Patent US5676672A successfully refreshed from Google Patents.
US4074334A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective device for a power element of an integrated circuit
Assignee: STMicroelectronics SRL
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Filing: 1976-09-17
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Granted: 1978-02-14
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Expires: 1996-09-17
Abstract
Abstract A protective device limiting the current flow through a power transistor 11 in a final stage of an integrated circuit comprises, as part of that circuit, a normally nonconductive shunt transistor 31 which is turned on by a monitoring transistor 22 whenever the collector current I and the collector-emitter voltage V CE of the power transistor reach values beyond a protective curve 52 plotted on a current/voltage diagram. The base-emitter circuit of the monitoring transistor 22 is connected across an output resistor R 2 , in series with the power transistor 11, via a diode 21 of logarithmic conduction characteristic, that diode being also connected across the power transistor in series with a voltage-sensing network. This network includes a voltage divider R 3 , R 5 in series with a Zener diode 33, the voltage divider being connected in parallel with a switching transistor 35 whose base is tied to a tap of the divider.
Inventors
- 👤 Sebastiano D'Arrigo
- 👤 Giovanni Ghiringhelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:19
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0826; H03F; H03F1/00; H03F1/52
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
189 words
In integrated circuitry including a power element traversed by an output current and a protective device for confining the values of said output current and of an accompanying voltage drop across said power element to a predetermined area of a current/voltage diagram partly bounded by a generally exponential curve, the improvement wherein said protective device comprises: an output resistance in series with said power element; a monitoring amplifier with input connections across said output resistance, said input connections including a unidirectionally conductive component with a generally logarithmic conduction characteristic connected to a junction of said power element with said output resistance; a threshold circuit connected across an input of said power element and controlled by said monitoring amplifier for shunting out part of an incoming signal upon said values approaching said boundary; and a voltage-sensing network connected in series with said component across said power element, said network including a series combination of electronic switch means and two-terminal breakdown means having a substantially current-independent voltage upon reaching a predetermined firing potential, said switch means significantly modifying the resistance of said network in a voltage range exceeding said firing potential.
Claim 2
Dependent Claim
189 words
In integrated circuitry including a power element traversed by an output current and a protective device for confining the values of said output current and of an accompanying voltage drop across said power element to a predetermined area of a current/voltage diagram partly bounded by a generally exponential curve, the improvement wherein said protective device comprises: an output resistance in series with said power element; a monitoring amplifier with input connections across said output resistance, said input connections including a unidirectionally conductive component with a generally logarithmic conduction characteristic connected to a junction of said power element with said output resistance; a threshold circuit connected across an input of said power element and controlled by said monitoring amplifier for shunting out part of an incoming signal upon said values approaching said boundary; and a voltage-sensing network connected in series with said component across said power element, said network including a series combination of electronic switch means and two-terminal breakdown means having a substantially current-independent voltage upon reaching a predetermined firing potential, said switch means significantly modifying the resistance of said network in a voltage range exceeding said firing potential.
Claim 3
Dependent Claim
33 words
The improvement defined in claim 1 wherein said power element is an output transistor having an emitter, a collector and a base, said junction being formed between said output resistance and said emitter
Claim 4
Dependent Claim
14 words
The improvement defined in claim 1 wherein said breakdown means comprises a Zener diode.
Claim 5
Dependent Claim
34 words
The improvement defined in claim 1 wherein said switch means comprises a transistor with a collector-emitter circuit shunted by a voltage divider and with a base connected to a tap on said voltage divider.
Claim 6
Dependent Claim
40 words
The improvement defined in claim 1 wherein said output resistance is part of a surface zone of said integrated circuitry and terminates at a metallic tab on said surface zone, said input connections including a lead extending to said tab.
Claim 7
Dependent Claim
14 words
The improvement defined in claim 1 wherein said unidirectionally conductive component is a diode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |