CN102545143A - Device and method for detection and protection and circuit board - Google Patents
Device and method for detection and protection and circuit board Download PDFInfo
- Publication number
- CN102545143A CN102545143A CN2010105835150A CN201010583515A CN102545143A CN 102545143 A CN102545143 A CN 102545143A CN 2010105835150 A CN2010105835150 A CN 2010105835150A CN 201010583515 A CN201010583515 A CN 201010583515A CN 102545143 A CN102545143 A CN 102545143A
- Authority
- CN
- China
- Prior art keywords
- voltage
- circuit
- peak
- supply line
- voltage threshold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
An embodiment of the invention discloses a device for detection and protection, which comprises a sampling resistor, an amplifier, a peak value detection circuit, a comparison circuit and an on-off control circuit. The sampling resistor converts current signals on a direct current power supply line into voltage signals. The amplifier amplifies and transmits the voltage signals to the peak value detection circuit. The peak value detection circuit comprises a diode, a resistor and a capacitor, the diode is connected with the resistor in series, one end of the capacitor is connected between the diode and the resistor, and the other end of the capacitor is connected with the ground. The comparison circuit compares peak voltage of a pulse packet with a voltage threshold, if the peak voltage of the pulse packet exceeds the voltage threshold, and the on-off control circuit is driven to cut off a power supply. The device for the detection and the protection cuts off the power supply when detecting that the peak voltage of the pulse packet exceeds the voltage threshold, so that fire hazards caused by electric leakage of a circuit board or too long short circuit time are avoided.
Description
Technical field
The present invention relates to the detection and the protection field of communication equipment, relate in particular to a kind of detection and protective device and method and circuit board of communication equipment.
Background technology
When communication equipment met with situation such as machine room leaks, mouse urinates pouring, electric leakage or short circuit took place in circuit board easily, thereby cause heating even on fire, can cause electrical fire to burn whole equipment room when serious.
A kind of existing scheme is the smog that produces when utilizing Smoke Sensor to detect burning, and the high temperature that produces when perhaps utilizing temperature sensor to detect burning is cut off the electricity supply by control module then, thereby reduces the speed of fire spreading.Yet this scheme reliability is lower and receive the interference of external environment easily.
When circuit board electric leakage or short circuit, the electric current in the supply line can increase, and another kind of existing scheme is that air circuit is serially connected in the supply line of communication equipment, utilizes the overcurrent protection characteristic of air circuit, realizes defencive function.
Enough big and duration of the effective value of electric current of air circuit of only flowing through, air circuit just can break off during long enough, and air circuit is generally very high to peak value and electric current that effective value is lower is insensitive.Yet when circuit board electric leakage or short circuit, the peak value of the electric current in the supply line is higher and effective value is lower.Fig. 1 is the break time of air circuit and the characteristic curve between the electric current, and wherein, ordinate is the required time of cutting off the electricity supply, abscissa be when cutting off the electricity supply the electric current in the supply line divided by the multiple of rated current.
If the maximum current I during the communication equipment operate as normal
MaxBe 20A, according to rule, the rated current of air circuit is I
Max1.2 times be 24A.When circuit board electric leakage or short circuit; Though the peak current in the supply line (is approximately 40～50A) very greatly; But the maximum current of the effective value of electric current during only than the communication equipment operate as normal increases 5～10A; Even calculate according to 10A, the effective value of electric current also is merely 30A, only equals 1.25 times of rated current of air circuit.As shown in Figure 1, under 1.25 times rated current, air circuit need continue 6 minutes ability at least and break off, this moment circuit board maybe be on fire in addition the intensity of a fire spread to uncontrollable stage.Therefore, air circuit can not just can break off at the initial stage of circuit board electric leakage or short circuit, often to arrive on fire afterwards in addition the intensity of a fire just can cut off the electricity supply after very big.
Summary of the invention
In view of this, the embodiment of the invention provides a kind of circuit board and detection and protective device.
A kind of detection and protective device comprise change-over circuit, peak-detector circuit, comparison circuit and ON-OFF control circuit.Change-over circuit converts the current signal on the direct current supply line into voltage signal.Peak-detector circuit comprises diode, resistance and electric capacity, and diode is connected in series with resistance, and electric capacity one end is connected between diode and the resistance, other end ground connection.Comparison circuit compares the crest voltage and the voltage threshold of said impulse train, if the crest voltage of said impulse train surpasses voltage threshold, then the driving switch control circuit is cut off the electricity supply.
A kind of circuit board, serial connection one detection and protective device on its direct current supply line.This detection and protective device comprise change-over circuit, peak-detector circuit, comparison circuit and ON-OFF control circuit.Change-over circuit converts the current signal on the direct current supply line into voltage signal.Peak-detector circuit comprises diode, resistance and electric capacity, and diode is connected in series with resistance, and electric capacity one end is connected between diode and the resistance, other end ground connection.Comparison circuit compares the crest voltage and the voltage threshold of said impulse train, if the crest voltage of said impulse train surpasses voltage threshold, then the driving switch control circuit is cut off the electricity supply.
A kind of detection and guard method comprise: convert the current signal on the direct current supply line into voltage signal; The filtering individual pulse detects the impulse train in the said voltage signal, and keeps the crest voltage of said impulse train; The crest voltage and a voltage threshold of said impulse train are compared,, then cut off the electricity supply if the crest voltage of said impulse train surpasses voltage threshold.
Above-mentioned detection and protective device are cut off the electricity supply when the crest voltage value that detects impulse train surpasses the predeterminated voltage value, avoid circuit board electric leakage or duration of short circuit long and cause fire.
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, does not constitute qualification of the present invention.
Fig. 1 is the sketch map that changes along with the current effective value in the supply line opening time of prior art air circuit breaker.
Fig. 2 detects in the embodiment of the invention and the sketch map that is connected of protective device.
Fig. 3 detects among Fig. 2 and the circuit diagram of protective device.
Fig. 4 is circuit board short circuit or the current waveform figure on the direct current supply line when leaking electricity.
Fig. 5 detects among Fig. 2 and the operation principle sketch map of the peak-detector circuit of protective device.
Fig. 6 detects among Fig. 2 and the another kind of circuit diagram of protective device.
Embodiment
Understand and realization the present invention for the ease of persons skilled in the art, combine accompanying drawing to describe embodiments of the invention at present.At this, illustrative examples of the present invention and explanation thereof are used to explain the present invention, but not as to qualification of the present invention.
As shown in Figure 2, serial connection one detects and protective device 23 and mains switch 25 on the direct current supply line 22 of communication equipment 21.Detection and protective device 23 comprise sampling resistor 231, amplifier 233, peak-detector circuit 235, comparison circuit 237 and ON-OFF control circuit 239.
Produce consecutive pulses crowd or several groups of Milliseconds impulse train at interval when circuit board electric leakage or short circuit on the direct current supply line 22; Peak-detector circuit 235 has low-frequency filter characteristics; And promptly do not respond individual pulse but can monitor said impulse train; Be used for detecting the impulse train of said voltage signal, and keep the crest voltage of said impulse train.
The physical circuit of ON-OFF control circuit 239 is by the type decided of mains switch 25, and mains switch 25 can be MOSFET, electromagnetic relay, solid-state relay etc., does not limit in the present embodiment.
Embodiment one
As shown in Figure 3, change-over circuit 231 comprises sampling resistor 2312 and amplifier 2314.Sampling resistor 2312 converts the current signal on the direct current supply line 22 into voltage signal and gives amplifier 2314.In order to reduce power loss, the resistance of sampling resistor 2312 is preferably enough little.
The resistance of sampling resistor 2312 is more little, and its pressure drop is also more little, and for the peak-detector circuit 235 of level after being beneficial to and the processing of comparison circuit 237, amplifier 2314 is sent into peak-detector circuit 235 after said voltage signal is amplified.For example, amplifier 233 is differential amplifiers.
As shown in Figure 4, be the current waveform figure on the direct current supply line 22, wherein, abscissa is the time that circuit board electric leakage or short circuit continue, ordinate is the size of current on the direct current supply line.Evidence, when circuit board electric leakage or short circuit, the current waveform on the direct current supply line 22 is consecutive pulses crowd or several groups of Milliseconds impulse train at interval.
Yet when the plug-and-play circuit plate perhaps powered on, communication equipment 21 all can produce the very high impulse current of peak value, and above-mentioned impulse current is an individual pulse.Cause comparison circuit 237 misoperations for fear of above-mentioned impulse current, said peak-detector circuit 235 should have the characteristic of the peak value that can not keep individual pulse, and has the characteristic of the peak value that can keep impulse train.
Common that peak-detector circuit is very responsive to individual pulse, when the input individual pulse, its output voltage can rise to the peak value of pulse of input rapidly.And it is as shown in Figure 5; Peak-detector circuit 235 in the present embodiment comprises diode D1, resistance R 2 and capacitor C 1; Diode D1 is connected in series with resistance R 2, and capacitor C 1 one ends are connected between diode D1 and the resistance R 2, other end ground connection; The A point is the input of peak-detector circuit 235, and the B point is the output of peak-detector circuit 235.
When individual pulse is applied to the input A of peak-detector circuit 235, diode D1 conducting, because the metering function of resistance R 2, capacitor C 1 is slowly charged, and makes voltage on the capacitor C 1 can not rise to crest voltage rapidly and can only slowly rise.
Behind the said individual pulse process output B of peak-detector circuit 235; There is leakage current in the comparison circuit 237 of level because capacitor C 1 reaches thereafter; Capacitor C 1 is discharge slowly, and after after a while, the voltage on the capacitor C 1 can fall the magnitude of voltage when getting back to communication equipment 21 steady operations.Can adjust the time constant of peak-detector circuit 235 through the value of adjustment resistance R 2 and capacitor C 1, prevent that the voltage of capacitor C 1 when individual pulse is imported from reaching the voltage threshold V of comparison circuit 237
ThThereby, avoid above-mentioned impulse current false triggering ON-OFF control circuit 239 switch 25 of cutting off the electricity supply.The value principle of resistance R 2 and capacitor C 1 is: amplitude and width according to the pulse that maximum impulse current possibly occur are adjusted; The pulse amplitude of the impulse current that possibly occur and width are big more; The value of resistance R 2 and C1 is big more, otherwise the value of resistance R 2 and C1 is more little.
And when impulse train was applied to the input A of peak-detector circuit 235, each pulse can build up the charging of capacitor C 1, and through after a certain number of pulse, the voltage on the capacitor C 1 can remain on the crest voltage of said impulse train.
Said voltage threshold V
ThSize depend on current threshold, for example, the maximum current during communication equipment 21 operate as normal is I
Max, then current threshold is 1.2*I
Max, said voltage threshold V
ThCan calculate by following formula: V
Th=1.2*I
Max* A*R1-VD1, wherein, A representes the multiplication factor of amplifying circuit 233, and R1 representes the resistance of sampling resistor 2312, and VD1 representes the pressure drop of diode D1.
Embodiment two
As shown in Figure 6, embodiment two is that comparison circuit 237 comprises analog-digital converter 2371 and microcontroller 2373 with the difference of embodiment one.Analog-digital converter 2371 converts the analog voltage signal of peak-detector circuit 235 outputs to digital signal.
The above; Be merely the preferable embodiment of the present invention; But protection scope of the present invention is not limited thereto, and detection and protective device 23 can be used as an independent device and be connected on outward on the direct current supply line 22 of communication equipment 21, perhaps are integrated on the circuit board of communication equipment 21.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.
Claims (9)
1. one kind is detected and protective device, it is characterized in that this detection and protective device comprise change-over circuit, peak-detector circuit, comparison circuit and ON-OFF control circuit;
Change-over circuit converts the current signal on the direct current supply line into voltage signal;
Peak-detector circuit comprises diode, resistance and electric capacity, and diode is connected in series with resistance, and electric capacity one end is connected between diode and the resistance, other end ground connection;
Comparison circuit compares the crest voltage and a voltage threshold of said impulse train, if the crest voltage of said impulse train surpasses voltage threshold, then the driving switch control circuit is cut off the electricity supply.
2. detection as claimed in claim 1 and protective device is characterized in that change-over circuit comprises sampling resistor and amplifier;
Sampling resistor is concatenated on the direct current supply line, converts the current signal on the direct current supply line into voltage signal;
Amplifier is sent into peak-detector circuit after this voltage signal is amplified.
3. detection as claimed in claim 2 and protective device is characterized in that said voltage threshold is calculated by following formula: V
Th=1.2*I
Max* A*R1-VD1, wherein, V
ThRepresent said voltage threshold, I
MaxMaximum current during the expression operate as normal on the direct current supply line; A representes the multiplication factor of amplifying circuit; R1 representes the resistance of sampling resistor; VD1 representes the pressure drop of diode.
4. detection as claimed in claim 1 and protective device is characterized in that comparison circuit comprises a comparator, and an end connects said resistance, and the other end applies said voltage threshold.
5. detection as claimed in claim 1 and protective device is characterized in that comparison circuit comprises analog-digital converter and microcontroller;
Analog-digital converter converts the crest voltage of the said impulse train of peak-detector circuit output to digital signal;
Microcontroller reads the magnitude of voltage of said digital signal, and this magnitude of voltage and said voltage threshold are compared, if this magnitude of voltage greater than said voltage threshold, driving switch control circuit deenergization then.
6. a circuit board is connected in series a detection and protective device on its direct current supply line, it is characterized in that this detection and protective device comprise change-over circuit, peak-detector circuit, comparison circuit and ON-OFF control circuit;
Change-over circuit converts the current signal on the direct current supply line into voltage signal;
Peak-detector circuit comprises diode, resistance and electric capacity, and diode is connected in series with resistance, and electric capacity one end is connected between diode and the resistance, other end ground connection;
Comparison circuit compares the crest voltage and a voltage threshold of said impulse train, if the crest voltage of said impulse train surpasses voltage threshold, then the driving switch control circuit is cut off the electricity supply.
7. circuit board as claimed in claim 6 is characterized in that change-over circuit comprises sampling resistor and amplifier;
Sampling resistor is concatenated on the direct current supply line, converts the current signal on the direct current supply line into voltage signal;
Amplifier is sent into peak-detector circuit after this voltage signal is amplified.
8. circuit board as claimed in claim 7 is characterized in that said voltage threshold is calculated by following formula: V
Th=1.2*I
Max* A*R1-VD1, wherein, V
ThRepresent said voltage threshold, I
MaxMaximum current during the expression operate as normal on the direct current supply line; A representes the multiplication factor of amplifying circuit; R1 representes the resistance of sampling resistor; VD1 representes the pressure drop of diode.
9. one kind is detected and guard method, it is characterized in that this method comprises:
Convert the current signal on the direct current supply line into voltage signal;
The filtering individual pulse detects the impulse train in the said voltage signal, and keeps the crest voltage of said impulse train;
The crest voltage and a voltage threshold of said impulse train are compared,, then cut off the electricity supply if the crest voltage of said impulse train surpasses voltage threshold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105835150A CN102545143A (en) | 2010-12-13 | 2010-12-13 | Device and method for detection and protection and circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105835150A CN102545143A (en) | 2010-12-13 | 2010-12-13 | Device and method for detection and protection and circuit board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102545143A true CN102545143A (en) | 2012-07-04 |
Family
ID=46351370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105835150A Pending CN102545143A (en) | 2010-12-13 | 2010-12-13 | Device and method for detection and protection and circuit board |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102545143A (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013189197A1 (en) * | 2012-06-19 | 2013-12-27 | 华为技术有限公司 | Protection circuit, control method therefor, and telecommunication subrack equipment |
| CN103715649A (en) * | 2013-12-20 | 2014-04-09 | 华为技术有限公司 | Direct current protection circuit and network equipment |
| CN105067974A (en) * | 2015-07-29 | 2015-11-18 | 深圳市金正方科技股份有限公司 | Multi-position tool and leakage current detection alarm device thereof |
| CN105098719A (en) * | 2014-05-07 | 2015-11-25 | 神讯电脑(昆山)有限公司 | Error detecting apparatus and method with multiple protections |
| CN106226585A (en) * | 2016-07-05 | 2016-12-14 | 广东威创视讯科技股份有限公司 | Voltage monitor and electronic equipment monitoring device |
| CN106383293A (en) * | 2016-10-19 | 2017-02-08 | 成都云处方科技有限责任公司 | Electrotherapeutical instrument with output electrode open circuit and short circuit detection function and detection method |
| CN106602502A (en) * | 2017-02-28 | 2017-04-26 | 广东欧珀移动通信有限公司 | Current detection circuit and terminal device |
| CN107886883A (en) * | 2017-12-05 | 2018-04-06 | 深圳市华星光电技术有限公司 | A kind of circuit and method for detecting the short circuit of public electrode cabling |
| CN107909972A (en) * | 2017-11-15 | 2018-04-13 | 深圳市华星光电技术有限公司 | Current foldback circuit and method |
| CN108092652A (en) * | 2018-02-13 | 2018-05-29 | 铜仁学院 | The control method of a kind of solid-state relay and solid-state relay, system |
| CN109147692A (en) * | 2018-08-31 | 2019-01-04 | 重庆惠科金渝光电科技有限公司 | Driving circuit, drive system and display |
| CN110928391A (en) * | 2019-11-14 | 2020-03-27 | 西安海的电子科技有限公司 | Computer host monitoring method |
| CN111352010A (en) * | 2020-04-23 | 2020-06-30 | 刘文辉 | Switch board insulation fault early warning device |
| CN111983271A (en) * | 2019-05-21 | 2020-11-24 | 上海海拉电子有限公司 | Protection circuit for high-voltage insulation test |
| CN112910248A (en) * | 2021-01-29 | 2021-06-04 | 国创移动能源创新中心(江苏)有限公司 | Power supply protection circuit and method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2208751Y (en) * | 1994-07-27 | 1995-09-27 | 乐清市正存电子开关厂 | Electronic automatic switch |
| CN1848577A (en) * | 2005-06-17 | 2006-10-18 | 华为技术有限公司 | Overcurrent protection circuit |
| CN101005202A (en) * | 2006-12-26 | 2007-07-25 | 华为技术有限公司 | Method and system for detecting DC over current protector |
| WO2010006224A1 (en) * | 2008-07-10 | 2010-01-14 | Siemens Industry, Inc. | Single-supply single-ended high voltage peak detector |
| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
-
2010
- 2010-12-13 CN CN2010105835150A patent/CN102545143A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2208751Y (en) * | 1994-07-27 | 1995-09-27 | 乐清市正存电子开关厂 | Electronic automatic switch |
| CN1848577A (en) * | 2005-06-17 | 2006-10-18 | 华为技术有限公司 | Overcurrent protection circuit |
| CN101005202A (en) * | 2006-12-26 | 2007-07-25 | 华为技术有限公司 | Method and system for detecting DC over current protector |
| WO2010006224A1 (en) * | 2008-07-10 | 2010-01-14 | Siemens Industry, Inc. | Single-supply single-ended high voltage peak detector |
| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013189197A1 (en) * | 2012-06-19 | 2013-12-27 | 华为技术有限公司 | Protection circuit, control method therefor, and telecommunication subrack equipment |
| CN103715649A (en) * | 2013-12-20 | 2014-04-09 | 华为技术有限公司 | Direct current protection circuit and network equipment |
| CN103715649B (en) * | 2013-12-20 | 2017-04-19 | 华为技术有限公司 | Direct current protection circuit and network equipment |
| CN105098719A (en) * | 2014-05-07 | 2015-11-25 | 神讯电脑(昆山)有限公司 | Error detecting apparatus and method with multiple protections |
| CN105067974A (en) * | 2015-07-29 | 2015-11-18 | 深圳市金正方科技股份有限公司 | Multi-position tool and leakage current detection alarm device thereof |
| CN106226585A (en) * | 2016-07-05 | 2016-12-14 | 广东威创视讯科技股份有限公司 | Voltage monitor and electronic equipment monitoring device |
| CN106383293B (en) * | 2016-10-19 | 2023-08-29 | 成都云处方科技有限责任公司 | Electrotherapy instrument with output electrode open-short circuit detection function and detection method |
| CN106383293A (en) * | 2016-10-19 | 2017-02-08 | 成都云处方科技有限责任公司 | Electrotherapeutical instrument with output electrode open circuit and short circuit detection function and detection method |
| CN106602502A (en) * | 2017-02-28 | 2017-04-26 | 广东欧珀移动通信有限公司 | Current detection circuit and terminal device |
| CN107909972A (en) * | 2017-11-15 | 2018-04-13 | 深圳市华星光电技术有限公司 | Current foldback circuit and method |
| CN107886883A (en) * | 2017-12-05 | 2018-04-06 | 深圳市华星光电技术有限公司 | A kind of circuit and method for detecting the short circuit of public electrode cabling |
| CN108092652A (en) * | 2018-02-13 | 2018-05-29 | 铜仁学院 | The control method of a kind of solid-state relay and solid-state relay, system |
| CN109147692A (en) * | 2018-08-31 | 2019-01-04 | 重庆惠科金渝光电科技有限公司 | Driving circuit, drive system and display |
| US11238822B2 (en) | 2018-08-31 | 2022-02-01 | Chongqing Hkc Optoelectronics | Drive circuit and drive system |
| CN111983271A (en) * | 2019-05-21 | 2020-11-24 | 上海海拉电子有限公司 | Protection circuit for high-voltage insulation test |
| CN110928391A (en) * | 2019-11-14 | 2020-03-27 | 西安海的电子科技有限公司 | Computer host monitoring method |
| CN111352010A (en) * | 2020-04-23 | 2020-06-30 | 刘文辉 | Switch board insulation fault early warning device |
| CN111352010B (en) * | 2020-04-23 | 2022-06-14 | 烟台海珐电气科技有限公司 | Switch board insulation fault early warning device |
| CN112910248A (en) * | 2021-01-29 | 2021-06-04 | 国创移动能源创新中心(江苏)有限公司 | Power supply protection circuit and method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102545143A (en) | Device and method for detection and protection and circuit board | |
| CN104348214A (en) | Charger with overvoltage and overcurrent protection and protection method thereof | |
| CN101957413B (en) | Relay protection device detection circuit | |
| CN101958638B (en) | Novel method for implementing current interruption protection of direct-current converter valve thyristor | |
| CN201838982U (en) | Residual current protection device and circuit breaker using same | |
| CN107681984B (en) | Millimeter wave fast pulse reflection excessive real-time protection circuit and protection method thereof | |
| CN105067945A (en) | Intelligent detection unit with direct-current arcing detection function and junction box | |
| CN205407576U (en) | Power delays start control device and mains operated circuit | |
| CN105743449A (en) | Protection device | |
| CN201345530Y (en) | Current foldback circuit | |
| CN202057714U (en) | Quick abnormal voltage fluctuation detection circuit | |
| CN205283092U (en) | Integrated circuit dedicated for A -type time -delay low -voltage leakage protector | |
| CN101534000A (en) | Leakage protector | |
| CN201408978Y (en) | Electric leakage protector | |
| CN201477173U (en) | Automatic detection module for power supply earth line failure | |
| CN101702515A (en) | Inter-phase arc short circuit protecting device of circuit breaker | |
| CN208621713U (en) | Fault electric arc detection circuit | |
| CN201035122Y (en) | A drive electric power capable of detecting semiconductor laser operation life | |
| CN103256996A (en) | Temperature detector | |
| CN207559951U (en) | A kind of millimeter wave fast-pulse reflects excessive real-time protection circuit | |
| CN203091933U (en) | Carrier wire short-circuit protection circuit and welding equipment | |
| CN203352132U (en) | Full-automatic over-voltage and under-voltage delay protector | |
| CN205157748U (en) | Fire control device power monitored control system data acquisition circuit | |
| CN105429098A (en) | Vehicle-mounted direct current motor driving chip overcurrent protection system | |
| CN202978239U (en) | IGBT straight-through overcurrent protection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20120704 |