor, and C is the capacitance value of the traditional compensation capacitor.

[0039] Comparing Vcomp with V, it can be seen that in this embodiment, only Rc=R / n and Cc=C / m are needed (i.e., the volume of the compensation module 2 in this embodiment is smaller than that of the traditional compensation module 2) to achieve the same loop compensation effect as the traditional technology. Theoretically, the larger the values ​​of m and n, the better the loop compensation effect, thus achieving a larger compensation effect with fewer chips. However, considering engineering implementation, an excessively large ratio would lead to excessively high current output of the increased current signal, increasing power consumption, while an excessively low current output of the reduced current signal would generate noise. Therefore, in this embodiment, the range of m and n is 3 to 5.

[0040] Therefore, compared with the existing conversion module, this embodiment adds a proportional conversion, which allows the compensation module 2 to be scaled down proportionally as well, resulting in a reduction in the volume of the compensation module 2 in the entire loop compensation circuit, thereby achieving the compatibility of the compensation module 2 in the loop compensation circuit.

[0041] Furthermore, in order to achieve the proportional conversion of the voltage signal to be compensated, the following steps are continued... Figure 1 As shown, in this embodiment, the above-mentioned proportional conversion module 1 includes: an auxiliary unit 11, a current amplification unit 12, and a current reduction unit 13; The auxiliary unit 11 is connected to the voltage output module 3, the current amplification unit 12 and the current reduction unit 13 respectively. The auxiliary unit 11 is used to receive the voltage signal to be compensated and transmit the voltage signal to be compensated to the current amplification unit 12 and the current reduction unit 13 respectively. The aforementioned current amplification unit 12 is used to amplify the aforementioned voltage signal to be compensated by a first preset ratio, and transmit the generated amplified current signal to the aforementioned compensation module 2. The aforementioned current reduction unit 13 is used to perform a second preset ratio reduction conversion on the aforementioned voltage signal to be compensated, and transmit the generated reduced current signal to the aforementioned compensation module 2.

[0042] It should be noted that the auxiliary unit 11 can be any unit with signal transmission and biasing functions. The current amplification unit 12 can be a unit that proportionally amplifies the voltage signal and converts it into a current signal. The current reduction unit 13 can be any unit that proportionally reduces the voltage signal and converts it into a current signal.

[0043] It is understood that the first preset ratio can be 3 or 5, and the second preset ratio can be 3 or 5.

[0044] In a specific implementation, the auxiliary unit 11 receives the voltage signal to be compensated transmitted by the voltage output module 3, and transmits the voltage signal to be compensated to the current amplification unit 12 and the current reduction unit 13 respectively. Upon receiving the voltage signal to be compensated, the current amplification unit 12 converts the voltage signal to be compensated into a current signal while simultaneously amplifying it by the first preset ratio, and transmits the generated amplified current signal to the compensation module 2. Similarly, upon receiving the voltage signal to be compensated, the current reduction unit 13 converts the voltage signal to be compensated into a current signal while simultaneously reducing it by the second preset ratio, and transmits the generated reduced current signal to the compensation module 2.

[0045] In this embodiment, the closed-loop feedback system of the switching power supply includes a loop compensation circuit. When the voltage signal to be compensated output by the voltage output module 3 reaches the proportional conversion module 1, the proportional conversion module 1 performs a proportional current conversion on the voltage to be compensated and simultaneously outputs an increased current signal and a decreased current signal to the compensation module 2. The compensation module 2 then compensates for the increased and decreased current signals to obtain the desired target voltage signal, which is then transmitted to the drive module 4. Compared to existing conversion modules, this embodiment incorporates a proportional conversion, allowing the compensation module 2 to also be proportionally reduced in size. This results in a smaller size of the compensation module 2 within the entire loop compensation circuit, thereby achieving compatibility of the compensation module 2 within the loop compensation circuit.

[0046] Reference Figure 4 , Figure 4 The circuit diagram of the proportional conversion module 1 in the first embodiment of the loop compensation circuit proposed in this invention is shown.

[0047] Based on the above embodiments, a second embodiment of the present invention is proposed. In order to transmit the voltage signal to be compensated to the current amplification unit 12 and the current reduction unit 13, as follows... Figure 4 As shown, in this embodiment, the auxiliary unit 11 includes: a reference power supply Vf, and a first MOS transistor M1 to an eighth MOS transistor M1C; The gate of the first MOSFET M1 is connected to the voltage output module 3. The source of the first MOSFET M1 is connected to the source of the second MOSFET M2 and the drain of the seventh MOSFET M1A. The drain of the first MOSFET M1 is connected to the drain of the third MOSFET M3, the gate of the third MOSFET M3, and the gate of the sixth MOSFET M3A. The gate of the second MOSFET M2 is connected to the drain of the fourth MOSFET M4, the gate of the fourth MOSFET M4, the current amplification unit 12, and the current reduction unit 12. Unit 13 is connected, the source of the third MOSFET M3 is grounded, the source of the fourth MOSFET M4 is grounded, the gate of the fifth MOSFET M2C is connected to the drain of the fifth MOSFET M2C, the drain of the sixth MOSFET M3A, the current amplification unit 12, and the current reduction unit 13, respectively, and the source of the fifth MOSFET M2C is connected to the source of the seventh MOSFET M1A, the source of the eighth MOSFET M1C, the current amplification unit 12, the current reduction unit 13, and the reference power supply Vf (i.e., Figure 4The source of the sixth MOS transistor M3A is grounded, the gate of the seventh MOS transistor M1A is connected to the gate of the eighth MOS transistor M1C and the drain of the eighth MOS transistor M1C, and the gate of the seventh MOS transistor M1A is also grounded.

[0048] It should be noted that the first MOSFET M1, the second MOSFET M2, the fifth MOSFET M2C, the seventh MOSFET M1A, and the eighth MOSFET M1C mentioned above can all be PMOS transistors. The third MOSFET M3, the fourth MOSFET M4, and the sixth MOSFET M3A mentioned above can all be NMOS transistors. The reference power supply Vf mentioned above can be 5V.

[0049] In a specific implementation, the negative terminal of the aforementioned voltage signal to be compensated is connected to the negative input terminal of the aforementioned auxiliary unit 11 (i.e., Figure 4 The -) in the above-mentioned current reduction unit 13 and current increase unit 12 are sequentially passed through the first MOSFET M1, the third MOSFET M3, the sixth MOSFET M3A and the fifth MOSFET M2C, respectively. The negative terminal of the voltage signal to be compensated passes through the positive input terminal of the auxiliary unit 11 (i.e. Figure 4 The +) in the middle passes through the second MOS transistor M2 and the fourth MOS transistor M4 in sequence to reach the current reduction unit 13 and the current increase unit 12.

[0050] Furthermore, in order to proportionally increase and convert the aforementioned voltage signal to be compensated, the process continues as follows: Figure 4 As shown, in this embodiment, the current amplification unit 12 includes: an amplification current output terminal OUTn, a first amplification MOS transistor M2B, and a second amplification MOS transistor M4B; The gate and source of the first increasing MOS transistor M2B are both connected to the auxiliary unit 11. The drain of the first increasing MOS transistor M2B is connected to the increasing current output terminal OUTn and the drain of the second increasing MOS transistor M4B, respectively. The gate of the second increasing MOS transistor M4B is connected to the auxiliary unit 11. The source of the second increasing MOS transistor M4B is grounded. The increasing current output terminal OUTn is connected to the compensation module 2.

[0051] It should be noted that the first enlarged MOS transistor M2B mentioned above can be a PMOS transistor, and the second enlarged MOS transistor M4B mentioned above can be an NMOS transistor.

[0052] It is understandable that the aforementioned increased current output terminal OUTn can be used to output the aforementioned increased current signal.

[0053] In a specific implementation, the first increasing MOSFET M2B is used to receive the negative terminal of the voltage signal to be compensated, and the second increasing MOSFET M4B is used to receive the positive terminal of the voltage signal to be compensated. Simultaneously, after receiving the voltage signal to be compensated, both the first increasing MOSFET M2B and the second increasing MOSFET M4B convert it into an increasing current signal according to the first preset ratio. The increasing current signal is then transmitted to the compensation module 2 through the increasing current output terminal OUTn.

