US5514893A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device for protecting an internal circuit from electrostatic damage
Assignee: RPX Corp
•
Filing: 1994-03-08
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Granted: 1996-05-07
•
Expires: 2014-03-08
Abstract
Abstract A semiconductor device includes an input/output terminal, an internal circuit connected to the input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, the device further including: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the second terminal, and a gate to be electrically connected to the first terminal; and a first switching element for switching between an electrically conductive state and a non-conductive state between the drain and the gate of the first n-channel MOS transistor, the switching element forming the electrically conductive state between the drain and the gate of the first n-channel MOS transistor when 1) a surge voltage lower than the first electrical potential is applied to the input/output terminal, and 2) an electrical potential difference between the drain and the gate of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate of the first n-channel MOS transistor. The formation of the electrically conductive state prevents the gate oxide of the first n-channel MOS transistor from being damaged.
Inventors
- 👤 Isao Miyanaga
- 👤 Kazumi Kurimoto
- 👤 Atsushi Hori
- 👤 Shinji Odanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:27
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/60; H10D89/601; H10D89/711; H03; H03K; H03K19/00; H03K19/003; H03K19/00315; H10D89/811
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
175 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the second terminal, and a gate electrode to be electrically connected to the first terminal; and first switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first n-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first n-channel MOS transistor, in a case where a surge voltage lower than the first electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first n-channel MOS transistor.
Claim 2
Dependent Claim
175 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the second terminal, and a gate electrode to be electrically connected to the first terminal; and first switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first n-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first n-channel MOS transistor, in a case where a surge voltage lower than the first electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first n-channel MOS transistor.
Claim 3
Dependent Claim
52 words
A semiconductor device according to claim 1, wherein the first switching means is a second n-channel MOS transistor having a source connected to the drain of the first n-channel MOS transistor, a drain connected to the gate electrode of the first n-channel MOS transistor, and a gate connected to the second terminal.
Claim 4
Dependent Claim
26 words
A semiconductor device according to claim 2, wherein a circuit element is provided between the gate of the second n-channel MOS transistor and the second terminal.
Claim 5
Dependent Claim
14 words
A semiconductor device according to claim 3, wherein the circuit element is a resistor.
Claim 6
Dependent Claim
14 words
A semiconductor device according to claim 3, wherein the circuit element is a transistor.
Claim 7
Dependent Claim
50 words
A semiconductor device according to claim 1, wherein the first switching means is an npn-bipolar transistor having an emitter connected to the drain of the first n-channel MOS transistor, a collector connected to the gate electrode of the first n-channel MOS transistor, and a base connected to the second terminal.
Claim 8
Dependent Claim
29 words
A semiconductor device according to claim 1, further comprising a p-channel MOS transistor having a drain connected to the input/output terminal and a source connected to the first terminal.
Claim 9
Dependent Claim
174 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first p-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the first terminal, and a gate electrode to be electrically connected to the second terminal; and switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first p-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first p-channel MOS transistor, in a case where a surge voltage higher than the second electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first p-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first p-channel MOS transistor.
Claim 10
Dependent Claim
174 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first p-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the first terminal, and a gate electrode to be electrically connected to the second terminal; and switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first p-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first p-channel MOS transistor, in a case where a surge voltage higher than the second electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first p-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first p-channel MOS transistor.
Claim 11
Dependent Claim
51 words
A semiconductor device according to claim 8, wherein the switching means is a second p-channel MOS transistor having a source connected to the drain of the first p-channel MOS transistor, a drain connected to the gate electrode of the first p-channel MOS transistor, and a gate connected to the first terminal.
Claim 12
Dependent Claim
26 words
A semiconductor device according to claim 9, wherein a circuit element is provided between the gate of the second p-channel MOS transistor and the first terminal.
Claim 13
Dependent Claim
14 words
A semiconductor device according to claim 10, wherein the circuit element is a resistor.
Claim 14
Dependent Claim
14 words
A semiconductor device according to claim 10, wherein the circuit element is a transistor.
Claim 15
Dependent Claim
49 words
A semiconductor device according to claim 8, wherein the switching means is a pnp-bipolar transistor having an emitter connected to the drain of the first p-channel MOS transistor, a collector connected to the gate electrode of the first p-channel MOS transistor, and a base connected to the first terminal.
Claim 16
Dependent Claim
30 words
A semiconductor device according to claim 8, further comprising a first n-channel MOS transistor having a drain connected to the input/output terminal and a source connected to the second terminal.
Claim 17
Dependent Claim
175 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to an internal circuit, and a gate electrode to be electrically connected to the first terminal; and first switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first n-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first n-channel MOS transistor, in a case where a surge voltage lower than the first electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first n-channel MOS transistor.
Claim 18
Dependent Claim
175 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to an internal circuit, and a gate electrode to be electrically connected to the first terminal; and first switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first n-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first n-channel MOS transistor, in a case where a surge voltage lower than the first electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first n-channel MOS transistor.
Claim 19
Dependent Claim
52 words
A semiconductor device according to claim 15, wherein the first switching means is a second n-channel MOS transistor having a source connected to the drain of the first n-channel MOS transistor, a drain connected to the gate electrode of the first n-channel MOS transistor, and a gate connected to the second terminal.
Claim 20
Dependent Claim
26 words
A semiconductor device according to claim 16, herein a circuit element is provided between the gate of the second n-channel MOS transistor and the second terminal.
Claim 21
Dependent Claim
14 words
A semiconductor device according to claim 17, wherein the circuit element is a resistor.
Claim 22
Dependent Claim
14 words
A semiconductor device according to claim 17, wherein the circuit element is a transistor.
