Power supply control circuit and control method thereof

Abstract

The invention discloses a power supply control circuit which is used for controlling a two-stage power supply conversion system. The power supply control circuit introduces a feedback signal representing load change into a control loop of the first-stage power supply conversion circuit, so that the first-stage power supply conversion circuit adjusts output in time according to the load change, and the transient response of the whole two-stage power supply conversion system is accelerated.

Description

Technical Field

[0001] Embodiments of the present invention relate to electronic circuits, and more particularly, to a power control circuit. Background Art

[0002] In the field of power converters, multi-stage power conversion systems are widely used to improve system efficiency while accommodating diverse load requirements. A multi-stage power conversion system typically includes multiple power conversion circuits and their respective control circuits. These multiple power conversion circuits can have different topologies. In particular, AC-to-DC power systems typically include a first-stage power conversion circuit for converting the AC input voltage into a DC voltage, and a second-stage power conversion circuit for converting the DC voltage provided by the first-stage power conversion circuit into an output voltage suitable for the load. In common applications, the first-stage and second-stage power conversion circuits are controlled by different control circuits and work together to convert the AC input voltage into a suitable output voltage.

[0003] In a multi-stage power conversion system, when the load changes, the regulation of the multi-stage power conversion system is slow, which may cause large fluctuations in the output voltage. Summary of the Invention

[0004] To solve the above technical problems, an embodiment of the present invention provides a power supply control circuit. In a two-stage power conversion system, a feedback signal representing the load change is introduced into the control loop of the first-stage power conversion circuit, so that the first-stage power conversion circuit can adjust the output in time according to the load change to accelerate the transient response of the system.

[0005] According to an embodiment of the present invention, a power supply control circuit is proposed for a power supply conversion system including a first-stage power supply conversion circuit and a second-stage power supply conversion circuit, the power supply control circuit including: a compensation control circuit, receiving a first feedback signal and a second feedback signal, and outputting a compensation control signal based on the first feedback signal and the second feedback signal, the first feedback signal representing a first output voltage provided by the first-stage power supply conversion circuit, and the second feedback signal representing a second output voltage provided by the second-stage power supply conversion circuit; and a front-stage control circuit, receiving the compensation control signal and outputting a switch control signal based on the compensation control signal, the switch control signal being used to control a main switch of the first-stage power supply conversion circuit.

[0006] According to an embodiment of the present invention, a power conversion system is also proposed, including the aforementioned power control circuit, and also including: a first-stage power conversion circuit, receiving an input voltage and providing the first output voltage based on the input voltage; and a second-stage power conversion circuit, receiving the first output voltage and outputting the second output voltage based on the first output voltage.

[0007] According to an embodiment of the present invention, a control method for a power conversion system including a first-stage power conversion circuit and a second-stage power conversion circuit is also proposed, including: receiving a first feedback signal representing a first output voltage provided by the first-stage power conversion circuit; receiving a second feedback signal representing a second output voltage provided by the second-stage power conversion circuit; outputting a compensation control signal based on the first feedback signal and the second feedback signal; and outputting a switch control signal for controlling a main switch of the first-stage power conversion circuit based on the compensation control signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to better understand the present invention, the present invention will be described in detail with reference to the following drawings:

[0009] Figure 1 shows a schematic diagram of the module structure of an existing two-stage power conversion system 10;

[0010] Figure 2 FIG2 shows a circuit structure diagram of a power conversion system 20 according to an embodiment of the present invention;

[0011] Figure 3 FIG. 2 shows a circuit structure diagram of a power conversion system 30 according to an embodiment of the present invention;

[0012] Figure 4 FIG. 4 is a schematic diagram showing a circuit structure of a feedback control circuit 40 according to an embodiment of the present invention;

[0013] Figure 5 FIG. 2 shows a circuit structure diagram of a feedback control circuit 50 according to an embodiment of the present invention;

[0014] Figure 6 A schematic diagram showing some signal waveforms of a power conversion system 30 according to an embodiment of the present invention is shown;

[0015] Figure 7 FIG. 2 shows a circuit structure diagram of a feedback control circuit 70 according to an embodiment of the present invention;

[0016] Figure 8 FIG. 2 shows a circuit module diagram of a compensation control circuit 80 according to an embodiment of the present invention;

[0017] Figure 9 FIG. 2 shows a schematic diagram of the circuit structure of a compensation control circuit 90 according to an embodiment of the present invention;

[0018] Figure 10 A control method 100 for controlling a power conversion system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] Specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the present invention. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not necessarily required to practice the present invention. In other instances, well-known circuits, materials, or methods are not described in detail to avoid obscuring the present invention.

[0020] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout this specification are not necessarily all referring to the same embodiment or example. In addition, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and that the figures are not necessarily drawn to scale. Like reference numerals indicate like elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] Figure 1 FIG1 shows a schematic diagram of the module structure of an existing two-stage power conversion system 10. The two-stage power conversion system 10 converts the input voltage Vin into an output voltage Vout and provides it to a load 13. Figure 1 As shown, the two-stage power conversion system 10 includes a first-stage power conversion circuit 11 and a second-stage power conversion circuit 12. The first-stage power conversion circuit 11 receives an input voltage Vin, converts it into an intermediate voltage Vbus', and provides it to the second-stage power conversion circuit 12. The second-stage power conversion circuit 12 receives the intermediate voltage Vbus', converts it into an output voltage Vout and provides it to the load 13. Figure 1In the embodiment, the two-stage power conversion system 10 further includes a first-stage control circuit 14 and a second-stage control circuit 15, which are respectively used to control the first-stage power conversion circuit 11 and the second-stage power conversion circuit 12. In some applications, the load may increase instantaneously, causing the output voltage Vout to undershoot instantaneously. After detecting a drop in the output voltage Vout, the second-stage control circuit 15 controls the second-stage power conversion circuit 12 to draw more energy from the first-stage power conversion circuit 11 to meet the demand of the increased load, resulting in a larger instantaneous undershoot of the intermediate voltage Vbus' output by the first-stage power conversion circuit 11. Through the regulation of the first-stage control circuit 14, the first-stage power conversion circuit 11 adjusts the undershoot of the intermediate voltage Vbus', drawing more energy from its input terminal to stabilize the intermediate voltage Vbus'. In this process, the regulation speed of the first-stage control circuit 14 and the second-stage control circuit 15 greatly affects the stability of the intermediate voltage Vbus' and the output voltage Vout.

[0022] Figure 2 FIG2 shows a schematic diagram of the circuit structure of a power conversion system 20 according to an embodiment of the present invention. The voltage conversion circuit 20 includes a first-stage power conversion circuit 21, a second-stage power conversion circuit 22, and a power control circuit 23. The first-stage power conversion circuit 21 converts the input voltage Vin into an intermediate voltage Vbus (also referred to as a first output voltage). The second-stage power conversion circuit 22 converts the intermediate voltage Vbus into an output voltage Vout (also referred to as a second output voltage) and provides it to a load ( Figure 2 Not shown). Figure 2 In the embodiment, the first-stage power conversion circuit 21 has a Boost topology and is used as a PFC (Power Factor Correction) circuit. The input voltage Vin can be a sine half-wave voltage after rectification of the AC voltage. The input current Iin follows the waveform of the input voltage Vin, thereby improving the power factor of the first-stage power conversion circuit 21. Specifically, the first-stage power conversion circuit 21 includes an inductor L1, a main switch Q1, a secondary switch D1 and an output capacitor Cb, as shown in FIG. Figure 2 The second-stage power conversion circuit 22 can be an LLC (Inductor-Inductor-Capacitor) circuit. It should be understood that the first-stage power conversion circuit 21 and the second-stage power conversion circuit 22 can adopt other topological circuits, such as buck circuits, flyback circuits, etc., according to the needs of the system application.

[0023] exist Figure 2 In the embodiment, the power control circuit 23 includes a compensation control circuit 231 , a pre-stage control circuit 232 and a driving circuit 233 .

[0024] The compensation control circuit 231 receives the first feedback signal Vfb1 and the second feedback signal Vfb2, and outputs the compensation control signal Vcomp based on the first feedback signal Vfb1 and the second feedback signal Vfb2. The first feedback signal Vfb1 represents the intermediate voltage Vbus provided by the first-stage power conversion circuit 21. Figure 2 In an embodiment, the power conversion system 20 further includes a feedback circuit 24 for receiving the intermediate voltage Vbus and converting it into a first feedback signal Vfb1. The feedback circuit 24 may be a voltage divider circuit, and the first feedback signal Vfb1 may be a voltage divider signal of the intermediate voltage Vbus. In other embodiments, if the first-stage power conversion circuit 21 has other topologies, such as an isolated flyback topology, etc., the feedback circuit 24 may also include an isolation device such as an optocoupler. In some embodiments, on the premise that the input requirements of the power control circuit 23 are met, the intermediate voltage Vbus may also be directly provided to the power control circuit 23 as the first feedback signal Vfb1. The second feedback signal Vfb2 represents the output voltage Vout provided by the second-stage power conversion circuit 22. Figure 2 In the embodiment, the power conversion system 20 further includes a feedback circuit 25 for receiving the output voltage Vout and converting it into a second feedback signal Vfb2. The feedback circuit 25 may be a voltage divider circuit, and the second feedback signal Vfb2 may be a voltage divider signal of the output voltage Vout. Figure 2 In the embodiment, the second-stage power conversion circuit 22 has an LLC topology, and the feedback circuit 25 includes an optocoupler. In some embodiments, the feedback circuit 25 includes an optocoupler and related circuit components, such as TL431. In some embodiments, under the premise of meeting the input requirements of the power control circuit 23, the output voltage Vout can also be directly provided to the power control circuit 23 as the second feedback signal Vfb2. Figure 2 In the embodiment, the second feedback signal Vfb2 corresponds to the load current Iout and is proportional to the magnitude of the load current Iout. Meanwhile, the second feedback signal Vfb2 is also related to the output voltage Vout and changes with changes in the output voltage Vout.

[0025] exist Figure 2 In the embodiment, the first-stage power conversion circuit 21 takes the PFC circuit as an example to illustrate the working principle of the technical solution of the present invention. Figure 2 In the embodiment, the pre-stage control circuit 232 is a control circuit of the PFC circuit. Figure 2As shown, the front-stage control circuit 232 receives the compensation control signal Vcomp, the current detection signal Ics, and the input voltage Vin, and outputs a switch control signal P1 for controlling the main switch Q1 of the first-stage power conversion circuit 21. The current detection signal Ics represents the input current Iin of the first-stage power conversion circuit 21. The input voltage Vin may also be provided to the front-stage control circuit 232 after voltage division. In other embodiments, when the first-stage power conversion circuit 21 has other topologies, such as a Buck topology, or is a common Boost circuit, and receives an input voltage Vin with a fixed value, the input voltage Vin and the input current Iin may not be involved in the control, that is, the front-stage control circuit 232 outputs the switch control signal P1 based on the compensation control signal Vcomp.

[0026] The driving circuit 233 is used to amplify the driving capability of the switch control signal P1. Figure 2 In the embodiment, the power driving signal VG1 provided to the control terminal of the main switch Q1 has the same phase as the switch control signal P1 , and the difference between the two lies in the driving capability.

[0027] Figure 3 FIG2 shows a circuit structure diagram of a power conversion system 30 according to an embodiment of the present invention. The power conversion system 30 includes a first-stage power conversion circuit 21 , a second-stage power conversion circuit 22 , and a power control circuit 33 .

[0028] exist Figure 3 In the embodiment, the power control circuit 33 includes a feedback control circuit 341 , a compensation control circuit 231 , a pre-stage control circuit 232 and a driving circuit 233 .

[0029] The feedback control circuit 341 receives the feedback voltage signal FB and converts it into a second feedback signal Vfb2. The feedback voltage signal FB is the voltage signal of the output voltage Vout after it passes through the feedback circuit 25. It corresponds to the output voltage Vout and is proportional to the magnitude of the load current Iout. The feedback control circuit 341 receives the feedback voltage signal FB and, based on its value range, generates a second feedback signal Vfb2, which is used to represent the load state. For example, when the load increases instantaneously, the feedback voltage signal FB increases instantaneously. In this case, the second feedback signal Vfb2 may have a first signal state to represent the circuit state. When the load decreases instantaneously, the feedback voltage signal FB decreases instantaneously. The second feedback signal Vfb2 may have a second signal state to represent the circuit state. The first and second signal states may be pulses of different lengths, pulses with different markers (the different markers correspond to different comparators), pulses with different voltage levels, and so on. In some embodiments, the second feedback signal Vfb2 may also be a digital signal containing state information of the feedback voltage signal FB. In other words, the second feedback signal Vfb2 reflects changes in the output voltage Vout and the load current Iout.

[0030] exist Figure 3 In this embodiment, the compensation control circuit 231, the pre-stage control circuit 232, and the driver circuit 233 are integrated into the control chip 31, while the feedback control circuit 341 is integrated into the control chip 32. The control chip 31 is used to provide a power drive signal VG1 to control the first-stage power conversion circuit 21, and the control chip 32 is used to provide a power drive signal VG2 to control the second-stage power conversion circuit 22. In other embodiments, the compensation control circuit 231, the pre-stage control circuit 232, the driver circuit 233, and the feedback control circuit 341 can also be integrated into the same chip. In some embodiments, the control chip 31 and the control chip 32 are integrated into the same package.

[0031] Figure 4 FIG. 4 shows a schematic diagram of the circuit structure of the feedback control circuit 40 according to an embodiment of the present invention. Figure 4 As shown, the feedback control circuit 40 includes an overshoot comparator CMP1, which receives the feedback voltage signal FB and an overshoot threshold Vh and outputs a second feedback signal Vfb2 based on the feedback voltage signal FB and the overshoot threshold Vh. When the load suddenly increases, i.e., when the load current Iout suddenly increases, causing the output voltage Vout to suddenly drop, the feedback voltage signal FB rises accordingly. When the feedback voltage signal FB rises to the overshoot threshold Vh, the second feedback signal Vfb2 transitions from a low level to a high level, indicating the sudden load increase.

[0032] Figure 5 FIG. 5 shows a schematic diagram of the circuit structure of a feedback control circuit 50 according to an embodiment of the present invention. Figure 5 As shown, the feedback control circuit 50 includes a comparison circuit 501 and an indication signal processing circuit 502. The comparison circuit 501 includes an overshoot comparator CMP1 and an undershoot comparator CMP2. The overshoot comparator CMP1 receives the feedback voltage signal FB and an overshoot threshold Vh, and outputs an overshoot indication signal CP1 based on the feedback voltage signal FB and the overshoot threshold Vh. The undershoot comparator CMP2 receives the feedback voltage signal FB and an undershoot threshold Vl, and outputs an undershoot indication signal CP2 based on the feedback voltage signal FB and the undershoot threshold Vl. The indication signal processing circuit 502 receives the overshoot indication signal CP1 and the undershoot indication signal CP2, and outputs a second feedback signal Vfb2 based on the overshoot indication signal CP1 and the undershoot indication signal CP2.

[0033] In one embodiment, when the load suddenly increases, causing the output voltage Vout to suddenly drop, the feedback voltage signal FB rises accordingly. When the feedback voltage signal FB rises to the overshoot threshold Vh, the overshoot indication signal CP1 transitions from a low level to a high level, indicating a sudden load increase. When the load suddenly decreases, causing the output voltage Vout to suddenly rise, the feedback voltage signal FB falls accordingly. When the feedback voltage signal FB falls to the undershoot threshold V1, the undershoot indication signal CP2 transitions from a low level to a high level, indicating a sudden load decrease.

[0034] The indication signal processing circuit 502 receives the overshoot indication signal CP1 and the undershoot indication signal CP2 and outputs a second feedback signal Vfb2 to indicate whether the feedback voltage signal FB rises to the overshoot threshold Vh or falls to the undershoot threshold Vl.

[0035] When the feedback control circuit 50 is applied to Figure 3 When the power conversion system 30 of the embodiment is used, the waveforms of the signals of the power conversion system 30 are shown as follows: Figure 6 As shown. The following combination Figure 3 、 Figure 5 and Figure 6 The operation of the power conversion system 30 will be described in detail.

[0036] like Figure 6 As shown, at time t1, the load current Iout suddenly increases, that is, the load suddenly increases. At this time, the output voltage Vout decreases and the feedback voltage signal FB increases. Figure 1In the illustrated prior art two-stage power conversion system 10, the independence of the first-stage control circuit 14 and the second-stage control circuit 15 results in a slow regulation speed for the entire system, resulting in a significant undershoot of the intermediate voltage Vbus' with an amplitude of ΔV1. Furthermore, the regulation time Tr1 for the intermediate voltage Vbus' is also longer. In an embodiment of the present invention, the state of the output voltage Vout is directly provided to the compensation control circuit 231 via a second feedback signal Vfb2. The second feedback signal Vfb2 and the first feedback signal Vfb1 representing the intermediate voltage Vbus jointly control the intermediate voltage Vbus. The compensation control circuit 231 generates a compensation control signal Vcomp, which is provided to the pre-stage control circuit 232. The pre-stage control circuit 232 then generates a switch control signal P1 to control the main switch Q1, thereby achieving rapid regulation of the intermediate voltage Vbus. Figure 6 The intermediate voltage Vbus is shown as Figure 3 The voltage provided by the first-stage power conversion circuit 21 in the embodiment. Figure 6 As shown, compared with the intermediate voltage Vbus′ in the prior art, the undershoot voltage amplitude ΔV2 of the intermediate voltage Vbus is significantly reduced through the regulation of the power control circuit 33 , and the regulation time Tr2 is also significantly shortened.

[0037] According to the same working principle, at time t2, the load current Iout suddenly decreases, that is, the load suddenly decreases. At this time, the output voltage Vout increases and the feedback voltage signal FB decreases. Figure 1 In the two-stage power conversion system 10 of the prior art shown, since the first-stage control circuit 14 and the second-stage control circuit 15 are independent of each other, the adjustment speed of the entire system is slow, and the intermediate voltage Vbus' will have a large overshoot, and its overshoot amplitude is ΔV3. And the time Tr3 for adjusting the intermediate voltage Vbus' is also long. In the embodiment of the present invention, the second feedback signal Vfb2 and the first feedback signal Vfb1 representing the intermediate voltage Vbus participate in the control of the intermediate voltage Vbus together, and the compensation control circuit 231 generates a compensation control signal Vcomp, which is provided to the front-stage control circuit 232, and then the front-stage control circuit 232 generates a switch control signal P1 to control the main switch Q1, thereby achieving the purpose of quickly adjusting the intermediate voltage Vbus. As shown Figure 6 As shown, compared with the intermediate voltage Vbus′ in the prior art, the overshoot voltage amplitude ΔV4 of the intermediate voltage Vbus is significantly reduced through the regulation of the power control circuit 33 , and the regulation time Tr4 is also significantly shortened.

[0038] Figure 7 FIG. 1 shows a schematic diagram of the circuit structure of a feedback control circuit 70 according to an embodiment of the present invention. Figure 7As shown, the feedback control circuit 70 includes a comparison circuit 701 and an indication signal processing circuit 702. The comparison circuit 701 includes multiple comparators CMP1-CMPn. Each comparator CMPk receives a feedback voltage signal FB and a corresponding reference signal Vk, and outputs a corresponding comparison signal CPk based on the comparison result between the feedback voltage signal FB and the corresponding reference signal Vk, where n is a natural number greater than 1 and k is any number between 1 and n. The comparison circuit 701 determines the interval within which the feedback voltage signal FB falls based on the received comparison signals CP1-CPn, and outputs a second feedback signal Vfb2 to represent the feedback voltage signal FB, that is, the interval within which the output voltage Vout falls, reflecting the state of the load current Iout. The second feedback signal Vfb2 can have multiple signal states to reflect the voltage level of the output voltage Vout and the magnitude of the load current Iout, or can be a pulse signal with different labels (to distinguish different comparators), or can be a digital signal containing information about the output voltage Vout.

[0039] Figure 8 FIG. 8 shows a schematic diagram of a circuit module of a compensation control circuit 80 according to an embodiment of the present invention. Figure 8 As shown, the compensation control circuit 80 includes a first compensation circuit 801, a second compensation circuit 802, and a compensation correction circuit 803. The first compensation circuit 801 outputs a first compensation signal Vcompo based on a first feedback signal Vfb1. The first compensation circuit 801 can be an existing compensation circuit used in a PFC circuit control loop. The second compensation circuit 802 outputs a corresponding second compensation signal Vcomps based on a second feedback signal Vfb2. The compensation correction circuit 803 outputs a compensation control signal Vcomp based on the first compensation signal Vcompo and the second compensation signal Vcomps.

[0040] Figure 9 FIG. 1 shows a schematic diagram of the circuit structure of a compensation control circuit 90 according to an embodiment of the present invention. Figure 9As shown, the compensation control circuit 90 includes a first compensation circuit 901, a second compensation circuit 902, and a compensation correction circuit 903. The first compensation circuit 901 includes an error amplifier circuit that receives a first feedback signal Vfb1 and a first reference signal Vref and outputs a first compensation signal Vcompo based on the first feedback signal Vfb1 and the first reference signal Vref. In some embodiments, the first compensation circuit 901 can also be implemented using a digital feedback circuit commonly used in the art. The second compensation circuit 902 includes a selection circuit that receives a second feedback signal Vfb2 and, based on the second feedback signal Vfb2, outputs a second compensation signal Vcomps having a different compensation value. In one embodiment, when the second feedback signal Vfb2 indicates that the output voltage Vout has dropped to a first voltage, the second compensation signal Vcomps has a first compensation value Vos1. When the second feedback signal Vfb2 indicates that the output voltage Vout has dropped to a second voltage, the second compensation signal Vcomps has a second compensation value Vos2, and so on. The first voltage is greater than the second voltage, and the first compensation value Vos1 is less than the second compensation value Vos2. That is, the greater the drop in the output voltage Vout, the greater the increase in the feedback voltage signal FB, and the greater the value of the second compensation signal Vcomps. In other embodiments, the second compensation circuit 902 can also be implemented using other circuits, such as a lookup table circuit or a storage circuit, with different compensation values ​​pre-set. The second compensation signal Vcomps with different compensation values ​​is provided based on the second feedback signal Vfb2. The compensation correction circuit 903 includes an addition circuit that superimposes the first compensation signal Vcompo and the second compensation signal Vcomps to provide the compensation control signal Vcomp. It should be understood that the compensation correction circuit 903 can be a different calculation circuit depending on the different correspondences between the compensation control signal Vcomp and the switching control signal P1. For example, in some embodiments, the larger the compensation control signal Vcomp, the smaller the duty cycle of the switching control signal P1, which is equivalent to less energy transferred from the input to the output of the first power conversion circuit during a single switching cycle. In this case, the compensation correction circuit 903 is a subtraction circuit.

