Control circuit, control chip, control system and voltage converter

Abstract

The present application is applicable to the technical field of voltage converters, and provides a control circuit, a control chip, a control system and a voltage converter. The control circuit includes a first switch module, a selection switch module, a reference module, a clamp module, a current limiting module, a first current bias module and a second current bias module. The first switch module is electrically connected to the reference module, the current limiting module and the first current bias module respectively, the selection switch module is electrically connected to the reference module, the clamp module and the current limiting module respectively, the clamp module is electrically connected to the second current bias module, the first switch module is electrically connected to the source of the switch tube, the selection switch module is electrically connected to the gate of the switch tube, and the current limiting module is electrically connected to the drain of the switch tube. The control circuit in the present application first uses the current limiting module to perform current limiting control, and then controls the switch tube to start slowly for precharging, so as to achieve precise current control, effectively limit the power consumption at the start-up moment, and greatly improve the stability and reliability of power supply to the load.

Description

Technical Field

[0001] The present application belongs to the technical field of voltage converters, and in particular relates to a control circuit, a control chip, a control system and a voltage converter. Background Art

[0002] Voltage converters, such as boost circuits, may have a current path from VIN to VOUT during the power-on process due to their architectural features. In order to prevent excessive surge current during startup, a switch tube is usually added to this current path in conventional applications. However, when existing control circuits control the switch tube, it is often difficult to achieve precise current control to effectively limit the power consumption at the startup moment. Summary of the invention

[0003] The embodiments of the present application provide a control circuit, a control chip, a control system and a voltage converter, which can solve the problem that when the existing control circuit controls the switch tube, it is often difficult to achieve precise current control to effectively limit the power consumption at the startup moment.

[0004] In a first aspect, an embodiment of the present application provides a control circuit, including a first switch module, a selection switch module, a reference module, a clamp module, a current limiting module, a first current bias module and a second current bias module, wherein the first switch module is electrically connected to the reference module, the current limiting module and the first current bias module respectively, the selection switch module is electrically connected to the reference module, the clamp module and the current limiting module respectively, the clamp module is electrically connected to the second current bias module, the first switch module is used to be electrically connected to the source of a switch tube outside the chip, the selection switch module is used to be electrically connected to the gate of the switch tube, and the current limiting module is used to be electrically connected to the drain and the load of the switch tube respectively;

[0005] When the control circuit is powered on, the first switch module is controlled to be turned on, the selection switch module is controlled to switch to a first state, the clamp module is used to output a first voltage according to the clamp voltage, the reference module is used to output a first current according to the first voltage, and the current limiting module outputs a second current; the first current is equal to the current output by the second current bias module;

[0006] When the voltage of the load is greater than or equal to a first preset voltage, the first switch module is controlled to be turned off, and the selection switch module is controlled to switch to a second state. The reference module is used to reduce the first voltage according to a third current and the first current, and the third current is equal to the current output by the first current bias module; when the first voltage is reduced to a second preset voltage, the switch tube is fully opened.

[0007] In a possible implementation of the first aspect, the first switch module includes a first switch, a first end of the first switch is electrically connected to the first current bias module, the current limiting module and the source of the switch tube, respectively, a second end of the first switch is electrically connected to the first current bias module and the reference module, respectively, and a control end of the first switch is used to receive a first logic control signal.

[0008] In a possible implementation manner of the first aspect, the selection switch module includes a second switch and a third switch, the first end of the second switch is electrically connected to the first end of the third switch, the reference module, and the clamping module respectively, the second end of the second switch is used to be electrically connected to the gate of the switch tube, the control end of the second switch is used to receive a second logic control signal, the second end of the third switch is electrically connected to the current limiting module, and the control end of the third switch is used to receive a third logic control signal;

[0009] When the selection switch module is in the first state, the second switch is turned off and the third switch is turned on; when the selection switch module is in the second state, the second switch is turned on and the third switch is turned off.

[0010] In a possible implementation of the first aspect, the reference module includes a first switch tube, a gate of the first switch tube is electrically connected to a drain of the first switch tube, the selection switch module and the clamping module, and a source of the first switch tube is electrically connected to the first current bias module and the first switch module.

[0011] In a possible implementation of the first aspect, the clamping module includes a second switch tube, a gate of the second switch tube is used to receive the clamping voltage, a source of the second switch tube is electrically connected to the reference module and the selection switch module respectively, and a drain of the second switch tube is electrically connected to the second current bias module.

[0012] In a possible implementation of the first aspect, the current limiting module includes a third switch tube, a gate of the third switch tube is electrically connected to the selection switch module, a source of the third switch tube is electrically connected to the first switch module, the first current bias module and the source of the switch tube respectively, and a drain of the third switch tube is used to be electrically connected to the drain of the switch tube and the load respectively.

[0013] In a possible implementation of the first aspect, the first current bias module includes a first current source, a first end of the first current source is electrically connected to the first switch module and the source of the switch tube, respectively, and a second end of the first current source is electrically connected to the first switch module and the reference module, respectively; the second current bias module includes a second current source, a first end of the second current source is electrically connected to the clamping module, and a second end of the second current source is grounded.

[0014] In a second aspect, an embodiment of the present application provides a control chip, in which the control circuit described in any one of the first aspects is disposed.

[0015] In a third aspect, an embodiment of the present application provides a control system, comprising a switch tube and the control chip described in the second aspect, wherein the gate of the switch tube is electrically connected to the selection switch module in the control chip, the source of the switch tube is electrically connected to the first switch module in the control chip and the first current bias module in the control chip, respectively, and the drain of the switch tube is electrically connected to the load and the current limiting module in the control chip, respectively.

[0016] In a fourth aspect, an embodiment of the present application provides a voltage converter, comprising the control system described in the third aspect.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0018] The control circuit provided in the embodiment of the present application includes a first switch module, a selection switch module, a reference module, a clamp module, a current limiting module, a first current bias module and a second current bias module. When the control circuit is powered on, the first switch module is controlled to be turned on, and the selection switch module is controlled to switch to the first state, that is, the selection switch module controls the reference module and the current limiting module to be turned on. The clamp module is used to output a first voltage according to the clamp voltage, and the reference module is used to output a first current according to the first voltage, so that the current limiting module outputs a second current to charge the load. This process is a current limiting stage, and the control circuit uses a current limiting module to realize current control to prevent excessive surge current from occurring at the startup moment of powering the load. When the voltage of the load is greater than or equal to the first preset voltage, that is, when the load is charged to a certain value, the first switch module is controlled to be turned off, and the selection switch module is controlled to switch to the second state, that is, the selection switch module controls the reference module and the gate of the switch tube to be turned on. The reference module is used to reduce the first voltage according to the third current and the first current. Since the reference module and the gate of the switch tube are turned on, the first voltage can be loaded to the gate of the switch tube. When the first voltage decreases to the second preset voltage, the switch tube is fully opened. That is, as the first voltage received by the gate of the switch tube gradually decreases, the switch tube can achieve slow start. This process is the pre-charging stage, and the switch tube slowly opens until it is fully opened, and the pre-charging stage ends. It can be seen that in the process of controlling the switch tube, the control circuit provided in the embodiment of the present application first uses a current limiting module to perform current limiting control, and then controls the switch tube to start slowly for pre-charging, thereby achieving precise current control, effectively limiting the power consumption at the startup moment, and greatly improving the stability and reliability of power supply to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 This is a typical application diagram of the Boost circuit;

[0021] Figure 2 is a principle block diagram of a control circuit provided in an embodiment of the present application;

[0022] Figure 3 Schematic diagram of circuit connection of a control circuit provided in one embodiment of the present application.

[0023] In the figure, 10, control circuit; 101, first switch module; 102, selection switch module; 103, reference module; 104, clamping module; 105, current limiting module; 106, first current bias module; 107, second current bias module; 20, load. DETAILED DESCRIPTION

[0024] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0025] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0028] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0030] like Figure 1 As shown, the existing control circuit has a Figure 1 When the M0 in the control is used, the current control is usually mainly achieved by the gate drive control module (ISO_DRV), which often makes it difficult to achieve accurate current control to effectively limit the power consumption at the start-up moment. Figure 1 The M0 in the figure is a PMOS tube.

[0031] Based on the above problems, the control circuit provided by the embodiment of the present application includes a first switch module, a selection switch module, a reference module, a clamp module, a current limiting module, a first current bias module and a second current bias module. When the control circuit is powered on, the first switch module is controlled to be turned on, and the selection switch module is controlled to switch to the first state, that is, the selection switch module controls the reference module and the current limiting module to be turned on. The clamp module is used to output a first voltage according to the clamp voltage, and the reference module is used to output a first current according to the first voltage, so that the current limiting module outputs a second current to charge the load. This process is a current limiting stage, and the control circuit uses a current limiting module to realize current control to prevent excessive surge current from occurring at the startup moment of powering the load. When the voltage of the load is greater than or equal to the first preset voltage, that is, when the load is charged to a certain value, the first switch module is controlled to be turned off, and the selection switch module is controlled to switch to the second state, that is, the selection switch module controls the reference module and the gate of the switch tube to be turned on. The reference module is used to reduce the first voltage according to the third current and the first current. Since the reference module and the gate of the switch tube are turned on, the first voltage can be loaded to the gate of the switch tube. When the first voltage decreases to the second preset voltage, the switch tube is fully opened. That is, as the first voltage received by the gate of the switch tube gradually decreases, the switch tube can achieve slow start. This process is the pre-charging stage, and the switch tube slowly opens until it is fully opened, and the pre-charging stage ends. It can be seen that in the process of controlling the switch tube, the control circuit provided in the embodiment of the present application first uses a current limiting module to perform current limiting control, and then controls the switch tube to start slowly for pre-charging, thereby achieving precise current control, effectively limiting the power consumption at the startup moment, and greatly improving the stability and reliability of power supply to the load.

[0032] In order to illustrate the technical solution described in this application, a specific embodiment is provided below for illustration.

[0033] Figure 2 FIG. 1 shows a functional block diagram of a control circuit 10 provided in an embodiment of the present application. Figure 2 As shown, the control circuit 10 includes a first switch module 101, a selection switch module 102, a reference module 103, a clamp module 104, a current limiting module 105, a first current bias module 106 and a second current bias module 107. The first switch module 101 is electrically connected to the reference module 103, the current limiting module 105 and the first current bias module 106 respectively, the selection switch module 102 is electrically connected to the reference module 103, the clamp module 104 and the current limiting module 105 respectively, the clamp module 104 is electrically connected to the second current bias module 107, the first switch module 101 is used to be electrically connected to the source of the switch tube M0 outside the chip, the selection switch module 102 is used to be electrically connected to the gate of the switch tube M0, and the current limiting module 105 is used to be electrically connected to the drain of the switch tube M0 and the load 20 respectively.

[0034] Specifically, when the control circuit 10 is powered on, the first switch module 101 is controlled to be turned on, and the switch module 102 is controlled to switch to the first state, that is, the switch module 102 is selected to control the reference module 103 and the current limiting module 105 to be turned on. The clamping module 104 is used to output the first voltage V1 according to the clamping voltage VCLAMP, and the reference module 103 is used to output the first current according to the first voltage V1, so that the current limiting module 105 outputs the second current to charge the load 20. This process is the current limiting stage, and the control circuit 10 uses the current limiting module 105 to realize current control to prevent excessive surge current from appearing at the startup moment of powering the load 20. When the voltage of the load 20 is greater than or equal to the first preset voltage, that is, when the load 20 is charged to a certain value, the first switch module 101 is controlled to be turned off, and the switch module 102 is controlled to switch to the second state, that is, the switch module 102 is selected to control the reference module 103 and the gate of the switch tube M0 to be turned on. The reference module 103 is used to reduce the first voltage V1 according to the third current and the first current. Since the reference module 103 and the gate of the switch tube M0 are conductive, the first voltage V1 can be loaded onto the gate of the switch tube M0. When the first voltage V1 decreases to the second preset voltage, the switch tube M0 is fully opened. That is, as the first voltage V1 received by the gate of the switch tube M0 gradually decreases, the switch tube M0 can achieve slow start. This process is the pre-charging stage, in which the switch tube M0 is slowly turned on until it is fully opened, and the pre-charging stage ends. It can be seen that in the process of controlling the switch tube M0, the control circuit 10 provided in the embodiment of the present application first uses the current limiting module 105 to perform current limiting control, and then controls the switch tube M0 to start slowly for pre-charging, thereby achieving precise current control, effectively limiting the power consumption at the startup moment, and greatly improving the stability and reliability of power supply to the load 20.

[0035] It should be noted that, during the slow start process, the difference between the voltage of LXI and the gate voltage of the switch tube M0 increases slowly until the clamping voltage VCLAMP, that is, when the first voltage V1 decreases to the second preset voltage, the VGS of the switch tube M0 is 5V, and the switch tube M0 is fully opened. The current limiting module 105 can also be used for pre-charging, and when the voltage of the load 20 is greater than or equal to the first preset voltage, the first switch module 101 is turned off. At this time, the switch module 102 is selected to be still in the first state, so that the reference module 103 and the current limiting module 105 are connected, and the first voltage V1 indicates that the switch device in the current limiting module 105 starts slowly for pre-charging.

