Load short-circuit discharge current suppression circuit and method of high-voltage small-current output power supply

Abstract

The invention belongs to the field of power supply protection, and relates to a load short-circuit discharge current suppression circuit and method of a high-voltage small-current output power supply. An abnormal working condition protection unit is connected with a power supply output equivalent load RL and an LR low-pass filtering unit, the LR low-pass filtering unit is connected with the power supply output equivalent load RL, and the abnormal working condition protection unit is used for being connected with a high-voltage small-current output power supply. The LR low-pass filtering unit is used for suppressing the peak value of transient impact current and preventing large current from entering the power supply. The abnormal working condition protection unit is used for further protecting the high-voltage small-current output power supply, preventing a power supply rectification side switching device from being impacted by abnormal electric stress, and maintaining stable work of a preceding-stage high-voltage power supply circuit. After the abnormal short-circuit working condition is eliminated, the initial output state can be quickly recovered. The short-circuit discharge current output by the high-voltage power supply can be effectively suppressed, and the power supply can quickly recover to the initial output state after the abnormal short-circuit working condition is eliminated.

Description

Technical Field

[0001] The invention belongs to the field of power supply protection, and relates to a load short-circuit discharge current suppression circuit and method for a high-voltage and low-current output power supply. Background Art

[0002] The working principle of the current commonly used high-voltage power supply output short-circuit discharge current suppression circuit is: by collecting the power supply input or output current peak signal, adjusting the power supply working state and output voltage, and then reducing the impact of the discharge current spike on the power supply itself. It mainly has the following problems: 1. The overall structure of the circuit is relatively complex, involving a relatively large number of functional circuits and components, and the development and production costs are high; 2. When a load short circuit occurs, the response of the commonly used high-voltage power supply output short-circuit discharge current suppression circuit is generally: the power supply output voltage drops or the power supply shuts off the output. When the load short circuit is eliminated, the power supply output self-recovery adjustment time is generally long and cannot quickly recover to the initial state.

[0003] In summary, the existing high-voltage power supply output short-circuit discharge current suppression circuit has the problems of complex circuit structure and inability to quickly recover to the initial state after the short circuit is eliminated. Summary of the invention

[0004] The purpose of the present invention is to provide a load short-circuit discharge current suppression circuit and method for a high-voltage and low-current output power supply, so as to solve the technical problems that the existing high-voltage power supply output short-circuit discharge current suppression circuit has a complex circuit structure, a long response time and cannot quickly recover to the initial state after the short circuit is eliminated. The present invention can effectively suppress the short-circuit discharge current of the high-voltage power supply output, and the power supply can quickly recover to the initial output state after the short-circuit abnormal condition is eliminated, and the circuit structure is simple.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply, comprising an LR low-pass filter unit and an abnormal operating condition protection unit, wherein the abnormal operating condition protection unit is respectively connected to the power supply output equivalent load R L And LR low-pass filter unit, LR low-pass filter unit is connected to the power supply output equivalent load R L The abnormal operating condition protection unit is used to connect the previous high voltage power supply circuit.

[0006] Furthermore, the LR low-pass filter unit includes a current limiting resistor R1, a transient current suppression inductor L1 and a kickback voltage absorption resistor R2. One end of the current limiting resistor R1 is connected to an equivalent load R through a power supply output. LThe abnormal operating condition protection unit is connected, and the other end of the current limiting resistor R1 is connected to the abnormal operating condition protection unit through the transient current suppression inductor L1, and the transient current suppression inductor L1 is connected in parallel with the kickback voltage absorption resistor R2.

[0007] Furthermore, the current limiting resistor R1 is a resistor capable of resisting transient current impact.

[0008] Further, if the high-voltage and low-current output power supply has no output filter inductor, the abnormal operating condition protection unit includes a first power supply output filter capacitor Cout1, one end of the first power supply output filter capacitor Cout1 is connected to the cathode of the transient current bypass diode V1, and the other end of the first power supply output filter capacitor Cout1 is connected to the anode of the transient current bypass diode V1 through the isolation resistor R4 and the isolation inductor L2 in sequence, and the LR low-pass filter unit is connected between the anode of the transient current bypass diode V1 and the isolation inductor L2, and the isolation inductor L2 is connected in parallel with the kickback voltage absorption resistor R3; The cathode of the transient current bypass diode V1 is used to connect the positive output terminal of the previous high-voltage power supply circuit, and the first power supply output filter capacitor Cout1 and the isolation resistor R4 are used to connect the negative output terminal of the previous high-voltage power supply circuit.

