CA1187929A - Protective module for telephone logic circuits - Google Patents
Protective module for telephone logic circuitsInfo
- Publication number
- CA1187929A CA1187929A CA000392085A CA392085A CA1187929A CA 1187929 A CA1187929 A CA 1187929A CA 000392085 A CA000392085 A CA 000392085A CA 392085 A CA392085 A CA 392085A CA 1187929 A CA1187929 A CA 1187929A
- Authority
- CA
- Canada
- Prior art keywords
- voltage
- arrestor
- heat
- transient suppressor
- suppressor
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
- H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/738—Interface circuits for coupling substations to external telephone lines
- H04M1/74—Interface circuits for coupling substations to external telephone lines with means for reducing interference; with means for reducing effects due to line faults
- H04M1/745—Protection devices or circuits for voltages surges on the line
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Emergency Protection Circuit Devices (AREA)
- Structure Of Telephone Exchanges (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved telephone protector circuitry for use with telephone circuits having incorporated logic elements. The device includes the usual gap arrestor, a heat-sensitive switch, and a transient suppressor providing a parallel interconnection between the protected line and a source of ground potential. The transient suppressor has a breakdown voltage substantially below that of the gap arrestor, and has a capability to react within a much shorter time period than that required by the arrestor.
An improved telephone protector circuitry for use with telephone circuits having incorporated logic elements. The device includes the usual gap arrestor, a heat-sensitive switch, and a transient suppressor providing a parallel interconnection between the protected line and a source of ground potential. The transient suppressor has a breakdown voltage substantially below that of the gap arrestor, and has a capability to react within a much shorter time period than that required by the arrestor.
Description
~7~2~
This inverltion relates generally to the field of excess voltage and current protection devices used in -the telephone art, and more particularly to an improved device particularly adaptQd for u~se with telephone circui-ts having logic element~
or other transistoriæed circuitry incorporated therein~
In the telephone protector module ar-~, most test speciEications address the problem of excess voltage and current transients and lightning strikes as well as power line crosses by re~uirins the protector to pass surges having a variety of rise rates to given voltages. Typical are 1.2/50, 2/50, 4/40, 4/200, 6/150, 8/20, 10/50 and 10/1,000, at various current levels. With a faster rise rate, the permitted breakdown voltage is correspondingly higher to allow for the typical ionization time of the commonly used discharge components, such as gas tubes, and air gap arrestors. Typical rise rat~s range from .l~s to 10~1,s .
However, standard TTL logic circuits and other similar circuits may respond to signals as fast as 3 ns. Thus, transients ~reater than 3 ns are likely to create error readings. Fur-ther, most MOS devices as well as many discreet semiconductors, especially fast switching tran-sistorq are very vulnerable to fast rise rate transients, ev~n at such low energy levels as ten microjoules. Given such sensitivity, it is apparent that known protective devices are not adequate.
~.
The problem is not solved by the mere provision at the board level of low clamping voltage transient suppressors alone~ The grounding available at the board level is not adequate to such large currents which may be fed through standard protective devices on the main frame. Such currents may be up to lO~s in duration, at voltages up to 1,~50 volts or more and at currents of several hundred amperes.
Briefly stated, the invention contemplates the provision oE a protective circuit including an air gap or gas tube arrestor, a heat coil, a heat~operative switch, and a transient suppressor in delta connection with the heat coll switch and arrestor~ The transient suppressor has a breakdown voltage substantially less than that of the gas tube or air gap, and a correspondingly shorter reaction time. As the transient wave front voltage rises, the transient suppressor clarnps the rising voltage as soon as it reaches the break-down voltage of the suppressor, with virtually no delay.
Thus the maximum voltage seen by the central oEfice equip-men-t is the voltage across the suppressor. Most of the current is conducted to ground at the main frame level. As voltage on the wave front continues to rise, the heat coil clrops the remainder of the voltage. When -the applied voltage reaches ~he breakdown voltage of the arrestor, a fur-ther clamp is applied at approximately 30 volts. If the current is sustained, the heat coil and hea-t-sensitive switch will function in normal manner.
In the drawings~ to which reference will be made in the specification;
Figure 1 is an electrical schematic view of an embodi-ment of the invention.
Figure 2 is a graph plotting voltaye agains-t time showing a typical transient wave front.
In accordance with the invention, the device, generally indicated by reference character 10, is connected in series with a -typical input line 11 having an outside plant side 12 and a central office equipment side 13~ The line 11 is connected to a source of ground potential 14 through the del-ta interconnection of an arrestor 15, a heat-sensitive switch 16 and a transient suppressor 17. A heat coil 19 operates the heat-ssnsi.tive switch 16, and is in series with the line 11, as is well k:nown in the art.
Figure 2 is a graph illustrating the progress of a transient wave front, in which the x axis 25 is callibrated ln terms of time, showing intervals of 1 ns at 26 and 1 ms at 2.7. The y axis 28 indicates voltage rise, including a first level ~9 corresponding to the breakdown voltage of the transient suppressor 17, and a second level 30 indicating the breakdown voltage of the arrestor 15.
Although a gas tube type arrestor ls illustrated in the drawing, the equally well known air gap type may be substituted to perform an equivalent function~ The rising wave front of a typical surge is illustrated by reference character 31.
As the transient wave front voltage rises, the transient suppressor clamps the same as soon as it reaches the break-down voltage of the suppressor, with virtually no delay.
rom this point forward, most of the current is now conducted through the transient suppressor to ground. As the voltage on the wave front continues to rise, the heat coil, in some instances, drops all of the remaining voltage.
In the case of stronger surges, as soon as the voltage of the wave front reaches the breakdown voltage of the arres-tor, a further clamp occurs at approximately 30 volts.
If the surge is of a sustained nature, the heat developed in the arrestor will operate the heat-sensi-tive switch causing permanent grounding.
~7~2~
Shvuld the surge be continuous, and be of less voltage -than the normal firing voltage of the arrestor, but higher -than the transient suppressor :breakdown voltage, the drop across the heat coil will continue to build heat, eventuall.y causing the heat-sensitive switch to close. This is assured by placiny a heat coil in series with the transient suppressor.
Finally, should the surge current be hlgher than the transient suppressor can accommoda-te, it will permanently fail short, causing all of the voltage drop to be across the heat coil to accelerate the operation of the hea-t-sensitive switch.
It may be seen that as a result of the provided structure, -the factor of rise rate is elimina-ted, with resultant protection of sensitive circuitry. The sensitivity of the transient suppressor being so much faster tha.n that of the arrestor r it serves to protect the protected circuitry against -the ictus of the wave front surge, without disturbing -the normal functions of the arrestor and the heat-sensitive swi-tcho
This inverltion relates generally to the field of excess voltage and current protection devices used in -the telephone art, and more particularly to an improved device particularly adaptQd for u~se with telephone circui-ts having logic element~
or other transistoriæed circuitry incorporated therein~
In the telephone protector module ar-~, most test speciEications address the problem of excess voltage and current transients and lightning strikes as well as power line crosses by re~uirins the protector to pass surges having a variety of rise rates to given voltages. Typical are 1.2/50, 2/50, 4/40, 4/200, 6/150, 8/20, 10/50 and 10/1,000, at various current levels. With a faster rise rate, the permitted breakdown voltage is correspondingly higher to allow for the typical ionization time of the commonly used discharge components, such as gas tubes, and air gap arrestors. Typical rise rat~s range from .l~s to 10~1,s .
However, standard TTL logic circuits and other similar circuits may respond to signals as fast as 3 ns. Thus, transients ~reater than 3 ns are likely to create error readings. Fur-ther, most MOS devices as well as many discreet semiconductors, especially fast switching tran-sistorq are very vulnerable to fast rise rate transients, ev~n at such low energy levels as ten microjoules. Given such sensitivity, it is apparent that known protective devices are not adequate.
