CN105990826A - Lightning protection circuit of digital weighing system bus interface - Google Patents
Lightning protection circuit of digital weighing system bus interface Download PDFInfo
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- CN105990826A CN105990826A CN201510063427.0A CN201510063427A CN105990826A CN 105990826 A CN105990826 A CN 105990826A CN 201510063427 A CN201510063427 A CN 201510063427A CN 105990826 A CN105990826 A CN 105990826A
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- suppression diode
- transient suppression
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Abstract
The invention relates to a lightning protection circuit of a digital weighing system bus interface. The lightning protection circuit comprises a power supply wire protection circuit and a signal wire protection circuit which are connected to the front end of a signal bus chip. The power supply wire protection circuit comprises a first discharge tube and a first bidirectional transient inhibition diode which are parallelly connected between a power supply wire and a working ground wire. A first positive temperature coefficient thermistor is connected between the first discharge tube and the first bidirectional transient inhibition diode. The signal wire protection circuit comprises a tripolar discharge tube and a second bidirectional transient inhibition diode which are parallelly connected between a first signal wire and a second signal wire, a second positive temperature coefficient thermistor and a third positive temperature coefficient thermistor which are connected between the tripolar discharge tube and the second bidirectional transient inhibition diode, a first transient inhibition diode connected between the first signal wire and the working ground wire, and a second transient inhibition diode connected between the second signal wire and the working ground wire. The lightning protection circuit is high in response speed, good in effect and capable of realizing suspension protection.
Description
Technical field
The present invention relates to the lightning protection circuit of a kind of digital weighing system bus interface.
Background technology
Quickly substituting simulation weighing technology in current digital weighing technology, digital weighing technology can solve the problem that the technical vulnerability such as weighing precision deficiency, short, the easy cheating of transmission range in analogue technique.But along with the extensive application of digital weighing, in digital weighing system, the problem of anti-lightning surge difference also comes out.Digital weighing system applies substantial amounts of electronic devices and components, having had contemplated that when being assembled into product various EMC disturbs, but the chip of seam is still easily damaged, reason is to have a longest segment distance between digital weighing sensor and digital instrument, and at outside work, it is vulnerable to the strike of induced lightening.
Authorization Notice No. is the Chinese utility model patent " protection device of weighing-appliance " of CN201742088U (Application No. 201020174780.9); in the protection device that it is disclosed that, holding wire, power line to LOAD CELLS have all carried out multiple protective; have employed the lightning protection of multiplex, it is possible to prevent the infringement that sensor and display instrument are caused by lightning induced surge voltage.But the varistor response speed used in its protection circuit is fast not, and is not suitable for the protection of high-frequency signal circuit.
Summary of the invention
First to be solved by this invention technical problem is that lightning protection effect is good, be capable of the lightning protection circuit of the digital weighing system bus interface that suspension is protected for above-mentioned prior art offer one fast response time.
The present invention solves the technical scheme that the problems referred to above are used: the lightning protection circuit of digital weighing system bus interface; including the power line protection circuit and the holding wire protection circuit that are connected to signal bus chip front end; it is characterized in that: described power line protection circuit includes the first discharge tube and the first two-way Transient Suppression Diode being connected in parallel between power line and working grounding cable, is also associated with the first semistor between described first discharge tube and the first two-way Transient Suppression Diode；
Wherein, the first end of described first discharge tube is connected with power line input, and the second end of the first discharge tube is connected with working grounding cable；
First end of described first two-way Transient Suppression Diode is connected with power line outfan, and the second end of the first two-way Transient Suppression Diode is connected with working grounding cable；
First end of the two ends of the first semistor Transient Suppression Diode two-way with the first discharge tube and first respectively is connected；
Described holding wire protection circuit includes being connected in the electrode surge arrester between the first holding wire and secondary signal line and the second two-way Transient Suppression Diode in parallel; connect the second semistor between electrode surge arrester and the second two-way Transient Suppression Diode and the 3rd semistor respectively; and the first Transient Suppression Diode being connected between the first holding wire and working grounding cable, the second Transient Suppression Diode being connected between secondary signal line and working grounding cable；
Wherein, the first end and the first holding wire input of electrode surge arrester are connected, and the second end of electrode surge arrester is connected with secondary signal line input, and the 3rd end of electrode surge arrester is connected with working grounding cable；
First end of the second two-way Transient Suppression Diode is connected with the first end of electrode surge arrester by the second semistor, and the second end of the second two-way Transient Suppression Diode is connected with the second end of electrode surge arrester by the 3rd semistor；
The positive pole of the first Transient Suppression Diode is connected with working grounding cable, and the first end of the negative pole of the first Transient Suppression Diode and the second two-way Transient Suppression Diode is connected；
The positive pole of the second Transient Suppression Diode is connected with working grounding cable, and the second end of the negative pole of the second Transient Suppression Diode and the second two-way Transient Suppression Diode is connected；
The most unsettled setting of described working grounding cable.
In order to realize adapting to multiple use environment, also include that one second discharge tube, described second discharge tube are connected between described working grounding cable and the earth ground wire.
In order to prevent circuit reversal connection, ensure circuit safety, being also associated with a diode between described first two-way Transient Suppression Diode and the outfan of power supply, the first end of the positive pole of diode and the first two-way Transient Suppression Diode is connected, and the negative pole of diode is connected with the outfan of power line.
Compared with prior art; it is an advantage of the current invention that: the lightning protection circuit fast response time of this digital weighing system bus interface; can quickly respond and realize first order protection; effectively high pressure or the benefit of big electric current and release can also be carried out second level protection; high pressure or big electric current can be released in time, and then be effectively protected the internal system circuit of digital weighing system bus interface and its rear end by multiple protection measure and be not damaged by.Additionally, the lightning protection circuit of this digital weighing system bus interface is in the use environment of drop point, it is possible to realize the suspension to device and protect, prevent the electrical leakage voltage damage to protection device, affect the work of digital weighing system.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of power line protection circuit in the embodiment of the present invention.
Fig. 2 is the circuit diagram of holding wire protection circuit in the embodiment of the present invention.
Fig. 3 is the circuit diagram that in the embodiment of the present invention, working grounding cable processes.
Detailed description of the invention
Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail.
Generally, power line VIN that the circuit of EBI entering digital weighing system is divided into direct current supply and the signal connection being attached with sensor, owing to characteristics of signals is different, protected mode is the most different, and the present invention realizes the lightning protection to two lines road simultaneously.
The lightning protection circuit of the digital weighing system bus interface in the present embodiment, including the power line protection circuit and the holding wire protection circuit that are connected to signal bus chip front end.
As shown in Figure 1; power line protection circuit includes the first discharge tube GDT1 and the first two-way Transient Suppression Diode TVS21 being connected in parallel between power line VIN and working grounding cable V-; the unsettled setting of working grounding cable V-, is also associated with the first semistor PTC1 between the first discharge tube GDT1 and the first two-way Transient Suppression Diode TVS21.
Wherein, first end of the first discharge tube GDT1 is connected with power line VIN input, and second end of the first discharge tube GDT1 is connected with working grounding cable V-, the unsettled setting of working grounding cable V-.
First end of the first two-way Transient Suppression Diode TVS21 is connected with power line VIN outfan, and second end of the first two-way Transient Suppression Diode TVS21 is connected with working grounding cable V-, the unsettled setting of working grounding cable V-.
It is also associated with a diode D between first two-way Transient Suppression Diode TVS21 and the outfan V+ of power supply, first end of the positive pole of diode D and the first two-way Transient Suppression Diode TVS21 is connected, and the negative pole of diode D is connected with the outfan of power line VIN.
First end of the first semistor PTC1 and first end of the first discharge tube GDT1 are connected, and first end of second end of the first semistor PTC1 and the first two-way Transient Suppression Diode TVS21 is connected.
Operationally, diode D can play anti-circuit reversal connection effect to power line protection circuit.
When the situation that thunderbolt occurs; rising along with thunderbolt voltage; when after the thunderbolt voltage set point more than the first two-way Transient Suppression Diode TVS21; first two-way Transient Suppression Diode TVS21 conducting; clamp down on the first two-way Transient Suppression Diode TVS21 both end voltage in the range of a setting; protection device behind is without damage, i.e. the device of protection EBI and internal system is without damage.
nullWhen the voltage that is struck by lightning raises further，Through the electric current of the first semistor PTC1 also with increase，Ultimately result in the first discharge tube GDT1 both end voltage the highest，Now clamp down on effect due to the first two-way Transient Suppression Diode TVS21，Within the voltage at the first two-way Transient Suppression Diode TVS21 two ends is limited in the voltage that the first two-way Transient Suppression Diode TVS21 sets，And the voltage of first end of the first semistor PTC1 is increased to the startup voltage of the first discharge tube GDT1 due to the pressure drop of the first semistor PTC1 self，First discharge tube GDT1 action conducting，The first discharge tube GDT1 both end voltage is made to quickly fall to safety range，Its concrete drop-out value is determined by the characteristic of the first discharge tube GDT1，So voltage of power line VIN outfan is limited in the scope that can bear all the time，The device at its rear portion is effectively protected.
Compared to second end of the first discharge tube GDT1 and second end of the first two-way Transient Suppression Diode TVS21 are connected to the earth ground wire by existing lightning protection circuit, when leaking electricity higher than 20V occurs in the outfan V+ of power supply, protection circuit makes the first two-way Transient Suppression Diode TVS21 turn on for a long time and then damage as leak electricity in the case of without thunderbolt, and all there is drain conditions in the big weighbridge of the domestic overwhelming majority, reach as high as more than 100V, second end of the first discharge tube GDT1 and the second end suspension of the first two-way Transient Suppression Diode TVS21 are processed by the lightning protection circuit in the present embodiment, thus form suspension protection, thunderbolt energy is allowed progressively to consume on wire and protection device.
As in figure 2 it is shown, during the work of holding wire protection circuit, the signal between the first holding wire A and working grounding cable V-therein, the signal between secondary signal line B and working grounding cable V-, signal between the first holding wire A and secondary signal line B are required for protecting.Holding wire protection circuit includes being connected in the electrode surge arrester GDT3 between the first holding wire A and secondary signal line B and the second two-way Transient Suppression Diode TVS22 in parallel, connect the second semistor PTC2 between electrode surge arrester GDT3 and the second two-way Transient Suppression Diode TVS22 and the 3rd semistor PTC3 respectively, and the first Transient Suppression Diode TVS11 being connected between the first holding wire A and working grounding cable V-, the the second Transient Suppression Diode TVS12 being connected between secondary signal line B and working grounding cable V-, the unsettled setting of working grounding cable V-.
Wherein, first end and the first holding wire A input of electrode surge arrester GDT3 are connected, second end of electrode surge arrester GDT3 is connected with secondary signal line B input, and the 3rd end of electrode surge arrester GDT3 is connected with working grounding cable V-, the unsettled setting of working grounding cable V-.
First end of the second two-way Transient Suppression Diode TVS22 is connected by first end of the second semistor PTC2 and electrode surge arrester GDT3, and second end of the second two-way Transient Suppression Diode TVS22 is connected by second end of the 3rd semistor PTC3 and electrode surge arrester GDT3.
The positive pole of the first Transient Suppression Diode TVS11 is connected with working grounding cable V-, the unsettled setting of working grounding cable V-, and first end of the negative pole of the first Transient Suppression Diode TVS11 and the second two-way Transient Suppression Diode TVS22 is connected.
The positive pole of the second Transient Suppression Diode TVS12 is connected with working grounding cable V-, the unsettled setting of working grounding cable V-, and second end of the negative pole of the second Transient Suppression Diode TVS12 and the second two-way Transient Suppression Diode TVS22 is connected.
When there is the situation of thunderbolt, second two-way Transient Suppression Diode TVS22 clamps down on the voltage between the first holding wire A and secondary signal line B, first Transient Suppression Diode TVS11 clamps down on the voltage between the first holding wire A and working grounding cable V-, and the second Transient Suppression Diode TVS12 clamps down on the voltage between secondary signal line B and working grounding cable V-.Thus prevent thunderbolt voltage from device thereafter being damaged.
When the voltage that is struck by lightning raises further; the work process of this holding wire protection circuit is with the work process of power line protection circuit; and second semistor PTC2 and the 3rd semistor PTC3 directly play decoupling function, it is achieved on two paths of signals line, the voltage on working grounding cable V-is the most effectively limited.
Varistor is connected compared to the first Transient Suppression Diode TVS11 in the present embodiment in prior art and the second Transient Suppression Diode TVS12 position; the parasitic capacitance of varistor is big; response time is long; the the first Transient Suppression Diode TVS11 used in the present embodiment and the nanosecond response time of the second Transient Suppression Diode TVS12 and minimum parasitic capacitance make its communication speed reach the baud rate of more than 100K; and using varistor 10K to be reached baud rate the most highly difficult, then the protective capability of varistor can be had a greatly reduced quality.
As it is shown on figure 3, if the user while working grounding cable V-normally to be connected when installing and using the earth, then connect the second discharge tube GDT2, to be grounded protection between working grounding cable V-and the earth ground wire EARTH.When the high pressure i.e. produced when working grounding cable V-outfan reaches certain value, the point that energy must be found from the earth impedance is minimum discharges, in discharge process, related device will burn out because of big electric current, and after accessing the second discharge tube GDT2, can be released as early as possible thunderbolt energy by the second discharge tube GDT2, reduce the voltage of working grounding cable V-end, so that circuit can bear higher thunderbolt.
In addition; lightning protection circuit in Fig. 3 is independent ground protection; even if under having big drain conditions; second discharge tube GDT2 damages; i.e. in the case of open-circuit condition occurs in the second discharge tube GDT2; other protection circuits are because working grounding cable V-suspension setting can also normally work, and the second discharge tube GDT2 is separate connection the earth ground wire EARTH, and damage will not " infect ".And existing current grounding design lightning protection circuit, then the second discharge tube GDT2 can be made to damage because of electric leakage, other protection device will damage successively, lightning protection circuit cisco unity malfunction.
Claims (3)
1. the lightning protection circuit of digital weighing system bus interface, including the power supply being connected to signal bus chip front end
Line protection circuit and holding wire protection circuit, it is characterised in that: described power line protection circuit includes being connected in power supply in parallel
The first discharge tube (GDT1) on line (VIN) and the first two-way Transient Suppression Diode (TVS21), described first discharge tube
(GDT1) it is also associated with the first semistor between and the first two-way Transient Suppression Diode (TVS21)
(PTC1)；
Wherein, the first end of described first discharge tube (GDT1) is connected with power line (VIN) input, the first discharge tube
(GDT1) the second end is connected with working grounding cable (V-)；
First end of described first two-way Transient Suppression Diode (TVS21) is connected with power line (VIN) outfan, and first
Second end of two-way Transient Suppression Diode (TVS21) is connected with working grounding cable (V-)；
The two ends of the first semistor (PTC1) respectively with the first discharge tube (GDT1) and the first two-way transient state
First end of suppression diode (TVS21) is connected；
Described holding wire protection circuit includes that three poles being connected in parallel between the first holding wire (A) and secondary signal line (B) are put
Fulgurite (GDT3) and the second two-way Transient Suppression Diode (TVS22), connect electrode surge arrester (GDT3) and second pair respectively
