Start control system of multi-stage circuit

Abstract

The invention discloses a starting control system of a multi-stage circuit, the multi-stage circuit comprises a first power supply circuit, a second power supply circuit and a load power supply circuit which are connected in sequence, and the starting control system comprises a first control module, a second control module and a time sequence control module. The first control module and the second control module control the first power supply circuit and the second power supply circuit respectively. The second enable signal end of the second control module is connected with the enable input end of the sequential control module, and the enable output end of the sequential control module is connected with the first enable signal end of the first control module. According to the invention, by using the time sequence control module, the signal of the first enable signal end of the first control module follows the signal of the second enable signal end of the second control module in the time sequence, so that the working state of the first power supply circuit follows the second power supply circuit in the time sequence, thereby ensuring that the working state of the first power supply circuit follows the working state of the second power supply circuit in the multi-stage circuit. The second-stage circuit enters a ready working state before the first-stage circuit.

Description

A multi-stage circuit start-up control system Technical Field

[0001] This invention relates to the field of power management technology, and in particular to a multi-stage circuit startup control system. Background Technology

[0002] As electronic device architectures become increasingly complex, higher demands are placed on the performance and reliability of power management systems. Multi-stage power conversion circuits, due to their advantages in improving overall energy efficiency, optimizing power quality, and achieving efficient conversion between different voltage domains, have been widely used in various high-reliability electronic devices and have become a standard configuration in modern power architectures. However, in the actual operation of multi-stage power conversion systems, especially during the dynamic processes of system startup and shutdown, several key technical challenges exist. Improper handling of these challenges will directly affect the system's reliability and lifespan.

[0003] First, during system startup, the startup sequence of each circuit stage needs to be precisely coordinated. If the first-stage circuit starts working before the second-stage and load-stage circuits, its output power cannot be received and consumed by subsequent circuits in time, causing a large amount of energy to accumulate on the input capacitor of the second-stage circuit. This will cause a sharp rise in the input voltage of the second-stage circuit, resulting in a huge current overshoot. This overshoot current may exceed the rated stress of the capacitor or switching device, leading to capacitor breakdown or switch damage, causing permanent hardware damage.

[0004] Secondly, after the system input is turned off, the main power path is disconnected, but the energy stored in the energy storage components (such as inductors, transformers, and capacitors) cannot be quickly released through an effective discharge circuit, thus maintaining a high residual voltage across the devices. If the system restarts during the window period before the residual voltage has completely dissipated, the drive duty cycle of the main switching transistor gradually increases during the soft-start process, while the drive of the freewheeling transistor complements this. At this time, the inductors or transformers in the power path will experience reverse excitation because the reverse volt-second product is greater than the forward volt-second product, thus entering a magnetic saturation state. Magnetic saturation will cause a sharp drop in inductance, triggering a large inrush current, which will cause strong electrothermal stress impact on the power switching devices. This stress accumulation will seriously affect the long-term operational reliability and service life of the system. Summary of the Invention

[0005] This invention provides a multi-stage circuit startup control system that eliminates the risk of energy accumulation, voltage rise, and huge current overshoot caused by the first-stage circuit starting first, effectively protecting the input capacitor and power switching devices from damage.

[0006] This invention provides a multi-stage circuit startup control system, comprising a first power supply circuit, a second power supply circuit, and a load power supply circuit connected in sequence. The first power supply circuit converts a reference voltage into a first voltage signal and inputs it to the second power supply circuit. The second power supply circuit converts the first voltage signal into a second voltage signal and inputs it to the load power supply circuit. The load power supply circuit converts the second voltage signal into a third voltage signal and outputs it. The startup control system includes a first control module, a second control module, and a timing control module. All three modules receive the reference voltage. The second control module includes a second enable signal terminal. When the reference voltage is powered on, the second enable signal terminal of the second control module is at a valid level, and the second control module controls the second power supply circuit to enter a ready-to-work state. When the reference voltage is powered off, the second enable signal terminal of the second control module is at an invalid level. The second control module controls the second power supply circuit to enter a standby state; the timing control module includes an enable input terminal and an enable output terminal; the enable input terminal is connected to the second enable signal terminal of the second control module; the timing control module is used to control the enable output terminal to be an effective level signal when the enable input terminal is an effective level signal; and is also used to control the enable output terminal to be an ineffective level signal when the enable input terminal is an ineffective level signal; the first control module includes a first enable signal terminal; the enable output terminal of the timing control module is connected to the first enable signal terminal of the first control module; when the enable output terminal is an effective level signal, the first enable signal terminal of the first control module is an effective level signal, and the first control module controls the first power supply circuit to enter a ready state; when the enable output terminal is an ineffective level signal, the first enable signal terminal of the first control module is an ineffective level signal, and the first control module controls the first power supply circuit to enter a standby state.

[0007] Optionally, the timing control module further includes a control output terminal; the timing control module is further configured to control the control output terminal to be a valid level signal when the enable input terminal is an invalid level signal, and to control the control output terminal to be an invalid level signal when the enable input terminal is a valid level signal; the start control system further includes a first protection module; the first protection module includes a first voltage input terminal and a first control input terminal; the first voltage input terminal receives the first voltage signal; the first control input terminal is connected to the control output terminal of the timing control module; when the first control input terminal is a valid level signal and the first voltage signal at the first voltage input terminal is greater than a first voltage threshold, the first protection module clamps the second enable signal terminal of the second control module to be an invalid level signal.

[0008] Optionally, the timing control module further includes a control output terminal; the timing control module is further configured to control the control output terminal to be a valid level signal when the enable input terminal is an invalid level signal, and to control the control output terminal to be an invalid level signal when the enable input terminal is a valid level signal; the start control system further includes a second protection module; the second protection module includes a second voltage input terminal and a second control input terminal; the second voltage input terminal receives the third voltage signal; the second control input terminal is connected to the control output terminal of the timing control module; when the second control input terminal is a valid level signal and the third voltage signal of the second voltage input terminal is greater than a second voltage threshold, the second protection module clamps the second enable signal terminal of the second control module to be an invalid level signal.

[0009] Optionally, the timing control module includes a first switch, a second switch, a first resistor, and a second resistor; the first switch includes a first control terminal, a first input terminal, and a first output terminal; the second switch includes a second control terminal, a second input terminal, and a second output terminal; the first resistor and the second resistor are connected in series between the reference voltage and the second enable signal terminal of the second control module, and the first resistor and the second resistor are connected to form a first connection node; the first control terminal of the first switch is connected to the first connection node; the first input terminal of the first switch is connected to the reference voltage; the first output terminal of the first switch is connected to the second control terminal of the second switch; the second output terminal of the second switch is connected to the first enable signal terminal of the first control module; and the second input terminal of the second switch is grounded.

