A combined power input high-voltage bus soft start protection circuit and combined power supply
By introducing a combination design of blocking unit, soft start control unit and current limiting resistor into the combined power supply, the problem of power switch damage caused by rapid voltage change of bus capacitor is solved, and the reliability and stability of the combined power supply are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CETC XIAN NAVIGATION TECH CO LTD
- Filing Date
- 2025-09-17
- Publication Date
- 2026-08-04
AI Technical Summary
In existing soft-start circuit designs, the bus capacitor generates a large instantaneous current when the DC input voltage changes rapidly, which can damage the power switching transistor and affect the reliability and stability of the combined power supply.
The design employs a combination of blocking unit, slow-start control unit, bus discharge unit and current-limiting resistor. By blocking the discharge circuit of the bus capacitor, the conduction of the power switch is delayed, and the charging current is carried by the current-limiting resistor to prevent the power switch from being damaged by overpower.
It effectively suppresses instantaneous high current, improves the reliability and stability of the circuit under complex power supply conditions, and ensures the stable operation of the combined power supply in complex environments.
Smart Images
Figure CN224596364U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of combined power supply technology, and in particular to a soft-start protection circuit for the input high-voltage bus of a combined power supply and a combined power supply. Background Technology
[0002] As an advanced power supply system, the core advantage of a combined power supply lies in its high integration of multiple power functions or modules, enabling precise matching of the diverse power supply needs of complex equipment. By cleverly integrating different power technologies, combined power supplies achieve efficient, flexible, and reliable power output, providing crucial support for numerous fields with stringent requirements for power supply stability.
[0003] In practical applications, combined power supplies typically convert a single input DC or AC power source into multiple outputs of different specifications through complex internal conversion circuits, providing stable power to various loads. Given the challenges posed by the complex and variable input power characteristics in their applications, such as voltage fluctuations and transient interference, combined power supplies must possess extremely high reliability to ensure continuous and stable operation under harsh conditions. Therefore, reverse connection protection circuits and soft-start circuits are crucial design elements for ensuring the reliability of combined power supplies. Reverse connection protection circuits prevent damage to equipment caused by incorrect power polarity connection, while soft-start circuits effectively suppress inrush currents during power-on, protecting circuit components.
[0004] However, existing soft-start circuit designs have serious flaws. Figure 1 Taking the circuit shown as an example, when the DC input voltage source V1 is rapidly de-energized, the bus capacitor C2 discharges through resistors R1 and R2. This discharge process causes the power switch Q1 to slowly transition from the saturation region to the cutoff region, keeping it in the linear region for an extended period. When the DC input voltage source V1 is rapidly energized, the impedance between the drain and source of the power switch Q1 is high because it remains in the linear region. According to the capacitor characteristic formula I = C2 * dv / dt, a large instantaneous current will be generated in the circuit of the bus capacitor C2 at the instant the voltage source V1 is rapidly energized. This large instantaneous current flowing between the drain and source of the power switch Q1 can cause instantaneous overpower damage, severely affecting the reliability and stability of the combined power supply, becoming a pressing technical problem that needs to be solved. Utility Model Content
[0005] This application provides a combined power input high-voltage bus soft-start protection circuit and a combined power supply, which solves the problems mentioned in the background art.
[0006] In a first aspect, embodiments of this application provide a combined power input high-voltage bus soft-start protection circuit, including:
[0007] The DC input terminal V1 is used to connect to a high-voltage DC power supply;
[0008] The blocking unit D1 has its first end connected to the positive terminal of the DC input terminal V1;
[0009] The source of the power switch Q1 is connected to the negative terminal of the DC input terminal V1;
[0010] The bus capacitor C2 has its positive terminal connected to the second terminal of the blocking unit D1 and its negative terminal connected to the drain of the power switch Q1.
[0011] A soft-start control unit includes a first resistor R1, a second resistor R2, and a soft-start capacitor C1, wherein the second resistor R2 is connected in parallel with the soft-start capacitor C1; the first end of the first resistor R1 is connected to the positive terminal of the DC input terminal V1, and its second end is connected to the gate of the power switch Q1, and a branch is connected to the second resistor R2 and the first end of the soft-start capacitor C1; the second ends of the second resistor R2 and the soft-start capacitor C1 are both connected to the source of the power switch Q1; wherein the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2, such that the voltage of the DC input terminal V1 divided to the voltage between the gate and source of the power switch Q1 is the turn-on voltage of the power switch Q1;
[0012] The bus discharge unit R4 is connected in parallel across the bus capacitor C2;
[0013] A current-limiting resistor R is connected in parallel between the source and drain of the power switch Q1;
[0014] Specifically, when the DC input terminal V1 is rapidly de-energized, the blocking unit D1 blocks the discharge circuit of the bus capacitor C2 through the slow-start control unit, causing the power switch Q1 to turn off rapidly; when the DC input terminal V1 is rapidly energized, the charging delay of the slow-start capacitor C1 keeps the power switch Q1 in the off state, and the charging current of the bus capacitor C2 is carried by the current-limiting resistor R; when the voltage across the slow-start capacitor C1 exceeds the threshold voltage for the power switch Q1 to turn on, the power switch Q1 turns on.
[0015] In conjunction with the first aspect, in one possible implementation, the combined power input high-voltage bus soft-start protection circuit further includes a slow-start capacitor discharge branch; the slow-start capacitor discharge branch includes a discharge resistor R3 connected in series and a unidirectional conducting element D2, connected between the positive terminal of the DC input terminal V1 and the first terminal of the slow-start capacitor C1, for releasing the energy stored in the slow-start capacitor C1 when the power is off.
[0016] In conjunction with the first aspect, in one possible implementation, the unidirectional conducting element D2 is a diode, whose anode is connected to the first terminal of the soft-start capacitor C1, and whose cathode is connected to the positive terminal of the DC input terminal V1 through the discharge resistor R3.
[0017] In conjunction with the first aspect, in one possible implementation, the blocking unit D1 is a diode, with its anode connected to the positive terminal of the DC input terminal V1 and its cathode connected to the positive terminal of the bus capacitor C2.
[0018] Secondly, embodiments of this application provide a combined power supply, including the combined power supply input high-voltage bus soft-start protection circuit described in the first aspect or any possible implementation of the first aspect, for suppressing over-power damage to the power switch Q1 caused by rapid switching of the input voltage.
[0019] One or more technical solutions provided in the embodiments of this application have at least the following technical effects:
[0020] The combined power input high-voltage bus soft-start protection circuit provided in this application embodiment includes a DC input terminal V1, a blocking unit D1, a bus capacitor C2, a power switch Q1, a soft-start control unit, a bus discharge unit R4, and a current-limiting resistor R. During circuit operation, when the DC input terminal V1 is rapidly de-energized, the blocking unit D1 quickly blocks the discharge circuit of the bus capacitor C2 through the soft-start control unit, causing the power switch Q1 to turn off quickly, preventing damage from excessive power due to prolonged operation in the linear region. When the DC input terminal V1 is rapidly energized, the charging delay of the soft-start capacitor C1 keeps the power switch Q1 off. At this time, the charging current of the bus capacitor C2 is carried by the current-limiting resistor R, effectively suppressing the instantaneous large current flowing through the power switch Q1 and preventing damage from excessive power. When the voltage across the soft-start capacitor C1 exceeds the threshold voltage for the power switch Q1 to turn on, the power switch Q1 turns on, and the current flowing through it drops to the load operating current range. This series of innovative designs enhances the reliability, stability, and safety of the circuit under complex power supply conditions, providing a solid guarantee for the stable operation of the combined power supply in complex environments. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 A schematic diagram of the prior art provided in the embodiments of this application;
[0023] Figure 2 A schematic diagram of the combined power input high-voltage bus soft-start protection circuit provided in the embodiments of this application. Detailed Implementation
[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0025] In the description of the embodiments of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.
