US5047663A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-power comparator which tolerates high-slew-rate incoming signals and deriving power from the incoming signals
Assignee: Maxim Integrated Products Inc
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Filing: 1989-07-28
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Granted: 1991-09-10
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Expires: 2009-07-28
Abstract
Abstract An integrated circuit which includes switching logic to select its negative power supply voltage from the more negative of two signals (preferably ground and an input signal). Special MOS clamp diodes are used to prevent sharp transients from collapsing the voltage drop of the internal power supply lines (and so disabling the chip).
Inventors
- 👤 Robert D. Lee
- 👤 Gary V. Zanders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:51
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/0264; H04L25/0292; H04L25/028; H10; H10D; H10D89/00; H10D89/211; H10D89/213; H04L25/0272
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
174 words
An integrated circuit, comprising: at least one contact pad for signal input, at least one contact pad for signal output, and at least one contact pad for receiving a power supply voltage; a comparator which compares the voltage of said signal input contact pad to ground, and provides a control signal output indicating whether the potential of said signal input pad is less than ground by at least a predetermined amount; one or more switching devices which are directly connected to said input contact pad, without any substantial intervening resistor, and which are controlled, in accordance with the output of said comparator, to selectively connect said input contact pad to a local ground line within the integrated circuit; at least one MOS diode, comprising an insulated-gate field-effect transistor having a source coupled to ground, a drain coupled to said local ground line, and a gate coupled to said drain thereof; whereby said MOS diode prevents sharp transients from pulling the potential of said local ground line near the potential of said power supply voltage.
Claim 2
Dependent Claim
174 words
An integrated circuit, comprising: at least one contact pad for signal input, at least one contact pad for signal output, and at least one contact pad for receiving a power supply voltage; a comparator which compares the voltage of said signal input contact pad to ground, and provides a control signal output indicating whether the potential of said signal input pad is less than ground by at least a predetermined amount; one or more switching devices which are directly connected to said input contact pad, without any substantial intervening resistor, and which are controlled, in accordance with the output of said comparator, to selectively connect said input contact pad to a local ground line within the integrated circuit; at least one MOS diode, comprising an insulated-gate field-effect transistor having a source coupled to ground, a drain coupled to said local ground line, and a gate coupled to said drain thereof; whereby said MOS diode prevents sharp transients from pulling the potential of said local ground line near the potential of said power supply voltage.
Claim 3
Dependent Claim
18 words
The integrated circuit of claim 1, wherein the integrated circuit includes only one said pad for signal input.
Claim 4
Dependent Claim
18 words
The integrated circuit of claim 1, wherein the integrated circuit includes only one said pad for signal output.
Claim 5
Dependent Claim
27 words
The integrated circuit of claim 1, wherein the integrated circuit includes only two said pads for receiving respective power supply voltages, in addition to a ground connection.
Claim 6
Dependent Claim
21 words
The integrated circuit of claim 1, wherein said predetermined amount approximately corresponds to one threshold voltage of an insulated-gate field-effect transistor.
Claim 7
Dependent Claim
15 words
The integrated circuit of claim 1, wherein said predetermined amount is at least 0.3 Volts.
Claim 8
Dependent Claim
14 words
The integrated circuit of claim 1, wherein said comparator consists of a digital circuit.
Claim 9
Dependent Claim
19 words
The integrated circuit of claim 1, wherein said comparator includes N-channel field-effect transistors and also includes P-channel field-effect transistors.
Claim 10
Dependent Claim
14 words
The integrated circuit of claim 1, wherein said switching devices are insulated-gate field-effect transistors.
Claim 11
Dependent Claim
181 words
An integrated circuit, comprising: at least one contact pad for signal input, at least one contact pad for signal output, and at least one contact pad for receiving a power supply voltage; a CMOS comparator which compares the voltage of said signal input contact pad to ground, and provides a control signal output indicating whether the potential of said signal input pad is less than ground by at least a predetermined amount; one or more switching devices, each comprising an N-channel field-effect transistor, which are directly connected to said input contact pad, without any substantial intervening resistor, and which are controlled, in accordance with the output of said comparator, to selectively connect said input contact pad to a local ground line within the integrated circuit; at least one MOS diode, comprising an insulated-gate field-effect transistor having a source coupled to ground, a drain coupled to said local ground line, and a gate coupled to said drain thereof; whereby said MOS diode prevents sharp transients from pulling the potential of said local ground line near the potential of said power supply voltage.
Claim 12
Dependent Claim
181 words
An integrated circuit, comprising: at least one contact pad for signal input, at least one contact pad for signal output, and at least one contact pad for receiving a power supply voltage; a CMOS comparator which compares the voltage of said signal input contact pad to ground, and provides a control signal output indicating whether the potential of said signal input pad is less than ground by at least a predetermined amount; one or more switching devices, each comprising an N-channel field-effect transistor, which are directly connected to said input contact pad, without any substantial intervening resistor, and which are controlled, in accordance with the output of said comparator, to selectively connect said input contact pad to a local ground line within the integrated circuit; at least one MOS diode, comprising an insulated-gate field-effect transistor having a source coupled to ground, a drain coupled to said local ground line, and a gate coupled to said drain thereof; whereby said MOS diode prevents sharp transients from pulling the potential of said local ground line near the potential of said power supply voltage.
Claim 13
Dependent Claim
18 words
The integrated circuit of claim 10, wherein the integrated circuit includes only one said pad for signal input.
Claim 14
Dependent Claim
18 words
The integrated circuit of claim 10, wherein the integrated circuit includes only one said pad for signal output.
Claim 15
Dependent Claim
27 words
The integrated circuit of claim 10, wherein the integrated circuit includes only two said pads for receiving respective power supply voltages, in addition to a ground connection.
Claim 16
Dependent Claim
21 words
The integrated circuit of claim 10, wherein said predetermined amount approximately corresponds to one threshold voltage of an insulated-gate field-effect transistor.
Claim 17
Dependent Claim
15 words
The integrated circuit of claim 10, wherein said predetermined amount is at least 0.3 Volts.
Claim 18
Dependent Claim
14 words
The integrated circuit of claim 10, wherein said comparator consists of a digital circuit.
Claim 19
Dependent Claim
19 words
The integrated circuit of claim 10, wherein said comparator includes N-channel field-effect transistors and also includes P-channel field-effect transistors.
Claim 20
Dependent Claim
14 words
The integrated circuit of claim 10, wherein said switching devices are insulated-gate field-effect transistors.
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) | 1994-09-09 | 1995-03-11 | 1995-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-09 | 1999-03-11 | 1999-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-09 | 2003-03-11 | 2003-09-10 | $7700.00 | Window Closed / Lapsed |