[0054] Furthermore, in order to proportionally reduce and convert the aforementioned voltage signal to be compensated, the process continues as follows: Figure 4 As shown, in this embodiment, the current reduction unit 13 includes: a reduced current output terminal OUTm, a first increased MOS transistor M2B, and a second increased MOS transistor M4B; The gate and source of the first reduced MOS transistor M2A are both connected to the auxiliary unit 11. The drain of the first reduced MOS transistor M2A is connected to the reduced current output terminal OUTm and the drain of the second reduced MOS transistor M4A, respectively. The gate of the second reduced MOS transistor M4A is connected to the auxiliary unit 11. The source of the second reduced MOS transistor M4A is grounded. The reduced current output terminal OUTm is connected to the compensation module 2.

[0055] It should be noted that the first shrunken MOS transistor M2A mentioned above can be a PMOS transistor, and the second shrunken MOS transistor M4A mentioned above can be an NMOS transistor.

[0056] It is understandable that the aforementioned reduced current output terminal OUTm can be used to output the aforementioned reduced current signal.

[0057] In the specific implementation, the first reduced MOSFET M2A is used to receive the negative terminal of the voltage signal to be compensated, and the second reduced MOSFET M4A is used to receive the positive terminal of the voltage signal to be compensated. Simultaneously, after receiving the voltage signal to be compensated, both the first reduced MOSFET M2A and the second reduced MOSFET M4A convert it into a reduced current signal according to the second preset ratio. The reduced current signal is then transmitted to the compensation module 2 through the reduced current output terminal OUTm.

[0058] Reference Figure 5 , Figure 5 This is a schematic diagram of the third embodiment of the loop compensation circuit proposed in this invention.

[0059] Based on the above embodiments, a third embodiment of the present invention is proposed. To compensate for the increased current signal and the decreased current signal, as follows: Figure 5As shown, in this embodiment, the compensation module 2 includes: a compensation output terminal 21, a resistance unit 23, and a capacitance unit 22; The capacitance unit 22 is connected to the proportional conversion module 1, the resistance unit 23 and the compensation output terminal 21 respectively, and the compensation output terminal 21 is connected to the drive module 4. The aforementioned resistance unit 23 is used to perform resistance compensation on the aforementioned increased current signal and the aforementioned decreased current signal, and to transmit the increased current signal and the decreased current signal after resistance compensation to the aforementioned compensation output terminal 21 through the aforementioned capacitance unit 22. The aforementioned capacitance unit 22 is used to perform capacitance compensation on the aforementioned reduced current signal and transmit the reduced current signal after capacitance compensation to the aforementioned compensation output terminal 21. The aforementioned compensation output terminal 21 is used to transmit the generated target voltage signal to the aforementioned drive module 4 based on the increased current signal and decreased current signal after the aforementioned resistor compensation and the decreased current signal after the aforementioned capacitor compensation.

[0060] It is understood that the aforementioned compensation output terminal 21 can be used to output the aforementioned target voltage signal.

[0061] It should be noted that the resistance unit 23 can be any unit with resistance compensation function, such as a compensation resistor Rc. The capacitance unit 22 can be any unit with capacitance compensation function, such as a compensation capacitor Cc.

[0062] In the specific implementation, according to the formula for generating the target voltage signal, the resistance unit 23 performs resistance compensation for the increased current signal and the decreased current signal, while the capacitance unit performs capacitance compensation for the decreased current signal. After the compensation work is completed, the resistance unit 23 and the capacitance unit 22 will pass the compensated increased current signal and decreased current signal through the compensation output terminal 21. The compensation output terminal 21 will then combine the increased current signal and the decreased current signal into the target voltage signal and transmit it to the driving module 4, so that the driving module 4 obtains the desired voltage signal.

[0063] Furthermore, in order to achieve resistance compensation, such as Figure 6 As shown, Figure 6 This is a circuit diagram of the loop compensation circuit in the third embodiment of the loop compensation circuit proposed in this invention. In this embodiment, the resistance unit 23 includes: a compensation resistor Rc; The first end of the compensation resistor Rc is connected to the proportional conversion module 1 and the capacitance unit 22, respectively, and the second end of the compensation resistor Rc is grounded.

[0064] It should be noted that the resistance value of the compensation resistor Rc can be adjusted according to the specific actual situation, and this embodiment does not impose any restrictions on it.

[0065] In practical implementation, when the aforementioned increased current signal and decreased current signal pass through the aforementioned compensation resistor Rc, the compensation resistor Rc will compensate for their resistance values. It should be noted that the aforementioned resistance compensation refers to using the compensation resistor Rc to generate a programmable zero in the loop transfer function to cancel out a pole introduced by the power stage output filter, thereby correcting the phase and making the closed-loop of the switching power supply both stable and fast.

[0066] Furthermore, in order to complete the capacitance compensation, continue as follows: Figure 6 As shown, in this embodiment, the capacitance unit 22 includes a compensation capacitor Cc; The first end of the compensation capacitor Cc is connected to the proportional conversion module 1 and the compensation output terminal 21, respectively, and the second end of the compensation capacitor Cc is connected to the resistance unit 23 and the proportional conversion module 1, respectively.

[0067] It should be noted that the capacitance value of the compensation capacitor Cc can be adjusted according to the specific actual situation, and this embodiment does not impose any restrictions on it.

[0068] In practical implementation, when the aforementioned reduced current signal passes through the aforementioned compensation capacitor Cc, the compensation capacitor Cc will perform capacitance compensation on the reduced current signal. It should be noted that the aforementioned capacitance compensation refers to using the compensation capacitor Cc to introduce a low-frequency pole in the loop transfer function, "pressing" the high gain of the error amplifier into the low-frequency range, thereby reducing the high-frequency gain, improving the phase margin, and preventing closed-loop oscillation of the switching power supply.

[0069] Furthermore, in order to perform voltage division on the aforementioned voltage signal to be compensated, the process continues as follows: Figure 6 As shown, in this embodiment, the above-mentioned loop compensation circuit further includes: a first voltage divider resistor R1 and a second voltage divider resistor R2; The first end of the first voltage divider resistor R1 is connected to the voltage output module 3, the second end of the first voltage divider resistor R1 is connected to the first end of the second voltage divider resistor R2 and the proportional conversion module 1, and the second end of the second voltage divider resistor R2 is grounded.

[0070] In a specific implementation, after the voltage output module 3 outputs the voltage signal to be compensated, it will be divided by the first voltage divider resistor R1 and the second voltage divider resistor R2 before reaching the proportional conversion module 1.

[0071] To achieve the above objectives, the present invention also proposes a closed-loop feedback system for a switching power supply, wherein the closed-loop feedback system for the switching power supply includes the loop compensation circuit described above.

[0072] It should be noted that the specific implementation of the switching power supply closed-loop feedback system provided in this embodiment can refer to the above embodiments, and this embodiment will not elaborate on it further. Therefore, the effects achieved by the switching power supply closed-loop feedback system in this embodiment can also refer to the above embodiments, and this embodiment will not elaborate on them further.

[0073] The above description is only a part of the embodiments of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A loop compensation circuit, characterized in that, The loop compensation circuit is applied to the closed-loop feedback system of the switching power supply. The circuit includes: a proportional conversion module and a compensation module. The proportional conversion module is connected to the compensation module and the voltage output module in the closed-loop feedback system of the switching power supply, respectively. The compensation module is connected to the drive module in the closed-loop feedback system of the switching power supply. The voltage output module is used to output the voltage signal to be compensated to the proportional conversion module; The proportional conversion module is used to proportionally convert the voltage signal to be compensated and transmit the generated increased current signal and decreased current signal to the compensation module. The compensation module is used to compensate for the increased current signal and the decreased current signal, and transmit the generated target voltage signal to the drive module.

2. The loop compensation circuit as described in claim 1, characterized in that, The proportional conversion module includes: an auxiliary unit, a current amplification unit, and a current reduction unit; The auxiliary unit is connected to the voltage output module, the current amplification unit, and the current reduction unit, respectively. The auxiliary unit is used to receive the voltage signal to be compensated and transmit the voltage signal to be compensated to the current amplification unit and the current reduction unit respectively. The current amplification unit is used to amplify the voltage signal to be compensated by a first preset ratio and transmit the generated amplified current signal to the compensation module. The current reduction unit is used to reduce the voltage signal to be compensated by a second preset ratio and transmit the generated reduced current signal to the compensation module.

