CN212462773U - High-voltage filtering protection circuit - Google Patents
High-voltage filtering protection circuit Download PDFInfo
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- CN212462773U CN212462773U CN202020753981.8U CN202020753981U CN212462773U CN 212462773 U CN212462773 U CN 212462773U CN 202020753981 U CN202020753981 U CN 202020753981U CN 212462773 U CN212462773 U CN 212462773U
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- 238000002955 isolation Methods 0.000 claims description 4
- 239000003985 ceramic capacitor Substances 0.000 claims description 3
- 229910000859 α-Fe Inorganic materials 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- 229910052755 nonmetal Inorganic materials 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
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- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
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- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
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- 238000009413 insulation Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
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Abstract
The utility model relates to a high-voltage filter protection circuit, which is formed by connecting a pre-stage protection circuit connected with a high-voltage charging power supply circuit and a post-stage filter circuit connected with a load discharge circuit; the front-stage protection circuit comprises a series current-limiting resistor R1, a series current-limiting resistor R2, a parallel current-limiting resistor R3, a parallel current-limiting resistor R4, a parallel discharge tube G1 and a transient voltage suppressor D1, wherein the series current-limiting resistor R2 is connected with the rear-stage filter circuit in series to form a first branch circuit, and the parallel current-limiting resistor R3 is connected with the parallel discharge tube G1 in series to form a second branch circuit; the parallel current limiting resistor R4 is connected with the transient voltage suppressor D1 in series to form a third branch circuit; and the series current limiting resistor R1 is connected with the first branch circuit, the second branch circuit and the third branch circuit. The circuit is mainly used for load pulse discharge, is easy to generate overvoltage and steep-front pulse, and is particularly suitable for working conditions such as capacitor discharge and the like.
Description
Technical Field
The invention relates to a high-voltage filter protection circuit, in particular to a filter protection circuit consisting of high-voltage passive devices, which isolates a load discharge circuit from a high-voltage charging power supply circuit, protects a high-voltage power supply and protects a high-voltage part and a low-voltage control part of the high-voltage power supply from being damaged by recoil caused by a fast front edge and a steep pulse generated by load discharge. The pulse absorber is mainly used for absorbing positive and negative high-voltage and steep-front pulses generated by high-voltage capacitive load discharge, and is particularly suitable for working conditions such as capacitance discharge and the like.
Background
In the field of pulse power, energy needs to be released instantaneously in order to achieve energy compression. When the capacitor is used for storing energy, a high-voltage steep-front pulse is generated on a load at the moment of discharging. The pulse is easy to cause overvoltage, the amplitude value of the pulse exceeds the rated voltage of the charging power supply, and high-voltage devices of a high-voltage main loop part of the charging power supply, such as a rectifier diode, an inverter switch and the like, are easy to damage; or the leading edge of the pulse is very steep, and the low-voltage control loop of the charging power supply can be interfered without an isolation measure, so that partial devices such as an operational amplifier chip, a pulse modulation chip and the like are damaged.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: a circuit formed by passive devices is adopted to protect the high-voltage charging power supply to normally work in a load charging and discharging state.
The technical scheme for solving the technical problem is as follows: a circuit with filtering and protecting functions is adopted to form a two-stage circuit, so that the amplitude of the recoil voltage of the load is reduced, the gradient of the recoil front edge of the load is slowed down, and the power supply is protected to work safely and reliably, and the specific technical scheme is as follows:
a high-voltage filter protection circuit is formed by connecting a front stage protection circuit connected with a high-voltage charging power supply loop and a rear stage filter circuit connected with a load discharging loop; the front-stage protection circuit comprises a series current-limiting resistor R1, a series current-limiting resistor R2, a parallel current-limiting resistor R3, a parallel current-limiting resistor R4, a parallel discharge tube G1 and a transient voltage suppressor D1, wherein the series current-limiting resistor R2 is connected with the rear-stage filter circuit in series to form a first branch circuit, and the parallel current-limiting resistor R3 is connected with the parallel discharge tube G1 in series to form a second branch circuit; the parallel current limiting resistor R4 is connected with the transient voltage suppressor D1 in series to form a third branch circuit; and the series current limiting resistor R1 is connected with the first branch circuit, the second branch circuit and the third branch circuit.
The high-voltage filter protection circuit is further designed as follows: the resistance values of the resistors are required to be R1= R2=100 Ω, R3=5 Ω and R4=20 Ω.
The high-voltage filter protection circuit is further designed as follows: the breakdown voltage of the discharge tube G1 and the transient voltage suppressor D1 is greater than or equal to the rated output voltage of the power supply.
The high-voltage filter protection circuit is further designed as follows: the post-stage filter circuit consists of isolation inductors L1 and L2 and a parallel capacitor C1.
The high-voltage filter protection circuit is further designed as follows: the inductors L1 and L2 are ferrite magnetic rods, the inductors are wound by adopting non-metal frameworks, and two ends of each inductor are insulated and chamfered.
The high-voltage filter protection circuit is further designed as follows: inductance L1= inductance L2=500 uH.
The high-voltage filter protection circuit is further designed as follows: the capacitor is a ceramic capacitor, C1=100pF, and the withstand voltage meets the withstand voltage requirement of the power output.
The high-voltage filter protection circuit is further designed as follows: the load side of the rear stage filter circuit is connected with a grounding resistor
The high-voltage filter protection circuit is further designed as follows: the grounding resistor is made of copper sheets.
After the invention is added between a power supply and a load, the invention has the following characteristics:
1. the output performance of the power supply is not greatly influenced. The output voltage of the high-voltage charging power supply enters the high-voltage filtering protection circuit after being rectified, the working frequency of the power supply is in the range of hundred kHz, the calculated inductive reactance of the inductors L1 and L2 is not large, and the influence on the output power of the power supply is not large.
2. The power dissipated across the resistor is small. The resistances of the resistors R1 and R2 are hundreds of ohms, the output current of a general kW-level high-voltage charging power supply is in mA level, the power consumed on the resistor is less than 10W, the heat consumption on the resistor accounts for less than 1% of the power supply, and the influence on the power consumption and the energy transmission of the power supply is small. The resistors R1 and R2 adopt common high-power resistors, and can meet the heat dissipation requirement without adopting special heat dissipation measures.
3. And reducing overvoltage pulse generated by load discharge. A discharge tube G1 with strong discharge capacity is added in the high-voltage filter protection circuit, most of overvoltage energy can be discharged, and the overvoltage energy fed into a power supply is very small; the high-voltage filter protection circuit is added with the transient voltage suppressor D1 with high response speed, so that the defect of slow response of the discharge tube G1 can be considered, and overvoltage pulse is further reduced.
4. The steep front pulse generated by the discharge of the load is slowed down. The steep front pulse generated by discharge firstly passes through a post-stage filter circuit, the high-frequency component of the pulse is absorbed through LC resonance, and the pulse voltage with the gradually-slowed front edge is fed into a pre-stage protection circuit for further absorption.
5. The volume is small and the effect is obvious. The device is selected from simple passive devices, and after reasonable parameter selection, the requirement of voltage resistance is met. The circuit has simple structure and strong practicability, and can protect the power supply from being damaged by the interference of load discharge to the maximum extent.
Drawings
FIG. 1 is a schematic diagram of a high voltage filter protection circuit
Fig. 2 is a high voltage filter protection circuit access diagram.
Detailed Description
The operation of the present invention will be described in detail with reference to the above drawings.
As shown in fig. 1, the circuit is formed by connecting a front stage protection circuit connected with a high-voltage charging power supply loop and a rear stage filter circuit connected with a load discharging loop; the pre-stage protection circuit consists of series current-limiting resistors R1 and R2, parallel current-limiting resistors R3 and R4, a parallel discharge tube G1 and a transient voltage suppressor D1. The resistors R1 and R2 are connected with the power supply in series and used for limiting and shunting, and a parallel circuit consisting of the resistors R3 and R4, the discharge tube and the D1 is used for discharging pulse energy. The resistance value meets the requirements that R2 is more than or equal to R1, R4 and R3. The inductors L1 and L2 are connected with the power supply in series and used for slowing down the leading edge of the discharge pulse, and the middle of the inductors is provided with a magnetic bar used for increasing the inductance value; the capacitor C1 is a high voltage capacitor for absorbing the energy of the discharge pulse. The resistance value of the resistor is selected according to the current flowing through the resistor, and the power consumption of the resistor is smaller than the rated power consumption; the discharge tube is selected to have breakdown voltage larger than the power supply output voltage, D1 is selected to be a TVS tube with high withstand voltage, and the withstand voltage value is larger than the power supply output voltage after series connection; the inductor is wound by a high-voltage wire, an insulating framework is arranged between the coil and the magnetic core, and the end part of the framework is isolated so as to increase the creepage distance; the capacitor is made of ceramic, and the withstand voltage value of the ceramic capacitor is high. The power output is negative pulse, the breakdown voltage of the discharge tube G1 and the reverse withstand voltage of the transient voltage suppressor D1 are higher than the power output voltage, the power output is in a high-resistance state when the power normally works, and the power output is connected in series with R2 through a resistor R1 and stably works.
When the load is capacitive and discharge occurs, the generated pulse front edge is very steep, which is equivalent to that the high-frequency component energy of the pulse is very large, and the pulse amplitude is very high and exceeds the output rated voltage of the power supply. The LC resonance frequency of the rear stage filter circuit is close to the high frequency component frequency range of the discharge pulse, when the pulse passes through the LC resonance circuit, most of the energy in the high frequency component frequency range is consumed due to resonance, and only the low frequency component is input to the front stage protection circuit. The values of the resistors R3 and R4 are both much smaller than the value of the resistor R1, and the current flowing through the resistors R3 and R4 is much larger than the current flowing through the resistor R1. When the amplitude of the pulse input to the pre-stage protection circuit is higher than the reverse breakdown voltage of the transient voltage suppressor D1 and the breakdown voltage of the discharge tube G1, the transient voltage suppressor D1 loop and the discharge tube G1 loop start to operate, and the amplitude of the voltage is clamped at a lower certain value. The transient voltage suppressor D1 loop is connected in parallel with the discharge tube G1 loop, the discharge tube G1 loop is mainly used for draining and absorbing most energy, and the diode is mainly used for clamping and maintaining the voltage flowing into the power supply within a safe voltage range.
In order to reduce power loss, the resistor R1= R2=100 Ω, and power is calculated according to the current flowing through the resistor; the resistor R3=5 Ω, the resistor R4=20 Ω, and the power is selected according to 1% of the output power of the power supply; inductance L1= L2=500uH, adopt ferrite bar magnet as the magnetic core, the inductance can double-deck coiling, and turn-to-turn and interlayer insulation design satisfy the requirement of power output voltage. The voltage resistance of the parallel capacitor C1 meets the requirement of power supply output voltage, and the capacitance value is generally selected to be about 100 pF.
The post-stage filter circuit consists of isolation inductors L1 and L2 and a parallel capacitor C1. The inductors L1 and L2 are connected in series with the capacitor C1 to form a resonant circuit, and the resonant frequency is close to the frequency of load discharge. The principle of the latter stage circuit is as follows: the high-voltage signal output by the preceding-stage protection circuit enters the LC circuit, and the resonance frequency of the LC is far greater than the working frequency of the power supply, so that the output of the power supply is not influenced.
The high voltage filter protection circuit is connected to the power supply output and the load input as shown in fig. 2. The circuit should have input and output terminal identification. Because the design voltage resistance of the general grounding terminal is lower, the wiring should also have the mark. The input and output high-voltage connecting wires of the high-voltage filter protection circuit are in a direct insertion type, and the high-voltage part cannot be directly exposed, so that electric shock accidents are prevented.
The grounding position is determined as shown in fig. 2. Generally, a load needs to be tested, a ground point at the moment of discharging is raised by the ground potential due to large current, the test equipment and the load to be tested need to be connected in common for protecting the test equipment, and the ground position is the load side ground.
After the high-voltage filter protection circuit is connected, the power supply charges the capacitive load through the protection circuit. When the load short circuit discharges to generate high voltage over pulse, the pulse enters the filter network. The inductor and the capacitor in the filter network form an LC oscillating circuit, high-frequency components of the over-pulse are absorbed, the pulse amplitude is reduced, and the residual low-frequency components enter a protection network. When the amplitude of the pulse voltage applied to the protection diode and the discharge tube exceeds its protection voltage, the diode and the discharge tube loop respond. The discharge tube has low response speed but strong current leakage capacity, can discharge most energy, has high response speed and can further absorb high-frequency components. At the moment, the amplitude of the pulse voltage fed into the power supply is further reduced, so that the devices of the power supply control part are effectively protected from overvoltage, and the power supply failure rate is reduced.
The circuit designed by the invention is added between the output end and the load input end of the capacitive load charging power supply, has a filtering protection function, is complete in function and has an obvious protection effect on the power supply.
Claims (9)
1. A high-voltage filter protection circuit is characterized in that: the high-voltage charging circuit is formed by connecting a front-stage protection circuit connected with a high-voltage charging power supply circuit and a rear-stage filter circuit connected with a load discharging circuit; the front-stage protection circuit comprises a series current-limiting resistor R1, a series current-limiting resistor R2, a parallel current-limiting resistor R3, a parallel current-limiting resistor R4, a parallel discharge tube G1 and a transient voltage suppressor D1, wherein the series current-limiting resistor R2 is connected with the rear-stage filter circuit in series to form a first branch circuit, and the parallel current-limiting resistor R3 is connected with the parallel discharge tube G1 in series to form a second branch circuit; the parallel current limiting resistor R4 is connected with the transient voltage suppressor D1 in series to form a third branch circuit; and the series current limiting resistor R1 is connected with the first branch circuit, the second branch circuit and the third branch circuit.
2. The high-voltage filter protection circuit according to claim 1, wherein: the resistance values of the resistors are required to be R1= R2=100 Ω, R3=5 Ω and R4=20 Ω.
3. The high-voltage filter protection circuit according to claim 1, wherein: the breakdown voltage of the discharge tube G1 and the transient voltage suppressor D1 is greater than or equal to the rated output voltage of the power supply.
4. The high-voltage filter protection circuit according to claim 1, wherein: the post-stage filter circuit consists of isolation inductors L1 and L2 and a parallel capacitor C1.
5. The high-voltage filter protection circuit according to claim 4, wherein: the inductors L1 and L2 are ferrite magnetic rods, the inductors are wound by adopting non-metal frameworks, and two ends of each inductor are insulated and chamfered.
6. The high-voltage filter protection circuit according to claim 5, wherein: inductance L1= inductance L2=500 uH.
7. The high-voltage filter protection circuit according to claim 4, wherein: the capacitor is a ceramic capacitor, C1=100pF, and the withstand voltage meets the withstand voltage requirement of the power output.
8. The high-voltage filter protection circuit according to claim 1, wherein: and the load side of the rear-stage filter circuit is connected with a grounding resistor.
9. The high-voltage filter protection circuit according to claim 8, wherein: the grounding resistor is made of copper sheets.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020753981.8U CN212462773U (en) | 2020-05-09 | 2020-05-09 | High-voltage filtering protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020753981.8U CN212462773U (en) | 2020-05-09 | 2020-05-09 | High-voltage filtering protection circuit |
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| CN212462773U true CN212462773U (en) | 2021-02-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020753981.8U Active CN212462773U (en) | 2020-05-09 | 2020-05-09 | High-voltage filtering protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116316504A (en) * | 2023-02-02 | 2023-06-23 | 深圳市华麒嘉电子有限公司 | Protection circuit, device and liquid crystal display comprising ceramic discharge tube |
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2020
- 2020-05-09 CN CN202020753981.8U patent/CN212462773U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116316504A (en) * | 2023-02-02 | 2023-06-23 | 深圳市华麒嘉电子有限公司 | Protection circuit, device and liquid crystal display comprising ceramic discharge tube |
| CN116316504B (en) * | 2023-02-02 | 2023-11-17 | 深圳市华麒嘉电子有限公司 | Protection circuit, device and liquid crystal display comprising ceramic discharge tube |
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