CN221177263U - Automatic ultra-high direct-current voltage input protection device - Google Patents
Automatic ultra-high direct-current voltage input protection device Download PDFInfo
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- CN221177263U CN221177263U CN202322778805.6U CN202322778805U CN221177263U CN 221177263 U CN221177263 U CN 221177263U CN 202322778805 U CN202322778805 U CN 202322778805U CN 221177263 U CN221177263 U CN 221177263U
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- 208000032368 Device malfunction Diseases 0.000 description 1
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Abstract
The utility model discloses an automatic protector for ultra-high DC voltage input. The structure of the high-voltage-stabilizing diode comprises a first photoelectric coupler, a second photoelectric coupler, a singlechip, a triode and two cascaded voltage-stabilizing diodes; the triode is respectively connected with the singlechip and the first photoelectric coupler, and the first photoelectric coupler is also connected with the signal input end and the signal output end; the triode is used for controlling the conduction of the first photoelectric coupler under the action of a control signal sent by the singlechip, so as to control the connection and disconnection of the signal input end; the second photoelectric coupler is respectively connected with the signal output end, the two cascaded voltage stabilizing diodes and the singlechip; and the second photoelectric coupler is used for sending a level change signal to the singlechip when the voltage input by the signal input end is higher than a preset value, and then the singlechip sends a low-level signal to the triode. The utility model can protect the circuit when the ultra-high voltage is input, and has simple circuit structure and lower circuit cost.
Description
Technical Field
The utility model relates to the technical field of high-voltage circuit protection, in particular to an automatic ultra-high direct-current voltage input protection device.
Background
With the development of science and technology, electric and electronic products are increasingly diversified and complicated, and circuit protection is becoming more important, so that an instrument is inevitably damaged due to the fact that input voltage exceeds a set threshold value in the use process. When a sensor signal or other analog signal is taken from outside the instrument, if the signal line leaks, or a surge noise voltage occurs, and the preceding device malfunctions, an excessive voltage may occur at the input terminal to damage the instrument. At this time, an overvoltage protection circuit needs to be designed to limit the output voltage within a certain safety value range.
A common protection circuit is shown in fig. 1 and 2, which are both power clamp protection methods. In order to protect the operational amplifier and prevent the operational amplifier from being damaged by the impact of large voltage, the field effect transistors Q1 and Q2 are designed as amplitude limiting designs at the input end in the figure 1, the diodes D3 and D4 are designed as amplitude limiting designs at the input end in the figure 2, but the circuits shown in the figures 1 and 2 have certain requirements on the input resistance of the front end. For fig. 1, if a 100V dc signal is input, the resistor R1 is subjected to a voltage of approximately 100V, and according to the power calculation formula p=u 2/R, p=10w is obtained, and according to this power requirement, only a wire-wound resistor with a larger size can be selected, which is obviously very difficult for a circuit design with a size requirement. Whereas if the usual lead resistance RJ17-2W-1K is used, the maximum input voltage cannot exceed 45V if a power of 2W is reached. However, for some practical applications, it is not ensured that there are no components of high frequency and high voltage in the input signal.
Fig. 3 is a TVS tube protection method, and fig. 4 is a triode protection method. The two methods effectively change the condition that the input voltage is too high, and the operational amplifier is not damaged, so that the reliability of the hardware circuit is improved.
However, the above circuits have problems of leakage current in addition to the fact that the input voltage cannot be excessively high, which is not allowed at all for signals with very high input impedance (for example, 1mΩ or more).
Disclosure of utility model
The utility model aims to provide an automatic ultra-high direct-current voltage input protection device which can protect a back-end circuit under the condition of ultra-high direct-current voltage input and greatly saves cost.
The technical scheme of the utility model is as follows:
An automatic protector for ultra-high DC voltage input comprises a first photoelectric coupler, a second photoelectric coupler, a singlechip, a triode and two cascaded voltage-stabilizing diodes;
The triode is respectively connected with the singlechip and the first photoelectric coupler, and the first photoelectric coupler is also connected with the signal input end; the triode is used for receiving a control signal sent by the singlechip and controlling the on/off of the first photoelectric coupler under the action of the control signal sent by the singlechip so as to realize the connection and disconnection of the input end of the control signal; the control signal is a high level signal or a low level signal;
The first photoelectric coupler is also connected with the signal output end through a resistor;
The second photoelectric coupler is connected with the signal output end on one hand, connected with the two cascaded voltage-stabilizing diodes on the other hand, and connected with the singlechip on the third hand; and the second photoelectric coupler is used for sending a level change signal to the singlechip when the voltage input by the signal input end is higher than a preset value, and then the singlechip sends a low-level signal to the triode.