[0009] Furthermore, the isolation resistor R4 is a resistor capable of resisting transient current impact.

[0010] Further, if the high-voltage and low-current output power supply has an output filter inductor, the abnormal operating condition protection unit includes a second power supply output filter capacitor Cout2, one end of the second power supply output filter capacitor Cout2 is connected to the cathode of the freewheeling diode V2, the other end of the second power supply output filter capacitor Cout2 is connected to the anode of the freewheeling diode V2 through the power supply output filter inductor L3 and the voltage spike absorption capacitor C1 in sequence, the power supply output filter inductor L3 is connected to the voltage negative end of the voltage spike absorption capacitor C1, the voltage positive end of the voltage spike absorption capacitor C1 is respectively connected to the anode of the freewheeling diode V2 and the cathode of the voltage spike clamping diode V3, the anode of the voltage spike clamping diode V3 is connected between the power supply output filter inductor L3 and the second power supply output filter capacitor Cout2 and the LR low-pass filter unit; The cathode of the freewheeling diode V2 is used to connect the positive output terminal of the preceding high-voltage power supply circuit, and the voltage negative terminal of the power output filter inductor L3 and the voltage peak absorption capacitor C1 is used to connect the negative output terminal of the preceding high-voltage power supply circuit.

[0011] Furthermore, the voltage spike absorption capacitor C1 is a high dv / dt pulse large current capacitor, and the voltage spike clamping diode V3 and the freewheeling diode V2 are diodes capable of withstanding high voltage and transient impact current.

[0012] Based on the above structure, the present invention also discloses a working method of a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply, comprising the following steps: Connect the front-stage high-voltage power supply circuit, abnormal operating condition protection unit and LR low-pass filter unit to the power supply output equivalent load R L connect; When the power supply output equivalent load R L When a short circuit occurs, a transient surge current I L , through the LR low-pass filter unit to suppress the transient impact current I L The impact peak value can be reduced to prevent large current from entering the high-voltage and low-current output power supply; The abnormal condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply.

[0013] Furthermore, if the high-voltage and low-current output power supply has no output filter inductor, the abnormal operating condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit and the steps to ensure the stable operation of the high-voltage and low-current output power supply are as follows: When the power supply output equivalent load R L When a short circuit occurs and a forward voltage appears across the transient current bypass diode V1, the diode acts as a bypass. The transient current bypass diode V1, the isolation resistor R4, and the isolation inductor L2 jointly maintain the stable operation of the high-voltage and low-current output power supply. When the power supply output equivalent load R L When a short circuit causes abnormal voltage fluctuations at the load end, the isolation resistor R4 and the isolation inductor L2 act as temporary loads to maintain stable operation of the previous circuit and prevent the high-voltage and low-current output power supply from experiencing a large output voltage drop or even shutting down and restarting. L After the short-circuit condition is eliminated, the high-voltage and low-current output power supply quickly returns to the initial output state.

[0014] Furthermore, if the high-voltage and low-current output power supply has an output filter inductor, the abnormal operating condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit and the steps to ensure the stable operation of the high-voltage and low-current output power supply are as follows: When the power supply output equivalent load R LWhen a short circuit occurs, the power supply output filter inductor L3 further suppresses the peak value of the transient impact current. At the same time, when the transient impact current flows through the power supply output filter inductor L3, a large voltage spike is generated on the power supply output filter inductor L3, and the voltage spike clamping diode V3 is forward-conducted, and the absorption capacitor C1 is charged to absorb the voltage spike. When the voltage across the absorption capacitor C1 is greater than the output voltage of the previous high-voltage power supply circuit, the freewheeling diode V2 is forward-conducted, and the absorption capacitor C1 is discharged, thereby achieving lossless absorption of electric energy and protecting the previous circuit from abnormal voltage stress.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The abnormal operating condition protection units of the present invention are respectively connected to the power supply output equivalent load R L And LR low-pass filter unit, LR low-pass filter unit is connected to the power supply output equivalent load R L The abnormal condition protection unit is used to connect the high-voltage and low-current output power supply. When the power supply outputs the equivalent load R L When a short circuit occurs, the LR low-pass filter unit is used to suppress the peak value of the transient impact current and prevent large current from entering the power supply. The abnormal operating condition protection unit is used to further protect the high-voltage and low-current output power supply, prevent the switching devices on the power supply rectifier side from being impacted by abnormal electrical stress, maintain the stable operation of the front-stage high-voltage power supply circuit, and quickly restore to the initial output state when the short-circuit abnormal operating condition is eliminated. That is, the present invention can effectively suppress the short-circuit discharge current output by the high-voltage power supply, and the power supply can quickly restore to the initial output state after the short-circuit abnormal operating condition is eliminated, and the circuit structure is simple.

[0016] 2. For a high-voltage and low-current output power supply without an output filter inductor, the transient current bypass diode V1 of the present invention is reversely cut off in a normal working state. When an abnormal working condition such as a load short circuit causes a forward voltage to appear at both ends, the transient current bypass diode V1 acts as a bypass to prevent the switch device on the rectifier side of the power supply from being impacted by abnormal electrical stress. The transient current bypass diode V1, the isolation resistor R4, and the isolation inductor L2 jointly maintain the stable operation of the front-stage high-voltage power supply circuit. At the same time, when an abnormal working condition such as a load short circuit causes an abnormal fluctuation in the load-end voltage, the isolation resistor R4 and the isolation inductor L2 act as a temporary load to maintain the stable operation of the front-stage high-voltage power supply circuit and avoid a large output voltage drop or even shutdown and restart of the high-voltage and low-current output power supply. When the power supply output equivalent load R L After the short-circuit condition is eliminated, the high-voltage and low-current output power supply quickly returns to the initial output state.

[0017] 3. For a high-voltage, low-current output power supply with an output filter inductor, the power supply output filter inductor L3 of the present invention further suppresses the peak value of the transient impact current. At the same time, when the transient impact current flows through the power supply output filter inductor L3, a large voltage spike is generated on the power supply output filter inductor L3, and the voltage spike clamping diode V3 is forward-conducted, and the absorption capacitor C1 is charged to absorb the voltage spike. When the voltage across the absorption capacitor C1 is greater than the output voltage of the previous high-voltage power supply circuit, the freewheeling diode V2 is forward-conducted, and the absorption capacitor C1 is discharged, thereby achieving lossless absorption of electric energy and protecting the previous high-voltage power supply circuit from abnormal voltage stress.

[0018] 4. The method of the present invention is used in the power supply output equivalent load R L A short circuit generates a transient surge current I L When the transient impact current I is suppressed by the LR low-pass filter unit L The impact peak value is reduced to prevent large current from entering the high-voltage and low-current output power supply, thus improving the stability and reliability of the entire power supply system. The abnormal operating condition protection unit isolates or suppresses the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply. Through the dual protection mechanism, the protection effect of the power supply in abnormal conditions such as short circuit is greatly enhanced, and the safety and reliability of the power supply are improved. When the abnormal working condition is eliminated, the power supply can continue to stably output high-voltage and low-current to meet the normal working requirements of the load, ensuring the continuity and stability of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply without an output filter inductor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply with an output filter inductor according to an embodiment of the present invention; Figure 3 The figure is a flow chart of the method of the present invention.

[0020] Among them: 1. LR low-pass filter unit; 2. Abnormal working condition protection unit. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 The present invention discloses a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply, comprising an LR low-pass filter unit 1 and an abnormal operating condition protection unit 2, wherein the abnormal operating condition protection unit 2 is connected to the power supply output equivalent load R L and LR low-pass filter unit 1, LR low-pass filter unit 1 is connected to the power supply output equivalent load R L , the abnormal condition protection unit 2 is used to connect the front-stage high-voltage power supply circuit. When the power supply output equivalent load R L When a short circuit occurs, the LR low-pass filter unit 1 is used to suppress the peak value of the transient impact current and prevent large current from entering the power supply. The abnormal operating condition protection unit 2 is used to further protect the high-voltage and low-current output power supply, prevent the switching devices on the power supply rectifier side from being impacted by abnormal electrical stress, maintain the stable operation of the front-stage high-voltage power supply circuit, and quickly restore to the initial output state when the short-circuit abnormal operating condition is eliminated. That is, the present invention can effectively suppress the short-circuit discharge current output by the high-voltage power supply, and the power supply can quickly restore to the initial output state after the short-circuit abnormal operating condition is eliminated, and the circuit structure is simple.

[0024] Embodiment 1: See also Figure 1 This embodiment discloses a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply, which is aimed at a high-voltage and low-current output power supply without an output filter inductor, and includes an LR low-pass filter unit 1 and an abnormal operating condition protection unit 2. The abnormal operating condition protection unit 2 is respectively connected to the power supply output equivalent load R L and LR low-pass filter unit 1, LR low-pass filter unit 1 is connected to the power supply output equivalent load R L The abnormal operating condition protection unit 2 is used to connect the front-stage high-voltage power supply circuit.

[0025] Preferably, the LR low-pass filter unit 1 includes a current limiting resistor R1, a transient current suppression inductor L1 and a kickback voltage absorption resistor R2, and one end of the current limiting resistor R1 is connected to an equivalent load R L The abnormal operating condition protection unit 2 is connected, and the other end of the current limiting resistor R1 is connected to the abnormal operating condition protection unit 2 through the transient current suppression inductor L1, and the transient current suppression inductor L1 is connected in parallel with the kickback voltage absorption resistor R2.

[0026] Preferably, the current limiting resistor R1 is a resistor capable of resisting transient current impact.

[0027] Preferably, the abnormal operating condition protection unit 2 includes a first power supply output filter capacitor Cout1, one end of the first power supply output filter capacitor Cout1 is connected to the cathode of the transient current bypass diode V1, the other end of the first power supply output filter capacitor Cout1 is connected to the anode of the transient current bypass diode V1 through the isolation resistor R4 and the isolation inductor L2 in sequence, the LR low-pass filter unit 1 is connected between the anode of the transient current bypass diode V1 and the isolation inductor L2, and the isolation inductor L2 is connected in parallel with the kickback voltage absorption resistor R3; The cathode of the transient current bypass diode V1 is used to connect the positive output terminal of the previous high-voltage power supply circuit, and the first power supply output filter capacitor Cout1 and the isolation resistor R4 are used to connect the negative output terminal of the previous high-voltage power supply circuit.

[0028] Preferably, the isolation resistor R4 is a resistor capable of resisting transient current impact.

[0029] Embodiment 2: See also Figure 1 This embodiment discloses a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply. The high-voltage and low-current output power supply has an output filter inductor, including an LR low-pass filter unit 1 and an abnormal operating condition protection unit 2. The abnormal operating condition protection unit 2 is respectively connected to the power supply output equivalent load R L and LR low-pass filter unit 1, LR low-pass filter unit 1 is connected to the power supply output equivalent load R L The abnormal operating condition protection unit 2 is used to connect the front-stage high-voltage power supply circuit.

[0030] Preferably, the LR low-pass filter unit 1 includes a current limiting resistor R1, a transient current suppression inductor L1 and a kickback voltage absorption resistor R2, and one end of the current limiting resistor R1 is connected to an equivalent load R L The abnormal operating condition protection unit 2 is connected, and the other end of the current limiting resistor R1 is connected to the abnormal operating condition protection unit 2 through the transient current suppression inductor L1, and the transient current suppression inductor L1 is connected in parallel with the kickback voltage absorption resistor R2.

[0031] Preferably, the current limiting resistor R1 is a resistor capable of resisting transient current impact.

[0032] Preferably, the abnormal operating condition protection unit 2 includes a second power supply output filter capacitor Cout2, one end of the second power supply output filter capacitor Cout2 is connected to the cathode of the freewheeling diode V2, the other end of the second power supply output filter capacitor Cout2 is connected to the anode of the freewheeling diode V2 through the power supply output filter inductor L3 and the voltage spike absorption capacitor C1 in sequence, the power supply output filter inductor L3 is connected to the voltage negative end of the voltage spike absorption capacitor C1, the voltage positive end of the voltage spike absorption capacitor C1 is respectively connected to the anode of the freewheeling diode V2 and the cathode of the voltage spike clamping diode V3, the anode of the voltage spike clamping diode V3 is connected between the power supply output filter inductor L3 and the second power supply output filter capacitor Cout2 and the LR low-pass filter unit 1; The cathode of the freewheeling diode V2 is used to connect the positive output terminal of the preceding high-voltage power supply circuit, and the voltage negative terminal of the power output filter inductor L3 and the voltage peak absorption capacitor C1 is used to connect the negative output terminal of the preceding high-voltage power supply circuit.

[0033] Preferably, the voltage spike absorption capacitor C1 is a high dv / dt pulse large current capacitor, and the voltage spike clamping diode V3 and the freewheeling diode V2 are diodes capable of withstanding high voltage and transient impact current.

[0034] Embodiment three: See also Figure 1 This embodiment is directed to a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply without an output filter inductor: the circuit is composed of a current limiting resistor R1, a transient current suppression inductor L1 and its kickback voltage absorption resistor R2, a transient current bypass diode V1, an isolation resistor R4, an isolation inductor L2, a kickback voltage absorption resistor R3 and a first power supply output filter capacitor Cout1.

[0035] One end of the current limiting resistor R1 is connected to the power supply output equivalent load R L The negative end of the load current is connected to the negative end, that is, the outflow end of the load current, and the other end is connected to the transient current suppression inductor L1; the transient current suppression inductor L1 is connected in parallel with the kickback voltage absorption resistor R2 and then connected in series with the current limiting resistor R1, and the other end of the transient current suppression inductor L1 is connected to the anode of the transient current bypass diode V1; the cathode of the transient current bypass diode V1 is connected to the output positive end of the previous high-voltage power supply circuit, that is, the output positive end of the high-voltage and low-current output power supply; the isolation inductor L2 is connected in parallel with the kickback voltage absorption resistor R3, one end of the isolation inductor L2 is connected to the anode of the transient current bypass diode V1, and the other end of the isolation inductor L2 is connected to the isolation resistor R4; the other end of the isolation resistor R4 is connected to the output negative end of the previous high-voltage power supply circuit; Cout1 is the output filter capacitor of the power supply.

[0036] When the power load is short-circuited, a transient surge current I L , the current limiting resistor R1 is connected in series with the current limiting inductor L1 to form an LR low-pass filter circuit, which effectively suppresses the peak value of the transient impact current and prevents large current from entering the power supply; the transient current bypass diode V1 is reversely cut off under normal working conditions. When abnormal working conditions such as load short circuit cause forward voltage to appear at both ends, the transient current bypass diode V1 acts as a bypass to prevent the switching devices on the rectifier side of the power supply from being impacted by abnormal electrical stress. The transient current bypass diode V1, the isolation resistor R4 and the isolation inductor L2 jointly maintain the stable operation of the previous high-voltage power supply circuit; when abnormal working conditions such as load short circuit cause abnormal fluctuations in the load terminal voltage, the isolation resistor R4 and the isolation inductor L2 act as temporary loads to maintain the stable operation of the previous high-voltage power supply circuit, avoid a large output voltage drop in the high-voltage power supply or even shut down and restart, so that the high-voltage power supply can quickly recover to the initial output state after the abnormal working conditions such as load short circuit are eliminated.

[0037] The selection and design of components for this circuit should pay attention to the following: the current limiting resistor R1 and the isolation resistor R4 should be selected with the ability to resist transient current impact, such as wirewound resistors, etc., and the parameter values ​​should take into account the self-voltage drop and power consumption under steady-state operation; the value of the reverse voltage absorption resistor R2 of the transient current suppression inductor L1 should be much larger than the current limiting resistor R1. Generally, the value of R2 is more than 10 times that of R1 to avoid the decrease of the equivalent impedance of the reverse voltage absorption resistor R2 and the transient current suppression inductor L1 when abnormal working conditions such as load short circuit occur, which affects the transient current suppression effect. At the same time, a larger resistance value is conducive to reducing the power consumption of the resistor itself under normal working conditions; the value of the reverse voltage absorption resistor R3 of the isolation inductor L2 should be as large as possible while meeting the absorption requirements to reduce the power consumption of the resistor itself under normal working conditions; the transient current bypass diode V1 should have the characteristics of high voltage resistance and transient impact current resistance.

[0038] Embodiment 4: See also Figure 2 This embodiment is directed to a load short-circuit discharge current suppression circuit for a high-voltage and low-current output power supply with an output filter inductor: the circuit is composed of a current limiting resistor R1, a transient current suppression inductor L1 and its kickback voltage absorption resistor R2, a power supply output filter inductor L3, a voltage spike absorption capacitor C1, a voltage spike clamping diode V3, a freewheeling diode V2, and a second power supply output filter capacitor Cout2.

[0039] One end of the current limiting resistor R1 is connected to the power supply output equivalent load R LThe negative end of the load current is connected to the negative end of the current limiting resistor R1, that is, the outflow end of the load current, and the other end of the current limiting resistor R1 is connected to the transient current suppression inductor L1; the transient current suppression inductor L1 is connected in parallel with its kickback voltage absorption resistor R2, the transient current suppression inductor L1 is connected in series with the current limiting resistor R1, and the other end of the transient current suppression inductor L1 is connected to the voltage negative end of the second power supply output filter capacitor Cout2; the voltage positive end of the second power supply output filter capacitor Cout2 is connected to the output positive end of the previous stage high-voltage power supply circuit, that is, the output positive end of the high-voltage and low-current output power supply; one end of the power supply output filter inductor L3 is connected to the voltage negative end of the second power supply output filter capacitor Cout2, and the other end is connected to the voltage negative end of the voltage spike absorption capacitor C1, that is, the output negative end of the previous stage high-voltage power supply circuit; the anode of the voltage spike clamping diode V3 is connected to the voltage negative end of the second power supply output filter capacitor Cout2, and the cathode of the voltage spike clamping diode V3 is connected to the voltage positive end of the voltage spike absorption capacitor C1, that is, the anode of the freewheeling diode V2; the cathode of the freewheeling diode V2 is connected to the output positive end of the previous stage high-voltage power supply circuit.

[0040] When the power load is short-circuited, a transient surge current I L The current limiting resistor R1 is connected in series with the current limiting inductor L1 to form an LR low-pass filter circuit, which effectively suppresses the peak value of the transient impact current and prevents large current from entering the power supply; the power supply output filter inductor L3 further suppresses the peak value of the transient impact current. At the same time, when the transient impact current flows through the power supply output filter inductor L3, a large voltage spike is generated on the power supply output filter inductor L3, and the voltage spike clamping diode V3 is forward-conducted, and the absorption capacitor C1 is charged to absorb the voltage spike. When the voltage across the absorption capacitor C1 is greater than the output voltage of the previous high-voltage power supply circuit, the freewheeling diode V2 is forward-conducted, and the absorption capacitor C1 is discharged, thereby realizing lossless absorption of electric energy and protecting the previous high-voltage power supply circuit from abnormal voltage stress.

[0041] The selection and design of components for this circuit should pay attention to the following: the current limiting resistor R1 should be a resistor with the ability to resist transient current impact, such as a wirewound resistor, and its parameter value should take into account its own voltage drop and power consumption under steady-state operation; the reverse voltage absorption resistor R2 of the transient current suppression inductor L1 should be much larger than the current limiting resistor R1. Generally, the value of R2 is more than 10 times that of R1 to avoid the decrease of the equivalent impedance of the reverse voltage absorption resistor R2 and the transient current suppression inductor L1 when abnormal conditions such as load short circuit occur, which affects the transient current suppression effect. At the same time, a larger resistance value is beneficial to reducing the power consumption of the resistor itself under normal working conditions; the absorption capacitor C1 has a fast charging and discharging speed and withstands a large transient current, so a high dv / dt pulse large current capacitor should be selected; the voltage spike clamping diode V3 and the freewheeling diode V2 should have the characteristics of withstanding high voltage and transient impact current.

[0042] Based on the above structure, the present invention also discloses a working method of a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply, see Figure 3 , specifically including the following steps: S1. Connect the front-stage high-voltage power supply circuit, abnormal operating condition protection unit 2 and LR low-pass filter unit 1 to the power supply output equivalent load R L connect; S2. When the power supply output equivalent load R L When a short circuit occurs, a transient surge current I L , through the LR low-pass filter unit 1 to suppress the transient impact current I L The impact peak is reduced, avoiding large current from entering the high-voltage and low-current output power supply, and improving the stability and reliability of the entire power supply system.

[0043] S3. Abnormal operating condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply.

[0044] The dual protection mechanism: LR low-pass filtering and abnormal operating condition protection unit 2 greatly enhances the protection effect of the power supply in abnormal conditions such as short circuit, and improves the safety and reliability of the power supply. After the abnormal condition is eliminated, the power supply can continue to stably output high voltage and low current to meet the normal working requirements of the load, ensuring the continuity and stability of the entire system.

[0045] Embodiment five: This embodiment discloses a working method of a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply for a high-voltage and low-current output power supply without an output filter inductor. Figure 3 , including the following steps: S1. Connect the front-stage high-voltage power supply circuit, abnormal operating condition protection unit 2 and LR low-pass filter unit 1 to the power supply output equivalent load R L connect; S2. When the power supply output equivalent load R L When a short circuit occurs, a transient surge current I L , through the LR low-pass filter unit 1 to suppress the transient impact current I L The impact peak value can be reduced to prevent large current from entering the high-voltage and low-current output power supply; S3. Abnormal condition protection unit 2 is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply, as follows: When the power supply output equivalent load R LWhen a short circuit occurs and a forward voltage appears across the transient current bypass diode V1, the diode acts as a bypass. The transient current bypass diode V1, the isolation resistor R4, and the isolation inductor L2 jointly maintain the stable operation of the high-voltage and low-current output power supply. When the power supply output equivalent load R L When a short circuit causes abnormal voltage fluctuations at the load end, the isolation resistor R4 and the isolation inductor L2 act as temporary loads to maintain stable operation of the previous circuit and prevent the high-voltage and low-current output power supply from experiencing a large output voltage drop or even shutting down and restarting. L After the short-circuit condition is eliminated, the high-voltage and low-current output power supply quickly returns to the initial output state.

[0046] Embodiment six: This embodiment discloses a working method of a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply with an output filter inductor, see Figure 3 , including the following steps: S1. Connect the front-stage high-voltage power supply circuit, abnormal operating condition protection unit 2 and LR low-pass filter unit 1 to the power supply output equivalent load R L connect; S2. When the power supply output equivalent load R L When a short circuit occurs, a transient surge current I L , through the LR low-pass filter unit 1 to suppress the transient impact current I L The impact peak value can be reduced to prevent large current from entering the high-voltage and low-current output power supply; S3. Abnormal condition protection unit 2 is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply, as follows: When the power supply output equivalent load R L When a short circuit occurs, the power supply output filter inductor L3 further suppresses the peak value of the transient impact current. At the same time, when the transient impact current flows through the power supply output filter inductor L3, a large voltage spike is generated on the power supply output filter inductor L3, and the voltage spike clamping diode V3 is forward-conducted, and the absorption capacitor C1 is charged to absorb the voltage spike. When the voltage across the absorption capacitor C1 is greater than the output voltage of the previous high-voltage power supply circuit, the freewheeling diode V2 is forward-conducted, and the absorption capacitor C1 is discharged, thereby achieving lossless absorption of electric energy and protecting the previous circuit from abnormal voltage stress.

[0047] In summary, the present invention can achieve transient current spike suppression of the high-voltage power supply under abnormal working conditions such as load short-circuit discharge, prevent transient large current from entering the power supply and causing over-electric stress damage to components, and improve the working reliability of the power supply. The present invention solves the problem of transient current impact on the power supply caused by abnormal working conditions such as high-voltage power supply load short-circuit discharge from the source by using a small number of components, thereby reducing the number of power devices and overcurrent protection devices used, reducing the research and production costs of the product, improving the working reliability of the system, making the product more competitive in the market, and having high practical value and economic value.

[0048] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply is characterized in that: It comprises an LR low-pass filter unit (1) and an abnormal operating condition protection unit (2), wherein the abnormal operating condition protection unit (2) is respectively connected to the power supply output equivalent load R L and LR low-pass filter unit (1), the LR low-pass filter unit (1) is connected to the power supply output equivalent load R L The abnormal operating condition protection unit (2) is used to connect to the front-stage high-voltage power supply circuit.

2. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 1, characterized in that: The LR low-pass filter unit (1) comprises a current limiting resistor R1, a transient current suppression inductor L1 and a kickback voltage absorption resistor R2. One end of the current limiting resistor R1 is connected to an equivalent load R via a power supply output. L The abnormal operating condition protection unit (2) is connected, the other end of the current limiting resistor R1 is connected to the abnormal operating condition protection unit (2) via the transient current suppression inductor L1, and the transient current suppression inductor L1 is connected in parallel with the kickback voltage absorption resistor R2.

3. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 2, characterized in that: The current limiting resistor R1 is a resistor with the ability to resist transient current impact.

4. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 1 or 2, characterized in that: If the high-voltage and low-current output power supply has no output filter inductor, the abnormal operating condition protection unit (2) comprises a first power supply output filter capacitor Cout1, one end of the first power supply output filter capacitor Cout1 is connected to the cathode of the transient current bypass diode V1, the other end of the first power supply output filter capacitor Cout1 is connected to the anode of the transient current bypass diode V1 through the isolation resistor R4 and the isolation inductor L2 in sequence, the LR low-pass filter unit (1) is connected between the anode of the transient current bypass diode V1 and the isolation inductor L2, and the isolation inductor L2 is connected in parallel with a kickback voltage absorption resistor R3; The cathode of the transient current bypass diode V1 is used to connect the positive output terminal of the previous high-voltage power supply circuit, and the first power supply output filter capacitor Cout1 and the isolation resistor R4 are used to connect the negative output terminal of the previous high-voltage power supply circuit.

5. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 4, characterized in that: The isolation resistor R4 is a resistor capable of resisting transient current impact.

6. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 1 or 2, characterized in that: If the high-voltage and low-current output power supply has an output filter inductor, the abnormal operating condition protection unit (2) comprises a second power supply output filter capacitor Cout2, one end of the second power supply output filter capacitor Cout2 is connected to the cathode of the freewheeling diode V2, the other end of the second power supply output filter capacitor Cout2 is connected to the anode of the freewheeling diode V2 via the power supply output filter inductor L3 and the voltage spike absorption capacitor C1 in sequence, the power supply output filter inductor L3 is connected to the voltage negative end of the voltage spike absorption capacitor C1, the voltage positive end of the voltage spike absorption capacitor C1 is respectively connected to the anode of the freewheeling diode V2 and the cathode of the voltage spike clamping diode V3, the anode of the voltage spike clamping diode V3 is connected between the power supply output filter inductor L3 and the second power supply output filter capacitor Cout2 and the LR low-pass filter unit (1); The cathode of the freewheeling diode V2 is used to connect the positive output terminal of the preceding high-voltage power supply circuit, and the voltage negative terminal of the power output filter inductor L3 and the voltage peak absorption capacitor C1 is used to connect the negative output terminal of the preceding high-voltage power supply circuit.

7. The load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 6, characterized in that: The voltage spike absorption capacitor C1 is a high dv / dt pulse large current capacitor, and the voltage spike clamping diode V3 and the freewheeling diode V2 are diodes capable of withstanding high voltage and transient impact current.

8. A working method of a load short-circuit discharge current suppression circuit of a high-voltage and low-current output power supply, characterized in that: The following steps are involved: Connect the front-stage high-voltage power supply circuit, the abnormal operating condition protection unit (2) and the LR low-pass filter unit (1) to the power supply output equivalent load R L connect; When the power supply output equivalent load R L When a short circuit occurs, a transient surge current I L , through the LR low-pass filter unit (1) to suppress the transient impact current I L The impact peak value can be reduced to prevent large current from entering the high-voltage and low-current output power supply; The abnormal condition protection unit (2) is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit ensures the stable operation of the high-voltage and low-current output power supply.

9. The working method of the load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 8, characterized in that: If the high-voltage and low-current output power supply has no output filter inductor, the abnormal operating condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit and the steps to ensure the stable operation of the high-voltage and low-current output power supply are as follows: When the power supply output equivalent load R L When a short circuit occurs and a forward voltage appears across the transient current bypass diode V1, the diode acts as a bypass. The transient current bypass diode V1, the isolation resistor R4, and the isolation inductor L2 jointly maintain the stable operation of the high-voltage and low-current output power supply. When the power supply output equivalent load R L When a short circuit causes abnormal voltage fluctuations at the load end, the isolation resistor R4 and the isolation inductor L2 act as temporary loads to maintain stable operation of the previous circuit and prevent the high-voltage and low-current output power supply from experiencing a large output voltage drop or even shutting down and restarting. L After the short-circuit condition is eliminated, the high-voltage and low-current output power supply quickly returns to the initial output state.

10. The working method of the load short-circuit discharge current suppression circuit of the high-voltage and low-current output power supply according to claim 8, characterized in that: If the high voltage and low current output power supply has an output filter inductor, the abnormal operating condition protection unit is used to isolate or suppress the impact current I L The impact on the previous high-voltage power supply circuit and the steps to ensure the stable operation of the high-voltage and low-current output power supply are as follows: When the power supply output equivalent load R L When a short circuit occurs, the power supply output filter inductor L3 further suppresses the peak value of the transient impact current. At the same time, when the transient impact current flows through the power supply output filter inductor L3, a large voltage spike is generated on the power supply output filter inductor L3, and the voltage spike clamping diode V3 is forward-conducted, and the absorption capacitor C1 is charged to absorb the voltage spike. When the voltage across the absorption capacitor C1 is greater than the output voltage of the previous high-voltage power supply circuit, the freewheeling diode V2 is forward-conducted, and the absorption capacitor C1 is discharged, thereby achieving lossless absorption of electric energy and protecting the previous circuit from abnormal voltage stress.

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