The second semistor (PTC2) between Transient Suppression Diode (TVS22) and the 3rd positive temperature coefficient heat
Quick resistance (PTC3), and it is connected to the first Transient Suppression Diode between the first holding wire (A) and working grounding cable (V-)
(TVS11) the second Transient Suppression Diode (TVS12), being connected between secondary signal line (B) and working grounding cable (V-)；
Wherein, the first end and the first holding wire (A) input of electrode surge arrester (GDT3) are connected, electrode surge arrester
(GDT3) the second end is connected with secondary signal line (B) input, the 3rd end and place of working of electrode surge arrester (GDT3)
Line (V-) is connected；
First end of the second two-way Transient Suppression Diode (TVS22) by the second semistor (PTC2) with
First end of electrode surge arrester (GDT3) is connected, and the second end of the second two-way Transient Suppression Diode (TVS22) is by the
Three semistors (PTC3) are connected with the second end of electrode surge arrester (GDT3)；
The positive pole of the first Transient Suppression Diode (TVS11) is connected with working grounding cable (V-), the first Transient Suppression Diode
(TVS11) negative pole and the first end of the second two-way Transient Suppression Diode (TVS22) are connected；
The positive pole of the second Transient Suppression Diode (TVS12) is connected with working grounding cable (V-), the second Transient Suppression Diode
(TVS12) negative pole and the second end of the second two-way Transient Suppression Diode (TVS22) are connected；
Described working grounding cable (V-) the most unsettled setting.
The lightning protection circuit of digital weighing system bus interface the most according to claim 1, it is characterised in that:
Also include that one second discharge tube (GDT2), described second discharge tube (GDT2) are connected to described working grounding cable (V-) and the earth ground
Between line (EARTH).
The lightning protection circuit of digital weighing system bus interface the most according to claim 1, it is characterised in that:
It is also associated with a diode (D) between described first two-way Transient Suppression Diode (TVS21) and the outfan (V+) of power supply,
The positive pole of diode (D) and the first end of the first two-way Transient Suppression Diode (TVS21) are connected, bearing of diode (D)
Pole is connected with the outfan of power line (VIN).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510063427.0A CN105990826A (en) | 2015-02-06 | 2015-02-06 | Lightning protection circuit of digital weighing system bus interface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510063427.0A CN105990826A (en) | 2015-02-06 | 2015-02-06 | Lightning protection circuit of digital weighing system bus interface |
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| Publication Number | Publication Date |
|---|---|
| CN105990826A true CN105990826A (en) | 2016-10-05 |
Family
ID=57037941
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510063427.0A Pending CN105990826A (en) | 2015-02-06 | 2015-02-06 | Lightning protection circuit of digital weighing system bus interface |
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| Country | Link |
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| CN (1) | CN105990826A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110571208A (en) * | 2019-08-19 | 2019-12-13 | 中国电子科技集团公司第四十三研究所 | Anti-lightning protection circuit, protection device and manufacturing method of protection device |
| CN115173385A (en) * | 2022-06-29 | 2022-10-11 | 杭州春来科技有限公司 | EMC protection line and EMC protection system |
| CN117156653A (en) * | 2023-10-27 | 2023-12-01 | 广东东菱电源科技有限公司 | Anti-interference isolation dimming circuit of tunnel lamp |
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| CN201601488U (en) * | 2009-12-07 | 2010-10-06 | 北京欧地安科技股份有限公司 | High energy electromagnetic pulse protection circuit of direct current power source |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110571208A (en) * | 2019-08-19 | 2019-12-13 | 中国电子科技集团公司第四十三研究所 | Anti-lightning protection circuit, protection device and manufacturing method of protection device |
| CN115173385A (en) * | 2022-06-29 | 2022-10-11 | 杭州春来科技有限公司 | EMC protection line and EMC protection system |
| CN117156653A (en) * | 2023-10-27 | 2023-12-01 | 广东东菱电源科技有限公司 | Anti-interference isolation dimming circuit of tunnel lamp |
| CN117156653B (en) * | 2023-10-27 | 2024-03-26 | 广东东菱电源科技有限公司 | Anti-interference isolation dimming circuit of tunnel lamp |
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Application publication date: 20161005 |