EP0148577A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Overvoltage protection device
Assignee: General Semiconductor Industries Inc
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Filing: 1984-11-13
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Granted: —
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Expires: 2004-11-13
Abstract
Abstract A low capacitance, overvoltage protection circuit comprising a relatively large area semiconductor overvoltage suppressor chip coupled between first and second power supply voltage conductor (12,3). A low capacitance PIN diode (13 A-N) has one of its electrodes connected to a like electrode of the overvoltage suppressor chip and the other of its electrodes connected to a high speed signal conductor (14 A-N). During normal operation, the diode is always reversed biased, resulting in very low capacitance loading on the high speed signal conductor. During a transient overvoltage, the PIN diode is forward biased by the overvoltage, and forces reverse junction breakdown of the suppressor chip to occur, thereby limiting the amplitude of the overvoltage.
Inventors
- 👤 William R. Skanadore
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 23:02
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/60; H10D89/601; H10D89/611
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
A low capacitance protection circuit (10) for protecting a high speed signal conductor (14A-N, 27-29, 32, 33) from transient overvoltages, said protection circuit comprising in combination: an overvoltage suppressor (2,30,60) having a first electrode and a second electrode; said overvoltage suppressor having a first capacitance; a first power supply voltage conductor (12,3,40, 36, 57) coupled to said first electrode of said overvoltage suppressor; a diode (13-A-N, 21-26, 38,39) having an anode and a cathode said diode having a second capacitance.; first means for coupling one of said anode and said cathode of said diode to said first electrode of said overvoltage suppressor; a second power supply voltage conductor (3,12,41, 37,65) coupled to said second electrode of said overvoltage suppressor; and second means for coupling said high speed signal conductor (14A-N, 27-29, 33,32) to the other of said anode and cathode of said diode.
Claim 2
Dependent Claim
143 words
A low capacitance protection circuit (10) for protecting a high speed signal conductor (14A-N, 27-29, 32, 33) from transient overvoltages, said protection circuit comprising in combination: an overvoltage suppressor (2,30,60) having a first electrode and a second electrode; said overvoltage suppressor having a first capacitance; a first power supply voltage conductor (12,3,40, 36, 57) coupled to said first electrode of said overvoltage suppressor; a diode (13-A-N, 21-26, 38,39) having an anode and a cathode said diode having a second capacitance.; first means for coupling one of said anode and said cathode of said diode to said first electrode of said overvoltage suppressor; a second power supply voltage conductor (3,12,41, 37,65) coupled to said second electrode of said overvoltage suppressor; and second means for coupling said high speed signal conductor (14A-N, 27-29, 33,32) to the other of said anode and cathode of said diode.
Claim 3
Dependent Claim
12 words
A circuit of Claim 1 wherein said diode is a PIN diode.
Claim 4
Dependent Claim
68 words
A circuit of Claim 1 or 2 including a further diode (13A-N, 21-26 ; 34,35,38,39) having an anode and a cathode, one of said anode and said cathode of said further diode being coupled to said first electrode of said overvoltage suppressor (2), the other one of said anode and said cathode of said further diode being coupled to a further high speed signal conductor (14A-N, 27-29, 32,33).
Claim 5
Dependent Claim
69 words
A circuit of Claim 1 or 2 including a further diode (22,24,26,35,39) having an anode and a cathode, said cathode of the first mentioned diode (21,23,25, 34,38) being coupled to said first electrode of said overvoltage suppressor (2), said anode of said further diode being coupled to said second electrode of said overvoltage suppressor, said cathode of said further diode being coupled to said high speed signal conductor (27-29,32,33).
Claim 6
Dependent Claim
38 words
A circuit of Claim 4 wherein said high speed signal conductor is a centre conductor (33) of a coaxial transmission line and said further high speed signal conductor is the outer conductor (32) of said coaxial transmission line.
Claim 7
Dependent Claim
34 words
A circuit of any preceding Claim wherein said overvoltage suppressor includes a PN junction overvoltage suppressor (2), said first electrode and said second electrode of said overvoltage suppressor being its cathode and anode, respectively.
Claim 8
Dependent Claim
32 words
A circuit of Claim 5 wherein the power supply voltages on said and said further power supply voltage conductors, respectively, maintain said PN junction overvoltage suppressor (2) in a reverse biased condition.
Claim 9
Independent Claim
265 words
A method of operating a circuit having first and second conductors conducting first and second power supply voltages and a third conductor conducting a high speed signal to protect said circuit from transient over/under voltages on said third conductor without causing unacceptable attenuation or distortion of said high speed signal during normal circuit operation, said method comprising the steps of: applying said first power supply voltage (+V) on said first conductor (12,40,36) to a first electrode of an overvoltage suppressor (2). applying said second power supply voltage (-V) on said second conductor (3,41,37) to a second electrode of said overvoltage suppressor (2), said overvoltage suppressor having a first capacitance between its first and second electrodes; applying said high speed signal on said third conductor (14-A-N, 27-29, 32,33) to a first electrode of a diode (13A-N, 21-26, 34,35,38,39) said diode also having a second electrode, said diode having a second capacitance between its first and second electrodes, said second capacitance being much less than said first capacitance; also applying said first voltage (+V) on said first conductor to said second electrode of said diode; said first power supply voltage and said high speed signal being related such that during normal operation of said current said diode is reverse biased during the entire duration of said high speed signal; and forward biasing said diode during a transient overvoltage or undervoltage to effect conducting that transient overvoltage to said first electrode of said overvoltage.suppressor to cause said overvoltage suppressor to undergo an increased current flow mechanism and limit the magnitude of that transient pvervoltage to a predetermined level.
Claim 10
Independent Claim
265 words
A method of operating a circuit having first and second conductors conducting first and second power supply voltages and a third conductor conducting a high speed signal to protect said circuit from transient over/under voltages on said third conductor without causing unacceptable attenuation or distortion of said high speed signal during normal circuit operation, said method comprising the steps of: applying said first power supply voltage (+V) on said first conductor (12,40,36) to a first electrode of an overvoltage suppressor (2). applying said second power supply voltage (-V) on said second conductor (3,41,37) to a second electrode of said overvoltage suppressor (2), said overvoltage suppressor having a first capacitance between its first and second electrodes; applying said high speed signal on said third conductor (14-A-N, 27-29, 32,33) to a first electrode of a diode (13A-N, 21-26, 34,35,38,39) said diode also having a second electrode, said diode having a second capacitance between its first and second electrodes, said second capacitance being much less than said first capacitance; also applying said first voltage (+V) on said first conductor to said second electrode of said diode; said first power supply voltage and said high speed signal being related such that during normal operation of said current said diode is reverse biased during the entire duration of said high speed signal; and forward biasing said diode during a transient overvoltage or undervoltage to effect conducting that transient overvoltage to said first electrode of said overvoltage.suppressor to cause said overvoltage suppressor to undergo an increased current flow mechanism and limit the magnitude of that transient pvervoltage to a predetermined level.
Claim 11
Dependent Claim
67 words
A method pf Claim 8 wherein said circuit has a fourth conductor (14A-N, 27-29,32,33) conducting a further high speed signal, said method including applying said further high speed signal on said fourth conductor to a first electrode of a further diode (21,23,25,34,38) said further diode also having a second electrode, and applying said first voltage on said first conductor to said second electrode of said further diode.
Claim 12
Dependent Claim
86 words
10 . A method according to Claim 8 further comprising applying said high speed signal on said third conductor (27-29,33) to the cathode of a further diode (22,24,26,39) the capacitance of which is much less than said first capacitance, . and applying said second power supply voltage (-V) on said second conductor (41,37) to the anode of said further diode, said second power supply voltage being less than said high speed signal during normal operation of said circuit so that said further diode remains reverse biased.
References Cited (Backward Citations)
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