3. The loop compensation circuit as described in claim 2, characterized in that, The auxiliary unit includes: a reference power supply and a first MOSFET to an eighth MOSFET; The gate of the first MOSFET is connected to the voltage output module. The source of the first MOSFET is connected to the source of the second MOSFET and the drain of the seventh MOSFET. The drain of the first MOSFET is connected to the drain of the third MOSFET, the gate of the third MOSFET, and the gate of the sixth MOSFET. The gate of the second MOSFET is connected to the drain of the fourth MOSFET, the gate of the fourth MOSFET, the current amplification unit, and the current reduction unit. The source of the third MOSFET is grounded. The source of the fourth MOSFET is grounded. The gate of the fifth MOSFET is connected to the drain of the fifth MOSFET, the drain of the sixth MOSFET, the current amplification unit, and the current reduction unit. The source of the fifth MOSFET is connected to the source of the seventh MOSFET, the source of the eighth MOSFET, the current amplification unit, the current reduction unit, and the reference power supply. The source of the sixth MOSFET is grounded. The gate of the seventh MOSFET is connected to the gate of the eighth MOSFET and the drain of the eighth MOSFET. The gate of the seventh MOSFET is also grounded.

4. The loop compensation circuit as described in claim 2, characterized in that, The current amplification unit includes: an amplification current output terminal, a first amplification MOSFET, and a second amplification MOSFET; The gate and source of the first increasing MOS transistor are both connected to the auxiliary unit. The drain of the first increasing MOS transistor is connected to the increasing current output terminal and the drain of the second increasing MOS transistor, respectively. The gate of the second increasing MOS transistor is connected to the auxiliary unit. The source of the second increasing MOS transistor is grounded. The increasing current output terminal is connected to the compensation module.

5. The loop compensation circuit as described in claim 2, characterized in that, The current reduction unit includes: a reduced current output terminal, a first enlarged MOSFET, and a second enlarged MOSFET; The gate and source of the first reduced MOS transistor are both connected to the auxiliary unit. The drain of the first reduced MOS transistor is connected to the reduced current output terminal and the drain of the second reduced MOS transistor, respectively. The gate of the second reduced MOS transistor is connected to the auxiliary unit. The source of the second reduced MOS transistor is grounded. The reduced current output terminal is connected to the compensation module.

6. The loop compensation circuit as described in claim 1, characterized in that, The compensation module includes: a compensation output terminal, a resistance unit, and a capacitance unit; The capacitance unit is connected to the proportional conversion module, the resistance unit and the compensation output terminal respectively, and the compensation output terminal is connected to the drive module; The resistance unit is used to perform resistance compensation on the increased current signal and the decreased current signal, and transmit the increased current signal and the decreased current signal after resistance compensation to the compensation output terminal through the capacitance unit. The capacitance unit is used to perform capacitance compensation on the reduced current signal and transmit the reduced current signal after capacitance compensation to the compensation output terminal. The compensation output terminal is used to transmit the generated target voltage signal to the drive module based on the increased current signal after resistor compensation, the decreased current signal after resistor compensation, and the decreased current signal after capacitor compensation.

7. The loop compensation circuit as described in claim 6, characterized in that, The resistance unit includes: a compensation resistor; The first end of the compensation resistor is connected to both the proportional conversion module and the capacitance unit, and the second end of the compensation resistor is grounded.

8. The loop compensation circuit as described in claim 5, characterized in that, The capacitance unit includes: a compensation capacitor; The first end of the compensation capacitor is connected to the proportional conversion module and the compensation output terminal, respectively, and the second end of the compensation capacitor is connected to the resistance unit and the proportional conversion module, respectively.

9. The loop compensation circuit as described in claim 1, characterized in that, The loop compensation circuit further includes: a first voltage divider resistor and a second voltage divider resistor; The first end of the first voltage divider resistor is connected to the voltage output module, the second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor and the proportional conversion module, and the second end of the second voltage divider resistor is grounded.

10. A closed-loop feedback system for a switching power supply, characterized in that, The closed-loop feedback system of the switching power supply includes the loop compensation circuit as described in any one of claims 1 to 9.

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