[0010] Optionally, the first protection module includes a first voltage detection unit and a first enable clamping unit; the first voltage detection unit includes a first voltage input terminal, a first control input terminal, and a first clamping control output terminal; the first voltage detection unit is used to detect the first voltage signal through the first voltage input terminal when the first control input terminal is a valid level signal; the first clamping control output terminal outputs a first control signal when the first voltage signal is greater than the first voltage threshold; the first enable clamping unit includes a first clamping control input terminal and a first enable clamping terminal; the first clamping control input terminal is connected to the first clamping control output terminal; the first enable clamping terminal is connected to the second enable signal terminal of the second control module; when the first enable clamping unit receives the first control signal, it clamps the second enable signal terminal of the second control module to an invalid level signal.

[0011] Optionally, the first voltage detection unit includes a third switch, a fourth switch, a third resistor, a fourth resistor, and a fifth resistor; the third switch includes a first control input terminal, a third input terminal, and a third output terminal; the fourth switch includes a fourth control terminal, a fourth input terminal, and a first clamping control output terminal; the third input terminal of the third switch is grounded; the third resistor, the fourth resistor, and the fifth resistor are connected in series between the first voltage input terminal and the third output terminal of the third switch, and the third resistor and the fourth resistor are connected to form a second connection node, and the fourth resistor and the fifth resistor are connected to form a third connection node; the fourth control terminal of the fourth switch is connected to the third connection node; the fourth input terminal of the fourth switch is connected to the second connection node.

[0012] Optionally, the first enable clamping unit includes a fifth switch, a sixth resistor, and a seventh resistor; the fifth switch includes a fifth control terminal, a fifth input terminal, and the first enable clamping terminal; one end of the sixth resistor is connected to the first clamping control output terminal, and the other end is connected to one end of the seventh resistor to form a fourth connection node; the other end of the seventh resistor is grounded; the fourth connection node is connected to the fifth control terminal of the fifth switch; and the fifth input terminal of the fifth switch is grounded.

[0013] Optionally, the second protection module includes a second voltage detection unit and a second enable clamping unit; the second voltage detection unit includes a second voltage input terminal, a second control input terminal, and a second clamping control output terminal; the second voltage detection unit detects the third voltage signal through the second voltage input terminal; the second clamping control output terminal outputs a second control signal when the second control input terminal is a valid level signal and the third voltage signal is greater than the second voltage threshold; the second enable clamping unit includes a second clamping control input terminal and a second enable clamping terminal; the second clamping control input terminal is connected to the second clamping control output terminal; the second enable clamping terminal is connected to the second enable signal terminal of the second control module; the second enable clamping unit is used to clamp the second enable signal terminal of the second control module to an invalid level signal when it receives the second control signal.

[0014] Optionally, the second voltage detection unit includes a sixth switch, an optocoupler, an eighth resistor, a ninth resistor, and a tenth resistor; the sixth switch includes a sixth control terminal, a sixth input terminal, and a second clamping control output terminal; the optocoupler includes a second voltage input terminal, a first ground terminal, a second ground terminal, and a seventh output terminal; both the first ground terminal and the second ground terminal of the optocoupler are grounded; the eighth resistor, the ninth resistor, and the tenth resistor are connected in series between the second control input terminal and the seventh output terminal of the optocoupler, and the eighth resistor and the ninth resistor are connected to form a fifth connection node, and the ninth resistor and the tenth resistor are connected to form a sixth connection node; the sixth control terminal of the sixth switch is connected to the sixth connection node; the sixth input terminal of the sixth switch is connected to the fifth connection node.

[0015] Optionally, the second enable clamping unit includes a seventh switch; the seventh switch includes a second clamping control input terminal, a second enable clamping terminal, and a seventh input terminal; the seventh input terminal is grounded.

[0016] Optionally, the second control module includes a first pull-up resistor and a first grounding capacitor; one end of the first pull-up resistor is connected to the reference voltage, and the other end is connected to one end of the first grounding capacitor to form the second enable signal terminal; the other end of the first grounding capacitor is grounded.

[0017] Optionally, the first control module includes a second pull-up resistor and a first grounding resistor; one end of the second pull-up resistor is connected to the reference voltage, and the other end is connected to the first grounding resistor to form the first enable signal terminal; the other end of the first grounding resistor is grounded.

[0018] The multi-stage circuit startup control system provided by this invention uses a timing control module to ensure that the signal of the first enable signal terminal of the first control module follows the signal of the second enable signal terminal of the second control module in timing. This enables the working state of the first power supply circuit to follow the second power supply circuit in timing, thereby ensuring that in the multi-stage circuit, the second stage circuit enters the working ready state before the first stage circuit. This eliminates the risk of energy accumulation, voltage rise, and huge current overshoot caused by the first stage circuit starting first, and effectively protects the input capacitor and power switching devices from damage.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the structure of a multi-level circuit start-up control system provided in an embodiment of the present invention; Figure 2 is a schematic diagram of the structure of another multi-level circuit start-up control system provided in an embodiment of the present invention; Figure 3 is a schematic diagram of the structure of yet another multi-level circuit start-up control system provided in an embodiment of the present invention; Figure 4 is a schematic diagram of the structure of a timing control module provided in an embodiment of the present invention; Figure 5 is a schematic diagram of the structure of a second control module provided in an embodiment of the present invention; Figure 6 is a waveform diagram of the operation of a multi-level circuit start-up control system provided in an embodiment of the present invention; Figure 7 is a schematic diagram of the structure of a first control module provided in an embodiment of the present invention; Figure 8 is a schematic diagram of the structure of a first protection module provided in an embodiment of the present invention; Figure 9 is a schematic diagram of the structure of a second protection module provided in an embodiment of the present invention. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0025] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0026] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0027] Figure 1 is a schematic diagram of a multi-stage circuit start-up control system provided in an embodiment of the present invention. As shown in Figure 1, the multi-stage circuit 10 includes a first power supply circuit 101, a second power supply circuit 102, and a load power supply circuit 103 connected in sequence. The first power supply circuit 101 converts the reference voltage VCC into a first voltage signal Vin and inputs it to the second power supply circuit 102. The second power supply circuit 102 converts the first voltage signal Vin into a second voltage signal and inputs it to the load power supply circuit 103. The load power supply circuit 103 converts the second voltage signal into a third voltage signal Vout for output.

[0028] Specifically, the multi-stage circuit 10 is used to gradually convert the reference voltage VCC into the voltage value required by the system. First, the first power supply circuit 101 receives the reference voltage VCC and converts it into a first voltage signal Vin, which is then input to the second power supply circuit 102. The second power supply circuit 102 acts as the load of the first power supply circuit 101. The first voltage signal Vin serves as the input voltage of the second power supply circuit 102. The second power supply circuit 102 converts the first voltage signal Vin into a second voltage signal, which is then input to the load power supply circuit 103 via the isolation transformer 104. The load power supply circuit 103 acts as the load of the second power supply circuit 102. The second voltage signal then serves as the input voltage of the load power supply circuit 103, which converts it into a third voltage signal Vout to supply power to the load.