[0036] It should be noted that if there is an output abnormality such as short circuit startup or startup overload, the voltage of the load 20 cannot be charged to the first preset voltage, and the first switch module 101 will not be turned off, that is, the low current charging mode is always maintained. In this way, the power consumption of the switch device in the current limiting module 105 can be effectively controlled, and the instantaneous high power will not burn out the switch tube M0.

[0037] It should be noted that the first switch module 101, the selection switch module 102, the reference module 103, the clamp module 104, the current limiting module 105, the first current bias module 106 and the second current bias module 107 in the control circuit 10 provided in the embodiment of the present application are all arranged in the chip, and the switch tube M0 is arranged on the periphery of the chip. Therefore, the first switch module 101 can receive the first logic control signal in the chip, and the selection switch module 102 can receive the second logic control signal and the third logic control signal in the chip. The first switch module 101 is used to turn on and off according to the received first logic control signal. When the power is turned on, that is, when there is an input voltage VIN, LX and LXI are pulled to the VIN potential. At this time, the first logic control signal in the chip controls the first switch module 101 to turn on. When the voltage of the load 20 reaches the first preset voltage, the first logic control signal in the chip controls the first switch module 101 to turn off.

[0038] It should be noted that the third current has the same direction as the first current, and the third current is less than the first current. When the first switch module 101 is turned off, the first current bias module 106, the reference module 103, the clamp module 104 and the second current bias module 107 form a current loop. Since the current in a current loop needs to be kept constant, the reference module 103 can reduce the first voltage V1 according to the third current and the first current, thereby ensuring that the switch tube M0 or the switch device in the current limiting module 105 is slowly started, thereby effectively limiting the power consumption at the moment of startup. When the system is stable, the current flowing through the reference module 103 is to keep the third current constant.

[0039] In one embodiment of the present application, Figure 3 As shown, the first switch module 101 includes a first switch S1, the first end of the first switch S1 is electrically connected to the first current bias module 106, the current limiting module 105 and the source of the switch tube M0, the second end of the first switch S1 is electrically connected to the first current bias module 106 and the reference module 103, and the control end of the first switch S1 is used to receive a first logic control signal.

[0040] Specifically, the first switch S1 is turned on and off according to the first logic control signal. When the first switch S1 is in the on state, the current flowing through the reference module 103 is the first current. At this time, the switch module 102 is selected to switch to the first state, so that the reference module 103 and the current limiting module 105 are connected, and the current limiting module 105 outputs the second current according to the first voltage V1 and the first current to charge the load 20. This process is the current limiting stage. The control circuit 10 uses the current limiting module 105 to realize current control to prevent excessive surge current from occurring at the startup moment of powering the load 20. When the first switch S1 is turned off, the first current bias module 106 is connected to the circuit, and the reference module 103 reduces the first voltage V1 according to the third current and the first current, ensuring that the switch tube M0 or the switch device in the current limiting module 105 is slowly started, thereby effectively limiting the power consumption at the startup moment.

[0041] Exemplarily, the first switch S1 may be replaced by a transistor, a MOS tube or other switch devices, as long as the functions of the present application can be achieved, and no limitation is made here.

[0042] In one embodiment of the present application, Figure 3 As shown, the selection switch module 102 includes a second switch S2 and a third switch S3, the first end of the second switch S2 is electrically connected to the first end of the third switch S3, the reference module 103 and the clamping module 104 respectively, the second end of the second switch S2 is used to be electrically connected to the gate of the switch tube M0, the control end of the second switch S2 is used to receive a second logic control signal, the second end of the third switch S3 is electrically connected to the current limiting module 105, and the control end of the third switch S3 is used to receive a third logic control signal. When the selection switch module 102 is in the first state, the second switch S2 is turned off and the third switch S3 is turned on. When the selection switch module 102 is in the second state, the second switch S2 is turned on and the third switch S3 is turned off.

