US4136354A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transistor including a sense emitter and a reference emitter for enabling power dissipation to be limited to less than a destructive level
Assignee: National Semiconductor Corp
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Filing: 1977-09-15
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Granted: 1979-01-23
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Expires: 1997-09-15
Abstract
Abstract A power transistor in which power dissipation may be limited to less than a destructive level is disclosed. The power transistor includes a base; a power emitter in the base; a sense emitter positioned in the base sufficiently close to the power emitter for enabling the temperature of the power emitter to be indicated as a function of the voltage across the junction of the base and the sense emitter; and a reference emitter positioned in a base at a remote position that would not be heated by the heat dissipated by the power emitter for enabling the temperature at the remote position to be indicated as a function of voltage across the junction of such base and the reference emitter. A voltage difference proportional to the temperature gradient in the power emitter induced by power dissipated in the power emitter can be sensed between the sense emitter and the reference emitter. Power dissipation in the power transistor may be limited in response to the sensed voltage difference.
Inventors
- 👤 Robert C. Dobkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:34
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/133; H10D62/135; H10D84/00; H10D84/101; H10D84/121
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
139 words
A power transistor comprising a base; a power emitter in the base; a sense emitter positioned in the base sufficiently close to the power emitter for enabling the temperature of the power emitter to be indicated as a function of the voltage across the junction of the base and the sense emitter; and a reference emitter positioned in the base at a remote position that would not be heated by the heat dissipated by the power emitter for enabling the temperature at the remote position to be indicated as a function of voltage across the junction of the base and the reference emitter; whereby a voltage difference proportional to the temperature gradient between the power emitter and the remote position induced by power dissipated in the power emitter can be sensed between the sense emitter and the reference emitter.
Claim 2
Dependent Claim
139 words
A power transistor comprising a base; a power emitter in the base; a sense emitter positioned in the base sufficiently close to the power emitter for enabling the temperature of the power emitter to be indicated as a function of the voltage across the junction of the base and the sense emitter; and a reference emitter positioned in the base at a remote position that would not be heated by the heat dissipated by the power emitter for enabling the temperature at the remote position to be indicated as a function of voltage across the junction of the base and the reference emitter; whereby a voltage difference proportional to the temperature gradient between the power emitter and the remote position induced by power dissipated in the power emitter can be sensed between the sense emitter and the reference emitter.
Claim 3
Dependent Claim
46 words
A power transistor according to claim 1, wherein the sense emitter is distributed around the power emitter for enabling a voltage difference proportional to the maximum instantaneous temperature gradient between the remote position and any part of the periphery of the power emitter to be sensed.
Claim 4
Dependent Claim
29 words
A powet transistor according to claim 1, wherein a plurality of said power emitters are contained in the base; and the sense emitter is positioned between the power emitters.
Claim 5
Dependent Claim
48 words
A power transistor according to claim 3, wherein the sense emitter is distributed around and between the power emitters for enabling a voltage difference proportional to the maximum instantaneous temperature gradient between the remote position and any part of the peripheries of the power emitters to be sensed.
Claim 6
Dependent Claim
147 words
A power transistor comprising first and second bases; a power emitter in the first base; a sense emitter positioned in the first base sufficiently close to the power emitter for enabling the temperature of the power emitter to be indicated as a function of the voltage across the junction of the first base and the sense emitter; and a reference emitter positioned in the second base at a remote position that would not be heated by the heat dissipated by the power emitter for enabling the temperature at the remote position to be indicated as a function of the voltage across the junction of the second base and the reference emitter; whereby a voltage difference proportional to the temperature gradient between the power emitter and the remote position induced by power dissipated in the power emitter can be sensed between the sense emitter and the reference emitter.
Claim 7
Dependent Claim
147 words
A power transistor comprising first and second bases; a power emitter in the first base; a sense emitter positioned in the first base sufficiently close to the power emitter for enabling the temperature of the power emitter to be indicated as a function of the voltage across the junction of the first base and the sense emitter; and a reference emitter positioned in the second base at a remote position that would not be heated by the heat dissipated by the power emitter for enabling the temperature at the remote position to be indicated as a function of the voltage across the junction of the second base and the reference emitter; whereby a voltage difference proportional to the temperature gradient between the power emitter and the remote position induced by power dissipated in the power emitter can be sensed between the sense emitter and the reference emitter.
Claim 8
Dependent Claim
46 words
A power transistor according to claim 5, wherein the sense emitter is distributed around the power emitter for enabling a voltage difference proportional to the maximum instantaneous temperature gradient between the remote position and any part of the periphery of the power emitter to be sensed.
Claim 9
Dependent Claim
30 words
A power transistor according to claim 5, wherein a plurality of said power emitters are contained in the first base; and the sense emitter is positioned between the power emitters.
Claim 10
Dependent Claim
48 words
A power transistor according to claim 7, wherein the sense emitter is distributed around and between the power emitters for enabling a voltage difference proportional to the maximum instantaneous temperature gradient between the remote position and any part of the peripheries of the power emitters to be sensed.
References Cited (Backward Citations)
US3751726A
Cited
US3911463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-22 | 1982-07-24 | 1983-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-22 | 1986-07-24 | 1987-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-22 | 1990-07-24 | 1991-01-23 | $7700.00 | Window Closed / Lapsed |