[0029] Furthermore, referring to Figure 1, in the multi-stage circuit 10, the input terminal of the second power supply circuit 102 typically includes an input capacitor Cin. Therefore, if the first power supply circuit 101 has already established a working state, that is, the first power supply circuit 101 has converted the reference voltage VCC into a first voltage signal Vin and input it to the second power supply circuit 102, and if the second power supply circuit 102 is not in a working state, that is, the second power supply circuit 102 cannot consume the energy provided by the first power supply circuit 101, then the energy generated by the first power supply circuit 101 will accumulate on the input capacitor Cin, resulting in hardware damage.

[0030] Based on this, referring to Figure 1, the startup control system 20 provided in this embodiment of the invention includes a first control module 201, a second control module 202, and a timing control module 203. The first control module 201, the second control module 202, and the timing control module 203 all receive a reference voltage VCC. The second control module 202 includes a second enable signal terminal 2021. When the reference voltage VCC is powered on, the second enable signal terminal 2021 of the second control module 202 is a valid level signal, and the second control module 202 controls the second power supply circuit 102 to enter a ready-to-work state. When the reference voltage VCC is powered off, the second enable signal terminal 2021 of the second control module 202 is an invalid level signal, and the second control module 202 controls the second power supply circuit 102 to enter a standby state. The timing control module 203 includes an enable input terminal 2031 and an enable output terminal 2032. The enable input terminal 2031 is connected to the second enable signal terminal 2021 of the second control module 202. The timing control module 203 controls the enable output terminal 2032 to be an effective level signal when the enable input terminal 2031 is an effective level signal, and also controls the enable output terminal 2032 to be an ineffective level signal when the enable input terminal 2031 is an ineffective level signal. The first control module 201 includes a first enable signal terminal 2011. The enable output terminal 2032 of the timing control module 203 is connected to the first enable signal terminal 2011 of the first control module 201. When the enable output terminal 2032 is an effective level signal, the first enable signal terminal 2011 of the first control module 201 is an effective level signal, and the first control module 201 controls the first power supply circuit 101 to enter a ready state. When the enable output terminal 2032 is an ineffective level signal, the first enable signal terminal 2011 of the first control module 201 is an ineffective level signal, and the first control module 2011 controls the first power supply circuit 101 to enter a standby state.

[0031] Specifically, the operating states of the first control module 201 and the second control module 202 are determined by the first enable signal terminal 2011 and the second enable signal terminal 2021, respectively. When the first control module 201 and the second control module 202 receive the reference voltage VCC, they can only control the first power supply circuit 101 and the second power supply circuit 102 to enter the ready-to-operate state when the first enable signal terminal 2011 and the second enable signal terminal 2021 are at valid levels. Therefore, to prevent the first power supply circuit 101 from entering the ready-to-operate state before the second power supply circuit 102, the first enable signal terminal 2011 can be controlled by the second enable signal terminal 2021.

[0032] Specifically, at the instant the reference voltage VCC is powered on, the second enable signal terminal 2021 of the second control module 202 is an invalid level signal. Subsequently, as the power-on time increases, the second enable signal terminal 2021 gradually changes from an invalid level signal to an valid level signal. For example, the invalid level signal can be a low level signal, and the valid level signal can be a high level signal. It can be understood that only after the second enable signal terminal 2021 changes to a valid level signal can the second power supply circuit 102 enter the ready-to-operate state.

[0033] Further, referring to Figure 1, the second enable signal terminal 2021 of the second control module 202 is connected to the enable input terminal 2031 of the timing control module 203, and the enable output terminal 2032 of the timing control module 203 is connected to the first enable signal terminal 2011 of the first control module 201. Therefore, the enable state of the second control module 202 will control the enable state of the first control module 201 through the timing control module 203. Specifically, when the second enable signal terminal 2021 of the second control module 202 is a valid level signal, it controls the second power supply circuit 102 to enter the working ready state. At the same time, the valid level signal is input to the timing control module 203, and after being processed by the timing control module 203, it is input to the first enable signal terminal 2011 of the first control module 201, thereby controlling the first power supply circuit 101 to subsequently enter the working ready state. When the second enable signal terminal 2021 of the second control module 202 is an invalid level signal, it controls the second power supply circuit 102 to enter a standby state. Simultaneously, this invalid level signal is transmitted through the timing control module 203 to the first enable signal terminal 2011 of the first control module 201, thereby controlling the first power supply circuit 101 to also enter a standby state. In this way, the operating state of the first power supply circuit 101 always follows the timing of the second power supply circuit 102, and the first power supply circuit 101 can only enter a ready state after the second power supply circuit 102 has entered a ready state. This avoids the potential current backflow or voltage surge problems that might occur if the first power supply circuit 101 starts before the second power supply circuit 102.

[0034] By using a timing control module, the signal at the first enable signal terminal of the first control module follows the signal at the second enable signal terminal of the second control module in timing. This enables the operating state of the first power supply circuit to follow that of the second power supply circuit in timing, thereby ensuring that in a multi-stage circuit, the second-stage circuit enters the ready-to-work state before the first-stage circuit. This eliminates the risk of energy accumulation, voltage rise, and huge current overshoot caused by the first-stage circuit starting first, effectively protecting the input capacitor and power switching devices from damage.

[0035] Optionally, Figure 2 is a schematic diagram of another multi-level circuit startup control system provided in an embodiment of the present invention. As shown in Figure 2, the timing control module 203 further includes a control output terminal 2033. The timing control module 203 is also used to control the control output terminal 2033 to be an effective level signal when the enable input terminal 2031 is an invalid level signal, and to control the control output terminal 2033 to be an invalid level signal when the enable input terminal 2031 is an effective level signal. The startup control system 20 also includes a first protection module 204, which includes a first voltage input terminal 2041 and a first control input terminal 2042. The first voltage input terminal 2041 receives a first voltage signal Vin, and the first control input terminal 2042 is connected to the control output terminal 2033 of the timing control module 203. When the first control input terminal 2042 is a valid level signal and the first voltage signal Vin of the first voltage input terminal 2041 is greater than the first voltage threshold, the first protection module 204 clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal.