Claim 23
Dependent Claim
50 words
A semiconductor device according to claim 15, wherein the first switching means is an npn-bipolar transistor having an emitter connected to the drain of the first n-channel MOS transistor, a collector connected to the gate electrode of the first n-channel MOS transistor, and a base connected to the second terminal.
Claim 24
Dependent Claim
29 words
A semiconductor device according to claim 15, further comprising a p-channel MOS transistor having a drain connected to the input/output terminal and a source connected to the internal circuit.
Claim 25
Dependent Claim
174 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first p-channel MOS transistor having a drain connected to the input/output terminal, a source connected to an internal circuit, and a gate electrode to be electrically connected to the first terminal; and switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first p-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first p-channel MOS transistor, in a case where a surge voltage higher than the second electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first p-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first p-channel MOS transistor.
Claim 26
Dependent Claim
174 words
A semiconductor device comprising an input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: a first p-channel MOS transistor having a drain connected to the input/output terminal, a source connected to an internal circuit, and a gate electrode to be electrically connected to the first terminal; and switching means for switching between an electrically conductive state and a non-conductive state between the drain and the gate electrode of the first p-channel MOS transistor, the means forming the electrically conductive state between the drain and the gate electrode of the first p-channel MOS transistor, in a case where a surge voltage higher than the second electrical potential is applied to the input/output terminal, and an electrical potential difference between the drain and the gate electrode of the first p-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate oxide of the first p-channel MOS transistor.
Claim 27
Dependent Claim
51 words
A semiconductor device according to claim 22, wherein the switching means is a second p-channel MOS transistor having a source connected to the drain of the first p-channel MOS transistor, a drain connected to the gate electrode of the first p-channel MOS transistor, and a gate connected to the first terminal.
Claim 28
Dependent Claim
27 words
A semiconductor device according to claim 23, wherein a circuit element is provided between the gate electrode of the second p-channel MOS transistor and the first terminal.
Claim 29
Dependent Claim
14 words
A semiconductor device according to claim 24, wherein the circuit element is a resistor.
Claim 30
Dependent Claim
14 words
A semiconductor device according to claim 24, wherein the circuit element is a transistor.
Claim 31
Dependent Claim
50 words
A semiconductor device according to claim 22, wherein the second switching means is a pnp-bipolar transistor having an emitter connected to the drain of the first p-channel MOS transistor, a collector connected to the gate electrode of the first p-channel MOS transistor, and a base connected to the first terminal.
Claim 32
Dependent Claim
30 words
A semiconductor device according to claim 22, further comprising a first n-channel MOS transistor having a drain connected to the input/output terminal and a source connected to the internal circuit.
Claim 33
Dependent Claim
210 words
A semiconductor device comprising an input/output terminal, an internal circuit connected to the input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: first protection means connected between the input/output terminal and the internal circuit, the first protection means guiding surge charges applied to the input/output terminal to the first terminal or the second terminal, thereby lowering an electrical potential due to the surge charges; and auxiliary protection means connected between the first protection means and the internal circuit, and further lowering the electrical potential due to the surge charges, the auxiliary protection means including a first electronic element connected to at least one of the first terminal and the second terminal, a first protection resistor provided between the first electronic element and the first protection means, and a second protection resistor provided between the first electronic element and the internal circuit, wherein a resistance of the second protection resistor is in a range between half of a total resistance of the first protection resistor and the second protection resistor, and nine-tenths of the total resistance of the first protection resistor and the second protection resistor.
Claim 34
Dependent Claim
210 words
A semiconductor device comprising an input/output terminal, an internal circuit connected to the input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, wherein the device further comprises: first protection means connected between the input/output terminal and the internal circuit, the first protection means guiding surge charges applied to the input/output terminal to the first terminal or the second terminal, thereby lowering an electrical potential due to the surge charges; and auxiliary protection means connected between the first protection means and the internal circuit, and further lowering the electrical potential due to the surge charges, the auxiliary protection means including a first electronic element connected to at least one of the first terminal and the second terminal, a first protection resistor provided between the first electronic element and the first protection means, and a second protection resistor provided between the first electronic element and the internal circuit, wherein a resistance of the second protection resistor is in a range between half of a total resistance of the first protection resistor and the second protection resistor, and nine-tenths of the total resistance of the first protection resistor and the second protection resistor.
Claim 35
Dependent Claim
15 words
A semiconductor device according to claim 29, wherein the electronic element includes an MOS transistor.
Claim 36
Dependent Claim
15 words
A semiconductor device according to claim 29, wherein the electronic element includes a bipolar transistor.
Claim 37
Dependent Claim
60 words
A semiconductor device according to claim 29, wherein the first electronic element includes a p-channel MOS transistor having a drain connected to the first protection resistor, a source and a gate connected to the first terminal; and an n-channel MOS transistor having a drain connected to the first protection resistor, a source and a gate connected to the second terminal.
Claim 38
Dependent Claim
55 words
A semiconductor device according to claim 29, wherein the auxiliary protection means further includes between the second protection resistor and the internal circuit, a second electronic element connected to at least one of the first terminal and the second terminal; and a third protection resistor provided between the second electronic element and the internal circuit.
Claim 39
Dependent Claim
20 words
A semiconductor device according to claim 29, wherein a resistance of the first protection resistor is 10 ohms or more.
Claim 40
Dependent Claim
60 words
A semiconductor device according to claim 29, wherein the first protection means includes a p-channel MOS transistor having a drain connected to the input/output terminal, and a source and a gate connected to the first terminal; and an n-channel MOS transistor having a drain connected to the input/output terminal, and a source and a gate connected to the second terminal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-05-07 | 1999-11-06 | 2000-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-07 | 2003-11-06 | 2004-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-07 | 2007-11-06 | 2008-05-07 | $7700.00 | Window Closed / Lapsed |