EP0032046A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Circuitry for protecting a semiconductor device against static electricity
Assignee: Fujitsu Ltd
•
Filing: 1980-12-23
•
Granted: —
•
Expires: 2000-12-23
Abstract
Abstract In a semiconductor device, such as a bipolar integrated circuit, an input element (12) requires protection, against possible damage by static electricity, by means capable of acting more rapidly and with less capacitance than a simple diode. Such means are provided by a PNP-transistor (16), having its emitter connected to an electrical reference potential point (14) of the device, and an NPN-transistor (17) having its emitter connected to a signal input point (10) of the input element (12), and having its collector and base connected respectively to the base and collector of the PNP-transistor (16), there being a resistive connection (18) between the respective bases of the two transistors (16,17).
Inventors
- 👤 Masayuki Kokado
- 👤 Hedezi Sumi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:55
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/081; H03K17/0812; H03K17/08126; H10; H10D; H10D84/00; H10D84/60; H10D84/676; H10D89/00; H10D89/60
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
1 . A semiconductor device having protective circuitry (15) for protecting an internal circuit (11) of the device against electrostatic damage, the protective circuitry being connected between an electrical reference potential point (14) of the said internal circuit and a signal input point (10) thereof, characterized in that the said protective circuitry comprises a PNP-transistor (16) having its emitter connected to the said electrical reference potential point (14); and an NPN-transistor (17) having its emitter connected to the said signal input point (10) of the internal circuit (11), and having its collector connected to the base of the PNP-transistor (16), and having its base connected to the collector of the PKP- transistor (16); there being a resistive connection (18) between the base of the PNP-transistor (16) and the base of the NPN-transistor (17).
Claim 2
Dependent Claim
133 words
1 . A semiconductor device having protective circuitry (15) for protecting an internal circuit (11) of the device against electrostatic damage, the protective circuitry being connected between an electrical reference potential point (14) of the said internal circuit and a signal input point (10) thereof, characterized in that the said protective circuitry comprises a PNP-transistor (16) having its emitter connected to the said electrical reference potential point (14); and an NPN-transistor (17) having its emitter connected to the said signal input point (10) of the internal circuit (11), and having its collector connected to the base of the PNP-transistor (16), and having its base connected to the collector of the PKP- transistor (16); there being a resistive connection (18) between the base of the PNP-transistor (16) and the base of the NPN-transistor (17).
Claim 3
Dependent Claim
37 words
A semiconductor device as claimed in claim 1, wherein the said electrical reference potential point (14) is connected to a most negative output point (V EE ) of a power supply when the device is in use.
Claim 4
Dependent Claim
94 words
A semiconductor device as claimed in claim 1 or 2, further characterized in that the PNP-transistor (16) has its emitter provided by a p-type substrate, its base provided by an n-type layer, and its collector provided by a p-type region of the device, and the NPN-transistor (17) has its collector provided by the said n-type layer, its base provided by the said p-type region, and its emitter provided by an n-type region of the device, the said n-type layer being connected to the said p-type region by conductive means provided externally of the device.
Claim 5
Dependent Claim
47 words
A semiconductor device as claimed in claim 3, wherein the said n-type region overlies part of the said p-type region which overlies part of the said n-type layer which overlies part of the said p-type substrate so that the protective circuitry is characterized by vertical PNPN operation.
Claim 6
Dependent Claim
85 words
A semiconductor device as claimed in claim 1, 2, 3 or 4, wherein the said protective circuitry (15) is so fabricated that it has a voltage versus current characteristic which includes a negative resistance portion corresponding to saturation of the said NPN-transistor (17). 6. A semiconductor device as claimed in any preceding claim, characterized in that it comprises a bipolar integrated circuit wherein the said internal circuit (11) includes an NPN input transistor (12) having its base connected to the said signal input point (10),
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.