[0036] Specifically, because the input terminal of the second power supply circuit 102 of the multi-stage circuit 10 contains a large input capacitor Cin, the first voltage signal Vin cannot discharge quickly after the reference voltage VCC is powered down. If the reference voltage VCC is immediately powered back on, the multi-stage circuit 10 will start under abnormal voltage conditions, which can easily cause reverse magnetic saturation of the power inductor, resulting in a damaging inrush current. Therefore, referring to Figure 2, a first protection module 204 is added to the startup control system 20. The first protection module 204 detects the first voltage signal Vin, and only when the first voltage signal Vin is low is the second enable signal terminal 2021 of the second control module 202 allowed to be a valid level signal, so that the second power supply circuit 102 enters the working ready state. For example, the valid level signal can be a high level signal, and the invalid level signal can be a low level signal.

[0037] Specifically, referring to Figure 2, the first protection module 204 includes a first voltage input terminal 2041 and a first control input terminal 2042. The first voltage input terminal 2041 is connected to the input terminal of the second power supply circuit 102 and is used to detect the first voltage signal Vin. Meanwhile, the timing control module 203 also includes a control output terminal 2033, which is connected to the first control input terminal 2042. This control output terminal 2033 is used to control whether the first protection module 204 starts detecting the first voltage signal Vin, preventing the multi-stage circuit 10 from erroneously clamping the second enable signal terminal 2021 of the second control module 202 to an invalid level signal when the first voltage signal Vin is greater than the first voltage threshold during normal operation of the multi-stage circuit 10, thus preventing the multi-stage circuit 10 from operating.

[0038] Specifically, when the second enable signal terminal 2021 of the second control module 202 is a valid level signal, it indicates that the multi-stage circuit 10 is in normal working condition. At this time, the control output terminal 2033 of the timing control module 203 is an invalid level signal, and the first protection module 204 does not detect the first voltage signal Vin. When the second enable signal terminal 2021 of the second control module 202 is an invalid level signal, it indicates that the reference voltage VCC is powered down, the multi-stage circuit 10 is in a non-working state, and the control output terminal 2033 of the timing control module 203 is a valid level signal. The first protection module 204 starts to detect the first voltage signal Vin, and when the first voltage signal Vin is greater than the first voltage threshold, it clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal, so that even when the reference voltage VCC is powered on, the second enable signal terminal 2021 of the second control module 202 cannot be a valid level signal, that is, it cannot control the second power supply circuit 102 to enter the working ready state. Furthermore, after the first voltage signal Vin detected by the first protection module 204 drops, the first protection module 204 no longer controls the second enable signal terminal 2021, the second enable signal terminal 2021 begins to change from an invalid level signal to an effective level signal, and the second power supply circuit 102 begins to enter the working ready state.

[0039] Optionally, Figure 3 is a schematic diagram of another multi-level circuit start-up control system provided by an embodiment of the present invention. As shown in Figure 3, the timing control module 203 further includes a control output terminal 2033. The timing control module 203 is also used to control the control output terminal 2033 to be an effective level signal when the enable input terminal 2031 is an invalid level signal, and to control the control output terminal 2033 to be an invalid level signal when the enable input terminal 2031 is an effective level signal. The start-up control system 20 also includes a second protection module 205, which includes a second voltage input terminal 2051 and a second control input terminal 2052. The second voltage input terminal 2051 receives a third voltage signal Vout. The second control input terminal 2052 is connected to the control output terminal 2033 of the timing control module 203. When the second control input terminal 2052 is an effective level signal and the third voltage signal Vout of the second voltage input terminal 2051 is greater than a second voltage threshold, the second protection module 205 clamps the second enable signal terminal 2021 of the second control module 202 to be an invalid level signal.

[0040] Specifically, because the output terminal of the load power supply circuit 103 of the multi-stage circuit 10 contains a large output capacitor Cout, the third voltage signal Vout cannot discharge quickly after the reference voltage VCC is powered down. If the reference voltage VCC is immediately powered back on, the multi-stage circuit 10 will start under abnormal voltage conditions, which can easily cause reverse magnetic saturation of the power inductor, resulting in a damaging inrush current. Therefore, referring to Figure 3, a second protection module 205 is added to the start-up control system 20. The second protection module 205 detects the third voltage signal Vout, and only when the third voltage signal Vout is low is the second enable signal terminal 2021 of the second control module 202 allowed to be a valid level signal.

[0041] Specifically, referring to Figure 3, the second protection module 205 includes a second voltage input terminal 2051 and a second control input terminal 2052. The second voltage input terminal 2051 is connected to the output terminal of the load power supply circuit 103 and is used to detect the third voltage signal Vout. Simultaneously, the timing control module 203 also includes a control output terminal 2033, which is connected to the second control input terminal 2052. Only when the second control input terminal 2052 is a valid level signal and the third voltage signal Vout of the second voltage input terminal 2051 is greater than the second voltage threshold, will the second protection module 205 clamp the second enable signal terminal 2021 of the second control module 202 to an invalid level signal. This avoids the multi-stage circuit 10 from erroneously clamping the second enable signal terminal 2021 of the second control module 202 to an invalid level signal when the third voltage signal Vout is greater than the second voltage threshold during normal operation, thus preventing the multi-stage circuit 10 from failing to operate.

[0042] Specifically, when the second enable signal terminal 2021 of the second control module 202 is a valid level signal, it indicates that the multi-stage circuit 10 is in normal working condition. At this time, the control output terminal 2033 of the timing control module 203 is an invalid level signal, and the second protection module 205 will not clamp the second enable signal terminal 2021. When the second enable signal terminal 2021 of the second control module 202 is an invalid level signal, it indicates that the reference voltage VCC is powered down, and the multi-stage circuit 10 is in a non-working state. At this time, the control output terminal 2033 of the timing control module 203 is a valid level signal. The second protection module 205 detects the third voltage signal Vout, and when the third voltage signal Vout is greater than the second voltage threshold, it clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal, so that even when the reference voltage VCC is powered on, the second enable signal terminal 2021 of the second control module 202 cannot be a valid level signal, that is, it cannot control the second power supply circuit 102 to enter the working ready state. Furthermore, when the third voltage signal Vout detected by the second protection module 205 decreases, the second protection module 205 no longer controls the second enable signal terminal 2021, the second enable signal terminal 2021 begins to change from an invalid level signal to an effective level signal, and the second power supply circuit 102 begins to enter the working ready state.

[0043] This invention, through the separate configuration of a first protection module and a second protection module, detects a first voltage signal and a third voltage signal when the second power supply circuit is in standby mode. When the control output is at a valid level and the first voltage signal is greater than a first voltage threshold, or when the control output is at a valid level and the third voltage signal is greater than a second voltage threshold, the second enable signal of the second control module is clamped to an invalid level, preventing the second power supply circuit from entering the ready-to-work state. When both the first and third voltage signals decrease, the first and second protection modules cease controlling the second enable signal, and the second enable signal transitions from an invalid level to a valid level, allowing the second power supply circuit to enter the ready-to-work state. This avoids excessive inrush current caused by residual voltage during a rapid restart after system power-down, which could lead to power device breakdown.

[0044] Optionally, Figure 4 is a schematic diagram of a timing control module provided in an embodiment of the present invention. As shown in Figure 4, the timing control module 203 includes a first switch Q2, a second switch Q1, a first resistor R1, and a second resistor R3. The first switch Q2 includes a first control terminal 2034, a first input terminal 2035, and a first output terminal 2036. The second switch Q1 includes a second control terminal 2037, a second input terminal 2038, and a second output terminal 2039. The first resistor R1 and the second resistor R3 are connected in series between the reference voltage VCC and the second enable signal terminal 2021 of the second control module 202, and the first resistor R1 and the second resistor R3 are connected to form a first connection node. The first control terminal 2034 of the first switch Q2 is connected to the first connection node, the first input terminal 2035 of the first switch Q2 is connected to the reference voltage VCC, and the first output terminal 2036 of the first switch Q2 is connected to the second control terminal 2037 of the second switch Q1. The second output terminal 2039 of the second switch Q1 is connected to the first enable signal terminal 2011 of the first control module 201, and the second input terminal 2038 of the second switch Q1 is grounded.

[0045] Specifically, in an optional embodiment, FIG5 is a schematic diagram of the structure of a second control module provided by an embodiment of the present invention. As shown in FIG4 and FIG5, the second control module 202 includes a first pull-up resistor R18 and a first grounding capacitor C1. One end of the first pull-up resistor R18 is connected to the reference voltage VCC, and the other end is connected to one end of the first grounding capacitor C1 to form a second enable signal terminal 2021. The other end of the first grounding capacitor C1 is grounded.

[0046] Figure 6 is a waveform diagram of the start-up control system of a multi-level circuit provided in an embodiment of the present invention. Referring to Figures 4-6, at the instant the reference voltage VCC is powered on, i.e., at time t0, the second enable signal terminal 2021 is an invalid level signal due to the first grounding capacitor C1. As the power-on time of the reference voltage VCC increases, at times t0~t1, the second enable signal terminal 2021 gradually changes from an invalid level signal to an effective level signal.

[0047] Furthermore, for the timing control module 203, at the instant the reference voltage VCC is powered on, when the second enable signal terminal 2021 is an invalid level signal, that is, when the second enable signal terminal 2021 is a low level signal, the voltage of the first control terminal 2034 of the first switch Q2 is determined by the voltage division of the first resistor R1 and the second resistor R3, and the first switch Q2 will be in the conducting state. Further, after the first switch Q2 is turned on, the voltage of the second control terminal 2037 of the second switch Q1 will be approximately equal to the reference voltage VCC, causing the second switch Q1 to be turned on. When the second switch Q1 is in the conducting state, the voltage of the second output terminal 2039 of the second switch Q1 will be equal to the voltage of the second input terminal 2038, that is, the second output terminal 2039 is a low level signal. Since the second output terminal 2039 of the second switch Q1 is connected to the first enable signal terminal 2011 of the first control module 201, the first enable signal terminal 2011 of the first control module 201 is clamped to a low level signal, i.e., an invalid level signal.

[0048] Furthermore, as the power-on time of the reference voltage VCC increases, at time t1, after the second enable signal terminal 2021 changes from an invalid level signal to an effective level signal, that is, after the second enable signal terminal 2021 changes from a low level signal to a high level signal, the first switch Q2 will switch from the on state to the off state. Since the second control terminal 2037 of the second switch Q1 is grounded through the first pull-down resistor R2, when the first switch Q2 is turned off, the second control terminal 2037 of the second switch Q1 will be a low level signal, causing the second switch Q1 to turn off.

[0049] Further, in an optional embodiment, FIG7 is a schematic diagram of the structure of a first control module provided by an embodiment of the present invention. Referring to FIG4-FIG7, the first control module 201 includes a second pull-up resistor R16 and a first grounding resistor R17. One end of the second pull-up resistor R16 is connected to the reference voltage VCC, and the other end is connected to the first grounding resistor R17 to form a first enable signal terminal 2011. The other end of the first grounding resistor R17 is grounded.

[0050] After the second switch Q1 is turned off, the voltage of the first enable signal terminal 2011 will be determined by the voltage division of the second pull-up resistor R16 and the first grounding resistor R17. Therefore, the first enable signal terminal 2011 is a high-level signal, i.e., an effective level signal.

[0051] Furthermore, referring to Figure 6, at time t2, the reference voltage VCC is energized. Due to the discharge of the first grounding capacitor C1, the second enable signal terminal 2021 gradually changes from an active level signal to an inactive level signal. Correspondingly, the first enable signal terminal 2011 also changes to an inactive level signal.

[0052] In summary, the embodiments of the present invention realize the control of the voltage of the first enable signal terminal by the voltage of the second enable signal terminal, so that the state of the first control module always follows the state of the second control module in terms of timing.

[0053] Optionally, Figure 8 is a schematic diagram of the structure of a first protection module provided in an embodiment of the present invention. As shown in Figure 8, the first protection module 204 includes a first voltage detection unit 206 and a first enable clamping unit 207. The first voltage detection unit 206 includes a first voltage input terminal 2041, a first control input terminal 2042, and a first clamping control output terminal 2061. The first voltage detection unit 206 is used to detect the first voltage signal Vin through the first voltage input terminal 2041 when the first control input terminal 2042 is a valid level signal. The first clamping control output terminal 2061 outputs a first control signal when the first voltage signal Vin is greater than a first voltage threshold. The first enable clamping unit 207 includes a first clamping control input terminal 2071 and a first enable clamping terminal 2072. The first clamping control input terminal 2071 is connected to the first clamping control output terminal 2061, and the first enable clamping terminal 2072 is connected to the second enable signal terminal 2021 of the second control module 202. When the first enable clamping unit 207 receives the first control signal, it clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal.

[0054] Specifically, referring to Figures 4-8, the timing control module 203 also includes a control output terminal 2033, which is connected to the first output terminal 2036 of the first switching transistor Q2. Therefore, at the instant the reference voltage VCC is powered on, when the second enable signal terminal 2021 is an invalid level signal, the control output terminal 2033 is an effective level signal, i.e., a high level signal. At this time, since the first control input terminal 2042 of the first voltage detection unit 206 is connected to the control output terminal 2033, the first voltage detection unit 206 will detect the first voltage signal Vin through the first voltage input terminal 2041 at the instant the reference voltage VCC is powered on.

[0055] Furthermore, when the first voltage signal Vin is greater than the first voltage threshold, it indicates that the power-on time is when the reference voltage VCC is powered down and then immediately powered on again, i.e., time t3 in Figure 6. At this time, the first voltage signal Vin has not been fully discharged, so the first clamp control output terminal 2061 outputs the first control signal. Furthermore, when the first enable clamp unit 207 receives the first control signal, it clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal, i.e., a low level signal, through the first enable clamp terminal 2072. This ensures that the second enable signal terminal 2021 of the second control module 202 remains an invalid level signal when the reference voltage VCC is powered on, thereby effectively preventing the multi-stage circuit 10 from starting under abnormal voltage.

[0056] In an optional embodiment, referring to FIG8, the first voltage detection unit 206 includes a third switch Q7, a fourth switch Q4, a third resistor R5, a fourth resistor R9, and a fifth resistor R10. The third switch Q7 includes a first control input terminal 2042, a third input terminal 2062, and a third output terminal 2063. The fourth switch Q4 includes a fourth control terminal 2064, a fourth input terminal 2065, and a first clamping control output terminal 2061. The third input terminal 2062 of the third switch Q7 is grounded. The third resistor R5, the fourth resistor R9, and the fifth resistor R10 are connected in series between the first voltage input terminal 2041 and the third output terminal 2063 of the third switch Q7, and the third resistor R5 and the fourth resistor R9 are connected to form a second connection node, and the fourth resistor R9 and the fifth resistor R10 are connected to form a third connection node. The fourth control terminal 2064 of the fourth switch Q4 is connected to the third connection node, and the fourth input terminal 2065 of the fourth switch Q4 is connected to the second connection node.

[0057] Specifically, referring to Figures 4-8, after the reference voltage VCC is powered down and then immediately powered back on (i.e., at time t3 in Figure 6), since the second enable signal terminal 2021 is a low-level signal at the instant the reference voltage VCC is powered on, the control output terminal 2033 of the timing control module 203 is a high-level signal, and the third switch Q7 is in the conducting state. Further, when the third switch Q7 is in the conducting state, the third output terminal 2063 of the third switch Q7 is a low-level signal, and the first voltage detection unit 206 begins to detect the first voltage signal Vin. When the first voltage signal Vin is large, it is divided by the third resistor R5, the fourth resistor R9, and the fifth resistor R10. When the voltage difference between the fourth control terminal 2064 and the fourth input terminal 2065 of the fourth switch Q4 is greater than the first voltage threshold, the fourth switch Q4 is turned on. The first voltage threshold can be the starting voltage of the fourth switch Q4.

[0058] Furthermore, after the fourth switch Q4 is turned on, the voltage at the fourth input terminal 2065 of the fourth switch Q4 is input to the first enable clamping unit 207.

[0059] In an optional embodiment, referring to FIG8, the first enable clamping unit 207 includes a fifth switch Q6, a sixth resistor R12, and a seventh resistor R15. The fifth switch Q6 includes a fifth control terminal 2073, a fifth input terminal 2074, and a first enable clamping terminal 2072. One end of the sixth resistor R12 is connected to the first clamping control output terminal 2061, and the other end is connected to one end of the seventh resistor R15 to form a fourth connection node. The other end of the seventh resistor R15 is grounded. The fourth connection node is connected to the fifth control terminal 2073 of the fifth switch Q6, and the fifth input terminal 2074 of the fifth switch Q6 is grounded.

[0060] Specifically, after the fourth switch Q4 is turned on, the voltage at the fourth input terminal 2065 of the fourth switch Q4 is divided by the sixth resistor R12 and the seventh resistor R15 and then input to the fifth control terminal 2073 of the fifth switch Q6, causing the fifth switch Q6 to turn on. Further, after the fifth switch Q6 is turned on, the first enable clamp terminal 2072 of the fifth switch Q6 is a low-level signal. Since the first enable clamp terminal 2072 is connected to the second enable signal terminal 2021 of the second control module 202, the second enable signal terminal 2021 of the second control module 202 is a low-level signal, i.e., an invalid level signal. In this way, when the reference voltage VCC is powered down and then immediately powered on again, and the first voltage signal Vin is large, the second enable signal terminal 2021 of the second control module 202 is clamped to an invalid level signal, preventing the multi-stage circuit 10 from starting under abnormal voltage conditions.

[0061] Furthermore, at time t4 in Figure 6, the first voltage signal Vin drops to a level insufficient to turn on the fourth switch Q4. At this time, the first enable clamping terminal 2072 of the fifth switch Q6 no longer clamps the second enable signal terminal 2021 of the second control module 202. Further, the reference voltage VCC begins to charge the first grounding capacitor C1 through the first pull-up resistor R18, causing the second enable signal terminal 2021 of the second control module 202 to gradually change from an invalid level signal to an effective level signal. At time t5 in Figure 6, the second enable signal terminal 2021 of the second control module 202 becomes an effective level signal. At this time, the first enable signal terminal 2011 of the first control module 201 is also an effective level signal, the control output terminal 2033 of the timing control module 203 is an invalid level signal, the multi-stage circuit 10 begins normal operation, the third switch Q7 is turned off, and the first voltage detection unit 206 stops detecting the first voltage signal Vin.

[0062] Optionally, Figure 9 is a schematic diagram of a second protection module provided in an embodiment of the present invention. As shown in Figure 9, the second protection module 205 includes a second voltage detection unit 208 and a second enable clamping unit 209. The second voltage detection unit 208 includes a second voltage input terminal 2051, a second control input terminal 2052, and a second clamping control output terminal 2081. The second voltage detection unit 208 detects the third voltage signal Vout through the second voltage input terminal 2051. The second clamping control output terminal 2081 outputs a second control signal when the second control input terminal 2052 is a valid level signal and the third voltage signal Vout is greater than the second voltage threshold. The second enable clamping unit 209 includes a second clamping control input terminal 2091 and a second enable clamping terminal 2092. The second clamping control input terminal 2091 is connected to the second clamping control output terminal 2081, and the second enable clamping terminal 2092 is connected to the second enable signal terminal 2021 of the second control module 202. The second enable clamping unit 209 is used to clamp the second enable signal terminal 2021 of the second control module 202 to an invalid level signal when the second control signal is received.

[0063] Specifically, referring to Figures 4-9, the timing control module 203 also includes a control output terminal 2033, which is connected to the first output terminal 2036 of the first switching transistor Q2. Therefore, when the reference voltage VCC is powered on, and the second enable signal terminal 2021 is an invalid level signal, the control output terminal 2033 is an effective level signal, i.e., a high level signal. Further, the second control input terminal 2052 of the second voltage detection unit 208 is connected to the control output terminal 2033. When the reference voltage VCC is powered on, the second control input terminal 2052 is an effective level signal. The second voltage input terminal 2051 is connected to the output terminal of the load power supply circuit 103 and is used to detect the third voltage signal Vout.

[0064] Furthermore, when the third voltage signal is greater than the second voltage threshold, it indicates that the power-on time is when the reference voltage VCC is powered down and then immediately powered on again, i.e., time t6 in Figure 6. At this time, the third voltage signal Vout has not been fully discharged, so the second clamping control output terminal 2081 outputs the second control signal. Furthermore, when the second enable clamping unit 209 receives the second control signal, it clamps the second enable signal terminal 2021 of the second control module 202 to an invalid level signal, i.e., a low level signal, through the second enable clamping terminal 2092. This ensures that the second enable signal terminal 2021 of the second control module 202 remains an invalid level signal when the reference voltage VCC is powered on, thereby effectively preventing the multi-stage circuit 10 from starting under abnormal voltage.

[0065] In an optional embodiment, referring to FIG9, the second voltage detection unit 208 includes a sixth switch Q3, an optocoupler U1, an eighth resistor R7, a ninth resistor R6, and a tenth resistor R8. The sixth switch Q3 includes a sixth control terminal 2082, a sixth input terminal 2083, and a second clamping control output terminal 2081. The optocoupler U1 includes a second voltage input terminal 2051, a first ground terminal 2084, a second ground terminal 2085, and a seventh output terminal 2086. The first ground terminal 2084 and the second ground terminal 2085 of the optocoupler U1 are both grounded. The eighth resistor R7, the ninth resistor R6, and the tenth resistor R8 are connected in series between the second control input terminal 2052 and the seventh output terminal 2086 of the optocoupler U1, and the eighth resistor R7 and the ninth resistor R6 are connected to form a fifth connection node, and the ninth resistor R6 and the tenth resistor R8 are connected to form a sixth connection node. The sixth control terminal 2082 of the sixth switch Q3 is connected to the sixth connection node, and the sixth input terminal 2083 of the sixth switch Q3 is connected to the fifth connection node.

[0066] Specifically, referring to Figures 4-9, after the reference voltage VCC is powered off and then immediately powered on again (i.e., at time t6 in Figure 6), since the second enable signal terminal 2021 is a low-level signal at the instant the reference voltage VCC is powered on, the control output terminal 2033 of the timing control module 203 is a high-level signal, causing the second control input terminal 2052 to be a high-level signal. Further, the second voltage input terminal 2051 of the optocoupler U1 is connected to the output terminal of the load power supply circuit 103 to detect the third voltage signal Vout. The first ground terminal 2084 of the optocoupler U1 is grounded. When the third voltage signal Vout is greater than the second voltage threshold, the seventh output terminal 2086 of the optocoupler U1 will be a low-level signal. The second voltage threshold can be the voltage value that makes the input side of the optocoupler U1 start emitting light. At this time, the voltage between the second control input terminal 2052 and the seventh output terminal 2086 is divided by the eighth resistor R7, the ninth resistor R6, and the tenth resistor R8, controlling the sixth switch Q3 to conduct. To achieve circuit isolation, the first ground terminal 2084 and the second ground terminal 2085 of the optocoupler U1 can be connected to different reference grounds.

[0067] Further, referring to Figures 4-9, after the sixth switch Q3 is turned on, the voltage at the sixth input terminal 2083 is input to the second enable clamping unit 209. In an optional embodiment, the second enable clamping unit 209 includes a seventh switch Q5. The seventh switch Q5 includes a second clamping control input terminal 2091, a second enable clamping terminal 2092, and a seventh input terminal 2093, with the seventh input terminal 2093 grounded.

[0068] Specifically, after the sixth switch Q3 is turned on, the voltage at the sixth input terminal 2083 is input to the second clamping control input terminal 2091, causing the seventh switch Q5 to turn on. Further, after the seventh switch Q5 is turned on, the second enable clamping terminal 2092 of the seventh switch Q5 is a low-level signal. Since the second enable clamping terminal 2092 is connected to the second enable signal terminal 2021 of the second control module 202, the second enable signal terminal 2021 of the second control module 202 is a low-level signal, i.e., an invalid level signal. In this way, after the reference voltage VCC is powered down and then immediately powered on again, when the third voltage signal Vout is large, the second enable signal terminal 2021 of the second control module 202 is clamped to an invalid level signal, preventing the multi-stage circuit 10 from starting under abnormal voltage conditions.

[0069] Furthermore, at time t7 in Figure 6, the third voltage signal Vout drops to a level insufficient to turn on the sixth switch Q3. At this time, the second enable clamping terminal 2092 of the seventh switch Q5 no longer clamps the second enable signal terminal 2021 of the second control module 202. Further, the reference voltage VCC begins charging the first grounding capacitor C1 through the first pull-up resistor R18, causing the second enable signal terminal 2021 of the second control module 202 to gradually change from an invalid level signal to an effective level signal. At time t8 in Figure 6, the second enable signal terminal 2021 of the second control module 202 becomes an effective level signal. At this time, the first enable signal terminal 2011 of the first control module 201 is also an effective level signal, the control output terminal 2033 of the timing control module 203 is an invalid level signal, the multi-stage circuit 10 begins normal operation, and the optocoupler U1 stops working.

[0070] Furthermore, referring to Figure 6, when either the first voltage signal Vin or the third voltage signal Vout is larger, the second enable signal terminal 2011 will be clamped to an invalid level signal. Only when both the first voltage signal Vin and the third voltage signal Vout are at a lower level, and the reference voltage VCC is powered on, will the second enable signal terminal 2011 be converted from an invalid level signal to an effective level signal.

[0071] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A multi-stage circuit start-up control system, characterized in that, The multi-level circuit includes a first power supply circuit, a second power supply circuit, and a load power supply circuit connected in sequence; The first power supply circuit is used to convert the reference voltage into a first voltage signal and input it to the second power supply circuit; The second power supply circuit is used to convert the first voltage signal into a second voltage signal and input it to the load power supply circuit; The load power supply circuit is used to convert the second voltage signal into a third voltage signal for output; the start control system includes: a first control module, a second control module, and a timing control module; the first control module, the second control module, and the timing control module all receive the reference voltage; the second control module includes a second enable signal terminal; when the reference voltage is powered on, the second enable signal terminal of the second control module is an active level signal, and the second control module controls the second power supply circuit to enter a ready state; when the reference voltage is powered off, the second enable signal terminal of the second control module is an inactive level signal, and the second control module controls the second power supply circuit to enter a standby state; the timing control module includes an enable input terminal and an enable output terminal; the enable input terminal is connected to the second control module's... The second enable signal terminal is connected; the timing control module is used to control the enable output terminal to be an effective level signal when the enable input terminal is an effective level signal; and is also used to control the enable output terminal to be an ineffective level signal when the enable input terminal is an ineffective level signal; the first control module includes a first enable signal terminal; the enable output terminal of the timing control module is connected to the first enable signal terminal of the first control module; when the enable output terminal is an effective level signal, the first enable signal terminal of the first control module is an effective level signal, and the first control module controls the first power supply circuit to enter a ready state; when the enable output terminal is an ineffective level signal, the first enable signal terminal of the first control module is an ineffective level signal, and the first control module controls the first power supply circuit to enter a standby state.

2. The starting control system according to claim 1, characterized in that, The timing control module further includes a control output terminal; the timing control module is also used to control the control output terminal to be a valid level signal when the enable input terminal is an invalid level signal, and to control the control output terminal to be an invalid level signal when the enable input terminal is a valid level signal; the start control system further includes a first protection module; the first protection module includes a first voltage input terminal and a first control input terminal; the first voltage input terminal receives the first voltage signal; the first control input terminal is connected to the control output terminal of the timing control module; when the first control input terminal is a valid level signal and the first voltage signal at the first voltage input terminal is greater than a first voltage threshold, the first protection module clamps the second enable signal terminal of the second control module to be an invalid level signal.

3. The starting control system according to claim 1, characterized in that, The timing control module further includes a control output terminal; the timing control module is also used to control the control output terminal to be a valid level signal when the enable input terminal is an invalid level signal, and to control the control output terminal to be an invalid level signal when the enable input terminal is a valid level signal; the start control system further includes a second protection module; the second protection module includes a second voltage input terminal and a second control input terminal; the second voltage input terminal receives the third voltage signal; the second control input terminal is connected to the control output terminal of the timing control module; when the second control input terminal is a valid level signal and the third voltage signal of the second voltage input terminal is greater than a second voltage threshold, the second protection module clamps the second enable signal terminal of the second control module to be an invalid level signal.

4. The starting control system according to claim 1, characterized in that, The timing control module includes a first switch, a second switch, a first resistor, and a second resistor. The first switch includes a first control terminal, a first input terminal, and a first output terminal. The second switch includes a second control terminal, a second input terminal, and a second output terminal. The first resistor and the second resistor are connected in series between the reference voltage and the second enable signal terminal of the second control module, and the first resistor and the second resistor are connected to form a first connection node. The first control terminal of the first switch is connected to the first connection node. The first input terminal of the first switch is connected to the reference voltage. The first output terminal of the first switch is connected to the second control terminal of the second switch. The second output terminal of the second switch is connected to the first enable signal terminal of the first control module. The second input terminal of the second switch is grounded.

5. The start-up control system according to claim 2, characterized in that, The first protection module includes a first voltage detection unit and a first enable clamping unit; the first voltage detection unit includes a first voltage input terminal, a first control input terminal, and a first clamping control output terminal; the first voltage detection unit is used to detect the first voltage signal through the first voltage input terminal when the first control input terminal is a valid level signal; the first clamping control output terminal outputs a first control signal when the first voltage signal is greater than the first voltage threshold. The first enable clamping unit includes a first clamping control input terminal and a first enable clamping terminal; the first clamping control input terminal is connected to the first clamping control output terminal; the first enable clamping terminal is connected to the second enable signal terminal of the second control module; when the first enable clamping unit receives the first control signal, it clamps the second enable signal terminal of the second control module to an invalid level signal.

6. The start-up control system according to claim 5, characterized in that, The first voltage detection unit includes a third switch, a fourth switch, a third resistor, a fourth resistor, and a fifth resistor; the third switch includes a first control input terminal, a third input terminal, and a third output terminal; the fourth switch includes a fourth control terminal, a fourth input terminal, and a first clamping control output terminal; the third input terminal of the third switch is grounded; the third, fourth, and fifth resistors are connected in series between the first voltage input terminal and the third output terminal of the third switch, and the third and fourth resistors are connected to form a second connection node, and the fourth and fifth resistors are connected to form a third connection node; the fourth control terminal of the fourth switch is connected to the third connection node; the fourth input terminal of the fourth switch is connected to the second connection node.

7. The start-up control system according to claim 5, characterized in that, The first enable clamping unit includes a fifth switch, a sixth resistor, and a seventh resistor; the fifth switch includes a fifth control terminal, a fifth input terminal, and the first enable clamping terminal; one end of the sixth resistor is connected to the first clamping control output terminal, and the other end is connected to one end of the seventh resistor to form a fourth connection node; the other end of the seventh resistor is grounded; the fourth connection node is connected to the fifth control terminal of the fifth switch; the fifth input terminal of the fifth switch is grounded.

8. The start-up control system according to claim 3, characterized in that, The second protection module includes a second voltage detection unit and a second enable clamping unit. The second voltage detection unit includes a second voltage input terminal, a second control input terminal, and a second clamping control output terminal. The second voltage detection unit detects the third voltage signal through the second voltage input terminal. When the second clamping control output terminal is a valid level signal at the second control input terminal and the third voltage signal is greater than the second voltage threshold, it outputs a second control signal. The second enable clamping unit includes a second clamping control input terminal and a second enable clamping terminal. The second clamping control input terminal is connected to the second clamping control output terminal. The second enable clamping terminal is connected to the second enable signal terminal of the second control module. The second enable clamping unit is used to clamp the second enable signal terminal of the second control module to an invalid level signal when it receives the second control signal.

9. The start-up control system according to claim 8, characterized in that, The second voltage detection unit includes a sixth switch, an optocoupler, an eighth resistor, a ninth resistor, and a tenth resistor; the sixth switch includes a sixth control terminal, a sixth input terminal, and a second clamping control output terminal; the optocoupler includes a second voltage input terminal, a first ground terminal, a second ground terminal, and a seventh output terminal; both the first ground terminal and the second ground terminal of the optocoupler are grounded; the eighth resistor, the ninth resistor, and the tenth resistor are connected in series between the second control input terminal and the seventh output terminal of the optocoupler, and the eighth resistor and the ninth resistor are connected to form a fifth connection node, and the ninth resistor and the tenth resistor are connected to form a sixth connection node; the sixth control terminal of the sixth switch is connected to the sixth connection node; the sixth input terminal of the sixth switch is connected to the fifth connection node.

10. The start-up control system according to claim 8, characterized in that, The second enable clamping unit includes a seventh switch transistor; the seventh switch transistor includes a second clamping control input terminal, a second enable clamping terminal, and a seventh input terminal; the seventh input terminal is grounded.

11. The starting control system according to claim 1, characterized in that, The second control module includes a first pull-up resistor and a first grounding capacitor; one end of the first pull-up resistor is connected to the reference voltage, and the other end is connected to one end of the first grounding capacitor to form the second enable signal terminal; the other end of the first grounding capacitor is grounded.

12. The starting control system according to claim 1, characterized in that, The first control module includes a second pull-up resistor and a first grounding resistor; one end of the second pull-up resistor is connected to the reference voltage, and the other end is connected to the first grounding resistor to form the first enable signal terminal; the other end of the first grounding resistor is grounded.

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