[0043] Specifically, the second switch S2 is used to receive the second logic control signal, and is turned on and off according to the second logic control signal. When the second switch S2 is turned on, the switch module 102 is selected to be in the second state, the reference module 103 and the gate of the switch tube M0 are connected, and the first voltage V1 can be transmitted to the gate of the switch tube M0. When the first switch S1 is turned off, as the first voltage V1 gradually decreases, the switch tube M0 realizes a slow start. The third switch S3 is used to receive the third logic control signal, and is turned on and off according to the third logic control signal. When the third switch S3 is turned on, the switch module 102 is selected to be in the first state, the reference module 103 and the current limiting module 105 are connected, and the first voltage V1 can be transmitted to the current limiting module 105. When the first switch S1 is turned off, as the first voltage V1 gradually decreases, the switch device in the current limiting module 105 realizes a slow start.

[0044] It should be noted that the second switch S2 and the third switch S3 are interlocked. When the second switch S2 is turned on, the third switch S3 is turned off. When the second switch S2 is turned off, the third switch S3 is turned on.

[0045] Exemplarily, a single-pole double-throw switch can be used as the selection switch module 102 to replace the second switch S2 and the third switch S3, and the function of selecting the gate of the reference module 103 and the switch tube M0 or connecting the reference module 103 and the current limiting module 105 can also be realized. The second switch S2 and the third switch S3 can be replaced by a triode, a MOS tube or other switch devices, as long as the functions in the present application can be realized, and are not limited here.

[0046] In one embodiment of the present application, Figure 3 As shown, the reference module 103 includes a first switch tube M1, the gate of the first switch tube M1 is electrically connected to the drain of the first switch tube M1, the selection switch module 102 and the clamping module 104, and the source of the first switch tube M1 is electrically connected to the first current bias module 106 and the first switch module 101.

[0047] Specifically, when the first switch S1 is turned on, that is, in the current limiting stage, the first switch tube M1 is used to provide a reference current (first current). In this process, the current flowing through the first switch tube M1 is the first current, so that the current limiting module 105 outputs the second current according to the first current to supply power to the load 20. When the first switch S1 is turned off, that is, in the pre-charging stage, the first switch tube M1 is used to reduce the first voltage V1 at the gate of the first switch tube M1 according to the third current and the first current. Since the first voltage V1 is also loaded to the gate of the switch tube M0, the switch tube M0 can be started slowly. Specifically, when the first switch S1 is turned off, the first current bias module 106 is connected to the circuit. In order to ensure that the current in a current loop remains constant, the gate capacitor of the first switch tube M1 needs to be discharged to supplement the difference between the first current and the third current. At this time, the gate capacitor of the first switch tube M1 needs to be discharged. Due to the capacitor discharge, the gate voltage of the first switch tube M1 is reduced, that is, the first voltage V1 is reduced, and it continues to decrease until the clamping module 104 just maintains the open state. Finally, the current flowing through the first switch tube M1 is kept constant at the third current.

[0048] For example, designers can select the type of the first switch tube M1 according to actual conditions, that is, fully controlled power devices such as metal oxide field effect transistors or insulated gate bipolar transistors can be used. For example, the first switch tube M1 can be selected as a PMOS tube.

[0049] In one embodiment of the present application, Figure 3As shown, the clamping module 104 includes a second switch tube M2, the gate of the second switch tube M2 is used to receive the clamping voltage VCLAMP, the source of the second switch tube M2 is electrically connected to the reference module 103 and the selection switch module 102 respectively, and the drain of the second switch tube M2 is electrically connected to the second current bias module 107.

[0050] Specifically, since the source of the second switch tube M2 is connected to the gate and drain of the first switch tube M1 respectively, the source voltage of the second switch tube M2 is equal to the gate voltage of the first switch tube M1. In order to ensure that the second switch tube M2 can output the first voltage V1, it is necessary to ensure that the difference between the gate and the source of the second switch tube M2 reaches the turn-on voltage of the second switch tube M2, that is, it is necessary to ensure that the gate voltage of the first switch tube M1 (the first voltage V1) is greater than or equal to the gate voltage of the second switch tube M2 (the clamping voltage VCLAMP), thereby ensuring that the VGS of the first switch tube M1 will not exceed the withstand voltage range and will not damage the first switch tube M1. When the reference module 103 and the switch tube M0 are turned on, the first voltage V1 is greater than or equal to the clamping voltage VCLAMP, which can also ensure that the VGS of the switch tube M0 will not exceed the withstand voltage range and will not damage the switch tube M0.

[0051] For example, the designer can select the type of the second switch tube M2 according to the actual situation, that is, a fully controlled power device such as a metal oxide field effect transistor or an insulated gate bipolar transistor can be used. For example, the second switch tube M2 can be selected as a PMOS tube.

[0052] In one embodiment of the present application, Figure 3 As shown, the current limiting module 105 includes a third switch tube M3, the gate of the third switch tube M3 is electrically connected to the selection switch module 102, the source of the third switch tube M3 is electrically connected to the first switch module 101, the first current bias module 106 and the source of the switch tube M0 respectively, and the drain of the third switch tube M3 is used to be electrically connected to the drain of the switch tube M0 and the load 20 respectively.

[0053] Specifically, when the first switch S1 and the third switch S3 are both turned on, the gate of the first switch tube M1 is electrically connected to the gate of the third switch tube M3, and the source of the first switch tube M1 is electrically connected to the source of the third switch tube M3. As a result, the first switch tube M1 and the third switch tube M3 form a current mirror, so the second current flowing through the third switch tube M3 is K times the first current flowing through the first switch tube M1. When the first switch S1 is turned off and the third switch S3 is turned on, it indicates that the third switch tube M3 is used for pre-charging. At this time, the first voltage V1 is transmitted to the gate of the third switch tube M3, and the third switch tube M3 is slowly started. Since the first voltage V1 is greater than or equal to the clamping voltage VCLAMP, it can also ensure that the VGS of the third switch tube M3 will not exceed the withstand voltage range and will not damage the third switch tube M3.

[0054] For example, the value of K can be selected according to the design requirements of the circuit. For example, K can be selected as 10 5 If the first current is 2uA, the second current is 200mA.

[0055] For example, the designer can select the type of the third switch tube M3 according to the actual situation, that is, a fully controlled power device such as a metal oxide field effect transistor or an insulated gate bipolar transistor can be used. For example, the third switch tube M3 can be selected as a PMOS tube.

[0056] In one embodiment of the present application, Figure 3 As shown, the first current bias module 106 includes a first current source I1, a first end of the first current source I1 is electrically connected to the first switch module 101 and the source of the switch tube M0, and a second end of the first current source I1 is electrically connected to the first switch module 101 and the reference module 103.

[0057] Specifically, the first current source I1 is used to provide a constant third current. When the first switch S1 is turned on, the first current source I1 is not connected to the circuit and cannot affect the first voltage V1. When the first switch S1 is turned off, the first current source I1 is connected to the circuit, and the first switch tube M1 reduces the first voltage V1 according to the third current and the first current, so that the third switch tube M3 or the switch tube M0 is slowly started.

[0058] In one embodiment of the present application, Figure 3 As shown, the second current bias module 107 includes a second current source I2 , a first end of the second current source I2 is electrically connected to the clamping module 104 , and a second end of the second current source I2 is grounded.

[0059] Specifically, the second current source I2 is used to provide a constant first current. When the first switch S1 is turned on, the current flowing through the first switch tube M1 is the first current. When the first switch S1 is turned off, the first switch tube M1 can reduce the first voltage V1 according to the third current and the first current, so that the third switch tube M3 or the switch tube M0 starts slowly.

[0060] The present application also discloses a control chip, in which the control circuit 10 mentioned above is arranged. The control circuit 10 is arranged in the control chip, and the switch tube M0 is arranged outside the chip. The modules in the control circuit 10 can be controlled by the control logic of the chip, so as to output a control signal for slow starting of the switch tube M0, thereby realizing precise current control, effectively limiting the power consumption at the startup moment, and greatly improving the stability and reliability of power supply to the load 20.

[0061] The present application also discloses a control system, which includes a switch tube M0 and the above-mentioned control chip, wherein the gate of the switch tube M0 is electrically connected to the selection switch module 102 in the control chip, the source of the switch tube M0 is electrically connected to the first switch module 101 in the control chip and the first current bias module 106 in the control chip, and the drain of the switch tube M0 is electrically connected to the load 20 and the current limiting module 105 in the control chip.

[0062] Specifically, the control system uses a control chip to control the switch tube M0 to start it slowly, which can achieve precise current control, effectively limit the power consumption at the start-up moment, and greatly improve the stability and reliability of power supply to the load 20.

[0063] In one embodiment of the present application, Figure 3 As shown, the control system also includes a first diode D1 on the periphery of the chip, the anode of the first diode D1 is used to receive the LX signal, and the cathode of the first diode D1 is electrically connected to the source of the switch tube M0. The first diode D1 is used as a unidirectional conducting diode to prevent current backflow and improve the reliability of the control system.

[0064] The present application also discloses a voltage converter, including the above-mentioned control system. The voltage converter adopts the above-mentioned control system to improve the working efficiency of the voltage converter and enhance the reliability and applicability of the voltage converter.

[0065] Since the processing and functions implemented by the control system and the voltage converter in this embodiment basically correspond to the embodiments, principles and examples of the aforementioned control circuit, for the details not exhaustive in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0066] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A control circuit, characterized in that: The present invention comprises a first switch module, a selection switch module, a reference module, a clamp module, a current limiting module, a first current bias module and a second current bias module, wherein the first switch module is electrically connected to the reference module, the current limiting module and the first current bias module respectively, the selection switch module is electrically connected to the reference module, the clamp module and the current limiting module respectively, the clamp module is electrically connected to the second current bias module, the first switch module is used to be electrically connected to the source of the switch tube outside the chip, the selection switch module is used to be electrically connected to the gate of the switch tube, and the current limiting module is used to be electrically connected to the drain and the load of the switch tube respectively; When the control circuit is powered on, the first switch module is controlled to be turned on, the selection switch module is controlled to switch to a first state, the clamp module is used to output a first voltage according to the clamp voltage, the reference module is used to output a first current according to the first voltage, and the current limiting module outputs a second current; the first current is equal to the current output by the second current bias module; When the voltage of the load is greater than or equal to a first preset voltage, the first switch module is controlled to be turned off, and the selection switch module is controlled to switch to a second state. The reference module is used to reduce the first voltage according to a third current and the first current, and the third current is equal to the current output by the first current bias module; when the first voltage is reduced to a second preset voltage, the switch tube is fully opened.

2. The control circuit according to claim 1, characterized in that: The first switch module includes a first switch, a first end of the first switch is electrically connected to the first current bias module, the current limiting module and the source of the switch tube respectively, a second end of the first switch is electrically connected to the first current bias module and the reference module respectively, and a control end of the first switch is used to receive a first logic control signal.

3. The control circuit according to claim 1, characterized in that: The selection switch module includes a second switch and a third switch, wherein the first end of the second switch is electrically connected to the first end of the third switch, the reference module and the clamping module respectively, the second end of the second switch is used to be electrically connected to the gate of the switch tube, the control end of the second switch is used to receive a second logic control signal, the second end of the third switch is electrically connected to the current limiting module, and the control end of the third switch is used to receive a third logic control signal; When the selection switch module is in the first state, the second switch is turned off and the third switch is turned on; when the selection switch module is in the second state, the second switch is turned on and the third switch is turned off.

4. The control circuit according to claim 1, characterized in that: The reference module includes a first switch tube, a gate of the first switch tube is electrically connected to a drain of the first switch tube, the selection switch module and the clamp module, and a source of the first switch tube is electrically connected to the first current bias module and the first switch module.

5. The control circuit according to claim 1, characterized in that: The clamping module includes a second switch tube, a gate of the second switch tube is used to receive the clamping voltage, a source of the second switch tube is electrically connected to the reference module and the selection switch module respectively, and a drain of the second switch tube is electrically connected to the second current bias module.

6. The control circuit according to claim 1, characterized in that: The current limiting module includes a third switch tube, the gate of the third switch tube is electrically connected to the selection switch module, the source of the third switch tube is electrically connected to the first switch module, the first current bias module and the source of the switch tube respectively, and the drain of the third switch tube is used to be electrically connected to the drain of the switch tube and the load respectively.

7. The control circuit according to claim 1, characterized in that: The first current bias module includes a first current source, a first end of the first current source is electrically connected to the first switch module and the source of the switch tube respectively, and a second end of the first current source is electrically connected to the first switch module and the reference module respectively; the second current bias module includes a second current source, a first end of the second current source is electrically connected to the clamping module, and a second end of the second current source is grounded.

8. A control chip, characterized in that: The control chip is provided with the control circuit according to any one of claims 1 to 7.

9. A control system, characterized in that: It includes a switch tube and the control chip as described in claim 8, the gate of the switch tube is electrically connected to the selection switch module in the control chip, the source of the switch tube is electrically connected to the first switch module in the control chip and the first current bias module in the control chip, and the drain of the switch tube is electrically connected to the load and the current limiting module in the control chip.

10. A voltage converter, characterized in that: Includes the control system described in claim 9.

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