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US5815431A
Expired / Lapsed
US
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Non-volatile digital circuits using ferroelectric capacitors
Assignee: NXP BV
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Filing: 1997-02-19
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Granted: 1998-09-29
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Expires: 2017-02-19
Abstract
Abstract A circuit including a ferroelectric capacitor can be used to store the value of nodes of volatile logic elements in a logic circuit. In this manner, the state of a complex logic circuit, such as a CPU or an I/O device, can be stored in the non-volatile ferroelectric capacitors. After an accidental or planned power outage, the non-volatile ferroelectric capacitors can be used to restore the values of the nodes. Additionally, a planned power loss can be save system power in circuits that are power consumption sensitive.
Inventors
- 👤 Deng-Yuan David Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:52
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/22
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
141 words
An apparatus including: a logic circuit including a volatile logic element having a node defining a logic state at a first time, the node of logic element being connected to an input of another volatile logic element of the logic circuit; and circuitry operatively connected to the volatile logic element, the circuitry including a ferroelectric capacitor, the ferroelectric capacitor defining a voltage versus charge hysteresis curve, the circuitry adapted to set the position of the ferroelectric capacitor on the hysteresis curve depending on a value of the logic state at the node, wherein the value at the node is lost when the power to the apparatus is off and the circuitry is further adapted to restore the value of the logic state at the node of the volatile logic element using the ferroelectric capacitor when power is restored to the apparatus.
Claim 2
Independent Claim
141 words
An apparatus including: a logic circuit including a volatile logic element having a node defining a logic state at a first time, the node of logic element being connected to an input of another volatile logic element of the logic circuit; and circuitry operatively connected to the volatile logic element, the circuitry including a ferroelectric capacitor, the ferroelectric capacitor defining a voltage versus charge hysteresis curve, the circuitry adapted to set the position of the ferroelectric capacitor on the hysteresis curve depending on a value of the logic state at the node, wherein the value at the node is lost when the power to the apparatus is off and the circuitry is further adapted to restore the value of the logic state at the node of the volatile logic element using the ferroelectric capacitor when power is restored to the apparatus.
Claim 3
Dependent Claim
13 words
The apparatus of claim 1, wherein the volatile logic element is a latch.
Claim 4
Dependent Claim
13 words
The apparatus of claim 1, wherein the volatile logic element is a flip-flop.
Claim 5
Dependent Claim
15 words
The apparatus of claim 1, wherein the volatile logic element includes matched pair of inverters.
Claim 6
Dependent Claim
14 words
The apparatus of claim 1, wherein the logic circuit comprises a central processing unit.
Claim 7
Dependent Claim
30 words
The apparatus of claim 1, wherein an additional volatile logic element having nodes associated with an additional circuitry includes ferroelectric capacitors to store and restore the value of the node.
Claim 8
Dependent Claim
18 words
The apparatus of claim 6, wherein same control lines are sent to the circuitry and the additional circuitry.
Claim 9
Dependent Claim
16 words
The apparatus of claim 1, further comprising a controller for sending control signals to the circuitry.
Claim 10
Dependent Claim
46 words
The apparatus of claim 1, wherein the circuitry is operably connected to an additional node of the volatile logic element, the additional node normally having the obverse value from said node, the circuitry having an additional ferroelectric capacitor to store the value of the additional node.
Claim 11
Dependent Claim
20 words
The apparatus of claim 1, wherein the circuitry comprises a pre-charge circuit to pull the value at node toward ground.
Claim 12
Dependent Claim
23 words
The apparatus of claim 1, wherein the circuitry comprises an isolating transistor that allows the ferroelectric capacitor to be isolated from the node.
Claim 13
Dependent Claim
45 words
The apparatus of claim 11, wherein the circuitry comprises a pre-charge circuitry positioned with respect to the isolating transistor so that the voltage on one side of the ferroelectric capacitor can be pulled down while isolating transistor isolates the node of the volatile logic element.
Claim 14
Independent Claim
177 words
An apparatus including: a logic circuit including a volatile logic element having a node defining a logic state at a first time, the node of logic element being connected to an input of another volatile logic element of the logic circuit; and circuitry operatively connected to the volatile logic element, the circuitry including a ferroelectric capacitor, the ferroelectric capacitor defining a voltage versus charge hysteresis curve, the circuitry including at least one isolating transistor that allows the ferroelectric capacitor to be selectively isolated from the node and a pre-charge circuit that can be used to pull down the voltage at the node, the circuitry adapted to set the position of the ferroelectric capacitor on the hysteresis curve depending on a value of the logic state at the node, wherein the value at the node is lost when the power to the apparatus is off and the circuitry is further adapted to restore the value of the logic state at the node of the volatile logic element using the ferroelectric capacitor when power is restored to the apparatus.
