Energy storage capacitor discharge protection circuit for laser range finder
Patent Information
- Application Number
- CN202522105346.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2035-09-29
AI Technical Summary
[0005]本实用新型的目的在于克服现有技术中激光测照器储能电容断电后放电速度慢、存在安全隐患且影响工作效率的问题，提供一种适用于大功率激光测照器的储能电容放电保护电路，该电路能够自动控制储能电容在短时间内完成安全放电，既避免操作人员遭受电击伤害、防止电容老化与半导体器件击穿，又能缩短放电等待时间，提升工作效率
[0016]Through the above technical solutions, the beneficial effects of this utility model are as follows: This application achieves fully automatic discharge by coordinating slow discharge and fast discharge circuits in an orderly manner, eliminating the need for manual contact with charged capacitors and completely avoiding the risk of electric shock to personnel; timely release of residual charge in capacitors can prevent capacitors from aging faster due to long-term charging, thus extending their lifespan, and can also prevent residual charge from damaging components such as ICs and MOSFETs, reducing equipment failure and maintenance costs; compared with traditional natural discharge or manual discharge methods, the RC delay control unit precisely controls the start-up time, significantly shortening the discharge cycle and significantly improving overall work efficiency.
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Figure CN224759960U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of laser measurement technology, and in particular to a discharge protection circuit for the energy storage capacitor of a laser measuring device. Background Technology
[0002] As a core device in the field of laser measurement, the laser illuminator has a complex internal structure, mainly comprising a control circuit, a detector drive circuit, a laser drive circuit, a TQ high-voltage circuit, and an energy storage capacitor charging circuit. Among these, the energy storage capacitor plays a crucial role in providing the laser with pulsed currents of up to several hundred amperes, such as... Figure 1 As shown, this circuit is a schematic diagram of an energy storage capacitor charging circuit. The main function of capacitors C19, C20, and C21 is to receive and store electrical energy from the charging circuit, forming a stable energy reserve. When the laser detector starts its operation, C19, C20, and C21, through their connection to the laser driver circuit, rapidly release the stored electrical energy, converting it into the large current pulses required by the laser. Based on this functional requirement, the energy storage capacitors used typically possess characteristics of large capacitance and high voltage.
[0003] After the laser detector completes testing and is powered off, the energy storage capacitor in existing technology discharges very slowly with the system, retaining a large amount of charge for a considerable period. This phenomenon causes several problems: First, if operators directly contact the charged energy storage capacitor, they are highly susceptible to electric shock, posing a serious threat to their personal safety. Second, the prolonged energization of the energy storage capacitor accelerates its aging, leading to a continuous decline in capacitor performance and shortening its lifespan, thus affecting the overall operational stability and lifespan of the laser detector. Third, if the circuit is operated while the energy storage capacitor is not discharged, the residual charge may be released through unexpected paths, damaging fragile semiconductor devices such as ICs and MOSFETs, causing equipment failure and increasing maintenance costs and difficulty. Fourth, waiting for the energy storage capacitor to completely discharge naturally or manually discharging it significantly extends preparation time before operation, slowing down the overall work progress and reducing work efficiency.
[0004] The core reason for the above problems is that, due to the large capacitance and high voltage of the energy storage capacitor in laser detectors, an effective discharge circuit cannot be formed without a dedicated discharge circuit. This results in the retention of charge for a long time, affecting the performance of the capacitor itself and causing many inconveniences for users. Therefore, there is an urgent need for an energy storage capacitor discharge protection circuit that can solve the above problems. Utility Model Content
[0005] The purpose of this invention is to overcome the problems of slow discharge speed, safety hazards, and reduced work efficiency of the energy storage capacitor in the existing laser detector after power failure. It provides a discharge protection circuit for the energy storage capacitor of a high-power laser detector. This circuit can automatically control the energy storage capacitor to complete safe discharge in a short time, which can not only prevent operators from being injured by electric shock and prevent capacitor aging and semiconductor device breakdown, but also shorten the discharge waiting time and improve work efficiency.
[0006] The technical solution is: a discharge protection circuit for the energy storage capacitor of a laser detector, including a slow discharge circuit and a fast discharge circuit; Both the slow discharge circuit and the fast discharge circuit are connected in parallel with the energy storage capacitor of the laser detector. When the laser detector is powered off, the slow discharge circuit starts and slowly discharges the energy storage capacitor when the first start time is reached; then, when the second start time is reached, the fast discharge circuit starts and works in conjunction with the slow discharge circuit to discharge the energy storage capacitor simultaneously until the discharge is complete.
[0007] Preferably, the slow discharge circuit includes a first switching unit, a first discharge unit, and a first delay control unit; The input terminal of the first switching unit is connected to the positive terminal of the energy storage capacitor, the output terminal is connected to the first discharge unit, and the control terminal is connected to the first delay control unit. The first delay control unit is used to trigger the first switching unit to conduct after the laser measuring device is powered off and the first turn-on time is reached, so that the energy storage capacitor can slowly discharge through the first discharge unit.
[0008] Preferably, the first switching unit includes a first transistor and a first MOSFET; The emitter of the first transistor is connected to the gate of the first MOSFET and the positive terminal of the energy storage capacitor, the base of the first transistor is connected to the first delay control unit, and the emitter of the first transistor is grounded. The drain of the first MOS transistor is connected to the positive terminal of the energy storage capacitor, and the source is connected to the first discharge unit.
[0009] Preferably, the first discharge unit includes a first discharge resistor, one end of which is connected to the source of the first MOS transistor, and the other end is grounded.
[0010] Preferably, the first delay control unit includes a first capacitor and a first resistor, and the first capacitor and the first resistor constitute an RC element for controlling the first turn-on time of the slow discharge circuit; One end of the first capacitor is connected to the base of the first transistor and the power supply of the laser detector, and the other end of the first capacitor is connected to one end of the first resistor, and the other end of the first resistor is grounded; the first turn-on time of the slow discharge circuit can be controlled by adjusting the parameters of the first capacitor and the first resistor.
[0011] Preferably, when the device is powered off, the first delay control unit causes the base voltage of the first transistor to slowly decrease through the discharge process of the first capacitor; when the base voltage of the first transistor drops below 0.7V, the first transistor turns on and drives the first MOSFET to turn on, thus initiating slow discharge.
[0012] Preferably, the fast discharge circuit includes a second switching unit, a second discharge unit, and a second delay control unit; The input terminal of the second switching unit is connected to the positive terminal of the energy storage capacitor, the output terminal is connected to the second discharge unit, and the control terminal is connected to the second delay control unit. The second delay control unit is used to trigger the second switching unit to conduct when the second turn-on time is reached, so that the energy storage capacitor can be quickly discharged through the second discharge unit.
[0013] Preferably, the second switching unit includes a second transistor and a second MOSFET; The emitter of the second transistor is connected to the gate of the second MOSFET and the positive terminal of the energy storage capacitor, the base of the second transistor is connected to the second delay control unit, and the emitter of the second transistor is grounded. The drain of the second MOS transistor is connected to the positive terminal of the energy storage capacitor, and the source is connected to the second discharge unit.
[0014] Preferably, the second discharge unit includes a second discharge resistor, one end of which is connected to the source of the second MOS transistor, and the other end is grounded.
[0015] Preferably, the second delay control unit includes a second capacitor and a second resistor, the second capacitor and the second resistor constituting an RC element for controlling the second turn-on time of the fast discharge circuit; One end of the second capacitor is connected to the base of the second transistor and the power supply of the laser detector, and the other end of the second capacitor is connected to one end of the second resistor, and the other end of the second resistor is grounded; the second turn-on time of the fast discharge circuit can be controlled by adjusting the parameters of the second capacitor and the second resistor.
[0016] Through the above technical solutions, the beneficial effects of this utility model are as follows: This application achieves fully automatic discharge by coordinating slow discharge and fast discharge circuits in an orderly manner, eliminating the need for manual contact with charged capacitors and completely avoiding the risk of electric shock to personnel; timely release of residual charge in capacitors can prevent capacitors from aging faster due to long-term charging, thus extending their lifespan, and can also prevent residual charge from damaging components such as ICs and MOSFETs, reducing equipment failure and maintenance costs; compared with traditional natural discharge or manual discharge methods, the RC delay control unit precisely controls the start-up time, significantly shortening the discharge cycle and significantly improving overall work efficiency. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of a charging circuit for an energy storage capacitor in the prior art.
[0018] Figure 2 This is a system module structure diagram of this utility model.
[0019] Figure 3 This is a schematic diagram of a slow discharge circuit according to an embodiment of the present invention.
[0020] Figure 4 This is a schematic diagram of a fast discharge circuit according to an embodiment of the present invention. Detailed Implementation
[0021] The foregoing and other technical contents, features and effects of this utility model are described in conjunction with the appendix below. Figure 2 To be continued Figure 4 The detailed description of the embodiments will make this clear. All structural details mentioned in the following embodiments are based on the accompanying drawings.
[0022] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.
[0023] like Figure 2 As shown, this application provides a discharge protection circuit for the energy storage capacitor of a laser detector, including a slow discharge circuit and a fast discharge circuit. Both the slow discharge circuit and the fast discharge circuit are connected in parallel with the energy storage capacitor of the laser detector and can be started sequentially according to preset logic after the device is powered off, working together to safely discharge the energy storage capacitor. Specifically, the slow discharge circuit is responsible for the initial discharge stage after the device is powered off, using low current discharge to avoid initial high voltage impacting circuit components; the fast discharge circuit starts after the slow discharge is initiated, forming a parallel discharge structure with the slow discharge circuit, increasing the discharge current to shorten the overall discharge time, and ultimately achieving complete discharge of the energy storage capacitor.
[0024] In the above, the slow discharge circuit includes a first switching unit, a first discharge unit, and a first delay control unit; the input terminal of the first switching unit is connected to the positive terminal of the energy storage capacitor, the output terminal is connected to the first discharge unit, and the control terminal is connected to the first delay control unit; the first delay control unit is used to trigger the first switching unit to conduct after the laser measuring device is powered off and the first turn-on time is reached, so that the energy storage capacitor can achieve slow discharge through the first discharge unit.
[0025] In one specific embodiment, such as Figure 3 As shown, the first switching unit includes a first transistor V2 and a first MOSFET V1. The first transistor V2 is the pilot control element of the slow discharge circuit. This transistor is a PNP type transistor. Its emitter is connected to the gate of the first MOSFET V1 and the positive terminal of the energy storage capacitor. Its base is connected to the first delay control unit, and its collector is directly grounded. It can control the gate potential of the first MOSFET V1 through its own conduction state. The first MOSFET V1 is the main switch of the slow discharge circuit. Its drain is connected to the positive terminal of the energy storage capacitor to obtain the capacitor charge, and its source is connected to the first discharge unit. When the gate receives the conduction signal transmitted by the first transistor V2, it can open the path between the energy storage capacitor and the first discharge unit. The core component of the first discharge unit is the first discharge resistor R2. One end of the resistor is connected to the source of the first MOSFET V1, and the other end is directly grounded. When the first MOSFET V1 is turned on, the charge of the energy storage capacitor can be transferred through the source of the first MOSFET V1 to the first discharge resistor R2, and then flow into the ground through the first discharge resistor R2. At the same time, the first discharge resistor R2 limits the discharge current through its own resistance value to achieve the effect of "slow discharge".
[0026] The first delay control unit, composed of a first capacitor C2 and a first resistor R3, is used to set the first turn-on time of the slow discharge circuit. One end of the first capacitor C2 is connected to both the base of the first transistor V2 and the power supply VOUT of the laser detector, allowing it to be continuously charged to a higher potential during normal power supply. The other end of the first capacitor C2 is connected to one end of the first resistor R3, which is grounded, forming a discharge circuit for the first capacitor C2. According to the principle of RC delay circuits, by adjusting the capacitance of the first capacitor C2 and the resistance of the first resistor R3, the discharge rate of the first capacitor C2 can be precisely controlled, thereby determining the first turn-on time of the slow discharge circuit and ensuring that the slow discharge circuit starts according to a preset rhythm after the device is powered off.