[0041] In some embodiments, the compensation control signal Vcomp is used to adjust the duty cycle of the switch control signal P1 after being operated on by the corresponding compensation reference signal. In these embodiments, the second compensation signal Vcomps can also be used to adjust the corresponding compensation reference signal, because adjusting the compensation reference signal is equivalent to adjusting the compensation control signal Vcomp. When the first-stage power conversion circuit 21 adopts a PFC circuit, such as Figure 3 As shown, the compensation reference signal is related to the input voltage Vin and the current detection signal Ics representing the input current Iin.

[0042] Figure 10 A control method 100 for controlling a power conversion system according to an embodiment of the present invention is shown. The power conversion system may be the power conversion system 20 or the power conversion system 30 described in the aforementioned embodiments, and includes a first-stage power conversion circuit 21 and a second-stage power conversion circuit 22. The control method 100 includes: step 101, receiving a first feedback signal representing a first output voltage provided by the first-stage power conversion circuit; step 102, receiving a second feedback signal representing a second output voltage provided by the second-stage power conversion circuit; step 103, outputting a compensation control signal based on the first feedback signal and the second feedback signal; and step 104, outputting a switch control signal for controlling a main switch of the first-stage power conversion circuit based on the compensation control signal. Steps 101-104 may be performed in no particular order.

[0043] In one embodiment, the second feedback signal represents an actual value of a load current of the power conversion system.

[0044] In one embodiment, the second feedback signal corresponds to a voltage value interval within which the second output voltage is located.

[0045] In one embodiment, step 103 includes: outputting a first compensation signal based on the first feedback signal; outputting a second compensation signal based on the second feedback signal; and outputting a compensation control signal after performing calculations on the first compensation signal and the second compensation signal.

[0046] In one embodiment, outputting the first compensation signal based on the first feedback signal includes: outputting the first compensation signal based on an error amplification result of the first feedback signal and a first reference signal.

[0047] In one embodiment, outputting the second compensation signal based on the second feedback signal includes: presetting a plurality of different compensation values; and selecting different compensation values ​​as the value of the second compensation signal based on the second feedback signal.

[0048] It should be understood that the circuits and working processes provided in the present invention are for illustrative purposes only, and any circuit that can implement the functions and working processes of the circuits of the present invention does not depart from the spirit or essence of the present invention.

[0049] While the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are descriptive and illustrative, rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope of the appended claims. All changes and modifications that fall within the scope of the claims or their equivalents are intended to be covered by the appended claims.

Claims

1. A power control circuit for a power conversion system including a first-stage power conversion circuit and a second-stage power conversion circuit, the power control circuit comprising: a compensation control circuit receiving a first feedback signal and a second feedback signal, and outputting a compensation control signal based on the first feedback signal and the second feedback signal, wherein the first feedback signal represents a first output voltage provided by the first-stage power conversion circuit, and the second feedback signal represents a second output voltage provided by the second-stage power conversion circuit; as well as The front-stage control circuit receives the compensation control signal and outputs a switch control signal based on the compensation control signal, wherein the switch control signal is used to control a main switch of the first-stage power conversion circuit.

2. The power supply control circuit according to claim 1, wherein the compensation control circuit comprises: a first compensation circuit, receiving the first feedback signal and a reference signal, and outputting a first compensation signal based on the first feedback signal and the reference signal; a second compensation circuit, receiving the second feedback signal and outputting a second compensation signal based on the second feedback signal; as well as The compensation correction circuit receives the first compensation signal and the second compensation signal, and outputs a compensation control signal based on the first compensation signal and the second compensation signal.

3. The power control circuit according to claim 2, wherein: The second compensation circuit includes a selection circuit, and the selection circuit outputs a second compensation signal with a different compensation value based on the second feedback signal.

4. The power control circuit according to claim 2, wherein: The compensation correction circuit includes a calculation circuit, which operates the first compensation signal and the second compensation signal and outputs the compensation control signal based on the operation result.

5. The power control circuit according to claim 1, wherein: The second feedback signal is proportional to the actual value of the load current.

6. The power supply control circuit according to claim 1, further comprising a feedback control circuit, wherein the feedback control circuit comprises: The overshoot comparator receives a feedback voltage signal and an overshoot threshold, and outputs a second feedback signal based on the feedback voltage signal and the overshoot threshold, wherein the feedback voltage signal is generated based on the second output voltage.

7. The power supply control circuit according to claim 1, further comprising a feedback control circuit, wherein the feedback control circuit comprises: an undershoot comparator, receiving a feedback voltage signal and an undershoot reference, and outputting an undershoot indication signal based on a comparison result of the feedback voltage signal and the undershoot reference; An overshoot comparator receives a feedback voltage signal and an overshoot reference, and outputs an overshoot indication signal based on a comparison result of the feedback voltage signal and the overshoot reference; as well as an indication signal processing circuit, receiving the overshoot indication signal and the undershoot indication signal, and outputting a second feedback signal based on the overshoot indication signal and the undershoot indication signal; Wherein, the feedback voltage signal is generated based on the second output voltage.

8. The power supply control circuit according to claim 1, further comprising a feedback control circuit, wherein the feedback control circuit comprises: A plurality of comparators, wherein each comparator receives a feedback voltage signal and a corresponding reference signal, and outputs a corresponding comparison signal based on a comparison result of the feedback voltage signal and the corresponding reference signal; as well as an indication signal processing circuit, receiving a plurality of comparison signals output by the plurality of comparators, and outputting a second feedback signal based on the plurality of comparison signals; Wherein, the feedback voltage signal is generated based on the second output voltage.

9. A power conversion system, comprising the power control circuit according to any one of claims 1 to 8, further comprising: A first-stage power conversion circuit receives an input voltage and provides the first output voltage based on the input voltage; as well as The second-stage power conversion circuit receives the first output voltage and outputs the second output voltage based on the first output voltage.

10. The power conversion system according to claim 9, wherein: The first-stage power conversion circuit includes a PFC (Power Factor Correction) circuit.

11. The power conversion system according to claim 9, wherein: The second-stage power conversion circuit includes an LLC (Inductor-Inductor-Capacitor) circuit. 12 . The power conversion system as claimed in claim 9 , further comprising a feedback circuit, wherein the feedback circuit comprises an optocoupler, and wherein the feedback circuit receives the second output voltage and outputs a feedback voltage signal based on the second output voltage.

13. A control method for a power conversion system including a first-stage power conversion circuit and a second-stage power conversion circuit, comprising: Receiving a first feedback signal representing a first output voltage provided by a first-stage power conversion circuit; receiving a second feedback signal representing a second output voltage provided by a second-stage power conversion circuit; outputting a compensation control signal based on the first feedback signal and the second feedback signal; as well as A switch control signal for controlling a main switch of the first-stage power conversion circuit is output based on the compensation control signal.

14. The control method according to claim 13, wherein: The second feedback signal represents an actual value of a load current of the power conversion system.

15. The control method according to claim 13, wherein: The second feedback signal corresponds to a voltage value interval within which the second output voltage is located.

16. The control method according to claim 13, wherein: Outputting a compensation control signal based on the first feedback signal and the second feedback signal includes: outputting a first compensation signal based on the first feedback signal; outputting a second compensation signal based on the second feedback signal; and The first compensation signal and the second compensation signal are operated and then a compensation control signal is output.

17. The control method according to claim 16, wherein: Outputting the first compensation signal based on the first feedback signal includes: outputting the first compensation signal based on an error amplification result of the first feedback signal and a first reference signal.

18. The control method according to claim 16, wherein: Outputting a second compensation signal based on the second feedback signal includes: Presetting a plurality of different compensation values; and A different compensation value is selected as the value of the second compensation signal based on the second feedback signal.

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