US3611072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multicathode gate-turnoff scr with integral ballast resistors
Assignee: Westinghouse Electric Corp
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Filing: 1969-08-27
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Granted: 1971-10-05
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Expires: 1989-08-27
Abstract
Abstract A gate controlled switch has a plurality of cathode regions distributed throughout but electrically isolated from the gate region of the switch. Each cathode region has an integral resistive portion which enables the region to control the last current flow which occurs when the switch is turned off so that each cathode region has two distinct separate regions integral with each other, and each having its own individual function. During normal operation of the switch, substantially all of the forward current flows through essentially all of the cathode except for the integral resistive portion of the region. During turnoff of the switch the last current to flow in the switch is caused to flow through the integral resistive element portion of the cathode region.
Inventors
- 👤 Donald R Hamilton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:20
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/141; H10D62/148; H10D18/00; H10D18/60; H10D64/00; H10D64/20; H10D64/23; H10D64/233
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
186 words
A high current gate controlled switch comprising a wafer of semiconductor material, said wafer having a top and bottom surface, said wafer having a plurality of first regions of first type semiconductivity and a second region of second type semiconductivity exposed on said top surface, each of said plurality of first regions being encircled by a portion of the second region, a plurality of first electrical contacts, each first electrical contact being disposed upon and joined in an electrically conductive relationship with a first region, each of the first contacts being disposed on only a portion of the surface of the respective first region to which it is joined, the remaining portion of the first region being an integral resistive portion, the radius of the integral resistive portion being greater than one-half the width of the remaining portion of the first region, a second electrical contact joined to the second region in an electrically conductive relationship therewith, and a third electrical contact joined to the bottom surface of the wafer comprising a surface of a third region of semiconductivity and in an electrically conductive relationship therewith.
Claim 2
Dependent Claim
186 words
A high current gate controlled switch comprising a wafer of semiconductor material, said wafer having a top and bottom surface, said wafer having a plurality of first regions of first type semiconductivity and a second region of second type semiconductivity exposed on said top surface, each of said plurality of first regions being encircled by a portion of the second region, a plurality of first electrical contacts, each first electrical contact being disposed upon and joined in an electrically conductive relationship with a first region, each of the first contacts being disposed on only a portion of the surface of the respective first region to which it is joined, the remaining portion of the first region being an integral resistive portion, the radius of the integral resistive portion being greater than one-half the width of the remaining portion of the first region, a second electrical contact joined to the second region in an electrically conductive relationship therewith, and a third electrical contact joined to the bottom surface of the wafer comprising a surface of a third region of semiconductivity and in an electrically conductive relationship therewith.
Claim 3
Dependent Claim
37 words
The high-current gate controlled switch of claim 1, wherein the plurality of first regions comprises at least a first portion of a first size disposed between adjacent first regions of a larger size than the first portion.
Claim 4
Dependent Claim
28 words
The high-current gate controlled switch of claim 1, wherein each of the plurality of first regions are disposed in a radial configuration from the center of the wafer.
Claim 5
Dependent Claim
35 words
The high current gate controlled switch of claim 1 wherein the integral resistive element of each of the plurality of first regions has a necked-down region adjacent to the first part of the first region.
Claim 6
Dependent Claim
40 words
The high current gate controlled switch of claim 1 wherein each of the plurality of first regions projects above the second region and the integral resistive element has a necked-down region adjacent to the first part of the first region.
Claim 7
Dependent Claim
33 words
The high current gate controlled switch of claim 1 wherein each first electrical contact is disposed on no greater than two-thirds the surface of the respective first region to which it is joined.
Claim 8
Dependent Claim
134 words
In an electrical device, a four region semiconductor gate controlled switch having a plurality of cathode regions, each of the cathode regions being entirely surrounded by a portion of a common gate region, an ohmic contact applied to only a portion of a surface of each cathode region said portion being no greater than two-thirds of the surface, and leaving a contiguous portion of the cathode region with no contact applied thereto to provide a resistive portion and a gate electrode applied to the common gate region whereby on turnoff of the electrical device, residual current within the switch tends to flow through the resistive portion of each of the plurality of cathode regions and thereby effecting equalization of the current and all of the cathode regions turn off at substantially the same time.
Claim 9
Dependent Claim
134 words
In an electrical device, a four region semiconductor gate controlled switch having a plurality of cathode regions, each of the cathode regions being entirely surrounded by a portion of a common gate region, an ohmic contact applied to only a portion of a surface of each cathode region said portion being no greater than two-thirds of the surface, and leaving a contiguous portion of the cathode region with no contact applied thereto to provide a resistive portion and a gate electrode applied to the common gate region whereby on turnoff of the electrical device, residual current within the switch tends to flow through the resistive portion of each of the plurality of cathode regions and thereby effecting equalization of the current and all of the cathode regions turn off at substantially the same time.
Claim 10
Dependent Claim
30 words
The electrical device of claim 7 wherein the resistive portion of each cathode region has a radius greater than one-half the width of the remaining portion of the cathode region.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |