US5064997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite circuit protection devices
Assignee: Tyco International Ltd Bermuda
•
Filing: 1989-12-22
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Granted: 1991-11-12
•
Expires: 2009-12-22
Abstract
Abstract Circuit protection devices which comprise a PTC conductive polymer element and a second electrical component which is thermally coupled to the PTC element and which, when a fault causes the current in the circuit to become excessive, generates heat which is transferred to the PTC element, thus reducing the time taken to "trip" the PTC element. The second component is for example a voltate-dependent resistor which is connected in series with the PTC element under the fault conditions and is thus protected from damage. Alternatively, the second component is a thick film resistor which is connected in series with the PTC element.
Inventors
- 👤 Shou-Mean Fang
- 👤 David A. Horsma
- 👤 Guillaume Peronnet
- 👤 Timothy E. Fahey
- 👤 Andrew N.S. Au
- 👤 William D. Carlomagno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:29
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; H01C7/13; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; H05B3/20; H05B3/34; H05B2203/00; H05B2203/009; H05B2203/01; H05B2203/013; H05B2203/017; H05B2203/02
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
191 words
Electrical apparatus which comprises (1) a first laminar substrate and a second laminar substrate, each of said substrates comprising a first laminar surface and a second laminar surface; (2) a first electrical component which (i) is physically adjacent to the first laminar surface of the first laminar substrate, (ii) is in good thermal contact with the second substrate, (iii) has a resistance R 1 , and (iv) comprises (a) a laminar PTC element composed of a conductive polymer which exhibits PTC behavior with a switching temperature T s , and (b) at least two laminar electrodes which can be connected to a source of electrical power so that current passes between the electrodes through the PTC element; (3) a plurality of second electrical components, one of which (a) is physically adjacent to the second laminar surface of the first laminar substrate, (b) is in good thermal contact with the first component, (c) is electrically connected in series with the first component; and (d) has a resistance R 2 ; and (4) an electrical lead which electrically connects an electrode of the first component in series with the said one second component.
Claim 2
Dependent Claim
191 words
Electrical apparatus which comprises (1) a first laminar substrate and a second laminar substrate, each of said substrates comprising a first laminar surface and a second laminar surface; (2) a first electrical component which (i) is physically adjacent to the first laminar surface of the first laminar substrate, (ii) is in good thermal contact with the second substrate, (iii) has a resistance R 1 , and (iv) comprises (a) a laminar PTC element composed of a conductive polymer which exhibits PTC behavior with a switching temperature T s , and (b) at least two laminar electrodes which can be connected to a source of electrical power so that current passes between the electrodes through the PTC element; (3) a plurality of second electrical components, one of which (a) is physically adjacent to the second laminar surface of the first laminar substrate, (b) is in good thermal contact with the first component, (c) is electrically connected in series with the first component; and (d) has a resistance R 2 ; and (4) an electrical lead which electrically connects an electrode of the first component in series with the said one second component.
Claim 3
Dependent Claim
16 words
Apparatus according to claim 1 wherein the said one second component is a thick film resistor.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 1 wherein the first component and the said one second component are mounted directly on the opposite surfaces of the substrate.
Claim 5
Dependent Claim
37 words
Apparatus according to claim 1 wherein, when electrical power flows through the first component, a thermal gradient induced in the PTC element is in the same direction as the direction of current flow through the PTC element.
Claim 6
Dependent Claim
42 words
Apparatus according to claim 1 which comprises (i) one first component, (ii) two second components, and (iii) two laminar substrates, wherein the first component is positioned adjacent one second component and each second component is physically adjacent to a different laminar substrate.
Claim 7
Dependent Claim
13 words
Apparatus according to claim 5 wherein the second components are thick film resistors.
Claim 8
Dependent Claim
11 words
Apparatus according to claim 5 wherein the laminar substrates are alumina.
Claim 9
Dependent Claim
42 words
Apparatus according to claim 5 wherein the ratio of the total resistance at room temperature of the second components connected in series to the PTC element to the resistance at room temperature of the PTC element R 1 is at least 20:1.
Claim 10
Dependent Claim
26 words
Apparatus according to claim 5 wherein the total resistance at room temperature of the first component and the two second components is at most 500 ohms.