[0027] The fast discharge circuit has the same structure as the slow discharge circuit, including a second switching unit, a second discharge unit, and a second delay control unit, and can work in conjunction with the slow discharge circuit to achieve rapid discharge. For example... Figure 4As shown, the second switching unit includes a second transistor V5 and a second MOSFET V3. The second transistor V5 is a PNP transistor, and its connection logic corresponds to that of the first switching unit, specifically as follows: The emitter of the second transistor V5 is connected to both the gate of the second MOSFET V3 and the positive terminal of the energy storage capacitor; its base is connected to the second delay control unit; and its collector is directly grounded. It controls the gate potential of the second MOSFET V3 through its own conduction state. The drain of the second MOSFET V3 is connected to the positive terminal of the energy storage capacitor, and its source is connected to the second discharge unit. When it is turned on, it establishes a path between the energy storage capacitor and the second discharge unit. The core component of the second discharge unit is the second discharge resistor R6. One end of this resistor is connected to the source of the second MOSFET V3, and the other end is directly grounded. When the second MOSFET V3 is turned on, the charge in the energy storage capacitor can be transferred through the source of the second MOSFET V3 to the second discharge resistor R6, and then flow into the ground through the second discharge resistor R6. At this time, the slow discharge circuit and the fast discharge circuit work simultaneously, achieving a "fast discharge" effect.
[0028] The second delay control unit is used to set the second turn-on time of the fast discharge circuit. It includes a second capacitor C3 and a second resistor R7. One end of the second capacitor C3 is connected to both the base of the second transistor V5 and the power supply VOUT of the laser detector, allowing it to be continuously charged during normal power supply. The other end is connected to one end of the second resistor R7, which is grounded, forming a discharge circuit for the second capacitor C3. According to the principle of RC delay circuit, by adjusting the capacitance of the second capacitor C3 and the resistance of the second resistor R7, the discharge rate of the second capacitor C3 can be controlled, thereby determining the second turn-on time of the fast discharge circuit. This ensures that the fast discharge circuit starts at the set time after the slow discharge circuit starts, forming a parallel discharge with the slow discharge circuit.
[0029] The specific workflow of this application is as follows: After the laser detector completes the test and is powered off, the voltage VOUT at the end of its energy storage capacitor charging circuit rapidly drops to 0V, and the first delay control unit of the slow discharge circuit immediately starts working. Due to the power outage, the first capacitor C2 in the first delay control unit begins to slowly discharge through the first resistor R3. As the discharge process progresses, the base voltage of the first transistor V2 connected to the first capacitor C2 gradually decreases. When the base voltage of the first transistor V2 drops below 0.7V, reaching the conduction condition, the first transistor V2 enters the conduction state, and the impedance between its collector and emitter decreases significantly, thereby causing the gate potential of the first MOSFET V1 to decrease accordingly, driving the first MOSFET V1 to conduct, and the slow discharge circuit officially starts. At this time, the charge in the energy storage capacitor flows sequentially through the drain of the first MOSFET V1, the source of the first MOSFET V1, and then into the ground through the first discharge resistor R2, achieving slow discharge. Subsequently, when the second turn-on time of the fast discharge circuit is reached, the second delay control unit of the fast discharge circuit begins to respond. The second capacitor C3 in the second delay control unit discharges through the second resistor R7, causing the base voltage of the second transistor V5 to drop to the conduction threshold. After the second transistor V5 turns on, it drives the second MOSFET V3 to turn on, and the fast discharge circuit starts. The charge of the energy storage capacitor simultaneously flows through the drain and source of the second MOSFET V3 in sequence, and then flows into the ground through the second discharge resistor R6. At this time, the slow discharge circuit and the fast discharge circuit are in parallel, jointly discharging the energy storage capacitor, significantly increasing the discharge current, until the charge of the energy storage capacitor is completely released, and the entire discharge process ends.
[0030] In summary, the energy storage capacitor discharge protection circuit for laser measuring devices in this application avoids the risk of electric shock to operators who directly contact charged capacitors through automatic discharge, thus ensuring personal safety. By timely releasing the charge in the energy storage capacitor, it prevents aging problems caused by prolonged charging, extends the capacitor's lifespan, and improves the overall operational stability of the laser measuring device. Furthermore, this circuit prevents the accidental release of residual charge from the energy storage capacitor, which could damage ICs and MOSFET semiconductor devices, protecting internal components and reducing the probability of equipment failure and maintenance costs. Finally, this circuit eliminates the need to wait for the energy storage capacitor to discharge naturally or manually, significantly shortening preparation time before equipment operation and improving overall work efficiency.
[0031] The above description is a further detailed explanation of the present utility model in conjunction with specific embodiments, and it should not be considered that the specific implementation of the present utility model is limited to this. For those skilled in the art to which the present utility model pertains and related fields, any extensions, operation methods, and data substitutions made based on the technical solution concept of the present utility model should fall within the protection scope of the present utility model.
Claims
1. A discharge protection circuit for the energy storage capacitor of a laser detector, characterized in that, Including slow discharge circuits and fast discharge circuits; Both the slow discharge circuit and the fast discharge circuit are connected in parallel with the energy storage capacitor of the laser detector. When the laser detector is powered off, the slow discharge circuit starts and slowly discharges the energy storage capacitor when the first start time is reached; then, when the second start time is reached, the fast discharge circuit starts and works in conjunction with the slow discharge circuit to discharge the energy storage capacitor simultaneously until the discharge is complete.
2. The energy storage capacitor discharge protection circuit according to claim 1, characterized in that, The slow discharge circuit includes a first switching unit, a first discharge unit, and a first delay control unit; The input terminal of the first switching unit is connected to the positive terminal of the energy storage capacitor, the output terminal is connected to the first discharge unit, and the control terminal is connected to the first delay control unit. The first delay control unit is used to trigger the first switching unit to conduct after the laser measuring device is powered off and the first turn-on time is reached, so that the energy storage capacitor can slowly discharge through the first discharge unit.
3. The energy storage capacitor discharge protection circuit according to claim 2, characterized in that, The first switching unit includes a first transistor and a first MOSFET; The emitter of the first transistor is connected to the gate of the first MOSFET and the positive terminal of the energy storage capacitor, the base of the first transistor is connected to the first delay control unit, and the emitter of the first transistor is grounded. The drain of the first MOS transistor is connected to the positive terminal of the energy storage capacitor, and the source is connected to the first discharge unit.
4. The energy storage capacitor discharge protection circuit according to claim 3, characterized in that, The first discharge unit includes a first discharge resistor, one end of which is connected to the source of the first MOS transistor, and the other end is grounded.
5. The energy storage capacitor discharge protection circuit according to claim 4, characterized in that, The first delay control unit includes a first capacitor and a first resistor, which together form an RC element for controlling the first turn-on time of the slow discharge circuit. One end of the first capacitor is connected to the base of the first transistor and the power supply of the laser detector, and the other end of the first capacitor is connected to one end of the first resistor, and the other end of the first resistor is grounded; the first turn-on time of the slow discharge circuit can be controlled by adjusting the parameters of the first capacitor and the first resistor.
6. The energy storage capacitor discharge protection circuit according to claim 5, characterized in that, When the device is powered off, the first delay control unit causes the base voltage of the first transistor to slowly decrease through the discharge process of the first capacitor; when the base voltage of the first transistor drops below 0.7V, the first transistor turns on and drives the first MOSFET to turn on, starting the slow discharge.
7. The energy storage capacitor discharge protection circuit according to claim 1, characterized in that, The fast discharge circuit includes a second switching unit, a second discharge unit, and a second delay control unit; The input terminal of the second switching unit is connected to the positive terminal of the energy storage capacitor, the output terminal is connected to the second discharge unit, and the control terminal is connected to the second delay control unit. The second delay control unit is used to trigger the second switching unit to conduct when the second turn-on time is reached, so that the energy storage capacitor can be quickly discharged through the second discharge unit.
8. The energy storage capacitor discharge protection circuit according to claim 7, characterized in that, The second switching unit includes a second transistor and a second MOSFET; The emitter of the second transistor is connected to the gate of the second MOSFET and the positive terminal of the energy storage capacitor, the base of the second transistor is connected to the second delay control unit, and the emitter of the second transistor is grounded. The drain of the second MOS transistor is connected to the positive terminal of the energy storage capacitor, and the source is connected to the second discharge unit.
9. The energy storage capacitor discharge protection circuit according to claim 8, characterized in that, The second discharge unit includes a second discharge resistor, one end of which is connected to the source of the second MOS transistor, and the other end is grounded.
10. The energy storage capacitor discharge protection circuit according to claim 9, characterized in that, The second delay control unit includes a second capacitor and a second resistor, which together form an RC element that controls the second turn-on time of the fast discharge circuit. One end of the second capacitor is connected to the base of the second transistor and the power supply of the laser detector, and the other end of the second capacitor is connected to one end of the second resistor, and the other end of the second resistor is grounded; the second turn-on time of the fast discharge circuit can be controlled by adjusting the parameters of the second capacitor and the second resistor.