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Patent US5231371A successfully refreshed from Google Patents.
US5231371A
Expired / Lapsed
US
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Overcurrent protection circuit
Assignee: TDK Corp
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Filing: 1990-02-27
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Granted: 1993-07-27
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Expires: 2010-02-27
Abstract
Abstract A feature of the present invention is that an overcurrent protection circuit is constituted so as to have the voltage relationship of V 2 /V 1 <V 3 /V 2 , wherein V 1 is a voltage applied to a positive temperature coefficient resistor at a steady current, V 2 is a voltage applied to said positive temperature coefficient resistor at the maximum current, and V 3 is a voltage applied to said positive temperature coefficient at the equilibrium current. The equilibrium current is rendered less than the steady current, so that heat generation of the load is effectively suppressed and the advantage of enhanced safety of the circuit is achieved.
Inventors
- 👤 Nobuo Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:33
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/02; H02H9/026
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
107 words
An overcurrent protection circuit which is composed of a power source, a load and an overcurrent protection element, characterized in that said overcurrent protection element is a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin, wherein a voltage applied to said positive temperature coefficient resistor at a steady current is V 1 , a voltage applied to said positive temperature coefficient resistor at the maximum current is V 2 , and a voltage applied to said positive temperature coefficient resistor at the equilibrium current is V 3 whereby a voltage relationship of V 2 /V 1 <V 3 /V 2 is maintained.
Claim 2
Dependent Claim
107 words
An overcurrent protection circuit which is composed of a power source, a load and an overcurrent protection element, characterized in that said overcurrent protection element is a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin, wherein a voltage applied to said positive temperature coefficient resistor at a steady current is V 1 , a voltage applied to said positive temperature coefficient resistor at the maximum current is V 2 , and a voltage applied to said positive temperature coefficient resistor at the equilibrium current is V 3 whereby a voltage relationship of V 2 /V 1 <V 3 /V 2 is maintained.
Claim 3
Dependent Claim
94 words
An overcurrent protection circuit, comprising: a power source; a load; and an overcurrent protection element that includes a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin such that a voltage applied to the positive temperature coefficient resistor at a steady current V 1 , a voltage applied to the positive temperature coefficient resistor at the maximum current V 2 and a voltage applied to the positive temperature coefficient resistor at the equilibrium current V 3 maintain a voltage relationship of V 2 /V 1 <V 3 /V 2 .
Claim 4
Dependent Claim
94 words
An overcurrent protection circuit, comprising: a power source; a load; and an overcurrent protection element that includes a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin such that a voltage applied to the positive temperature coefficient resistor at a steady current V 1 , a voltage applied to the positive temperature coefficient resistor at the maximum current V 2 and a voltage applied to the positive temperature coefficient resistor at the equilibrium current V 3 maintain a voltage relationship of V 2 /V 1 <V 3 /V 2 .
Claim 5
Dependent Claim
101 words
In an overcurrent protection circuit which is composed of a power source, a load and an overcurrent protection element, the overcurrent protection element comprising: a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin such that a voltage applied to said positive temperature coefficient resistor at a steady current V 1 , a voltage applied to said positive temperature coefficient resistor at the maximum current V 2 and a voltage applied to said positive temperature coefficient resistor at the equilibrium current V 3 maintain a voltage relationship of V 2 /V 1 <V 3 /V 2 .
Claim 6
Dependent Claim
101 words
In an overcurrent protection circuit which is composed of a power source, a load and an overcurrent protection element, the overcurrent protection element comprising: a positive temperature coefficient resistor in which carbon black is dispersed in crystalline resin such that a voltage applied to said positive temperature coefficient resistor at a steady current V 1 , a voltage applied to said positive temperature coefficient resistor at the maximum current V 2 and a voltage applied to said positive temperature coefficient resistor at the equilibrium current V 3 maintain a voltage relationship of V 2 /V 1 <V 3 /V 2 .
References Cited (Backward Citations)
JPS58190230A
Cited
US4481498A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-07-26 | 1997-01-25 | 1997-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-26 | 2001-01-25 | 2001-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-26 | 2005-01-25 | 2005-07-27 | $7700.00 | Window Closed / Lapsed |