~.
The problem is not solved by the mere provision at the board level of low clamping voltage transient suppressors alone~ The grounding available at the board level is not adequate to such large currents which may be fed through standard protective devices on the main frame. Such currents may be up to lO~s in duration, at voltages up to 1,~50 volts or more and at currents of several hundred amperes.
Briefly stated, the invention contemplates the provision oE a protective circuit including an air gap or gas tube arrestor, a heat coil, a heat~operative switch, and a transient suppressor in delta connection with the heat coll switch and arrestor~ The transient suppressor has a breakdown voltage substantially less than that of the gas tube or air gap, and a correspondingly shorter reaction time. As the transient wave front voltage rises, the transient suppressor clarnps the rising voltage as soon as it reaches the break-down voltage of the suppressor, with virtually no delay.
Thus the maximum voltage seen by the central oEfice equip-men-t is the voltage across the suppressor. Most of the current is conducted to ground at the main frame level. As voltage on the wave front continues to rise, the heat coil clrops the remainder of the voltage. When -the applied voltage reaches ~he breakdown voltage of the arrestor, a fur-ther clamp is applied at approximately 30 volts. If the current is sustained, the heat coil and hea-t-sensitive switch will function in normal manner.
In the drawings~ to which reference will be made in the specification;
Figure 1 is an electrical schematic view of an embodi-ment of the invention.
Figure 2 is a graph plotting voltaye agains-t time showing a typical transient wave front.
In accordance with the invention, the device, generally indicated by reference character 10, is connected in series with a -typical input line 11 having an outside plant side 12 and a central office equipment side 13~ The line 11 is connected to a source of ground potential 14 through the del-ta interconnection of an arrestor 15, a heat-sensitive switch 16 and a transient suppressor 17. A heat coil 19 operates the heat-ssnsi.tive switch 16, and is in series with the line 11, as is well k:nown in the art.
Figure 2 is a graph illustrating the progress of a transient wave front, in which the x axis 25 is callibrated ln terms of time, showing intervals of 1 ns at 26 and 1 ms at 2.7. The y axis 28 indicates voltage rise, including a first level ~9 corresponding to the breakdown voltage of the transient suppressor 17, and a second level 30 indicating the breakdown voltage of the arrestor 15.
Although a gas tube type arrestor ls illustrated in the drawing, the equally well known air gap type may be substituted to perform an equivalent function~ The rising wave front of a typical surge is illustrated by reference character 31.
As the transient wave front voltage rises, the transient suppressor clamps the same as soon as it reaches the break-down voltage of the suppressor, with virtually no delay.
rom this point forward, most of the current is now conducted through the transient suppressor to ground. As the voltage on the wave front continues to rise, the heat coil, in some instances, drops all of the remaining voltage.
In the case of stronger surges, as soon as the voltage of the wave front reaches the breakdown voltage of the arres-tor, a further clamp occurs at approximately 30 volts.
If the surge is of a sustained nature, the heat developed in the arrestor will operate the heat-sensi-tive switch causing permanent grounding.
~7~2~
Shvuld the surge be continuous, and be of less voltage -than the normal firing voltage of the arrestor, but higher -than the transient suppressor :breakdown voltage, the drop across the heat coil will continue to build heat, eventuall.y causing the heat-sensitive switch to close. This is assured by placiny a heat coil in series with the transient suppressor.
Finally, should the surge current be hlgher than the transient suppressor can accommoda-te, it will permanently fail short, causing all of the voltage drop to be across the heat coil to accelerate the operation of the hea-t-sensitive switch.
It may be seen that as a result of the provided structure, -the factor of rise rate is elimina-ted, with resultant protection of sensitive circuitry. The sensitivity of the transient suppressor being so much faster tha.n that of the arrestor r it serves to protect the protected circuitry against -the ictus of the wave front surge, without disturbing -the normal functions of the arrestor and the heat-sensitive swi-tcho
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An improved current and voltage surge protection circuitry for use in conjunction with a telephone line having components which are particularly sensitive to fast voltage rise rates comprising: a heat coil in series with the telephone circuit, a plural connection of said telephone circuit to ground potential including, in delta, a gap arrestor, a heat-sensitive switch and a transient suppressor, said transient suppressor being in series connection with said heat coil, said heat-sensitive switch being responsive to heat developed in said heat coil and said arrestor, said transient suppressor having a break down voltage substantially lower than that of said arrestor; whereby upon the occurrence of a voltage surge through said circuitry having a progressively rising voltage, said transient suppressor first clamps the rising voltage upon reaching the break down voltage of the suppressor, and said heat coil through inductance drops the remainder of said voltage as it continues to rise to the break down voltage of said gap arrestor.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8107348A SE445409B (en) | 1981-12-08 | 1981-12-08 | CURRENT AND VOLTAGE PROTECTION CIRCUIT FOR USE IN CONNECTION WITH A PHONE CORD |
| CA000392085A CA1187929A (en) | 1981-12-08 | 1981-12-11 | Protective module for telephone logic circuits |
| JP56203866A JPS58107023A (en) | 1981-12-08 | 1981-12-14 | Telephone protecting system |
| GB08138001A GB2111771B (en) | 1981-12-08 | 1981-12-16 | Surge protection circuits |
| FR8124177A FR2518838B1 (en) | 1981-12-08 | 1981-12-23 | PROTECTION MODULE FOR TELEPHONY LOGIC CIRCUITS |
| DE19813151539 DE3151539A1 (en) | 1981-12-08 | 1981-12-28 | OVERVOLTAGE AND OVERCURRENT PROTECTION CIRCUIT FOR MESSAGE, IN PARTICULAR TELECOMMUNICATIONS |
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8107348A SE445409B (en) | 1981-12-08 | 1981-12-08 | CURRENT AND VOLTAGE PROTECTION CIRCUIT FOR USE IN CONNECTION WITH A PHONE CORD |
| CA000392085A CA1187929A (en) | 1981-12-08 | 1981-12-11 | Protective module for telephone logic circuits |
| JP56203866A JPS58107023A (en) | 1981-12-08 | 1981-12-14 | Telephone protecting system |
| GB08138001A GB2111771B (en) | 1981-12-08 | 1981-12-16 | Surge protection circuits |
| FR8124177A FR2518838B1 (en) | 1981-12-08 | 1981-12-23 | PROTECTION MODULE FOR TELEPHONY LOGIC CIRCUITS |
| DE19813151539 DE3151539A1 (en) | 1981-12-08 | 1981-12-28 | OVERVOLTAGE AND OVERCURRENT PROTECTION CIRCUIT FOR MESSAGE, IN PARTICULAR TELECOMMUNICATIONS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187929A true CA1187929A (en) | 1985-05-28 |
Family
ID=27543326
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000392085A Expired CA1187929A (en) | 1981-12-08 | 1981-12-11 | Protective module for telephone logic circuits |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS58107023A (en) |
| CA (1) | CA1187929A (en) |
| DE (1) | DE3151539A1 (en) |
| FR (1) | FR2518838B1 (en) |
| GB (1) | GB2111771B (en) |
| SE (1) | SE445409B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4538201A (en) * | 1983-05-02 | 1985-08-27 | International Standard Electric Corporation | Surge protector |
| GB2160721B (en) * | 1984-05-19 | 1987-08-19 | Measurement Tech Ltd | Protection of electrical/electronic equipment |
| GB8506270D0 (en) * | 1985-03-11 | 1985-04-11 | Dubilier Beswick Div | Overvoltage protection arrangements |
| IT1215281B (en) * | 1985-06-28 | 1990-01-31 | Ates Componenti Elettron | APPARATUS AND METHOD FOR PROTECTION FROM VOLTAGE / CURRENT TRANSITORS. |
| GB8802434D0 (en) * | 1988-02-03 | 1988-03-02 | British Telecomm | Protector device |
| GB9021222D0 (en) * | 1990-09-28 | 1990-11-14 | Raychem Ltd | Circuit protection device |
| KR0126541Y1 (en) * | 1994-07-05 | 1998-10-15 | 정기호 | Over-current protecting device with an earthing function |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3743888A (en) * | 1972-08-24 | 1973-07-03 | Reliable Electric Co | Line protector for a communication circuit |
| US3852539A (en) * | 1973-09-10 | 1974-12-03 | Porta Systems Corp | Line surge protection device for telephone lines |
| US3890543A (en) * | 1973-09-14 | 1975-06-17 | Telecommunications Ind | Low voltage surge protection network |
| DE2405671B2 (en) * | 1974-02-06 | 1976-08-26 | Siemens AG, 1000 Berlin und 8000 München | CIRCUIT ARRANGEMENT FOR LIMITING OVERVOLTAGES |
| DE2912415A1 (en) * | 1979-03-29 | 1980-10-09 | Staco Werner Stauber Gmbh | OVERVOLTAGE PROTECTION CIRCUIT |
| DE2917256A1 (en) * | 1979-04-27 | 1980-11-06 | Kraftwerk Union Ag | OVERVOLTAGE PROTECTION DEVICE FOR ELECTRONIC DEVICES |
-
1981
- 1981-12-08 SE SE8107348A patent/SE445409B/en not_active IP Right Cessation
- 1981-12-11 CA CA000392085A patent/CA1187929A/en not_active Expired
- 1981-12-14 JP JP56203866A patent/JPS58107023A/en active Pending
- 1981-12-16 GB GB08138001A patent/GB2111771B/en not_active Expired
- 1981-12-23 FR FR8124177A patent/FR2518838B1/en not_active Expired
- 1981-12-28 DE DE19813151539 patent/DE3151539A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| SE8107348L (en) | 1983-06-09 |
| DE3151539A1 (en) | 1983-07-07 |
| SE445409B (en) | 1986-06-16 |
| FR2518838B1 (en) | 1985-10-18 |
| GB2111771B (en) | 1985-04-03 |
| JPS58107023A (en) | 1983-06-25 |
| GB2111771A (en) | 1983-07-06 |
| FR2518838A1 (en) | 1983-06-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4571656A (en) | Electrical circuit for protection against surge overvoltage of transients | |
| US5625521A (en) | Surge protection circuitry | |
| US4695916A (en) | Protector circuit | |
| US3934175A (en) | Power surge protection system | |
| US4661878A (en) | Overvoltage protection circuit | |
| KR100454013B1 (en) | Telephone facility protection circuit | |
| EP0186873B1 (en) | Protector circuit | |
| US20090021881A1 (en) | Overvoltage protection device with improved leakage-current-interrupting capacity | |
| JPS5928836A (en) | Vertical surge protecting housing | |
| GB1486448A (en) | Low voltage protection network | |
| CA1187929A (en) | Protective module for telephone logic circuits | |
| US5883775A (en) | Overvoltage protector | |
| JP2022061019A (en) | Ultra-low clamping voltage surge protection module using depletion mode mosfet | |
| CN113725810A (en) | Protection circuit and circuit protection device | |
| CN219513785U (en) | Surge protection device and charging system | |
| US3858089A (en) | Electrical protective device using a reed relay | |
| US4439802A (en) | Overvoltage guard for electronic circuits | |
| EP0286739A1 (en) | Transit suppression system | |
| US3760227A (en) | Gas tube protector having an internal fuse link | |
| GB2179214A (en) | Surge voltage protection arrangement | |
| US5721663A (en) | Overvoltage protection modules with back-up protection for communication lines | |
| GB1594313A (en) | Equipment for power line surge eliminator | |
| CN210404733U (en) | Alternating current power supply lightning protection device with overcurrent and overvoltage protection functions | |
| KR102582296B1 (en) | Surge protection apparatus for LED | |
| CN210430915U (en) | DC power supply lightning protection device with overcurrent and overvoltage protection function |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |