Reverse connection prevention and slow start circuit for DC power supply

Abstract

This application provides a reverse connection protection soft-start circuit for a DC power supply, comprising: a reverse connection protection circuit that, in response to an input voltage positively connected between a first input terminal and a second input terminal of the reverse connection protection circuit, transmits the input voltage to a first output terminal and a second output terminal of the reverse connection protection circuit; and, in response to an input voltage reversely connected between the first input terminal and the second input terminal of the reverse connection protection circuit, disconnects the connection of the input voltage transmitted to the first output terminal and the second output terminal of the reverse connection protection circuit. A control circuit includes at least one control terminal, each corresponding to at least one soft-start circuit. The control circuit can control the on / off state of the corresponding soft-start circuit through a signal from the control terminal. When the soft-start circuit is on, the control circuit controls the soft-start duration of the on-state soft-start circuit based on a signal from the corresponding control terminal determined by the value of the inrush current input to the on-state soft-start circuit. This application embodiment can achieve both soft-start and reverse connection protection.

Description

Technical Field

[0001] This application relates to the field of DC power supply technology, and more specifically, to a reverse connection protection soft-start circuit for a DC power supply. Background Technology

[0002] In the field of DC power supplies, reversing the polarity of the input voltage can damage components. Furthermore, the large inrush current at the input terminal of a DC power supply during startup can cause momentary overload of the power supply equipment or trigger its overload protection shutdown, thereby causing other equipment in the entire power supply system to shut down. For example, in the radar field, to meet requirements such as pulse power throttling, a large number of high-capacity energy storage capacitors need to be installed before the load at the downstream end of the DC power supply. Thus, during DC power supply startup, these energy storage capacitors need to be charged. During the initial charging phase, the energy storage capacitors are equivalent to a short circuit, resulting in a large inrush current, which can easily lead to malfunctions in the power supply equipment.

[0003] Therefore, there is an urgent need to provide a reverse connection protection soft-start circuit for DC power supplies to solve the problems of reverse input voltage and large inrush current. Summary of the Invention

[0004] This application provides a reverse connection protection soft-start circuit for DC power supplies to solve the aforementioned problems.

[0005] In a first aspect, embodiments of this application provide a reverse connection protection soft-start circuit for a DC power supply, comprising:

[0006] A reverse connection protection circuit is configured to, in response to an input voltage positively connected between a first input terminal and a second input terminal of the reverse connection protection circuit, transmit the input voltage to a first output terminal and a second output terminal of the reverse connection protection circuit, and, in response to an input voltage reversely connected between the first input terminal and a second input terminal of the reverse connection protection circuit, disconnect the connection of the input voltage transmitted to the first output terminal and the second output terminal of the reverse connection protection circuit; at least one soft-start circuit is configured such that, for each soft-start circuit, a first input terminal is connected to a first output terminal of the reverse connection protection circuit, and a second input terminal is connected to a second output terminal of the reverse connection protection circuit; a control circuit includes at least one control terminal, each of which corresponds one-to-one with the at least one soft-start circuit. The control terminal is connected to the third input terminal of the corresponding soft-start circuit; the control circuit is used to control the on / off state of the first soft-start circuit through the signal of the first control terminal, and when the first soft-start circuit is turned on, to control the soft-start duration of the first soft-start circuit through the signal of the first control terminal determined based on the value of the inrush current input to the first soft-start circuit; wherein, the first control terminal is any one of the at least one control terminal, and the first soft-start circuit is the soft-start circuit corresponding to the first control terminal; the first soft-start circuit is used to turn on or off in response to the signal of the first control terminal, and, when turned on, to perform a soft-start operation within the corresponding soft-start duration in response to the signal of the first control terminal.

[0007] In one possible implementation, the control circuit is further configured to determine the signal of the first control terminal based on the value of the inrush current input to the first soft-start circuit and in conjunction with a lookup table before controlling the soft-start duration of the first soft-start circuit; wherein the lookup table is used to indicate the corresponding mapping relationship between the value of the inrush current and the parameters of the signal.

[0008] In one possible implementation, the DC power supply reverse connection soft start circuit further includes: a surge protection circuit connected between the first and second output terminals of the reverse connection protection circuit, used to discharge the surge in the input voltage when a surge occurs in the input voltage.

[0009] In one possible implementation, the surge protection circuit includes:

[0010] The transient voltage suppression diode has its anode connected to the second output terminal of the reverse connection protection circuit, and its cathode connected to the first output terminal of the reverse connection protection circuit.

[0011] In one possible implementation, the reverse connection protection circuit includes:

[0012] The first resistor has its first end connected to the first output end and the first input end of the reverse connection protection circuit.

[0013] The first NMOS transistor has its gate connected to the second terminal of the first resistor, its source connected to the second output terminal of the reverse connection protection circuit, and its drain connected to the second input terminal of the reverse connection protection circuit.

[0014] The first capacitor is connected between the gate and the source of the first NMOS transistor;

[0015] The first Zener diode has its anode connected to the second output terminal of the reverse connection protection circuit, and its cathode connected to the second terminal of the first resistor.

[0016] In one possible implementation, the first soft-start circuit includes:

[0017] The second resistor has its first end connected to the first input and first output terminals of the first soft-start circuit.

[0018] The first switching element has a control terminal connected to the first control terminal and a first terminal connected to the second terminal of the second resistor;

[0019] The second NMOS transistor has its gate connected to the second terminal of the first switching element, its source connected to the second input terminal of the first soft-start circuit, and its drain connected to the second output terminal of the first soft-start circuit.

[0020] The second capacitor is connected between the gate and source of the second NMOS transistor;

[0021] The third capacitor is connected between the gate and drain of the second NMOS transistor;

[0022] The third resistor is connected between the gate and source of the second NMOS transistor;

[0023] The second Zener diode has its anode connected to the source of the second NMOS transistor and its cathode connected to the gate of the second NMOS transistor.

[0024] Secondly, embodiments of this application provide a power supply circuit, including: a reverse connection protection soft-start circuit for a DC power supply as described in the first aspect, and at least one DC power supply; wherein, the at least one DC power supply corresponds one-to-one with at least one soft-start circuit in the reverse connection protection soft-start circuit for the DC power supply; for each DC power supply, the DC power supply is connected between the first output terminal and the second output terminal of the corresponding soft-start circuit.

[0025] Thirdly, embodiments of this application provide a chip, characterized in that it includes: a DC power supply anti-reverse connection soft-start circuit as described in any one of the first aspects or a power supply circuit as described in the second aspect.

[0026] The beneficial effects of the reverse polarity protection soft-start circuit for DC power supply in the embodiments of this application are:

[0027] Because the DC power supply's reverse connection protection soft-start circuit includes a reverse connection protection circuit, and this circuit can respond to an input voltage connected between its first and second input terminals in positive orientation, transmitting the input voltage to its first and second output terminals, and responding to an input voltage connected in reverse orientation between its first and second input terminals, disconnecting the input voltage transmission to the circuit's first and second output terminals. In other words, the reverse connection protection circuit can transmit the input voltage from its input terminal to its output terminal to power the soft-start circuit when the input voltage is positively connected, ensuring normal power supply and operation of the circuit. Conversely, it can prevent the input voltage from being transmitted from its input terminal to its output terminal when the input voltage is reversed, thus preventing damage to other components in the circuit and ensuring circuit safety.

[0028] Furthermore, the DC power supply reverse connection protection soft-start circuit also includes at least one soft-start circuit and a control circuit. At least one control terminal of the control circuit corresponds one-to-one with at least one soft-start circuit, and each control terminal is connected to the third input terminal of the corresponding soft-start circuit. Regarding the first control terminal and the first soft-start circuit, the first control terminal is any one of the at least one control terminal, and the first soft-start circuit is the soft-start circuit corresponding to the first control terminal. The control circuit can control the on / off state of the first soft-start circuit through the signal from the first control terminal. The first soft-start circuit can be turned on or off in response to the signal from the first control terminal. That is, the control circuit can control the on / off state of each of the at least one soft-start circuits through the signal from its control terminal, selectively turning on or off the soft-start circuits, and selectively transmitting the input voltage to the output terminal of the turned-on soft-start circuit.

[0029] Furthermore, when the first soft-start circuit is turned on, the control circuit can control the soft-start duration of the first soft-start circuit through a signal from the first control terminal determined based on the value of the inrush current input to the first soft-start circuit. The first soft-start circuit can, when turned on, respond to the signal from the first control terminal and perform a soft-start operation within the corresponding soft-start duration. In other words, the control circuit can determine the signal from the control terminal corresponding to the turned-on soft-start circuit based on the value of the inrush current at the input terminal of the turned-on soft-start circuit, thereby controlling the soft-start duration of the turned-on soft-start circuit. This means controlling the soft-start duration based on the magnitude of the inrush current, so that the turned-on soft-start current suppresses inrush currents of different magnitudes for different durations, improving the suppression effect of inrush currents of different magnitudes and enhancing the flexibility of suppressing inrush currents of different magnitudes. Attached Figure Description

[0030] Figure 1 An example diagram of a reverse connection protection soft-start circuit for a DC power supply provided in an embodiment of this application;

[0031] Figure 2 An example diagram of another DC power supply anti-reverse connection soft-start circuit provided in an embodiment of this application. Detailed Implementation

[0032] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0033] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0034] The term "comprising" and its variations as used herein 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"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0035] 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".

[0036] The names of the messages or information exchanged between the multiple devices in the embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0037] like Figure 1As shown in the figure, this application provides a reverse connection protection soft-start circuit for a DC power supply. This DC power supply reverse connection protection soft-start circuit may include: a reverse connection protection circuit 110, a control circuit 120, and at least one soft-start circuit 130. Wherein:

[0038] The reverse connection protection circuit 110 can transmit the input voltage to the first output terminal Vout1 and the second output terminal Vout2 of the reverse connection protection circuit 110 in response to the input voltage connected between the first input terminal Vin1 and the second input terminal Vin2 of the reverse connection protection circuit 110, and disconnect the connection of the input voltage transmitted to the first output terminal Vout1 and the second output terminal Vout2 of the reverse connection protection circuit 110 in response to the input voltage connected in reverse between the first input terminal Vin1 and the second input terminal Vin2 of the reverse connection protection circuit 110.

[0039] For each soft-start circuit 130, the first input terminal Vin3 of the soft-start circuit 130 is connected to the first output terminal Vout1 of the reverse connection protection circuit 110, and the second input terminal Vin4 of the soft-start circuit 130 is connected to the second output terminal Vout2 of the reverse connection protection circuit 110.

[0040] The control circuit 120 may include at least one control terminal, which corresponds one-to-one with at least one soft-start circuit 130, and each control terminal is connected to the third input terminal of the corresponding soft-start circuit 130.

[0041] The principles of control circuit 120 and soft start circuit 130 will be explained below, taking the first control terminal as any one of the at least one control terminal and the first soft start circuit as the soft start circuit corresponding to the first control terminal as an example.

[0042] The control circuit 120 can control the on / off state of the first soft-start circuit through the signal of the first control terminal, and when the first soft-start circuit is turned on, it controls the soft-start duration of the first soft-start circuit through the signal of the first control terminal determined based on the value of the inrush current input to the first soft-start circuit.

[0043] Specifically, the inrush current can be the starting inrush current generated when the load downstream of the reverse connection protection soft-start circuit of the DC power supply is turned on. The value of the inrush current can be obtained in ways including, but not limited to, calculation based on the electrical parameters of the load or acquisition via a sampling resistor. The load includes, but is not limited to, the DC power supply.

[0044] Different inrush current values ​​correspond to different signals at the control terminal, and different signals at the control terminal correspond to different soft-start durations. Specifically, the larger the inrush current, the longer the soft-start duration; the smaller the inrush current, the shorter the soft-start duration. In other words, a larger inrush current requires a longer soft-start duration to suppress the larger inrush current. Conversely, a smaller inrush current requires a shorter soft-start duration to suppress the smaller inrush current and ensure the safe start-up of the circuit.

[0045] The first soft-start circuit can be turned on or off in response to a signal from the first control terminal, and when turned on, it performs a soft-start operation within the corresponding soft-start duration in response to a signal from the first control terminal.

[0046] The two output terminals of the first soft-start circuit can be connected to a load such as a DC power supply, and this application embodiment does not impose any special limitations on this.

[0047] Clearly, since the DC power supply's reverse connection protection soft-start circuit includes a reverse connection protection circuit, and this circuit can respond to an input voltage connected between its first and second input terminals (if the input voltage is positively connected), it can transmit the input voltage to its first and second output terminals. Conversely, it can respond to an input voltage reversed between its first and second input terminals (if the input voltage is reversed), it can disconnect the input voltage transmission to the first and second output terminals. In other words, the reverse connection protection circuit can transmit the input voltage from its input terminal to its output terminal when the input voltage is positively connected, supplying power to the soft-start circuit and ensuring normal power supply and operation. Furthermore, it can prevent the input voltage from being transmitted from its input terminal to its output terminal when the input voltage is reversed, thus preventing damage to other components in the circuit and ensuring circuit safety.

[0048] Furthermore, the DC power supply reverse connection protection soft-start circuit also includes at least one soft-start circuit and a control circuit. At least one control terminal of the control circuit corresponds one-to-one with at least one soft-start circuit, and each control terminal is connected to the third input terminal of the corresponding soft-start circuit. Regarding the first control terminal and the first soft-start circuit, the first control terminal is any one of the at least one control terminal, and the first soft-start circuit is the soft-start circuit corresponding to the first control terminal. The control circuit can control the on / off state of the first soft-start circuit through the signal from the first control terminal. The first soft-start circuit can be turned on or off in response to the signal from the first control terminal. That is, the control circuit can control the on / off state of each of the at least one soft-start circuits through the signal from its control terminal, selectively turning on or off the soft-start circuits, and selectively transmitting the input voltage to the output terminal of the turned-on soft-start circuit.

[0049] Furthermore, when the first soft-start circuit is turned on, the control circuit can control the soft-start duration of the first soft-start circuit through a signal from the first control terminal determined based on the value of the inrush current input to the first soft-start circuit. The first soft-start circuit can, when turned on, respond to the signal from the first control terminal and perform a soft-start operation within the corresponding soft-start duration. In other words, the control circuit can determine the signal from the control terminal corresponding to the turned-on soft-start circuit based on the value of the inrush current at the input terminal of the turned-on soft-start circuit, thereby controlling the soft-start duration of the turned-on soft-start circuit. This means controlling the soft-start duration based on the magnitude of the inrush current, so that the turned-on soft-start current suppresses inrush currents of different magnitudes for different durations, improving the suppression effect of inrush currents of different magnitudes and enhancing the flexibility of suppressing inrush currents of different magnitudes.

[0050] In some embodiments, the control circuit 120 may further determine the signal of the first control terminal based on the value of the inrush current input to the first soft-start circuit and in conjunction with a lookup table before controlling the soft-start duration of the first soft-start circuit.

[0051] The lookup table is used to indicate the mapping relationship between the value of the impact current and the parameters of the signal.

[0052] The parameters of the signal may include the soft-start duration, the signal level change during the soft-start duration, and the signal level after the soft-start duration ends, etc., and this application embodiment does not impose any special limitations on these parameters. Thus, the parameters of the corresponding signal can be determined from a lookup table based on the value of the inrush current input to the first soft-start circuit, and a signal can be generated based on the corresponding signal parameters to control the first soft-start circuit, causing the first soft-start circuit to perform a soft-start operation within the corresponding soft-start duration.

[0053] In some embodiments, such as Figure 2 As shown, the DC power supply reverse connection soft start circuit also includes: surge protection circuit 140.

[0054] The surge protection circuit 140 is connected between the first output terminal Vout1 and the second output terminal Vout2 of the reverse connection protection circuit 110. When a surge occurs in the input voltage, the surge protection circuit 140 can discharge the surge in the input voltage, so that the surge cannot be transmitted to the downstream circuit, thus realizing the surge protection function.

[0055] In some embodiments, such as Figure 2 As shown, the surge protection circuit 140 may include: a transient voltage suppression diode V4

[0056] The anode of the transient voltage suppression diode V4 is connected to the second output terminal Vout2 of the reverse connection protection circuit 110, and the cathode of the transient voltage suppression diode V4 is connected to the first output terminal Vout1 of the reverse connection protection circuit 110.

[0057] Specifically, when the input voltage is positively connected, if a surge occurs in the input voltage, the transient voltage suppression diode V4 will break down to absorb the surge energy, preventing the surge from being transmitted to the downstream circuit, thus achieving surge protection and improving the safety of circuit operation.

[0058] In some embodiments, such as Figure 1 As shown, the reverse connection protection circuit 110 may include: a first resistor R1, a first NMOS transistor V1, a first capacitor C1, and a first Zener diode V3, wherein:

[0059] The first terminal of the first resistor R1 is connected to the first output terminal Vout1 and the first input terminal Vin1 of the reverse connection protection circuit 110. The gate of the first NMOS transistor V1 is connected to the second terminal of the first resistor R1, the source of the first NMOS transistor V1 is connected to the second output terminal Vout2 of the reverse connection protection circuit 110, and the drain of the first NMOS transistor V1 is connected to the second input terminal Vin2 of the reverse connection protection circuit 110. The first capacitor C1 is connected between the gate and the source of the first NMOS transistor V1. The anode of the first Zener diode V3 is connected to the second output terminal Vout2 of the reverse connection protection circuit 110, and the cathode of the first Zener diode V3 is connected to the second terminal of the first resistor R1.

[0060] The operation of the reverse connection protection circuit 110 is as follows:

[0061] When the input voltage is positive, i.e., when the two input terminals of the reverse connection protection circuit 110 are positive at the top and negative at the bottom, the first resistor R1, the first capacitor C1, and the body diode V2 of the first NMOS transistor V1 form a charging path to charge the first capacitor C1. Furthermore, the input voltage can be transmitted to the output terminal through the conducting body diode V2 of the first NMOS transistor V1. As the first capacitor C1 charges, the voltage across it continuously increases. When the voltage across the first capacitor C1 exceeds the threshold voltage of the first NMOS transistor V1, the first NMOS transistor V1 turns on (i.e., the channel of the first NMOS transistor V1 opens). As the first capacitor C1 continues to charge, the voltage across it continues to increase, and the channel of the first NMOS transistor V1 continues to open. After the channel of the first NMOS transistor V1 is fully open, the first NMOS transistor V1 is fully conducting. At this time, the reverse connection protection circuit 110 is fully conducting, and the input voltage is transmitted to the output terminal of the reverse connection protection circuit 110 through the conducting first NMOS transistor V1. Furthermore, since the first Zener diode V3 is connected in parallel between the gate and source of the first NMOS transistor V1, the first Zener diode V3 can stabilize the voltage between the gate and source of the first NMOS transistor V1 at a fixed value, which can be the voltage between the gate and source of the first NMOS transistor V1 after it is fully turned on.

[0062] When the input voltage is reversed, i.e., when the two input terminals of the reverse connection protection circuit 110 are positive at the bottom and negative at the top, the voltage between the gate and source of the first NMOS transistor V1 cannot reach its turn-on voltage, so the first NMOS transistor V1 is in the off state. Furthermore, when the input voltage is reversed, the body diode V2 of the first NMOS transistor V1 is turned off. Clearly, when the input voltage is reversed, the reverse connection protection circuit 110 is turned off, and the input voltage will not be transmitted to the output terminal of the reverse connection protection circuit 110, protecting the downstream circuit from being affected and achieving the reverse connection protection function.

[0063] In some embodiments, such as Figure 1 As shown, the first soft-start circuit may include: a second resistor R2, a first switching element V8, a second NMOS transistor V6, a second capacitor C2, a third capacitor C3, a third resistor R3, and a second Zener diode V5. Wherein:

[0064] The first end of the second resistor R2 is connected to the first input terminal Vin3 and the first output terminal Vout3 of the first soft-start circuit. The control terminal of the first switching element V8 is connected to the first control terminal, and the first end of the first switching element V8 is connected to the second end of the second resistor R2. The gate of the second NMOS transistor V6 is connected to the second end of the first switching element V8, the source of the second NMOS transistor V6 is connected to the second input terminal Vin4 of the first soft-start circuit, and the drain of the second NMOS transistor V6 is connected to the second output terminal Vout2 of the first soft-start circuit. The second capacitor C2 is connected between the gate and the source of the second NMOS transistor V6. The third capacitor C3 is connected between the gate and the drain of the second NMOS transistor V6. The third resistor R3 is connected between the gate and the source of the second NMOS transistor V6. The anode of the second Zener diode V5 is connected to the source of the second NMOS transistor V6, and the cathode of the second Zener diode V5 is connected to the gate of the second NMOS transistor V6.

[0065] It should be noted that the first switching element V8 can be a three-terminal switching element, such as an NMOS transistor.

[0066] The operation of the first soft-start circuit can be described as follows:

[0067] The control circuit 120 can turn off the first switching element V8 by the signal from the first control terminal, thereby turning off the first soft-start circuit.

[0068] The control circuit 120 can turn on the first switching element V8 via the signal from the first control terminal to activate the first soft-start circuit. At this time, the second resistor R2, the activated first switching element V8, and the second capacitor C2 form a charging path to charge the second capacitor C2. Since the body diode V7 of the second NMOS transistor V6 is off at this time, the third capacitor C3 is not activated. As the second capacitor C2 charges, the voltage across it continuously increases. When the voltage of the second capacitor C2 exceeds the threshold voltage of the second NMOS transistor V6, the second NMOS transistor V6 begins to conduct. At this time, the second resistor R2, the first switching element V8, the third capacitor C3, and the activated second NMOS transistor V6 form a charging path to charge the third capacitor C3. At this time, by charging the third capacitor C3, the charging current of the second capacitor C2 is reduced, the charging speed of the second capacitor C2 is slowed down, and the rise rate of the voltage across the second capacitor C2 is reduced. This allows the second NMOS transistor V6 to remain on the Miller plateau; that is, the shunting effect of the third capacitor C3 extends the duration for which the second NMOS transistor V6 remains on the Miller plateau. Since the second NMOS transistor V6 is not fully turned on when it is on the Miller plateau, it has a certain on-resistance, which is greater than its impedance when fully turned on. Therefore, the on-resistance of the second NMOS transistor V6 in maintaining its position on the Miller plateau can suppress the inrush current in the first soft-start circuit. As the second capacitor C2 is charged, the voltage across the second capacitor C2 continues to rise. When the voltage across the second capacitor C2 reaches the voltage at which the second NMOS transistor V6 can be fully turned on, the second NMOS transistor V6 is fully turned on. At this time, the on-resistance of the second NMOS transistor V6 drops rapidly. The circuit has completed the soft start and entered the normal operating state. After the soft start, the on-resistance drops rapidly, which can reduce power consumption.

[0069] Clearly, in the above process, the soft-start duration is the duration for which the second NMOS transistor V6 remains on the Miller plateau. The signal at the first control terminal can be at least a signal capable of turning the first switching element V8 on or off. The soft-start operation can be understood as the operation of controlling the second NMOS transistor V6 to remain on the Miller plateau.

[0070] It should be noted that after the power is cut off at the front end of the first soft-start circuit or the first switching element V8 is turned off, the second capacitor C2 and the third capacitor C3 discharge through the third resistor R3.

[0071] The second Zener diode V5 is used to stabilize the gate-source voltage of the second NMOS transistor V6 to prevent excessive voltage from damaging the second NMOS transistor V6.

[0072] Since the inrush current can vary greatly, different signals need to be set for different inrush current values ​​to effectively suppress them. These different signals correspond to different soft-start durations (i.e., the duration of time maintained on the Miller plateau). Specifically, the larger the inrush current value, the longer the soft-start duration; the smaller the inrush current value, the shorter the soft-start duration. Thus, the soft-start duration (i.e., the duration of time maintained on the Miller plateau) can be controlled by signal-controlled switching of the first switching element V8.

[0073] Specifically, after the first switching element V8 is turned on for the first time, the second NMOS transistor V6 remains on the Miller plateau based on the above process. Before the second NMOS transistor V6 is fully turned on, the first switching element V8 is turned off to discharge the second capacitor C2 and the third capacitor C3 through the third resistor R3, thereby reducing the voltage across the second capacitor C2 and extending the duration for which the second NMOS transistor V6 remains on the Miller plateau. Before the voltage across the second capacitor C2 drops to the turn-on voltage of the second NMOS transistor V6, the first switching element V8 is turned on to charge the second capacitor C2 and the third capacitor C3, causing the voltage across the second capacitor C2 to continue to rise, thus continuing to maintain the second NMOS transistor V6 on the Miller plateau. To further extend the duration on the Miller plateau, the first switching element V8 is turned off again based on the above principle. This process is repeated until the duration on the Miller plateau (i.e., the soft-start duration) meets the requirement, and after the requirement is met, the first switching element V8 is no longer turned off, thus completing the soft-start process.

[0074] Obviously, the soft-start duration can be determined by the magnitude of the inrush current. By using the soft-start duration and combining it with the above principle, the number and timing of switching the second switching element V8 on and off can be set, thereby determining the signal parameters and generating a signal based on the signal parameters.

[0075] In summary, the duration for which the second NMOS transistor V6 remains on the Miller platform (i.e., the soft-start duration) can be controlled by controlling the number of times the first switching element V8 is turned on and off via a signal, thereby suppressing inrush currents of different values.

[0076] This application embodiment also provides a power supply circuit, including: the above-mentioned reverse connection protection soft-start circuit for DC power supply and at least one DC power supply. Wherein:

[0077] At least one DC power supply corresponds one-to-one with at least one soft-start circuit in the DC power supply reverse connection protection soft-start circuit. For each DC power supply, the DC power supply is connected between the first and second output terminals of the corresponding soft-start circuit.

[0078] This application also provides a chip, including: the above-described DC power supply reverse connection soft start circuit or the above-described power supply circuit.

[0079] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A reverse connection protection soft-start circuit for a DC power supply, characterized in that, include: A reverse connection protection circuit is configured to transmit the input voltage to the first and second output terminals of the reverse connection protection circuit in response to an input voltage connected between the first and second input terminals of the reverse connection protection circuit, and to disconnect the connection of the input voltage transmitted to the first and second output terminals of the reverse connection protection circuit in response to an input voltage connected between the first and second input terminals of the reverse connection protection circuit. At least one soft-start circuit, wherein for each soft-start circuit, a first input terminal is connected to a first output terminal of the reverse connection protection circuit, and a second input terminal is connected to a second output terminal of the reverse connection protection circuit; The control circuit includes at least one control terminal, each of which corresponds to one of the at least one soft-start circuits, and each control terminal is connected to the third input terminal of the corresponding soft-start circuit. The control circuit is used to control the on / off state of the first soft-start circuit through the signal of the first control terminal, and when the first soft-start circuit is turned on, to control the soft-start duration of the first soft-start circuit through the signal of the first control terminal determined based on the value of the inrush current input to the first soft-start circuit. Wherein, the first control terminal is any one of the at least one control terminal, and the first soft start circuit is the soft start circuit corresponding to the first control terminal; The first soft-start circuit is configured to turn on or off in response to a signal from the first control terminal, and when turned on, to perform a soft-start operation within a corresponding soft-start duration in response to a signal from the first control terminal.

2. The circuit according to claim 1, characterized in that, The control circuit is further configured to determine the signal of the first control terminal based on the value of the inrush current input to the first soft-start circuit and in conjunction with a lookup table before controlling the soft-start duration of the first soft-start circuit. The lookup table is used to indicate the mapping relationship between the value of the impact current and the parameters of the signal.

3. The circuit according to claim 1, characterized in that, The DC power supply reverse connection protection soft-start circuit also includes: A surge protection circuit is connected between the first and second output terminals of the reverse connection protection circuit to discharge surges in the input voltage when a surge occurs.

4. The circuit according to claim 3, characterized in that, The surge protection circuit includes: The transient voltage suppression diode has its anode connected to the second output terminal of the reverse connection protection circuit, and its cathode connected to the first output terminal of the reverse connection protection circuit.

5. The circuit according to claim 1, characterized in that, The reverse connection protection circuit includes: The first resistor has its first end connected to the first output end and the first input end of the reverse connection protection circuit. The first NMOS transistor has its gate connected to the second terminal of the first resistor, its source connected to the second output terminal of the reverse connection protection circuit, and its drain connected to the second input terminal of the reverse connection protection circuit. The first capacitor is connected between the gate and the source of the first NMOS transistor; The first Zener diode has its anode connected to the second output terminal of the reverse connection protection circuit, and its cathode connected to the second terminal of the first resistor.

6. The circuit according to claim 1, characterized in that, The first soft-start circuit includes: The second resistor has its first end connected to the first input and first output terminals of the first soft-start circuit. The first switching element has a control terminal connected to the first control terminal and a first terminal connected to the second terminal of the second resistor; The second NMOS transistor has its gate connected to the second terminal of the first switching element, its source connected to the second input terminal of the first soft-start circuit, and its drain connected to the second output terminal of the first soft-start circuit. The second capacitor is connected between the gate and source of the second NMOS transistor; The third capacitor is connected between the gate and drain of the second NMOS transistor; The third resistor is connected between the gate and source of the second NMOS transistor; The second Zener diode has its anode connected to the source of the second NMOS transistor and its cathode connected to the gate of the second NMOS transistor.

7. A power supply circuit, characterized in that, include: The DC power supply anti-reverse connection soft-start circuit and at least one DC power supply as described in any one of claims 1 to 6; The at least one DC power supply corresponds one-to-one with at least one soft-start circuit in the DC power supply anti-reverse connection soft-start circuit; For each of the DC power supplies, the DC power supply is connected between the first and second output terminals of the corresponding soft-start circuit.

8. A chip, characterized in that, include: The reverse connection protection soft-start circuit for a DC power supply according to any one of claims 1 to 6, or the power supply circuit according to claim 7.

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