Method and circuit for dynamic reading of a memory cell, in particular a multi-level nonvolatile memory cell
AssigneeSTMicroelectronics S.r.l.
InventorsGiovanni Campardo, Rino Micheloni
Life of this patent
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Abstract
The method for reading a memory cell is based upon integration in time of the current supplied to the memory cell by a capacitive element. The capacitive element is initially charged and then discharged linearly in a preset time, while the memory cell is biased at a constant voltage. In a first operating mode, initially a first capacitor and a second capacitor are respectively charged to a first charge value and to a second charge value. The second capacitor is discharged through the memory cell at a constant current in a preset time; the first charge is shared between the first capacitor and the second capacitor; and then the shared charge is measured.
Claims23
A method for reading a memory cell, comprising:
- supplying a current to said memory cell via a capacitive element;
- and
- integrating said current over time to produce a voltage corresponding to said current.
A device for reading a memory cell, comprising:
- a capacitive element;
- connection and biasing means connecting said capacitive element to said memory cell and supplying a constant current to said memory cell;
- and
- integration means integrating said current over time to produce a voltage corresponding to said current.
A device for reading a memory cell, comprising:
- a capacitive element structured to supply the memory cell with a current while the capacitive element is being discharged;
- a voltage sensing circuit structured to sense a sense voltage proportional to the current supplied to the memory cell;
- and
- an integrating switch connected to the capacitive element and connected between the memory cell and the voltage sensing circuit, the integrating switch having a first conduction terminal coupled to the voltage sensing circuit, a second conduction terminal coupled to the memory cell, and a control terminal coupled to the second conduction terminal.
Dependencies are inferred from the claim text.