[0026] This application provides a combined power input high-voltage bus soft-start protection circuit, such as... Figure 2As shown. This combined power input high-voltage bus soft-start protection circuit includes a DC input terminal V1, a blocking unit D1, a bus capacitor C2, a power switch Q1, a soft-start control unit, a bus discharge unit R4, and a current-limiting resistor R. The DC input terminal V1 is used to connect to a high-voltage DC power supply. The first terminal of the blocking unit D1 is connected to the positive terminal of the DC input terminal V1. The source of the power switch Q1 is connected to the negative terminal of the DC input terminal V1. The positive terminal of the bus capacitor C2 is connected to the second terminal of the blocking unit D1, and the negative terminal is connected to the drain of the power switch Q1. The power switch Q1 is a MOSFET. The soft-start control unit includes a first resistor R1, a second resistor R2, and a soft-start capacitor C1. The second resistor R2 is connected in parallel with the soft-start capacitor C1. The first terminal of the first resistor R1 is connected to the positive terminal of the DC input terminal V1, and its second terminal is connected to the gate of the power switch Q1, and branched off to connect the second resistor R2 and the first terminal of the soft-start capacitor C1. The second terminals of both the second resistor R2 and the soft-start capacitor C1 are connected to the source of the power switch Q1. In this design, the resistance of the first resistor R1 is greater than that of the second resistor R2, ensuring that the voltage across the gate-source junction of the DC input voltage V1 is the turn-on voltage of the power switch Q1. Specifically, this application sets the resistance of the first resistor R1 to be significantly greater than that of the second resistor R2, so that the voltage across the DC input voltage V1, after being divided, can form a sufficient turn-on voltage between the gate and source of the power switch Q1. The bus discharge unit R4 is connected in parallel across the bus capacitor C2. The current-limiting resistor R is connected in parallel between the source and drain of the power switch Q1.
[0027] It should be noted that during circuit operation, when the DC input terminal V1 is rapidly de-energized, the blocking unit D1 quickly blocks the discharge circuit of the bus capacitor C2 through the slow-start control unit, causing the power switch Q1 to turn off quickly and preventing damage from excessive power due to prolonged operation in the linear region. When the DC input terminal V1 is rapidly energized, the charging delay of the slow-start capacitor C1 keeps the power switch Q1 off. At this time, the charging current of the bus capacitor C2 is carried by the current-limiting resistor R, effectively suppressing the instantaneous large current passing through the power switch Q1 and preventing damage from excessive power. When the voltage across the slow-start capacitor C1 exceeds the threshold voltage for the power switch Q1 to turn on, the power switch Q1 turns on, and the current flowing through it drops to the load operating current range. This series of innovative designs improves the reliability, stability, and safety of the circuit under complex power supply conditions, providing a solid guarantee for the stable operation of the combined power supply in complex environments.
[0028] In this embodiment, the combined power input high-voltage bus soft-start protection circuit further includes a slow-start capacitor discharge branch. The slow-start capacitor discharge branch includes a discharge resistor R3 connected in series and a unidirectional conducting element D2, which is connected between the positive terminal of the DC input terminal V1 and the first terminal of the slow-start capacitor C1, and is used to release the energy stored in the slow-start capacitor C1 when the power is off.
[0029] It should be noted that when the DC input terminal V1 is rapidly de-energized, the slow-start capacitor C1, the unidirectional conducting element D2, the bleeder resistor R3, the first resistor R1, and the second resistor R2 constitute the slow-start capacitor bleeder circuit. If the energy stored in the slow-start capacitor C1 is not released in time, it will damage circuit components and affect the stability and reliability of the circuit. This slow-start capacitor bleeder circuit can utilize the unidirectional conducting characteristic of the unidirectional conducting element D2 to allow the slow-start capacitor C1 to discharge rapidly through the bleeder resistor R3, avoiding adverse effects and improving the stability and reliability of the combined power supply input high-voltage bus soft-start protection circuit under complex operating conditions.
[0030] In this embodiment, the unidirectional conducting element D2 is a diode, whose anode is connected to the first terminal of the slow-start capacitor C1, and whose cathode is connected to the positive terminal of the DC input terminal V1 through the discharge resistor R3.