Claim 15
Independent Claim
177 words
An apparatus including: a logic circuit including a volatile logic element having a node defining a logic state at a first time, the node of logic element being connected to an input of another volatile logic element of the logic circuit; and circuitry operatively connected to the volatile logic element, the circuitry including a ferroelectric capacitor, the ferroelectric capacitor defining a voltage versus charge hysteresis curve, the circuitry including at least one isolating transistor that allows the ferroelectric capacitor to be selectively isolated from the node and a pre-charge circuit that can be used to pull down the voltage at the node, the circuitry adapted to set the position of the ferroelectric capacitor on the hysteresis curve depending on a value of the logic state at the node, wherein the value at the node is lost when the power to the apparatus is off and the circuitry is further adapted to restore the value of the logic state at the node of the volatile logic element using the ferroelectric capacitor when power is restored to the apparatus.
Claim 16
Dependent Claim
47 words
The apparatus of claim 13, wherein the isolating transistor is positioned with respect to the pre-charge circuit so that when the node of the volatile logic element is isolated from the ferroelectric capacitor, one side of the ferroelectric capacitor can set toward ground with the pre-charge circuit.
Claim 17
Dependent Claim
18 words
The apparatus of claim 1 wherein one end of the ferroelectric capacitor is connected to the isolating transistor.
Claim 18
Independent Claim
79 words
A method comprising: operating a logic circuit including a volatile logic element, the volatile logic element having a node defining a logic state at a first time, the node of the logic element being connected to an input of another volatile logic element of the logic circuit; storing the value of the node using a ferroelectric capacitor; and after power to the volatile logic element is lost then restored, restoring a value at the node using the ferroelectric capacitor.
Claim 19
Independent Claim
79 words
A method comprising: operating a logic circuit including a volatile logic element, the volatile logic element having a node defining a logic state at a first time, the node of the logic element being connected to an input of another volatile logic element of the logic circuit; storing the value of the node using a ferroelectric capacitor; and after power to the volatile logic element is lost then restored, restoring a value at the node using the ferroelectric capacitor.
Claim 20
Dependent Claim
31 words
The method of claim 16, wherein the storing step includes using an isolating transistor to electrically connect and then isolate the node of the volatile logic element from the ferroelectric capacitor.
Claim 21
Dependent Claim
49 words
The method of claim 16, wherein one end of the ferroelectric capacitor is connected to a set line, wherein the storing step includes forcing the set line high, then low, while the node of the volatile logic element is electrically connected to the other end of the ferroelectric capacitor.
Claim 22
Dependent Claim
19 words
The method of claim 18, wherein the storing step includes setting the other end of the ferroelectric capacitor low.
Claim 23
Dependent Claim
37 words
The method of claim 19, wherein the storing step includes isolating the node of the volatile logic element from the other end of the ferroelectric capacitor, when the other end of the ferroelectric capacitor is set low.
Claim 24
Dependent Claim
23 words
The method of claim 16, wherein the restoring step comprises using more than one ferroelectric capacitors to store the value of multiple nodes.
Claim 25
Dependent Claim
29 words
The method of claim 16, wherein the restoring step comprises electrically connecting the other end of the ferroelectric capacitor to the node and pre-charging to set the nodes low.
Claim 26
Dependent Claim
29 words
The method of claim 16, wherein the restoring step comprises electrically connecting the other end of the ferroelectric capacitor to the node and pre-charging to set the nodes low.
Claim 27
Dependent Claim
25 words
The method of claim 23, wherein the restoring step further comprises stopping the pre-charge and forcing a set line attached to the ferroelectric capacitor high.
Claim 28
Dependent Claim
17 words
The method of claim 24, wherein the restoring step further comprises, thereafter, forcing the set line low.
Claim 29
Dependent Claim
28 words
The method of claim 25, wherein the restoring step further comprises electrically isolating the ferroelectric capacitor from the node and pre-charging the other end of the ferroelectric capacitor.
Claim 30
Dependent Claim
34 words
The method of claim 16, wherein the logic circuit is not part of a memory array and wherein the restoring step can be done without re-booting a central processing unit from the memory array.
Claim 31
Dependent Claim
41 words
The apparatus of claim 1, wherein the logic circuit is not part of a memory array and wherein the circuitry can restore the value of the node after a power failure without re-booting the central processing unit from a memory array.
Claim 32
Dependent Claim
14 words
The apparatus of claim 1, wherein the logic circuit is a central processing unit.
Claim 33
Dependent Claim
13 words
The apparatus of claim 1, wherein the logic circuit is an input/output circuit.
Claim 34
Dependent Claim
41 words
The apparatus of claim 13, wherein the logic circuit is not part of a memory array and wherein the circuitry can restore the value of the node after a power failure without re-booting the central processing unit from a memory array.
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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) | 2001-09-28 | 2002-03-30 | 2002-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-28 | 2006-03-30 | 2006-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-28 | 2010-03-30 | 2010-09-29 | $7700.00 | Window Closed / Lapsed |