Claim 11
Dependent Claim
36 words
Apparatus according to claim 2 wherein the resistor if subject to a temperature exceeding a predetermined level is subject to damage and the PTC element is converted to a high resistance state below said predetermined level.
Claim 12
Dependent Claim
13 words
Apparatus according to claim 1 which is mounted on a printed circuit board.
Claim 13
Dependent Claim
13 words
Apparatus according to claim 1 wherein the first laminar substrate is electrically insulating.
Claim 14
Dependent Claim
11 words
Apparatus according to claim 2 wherein the resistor is ruthenium oxide.
Claim 15
Dependent Claim
13 words
Apparatus according to claim 2 wherein the resistor is a polymer thick film.
Claim 16
Dependent Claim
16 words
Apparatus according to claim 1 wherein the apparatus has a resistance of at most 500 ohms.
Claim 17
Dependent Claim
16 words
Apparatus according to claim 15 wherein the apparatus has a resistance of at most 100 ohms.
Claim 18
Dependent Claim
18 words
Apparatus according to claim 1 wherein each of the second components has the same resistance R 2 .
Claim 19
Dependent Claim
16 words
Apparatus according to claim 3 wherein the said one second component is a thick film resistor.
Claim 20
Dependent Claim
43 words
Apparatus according to claim 1 which comprises (i) one first component, (ii) two second components, and (iii) two laminar substrates, wherein the first component is positioned between the two laminar substrates and each second component is physically adjacent to a different laminar substrate.
Claim 21
Dependent Claim
13 words
Apparatus according to claim 19 wherein the second components are thick film resistors.
Claim 22
Dependent Claim
11 words
Apparatus according to claim 19 wherein the laminar substrates are alumina.
Claim 23
Dependent Claim
42 words
Apparatus according to claim 19 wherein the ratio of the total resistance at room temperature of the second components connected in series to the PTC element to the resistance at room temperature of the PTC element R 1 is at least 20:1.
Claim 24
Dependent Claim
26 words
Apparatus according to claim 19 wherein the total resistance at room temperature of the first component and the two second components is at most 500 ohms.
Claim 25
Dependent Claim
225 words
An electrical circuit comprising (2) a power source; (2) an electrical load; and (3) a circuit protection device which is electrically in series with the load and which comprises (a) a first laminar substrate and a second laminar substrate, each of said substrates comprising a first laminar surface and a second laminar surface; (b) a first electrical component which is physically adjacent to the first laminar surface of the first laminar substrate and is in good thermal contact with the second laminar substrate, said first component comprising (i) a laminar PTC element composed of a conductive polymer which exhibits PTC behavior with a switching temperature Ts, and (ii) at least two laminar electrodes which can be connected to source of electrical power so that current passes between the electrodes through the PTC element; (c) a plurality of second electrical components, one of which (i) is physically adjacent to the second laminar surface of the first laminar substrate, (ii) is in good thermal contact with the first component, and (iii) is electrically connected in series with the first component; (d) an electrical lead which electrically connects an electrode of the first component in series with the said second component, said circuit having a normal operating condition in which the PTC conductive polymer composition of the circuit protection device is in its low temperature, low resistivity state.
Claim 26
Dependent Claim
225 words
An electrical circuit comprising (2) a power source; (2) an electrical load; and (3) a circuit protection device which is electrically in series with the load and which comprises (a) a first laminar substrate and a second laminar substrate, each of said substrates comprising a first laminar surface and a second laminar surface; (b) a first electrical component which is physically adjacent to the first laminar surface of the first laminar substrate and is in good thermal contact with the second laminar substrate, said first component comprising (i) a laminar PTC element composed of a conductive polymer which exhibits PTC behavior with a switching temperature Ts, and (ii) at least two laminar electrodes which can be connected to source of electrical power so that current passes between the electrodes through the PTC element; (c) a plurality of second electrical components, one of which (i) is physically adjacent to the second laminar surface of the first laminar substrate, (ii) is in good thermal contact with the first component, and (iii) is electrically connected in series with the first component; (d) an electrical lead which electrically connects an electrode of the first component in series with the said second component, said circuit having a normal operating condition in which the PTC conductive polymer composition of the circuit protection device is in its low temperature, low resistivity state.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-11 | 1995-05-13 | 1995-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-11 | 1999-05-13 | 1999-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-11 | 2003-05-13 | 2003-11-12 | $7700.00 | Window Closed / Lapsed |