Preferably, the model of the first photoelectric coupler is AQV258, and the model of the triode is MMBT3904LT1; the singlechip is connected with the base electrode of the triode through a resistor, the emitter electrode of the triode is grounded, and the collector electrode of the triode is connected with the 2 pin of the first photoelectric coupler; the pin 4 of the first photoelectric coupler is connected with the signal input end, and the pin 6 of the first photoelectric coupler is connected with the signal output end through a resistor.
Preferably, the model of the singlechip is STC15F100, and the model of the second photoelectric coupler is PS2505L-1; and the pin 4 of the second photoelectric coupler is connected with the pin 7 of the singlechip, the pin 1 of the second photoelectric coupler is connected with the signal output end, and the pin 3 of the second photoelectric coupler is connected with the power supply ground.
Preferably, the two cascaded zener diodes are a first zener diode and a second zener diode respectively; the positive pole of the first voltage stabilizing diode is connected with the positive pole of the second voltage stabilizing diode, the negative pole of the first voltage stabilizing diode is connected with the 2 pin of the second photoelectric coupler, and the negative pole of the second voltage stabilizing diode is grounded.
Preferably, a timer is arranged in the singlechip, after the singlechip transmits a low-level signal to the triode, the singlechip controls the timer to start, and after the time set by the timer is reached, the singlechip transmits a high-level signal to the triode.
Preferably, both zener diodes are of the BZT52C13 type.
The beneficial effects brought by adopting the technical scheme are as follows:
1. According to the description, the voltage limiting amplitude of the common protection circuit is not more than 50V, and the voltage limiting amplitude of the circuit can reach 1000V, so that the production design requirements of most high-voltage protection are greatly met. The switching speed of the first photoelectric coupler adopted by the utility model reaches 40 mu s, and the switching speed of the second photoelectric coupler reaches 5 mu s, so that the utility model can immediately respond under the condition of high voltage input in ultra-short time, disconnect the input end and protect the back-end circuit.
2. The third resistor in the circuit acts as a current limiting resistor, which, according to the principles of the analysis of fig. 1 and 2, should be a very large power resistor, but only a common RJ14-1/4W resistor is required to be installed in the circuit. As described in the introduction of the item 1, since the reaction speed is very fast, when the power on the resistor does not reach the rated power value yet, the signal at the signal input terminal is already disconnected, and the resistor is also protected by phase change. And therefore the choice of components is very flexible.
3. Compared with 1000V input end, the utility model only adopts two photoelectric couplers, one triode, two voltage stabilizing diodes, three resistors and a singlechip (CPU) with 8 pins, and has great cost advantage.
Drawings
Fig. 1 is a schematic circuit diagram of a power clamp protection method in the related art.
Fig. 2 is another schematic circuit diagram of the power clamp protection scheme in the background.
Fig. 3 is a circuit schematic of a TVS tube protection method in the background art.
Fig. 4 is a schematic circuit diagram of a transistor protection method in the background art.
Fig. 5 is a schematic circuit diagram of an automatic ultra-high dc voltage input protection device according to an embodiment of the present utility model.
Detailed Description
The utility model is further described below with reference to the accompanying drawings.
As shown in fig. 5, the automatic protection device for the uhd voltage input provided by the utility model adopts a two-stage optocoupler isolation design mode, and specifically, the automatic protection device for the uhd voltage input comprises: the device comprises a first photoelectric coupler U1, a second photoelectric coupler U2, a singlechip U3, a triode Q1 and two cascaded voltage stabilizing diodes. The two cascaded zener diodes are a first zener diode D1 and a second zener diode D2, respectively. The types of the components in fig. 1 are as follows: the model of the first photoelectric coupler U1 is AQV258, the model of the second photoelectric coupler U2 is PS2505L-1, the model of the singlechip U3 is STC15F100, the model of the triode Q1 is MMBT3904LT1, and the models of the two voltage stabilizing diodes are BZT52C13.