[0031] It should be noted that the slow-start capacitor discharge branch formed by the unidirectional conducting element D2 can guide the slow-start capacitor C1 to release the stored energy in time through the discharge resistor R3 when the power is off, preventing energy accumulation from causing adverse effects on the circuit.
[0032] In this embodiment, the blocking unit D1 is a diode, with its anode connected to the positive terminal of the DC input terminal V1 and its cathode connected to the positive terminal of the bus capacitor C2.
[0033] It should be noted that when the DC input is quickly de-energized, the blocking unit D1 uses the unidirectional conduction characteristic of the diode to quickly block the discharge circuit of the bus capacitor C2 through the slow-start control unit, so that the power switch Q1 can be turned off quickly, avoiding damage to it due to being in the linear region for a long time.
[0034] This application provides a combined power supply, including the aforementioned combined power supply input high voltage bus soft-start protection circuit, which is used to suppress over-power damage to the power switch Q1 caused by rapid input voltage switching, and ensure stable and reliable operation of the combined power supply under various complex power supply conditions.
[0035] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.
[0036] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.
Claims
1. A soft-start protection circuit for a combined power input high-voltage bus, characterized in that, include: The DC input terminal V1 is used to connect to a high-voltage DC power supply; The blocking unit D1 has its first end connected to the positive terminal of the DC input terminal V1; The source of the power switch Q1 is connected to the negative terminal of the DC input terminal V1; The bus capacitor C2 has its positive terminal connected to the second terminal of the blocking unit D1 and its negative terminal connected to the drain of the power switch Q1. A soft-start control unit includes a first resistor R1, a second resistor R2, and a soft-start capacitor C1; the second resistor R2 is connected in parallel with the soft-start capacitor C1; the first end of the first resistor R1 is connected to the positive terminal of the DC input terminal V1, and its second end is connected to the gate of the power switch Q1, and a branch is connected to the second resistor R2 and the first end of the soft-start capacitor C1; the second ends of the second resistor R2 and the soft-start capacitor C1 are both connected to the source of the power switch Q1; wherein, the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2, so that the voltage of the DC input terminal V1 divided to the voltage between the gate and source of the power switch Q1 is the turn-on voltage of the power switch Q1; The bus discharge unit R4 is connected in parallel across the bus capacitor C2; A current-limiting resistor R is connected in parallel between the source and drain of the power switch Q1; Specifically, when the DC input terminal V1 is rapidly de-energized, the blocking unit D1 blocks the discharge circuit of the bus capacitor C2 through the slow-start control unit, causing the power switch Q1 to turn off rapidly; when the DC input terminal V1 is rapidly energized, the charging delay of the slow-start capacitor C1 keeps the power switch Q1 in the off state, and the charging current of the bus capacitor C2 is carried by the current-limiting resistor R; when the voltage across the slow-start capacitor C1 exceeds the threshold voltage for the power switch Q1 to turn on, the power switch Q1 turns on.
2. The combined power input high-voltage bus soft-start protection circuit according to claim 1, characterized in that, It also includes a slow-start capacitor discharge branch; The slow-start capacitor discharge branch includes a discharge resistor R3 and a unidirectional conducting element D2 connected in series between the positive terminal of the DC input terminal V1 and the first terminal of the slow-start capacitor C1, and is used to release the energy stored in the slow-start capacitor C1 when the power is off.
3. The combined power input high-voltage bus soft-start protection circuit according to claim 2, characterized in that, The unidirectional conducting element D2 is a diode, whose anode is connected to the first terminal of the slow-start capacitor C1, and whose cathode is connected to the positive terminal of the DC input terminal V1 through the discharge resistor R3.
4. The combined power input high-voltage bus soft-start protection circuit according to claim 1, characterized in that, The blocking unit D1 is a diode, with its anode connected to the positive terminal of the DC input terminal V1 and its cathode connected to the positive terminal of the bus capacitor C2.
5. A combined power supply, characterized in that, The combined power input high-voltage bus soft-start protection circuit according to any one of claims 1-4 is used to suppress over-power damage to the power switch Q1 caused by rapid switching of input voltage.