Electrically alterable non-volatile memory with N-bits per cell
DC CAFCFirst Claim
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1. A multi-level memory device comprising:
- an electrically alterable non-volatile multi-level memory cell for storing input information in a corresponding one of Kn predetermined memory states of said multi-level memory cell, where K is a base of a predetermined number system, n is a number of bits stored per cell, and Kn >
2;
memory cell programming means for programming said multi-level memory cell in accordance with said input information;
reference voltage selecting means for selecting one of a plurality of reference voltages in accordance with said input information, each of said reference voltages corresponding to a different one of said predetermined memory states; and
comparator means for comparing a voltage of said multi-level memory cell with the selected reference voltage, said comparator means further generating a control signal indicating whether the state of said multi-level memory cell is the state corresponding to said input information.
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Abstract
An electrically alterable, non-volatile multi-bit memory cell has Kn predetermined memory states (Kn >2), where K is a base of a predetermined number system and n is a number of bits stored per cell. Programming of the cell is verified by selecting a reference signal corresponding to the information to be stored and comparing a signal of the cell with the selected reference signal.
165 Citations
47 Claims
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1. A multi-level memory device comprising:
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an electrically alterable non-volatile multi-level memory cell for storing input information in a corresponding one of Kn predetermined memory states of said multi-level memory cell, where K is a base of a predetermined number system, n is a number of bits stored per cell, and Kn >
2;memory cell programming means for programming said multi-level memory cell in accordance with said input information; reference voltage selecting means for selecting one of a plurality of reference voltages in accordance with said input information, each of said reference voltages corresponding to a different one of said predetermined memory states; and comparator means for comparing a voltage of said multi-level memory cell with the selected reference voltage, said comparator means further generating a control signal indicating whether the state of said multi-level memory cell is the state corresponding to said input information. - View Dependent Claims (2)
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3. Multi-level memory apparatus, comprising
an electrically alterable non-volatile memory cell having more than two predetermined memory states; -
a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; and a comparator which compares a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (4, 5)
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6. Multi-level memory apparatus, comprising:
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an electrically alterable non-volatile memory cell having more than two predetermined memory states; a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; and a verifying device which detects a parameter indicating the state of said memory cell and verifies whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (7, 8)
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9. Multi-level memory apparatus, comprising:
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an electrically alterable non-volatile memory cell having more than two predetermined memory states; a selecting device which selects one of a plurality of predetermined reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source which applies a programming signal to said memory cell; and a comparator which compares a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (10, 11)
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12. Multi-level memory apparatus, comprising:
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an electrically alterable non-volatile memory cell having more than two predetermined memory states; a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source which applies a programming signal to said memory cell; and a verifying device which detects a parameter indicating the state of said memory cell and which verifies whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (13, 14)
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15. Multi-level memory apparatus, comprising:
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an electrically alterable non-volatile memory cell having more than two predetermined memory states; a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source which applies a programming signal to said memory cell; and a control device which controls the application of said programming signal to said memory cell based on the selected reference signal. - View Dependent Claims (16, 17)
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18. Apparatus for verifying programming of an electrically alterable non-volatile memory cell having more than two predetermined memory states, comprising:
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a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; and a comparator to compare a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (19, 20)
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21. Apparatus for verifying programming of an electrically alterable non-volatile memory cell having more than two predetermined memory states, comprising:
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a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; and a verifying device to detect a parameter indicating the state of said memory cell and to verify whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (22, 23)
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24. Apparatus for programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, comprising:
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a selecting device which selects one of a plurality of predetermined reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source to apply a programming signal to said memory cell; and a comparator to compare a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (25, 26)
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27. Apparatus for programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, comprising:
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a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source to apply a programming signal to said memory cell; and a verifying device to detect a parameter indicating the state of said memory cell and to verify whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (28, 29)
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30. Apparatus for programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, comprising:
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a selecting device which selects one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; a programming signal source to apply a programming signal to said memory cell; and a control device to control the application of said programming signal to said memory cell based on the selected reference signal. - View Dependent Claims (31, 32)
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33. A method of verifying programming of an electrically alterable non-volatile memory cell having more than two predetermined memory states, said method comprising:
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selecting one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; and comparing a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (34, 35)
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36. A method of verifying programming of an electrically alterable non-volatile memory cell having more than two predetermined memory states, said method comprising:
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selecting one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; detecting a parameter indicating the state of said memory cell; and verifying whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (37, 38)
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39. A method of programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, said method comprising:
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selecting one of a plurality of predetermined reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; applying a programming signal to said memory cell; and comparing a signal corresponding to the state of said memory cell with the selected reference signal to verify whether said memory cell is programmed to the state indicated by said information. - View Dependent Claims (40, 41)
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42. A method of programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, said method comprising:
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selecting one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; applying a programming signal to said memory cell; detecting a parameter indicating the state of said memory cell; and verifying whether said memory cell is programmed to the state indicated by said information based on the detected parameter and the selected reference signal. - View Dependent Claims (43, 44)
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45. A method of programming an electrically alterable non-volatile memory cell having more than two predetermined memory states, said method comprising:
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selecting one of a plurality of reference signals in accordance with information indicating a memory state to which said memory cell is to be programmed, each reference signal corresponding to a different memory state of said memory cell; applying a programming signal to said memory cell; and
controlling the application of said programming signal to said memory cell based on the selected reference signal. - View Dependent Claims (46, 47)
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Specification