The singlechip U3 is respectively and electrically connected with the triode Q1 and the second photoelectric coupler U2, and the triode Q1 is also electrically connected with the first photoelectric coupler U1; the first photoelectric coupler U1 is connected with the signal input end Vin, and meanwhile, the first photoelectric coupler U1 is also connected with the signal output end Vout through a third resistor R3; the second photoelectric coupler U2 is connected with the signal output end Vout, and the second photoelectric coupler U2 is also connected with two cascaded zener diodes.
The singlechip U3 and the triode Q1 are connected through a second resistor R2 (3.16 KΩ), and specifically: the 6 feet (CON end) of the singlechip U3 are connected with one end of a second resistor R2, the other end of the second resistor R2 is connected with the base electrode of a triode Q1, the emitter electrode of the triode Q1 is grounded (power ground), the collector electrode of the triode Q1 is connected with the 2 feet of a first photoelectric coupler U1, the 1 foot of the first photoelectric coupler U1 is connected with a +5V power supply through a first resistor R1 (215 omega), the 4 feet of the first photoelectric coupler U1 are connected with a signal input end Vin, and the 6 feet of the first photoelectric coupler U1 are connected with a signal output end Vout through a third resistor R3 (1 Komega). When the circuit works normally, the base electrode of the triode Q1 is controlled to be in a high level by the 6 pin (CON end) of the singlechip U3, and the triode Q1 is in a conducting state at the moment, so that the light emitting diode in the first photoelectric coupler U1 has current, and the 4 pin and the 6 pin of the first photoelectric coupler U1 are in a conducting state, and therefore input signals can be input normally. The connection and disconnection of the signal input end Vin are realized by controlling the connection or disconnection of the first photoelectric coupler U1 through the high and low level of the triode Q1.
The isolation voltage parameter of the first photoelectric coupler U1 reaches 1500Vrms, the load current reaches 0.02A, the ultra-high direct current voltage of the circuit is 1000V, and the circuit can be protected under the condition of high voltage input. The switching speed of the first photo coupler U1 reaches 40 μs and the switching speed of the second photo coupler U2 reaches 5 μs.
The 1 foot of the second photoelectric coupler U2 is directly connected with the signal output end Vout, the 2 foot of the second photoelectric coupler U2 is connected with the cathode of the first zener diode D1, the anode of the first zener diode D1 is connected with the anode of the second zener diode D2, and the cathode of the second zener diode D2 is grounded (signal ground). The first zener diode D1 and the second zener diode D2 are all 13V zener diodes, and the cascade connection of the first zener diode D1 and the second zener diode D2 is designed to ensure that positive and negative voltages can be input.
The 3 pins of the second photoelectric coupler U2 are grounded (power ground), and the 4 pins of the second photoelectric coupler U2 are connected with the 7 pins (INT end) of the singlechip U3. The 2 feet of the singlechip U3 are connected with a +5V power supply, and the 4 feet of the singlechip U3 are grounded (power supply ground).
When a higher voltage is input to the signal input terminal Vin, the first zener diode D1 will function, the voltage of the first zener diode D1 is about 13V, the voltage difference of the diode itself is about 0.6V, and the negative electrode of the second zener diode D2 is grounded, so that the voltage difference of the second zener diode D2 is about 0.6V, the voltage cut-off to the positive electrode of the first zener diode D1 is 13+0.6v, at this time, the internal diode of the second photo coupler U2 is also turned on, and the voltage difference is about 0.6V, so that the amplitude limiting protection amplitude in fig. 5 is about 13+0.6+0.6=14.2V, i.e. when the amplitude of the signal input terminal Vin is greater than 14.2V, the second photo coupler U2 will act, i.e. the level of the 4 pin of the second photo coupler U2 will change, and the 7 pin (i.e. the interrupt pin 0) of the single chip microcomputer U3 will be generated when the level change. After interruption occurs, the singlechip U3 immediately knows that the current input voltage exceeds the preset amplitude requirement, so that the control level of the triode Q1 is immediately changed, namely, the input channel of the first photoelectric coupler U1 is disconnected, and the circuit connected behind the signal output end Vout is protected.
When the input channel is in an off state, the circuit cannot operate normally even if a signal of less than 14.2V is input. In practical application, the circuit needs to be restored to a normal state, a timer T0 (1 pin) in the singlechip U3 is utilized, a timing function is designed by utilizing the timer, and the timer is started from the moment of generating the interrupt. The time can be changed according to the specific application, and assuming that the time is set to 10ms, after 10ms, the singlechip U3 resumes the base level control of the triode Q1, so that the 4 pins and the 6 pins of the first photo coupler U1 are connected. If the voltage is still high, the working state of the scheme is repeated, the switching-off state is again entered, and the cycle is repeated. If the input signal is smaller than 14.2V at this time, the singlechip U3 will not generate interruption, and will not generate action of disconnecting the signal input end Vin, and enter a normal working state.
Claims (6)
1. The automatic ultra-high direct-current voltage input protection device is characterized by comprising a first photoelectric coupler, a second photoelectric coupler, a singlechip, a triode and two cascaded voltage-stabilizing diodes;
The triode is respectively connected with the singlechip and the first photoelectric coupler, and the first photoelectric coupler is also connected with the signal input end; the triode is used for receiving a control signal sent by the singlechip and controlling the on/off of the first photoelectric coupler under the action of the control signal sent by the singlechip so as to realize the connection and disconnection of the input end of the control signal; the control signal is a high level signal or a low level signal;
The first photoelectric coupler is also connected with the signal output end through a resistor;
The second photoelectric coupler is connected with the signal output end on one hand, connected with the two cascaded voltage-stabilizing diodes on the other hand, and connected with the singlechip on the third hand; and the second photoelectric coupler is used for sending a level change signal to the singlechip when the voltage input by the signal input end is higher than a preset value, and then the singlechip sends a low-level signal to the triode.
2. The automatic ultra-high direct-current voltage input protection device according to claim 1, wherein the model of the first photoelectric coupler is AQV258, and the model of the triode is MMBT3904LT1;
The singlechip is connected with the base electrode of the triode through a resistor, the emitter electrode of the triode is grounded, and the collector electrode of the triode is connected with the 2 pin of the first photoelectric coupler; the pin 4 of the first photoelectric coupler is connected with the signal input end, and the pin 6 of the first photoelectric coupler is connected with the signal output end through a resistor.
3. The automatic ultra-high direct-current voltage input protection device according to claim 1, wherein the model of the single-chip microcomputer is STC15F100, and the model of the second photoelectric coupler is PS2505L-1; and the pin 4 of the second photoelectric coupler is connected with the pin 7 of the singlechip, the pin 1 of the second photoelectric coupler is connected with the signal output end, and the pin 3 of the second photoelectric coupler is connected with the power supply ground.
4. The automatic ultra-high direct-current voltage input protection device according to claim 3, wherein the two cascaded zener diodes are a first zener diode and a second zener diode respectively; the positive pole of the first voltage stabilizing diode is connected with the positive pole of the second voltage stabilizing diode, the negative pole of the first voltage stabilizing diode is connected with the 2 pin of the second photoelectric coupler, and the negative pole of the second voltage stabilizing diode is grounded.
5. The automatic ultra-high direct-current voltage input protection device according to claim 1, wherein a timer is arranged in the singlechip, and after the singlechip sends a low-level signal to the triode, the singlechip controls the timer to start, and after the time set by the timer is reached, the singlechip sends a high-level signal to the triode.
6. The automatic ultra-high dc voltage input protector according to claim 1, wherein both zener diodes are of the BZT52C13 type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322778805.6U CN221177263U (en) | 2023-10-17 | 2023-10-17 | Automatic ultra-high direct-current voltage input protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322778805.6U CN221177263U (en) | 2023-10-17 | 2023-10-17 | Automatic ultra-high direct-current voltage input protection device |
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| Publication Number | Publication Date |
|---|---|
| CN221177263U true CN221177263U (en) | 2024-06-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322778805.6U Active CN221177263U (en) | 2023-10-17 | 2023-10-17 | Automatic ultra-high direct-current voltage input protection device |
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| CN (1) | CN221177263U (en) |
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- 2023-10-17 CN CN202322778805.6U patent/CN221177263U/en active Active
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