System and method for detecting flash memory threshold voltages
AssigneeAdvanced Micro Devices, Inc.
InventorFeng Pan
Life of this patent
Estimating the term…
Abstract
A memory array includes a first flash memory cell, a second flash memory cell having a programmed threshold voltage, a first current sink, a second current sink, and a control circuit. The first flash memory cell is electrically interconnected with the first current sink and the controller. The second flash memory cell is interconnected with the second current sink and the controller. A method that identifies the threshold voltage range of the first memory cell monitors the current drawn from the first and the second flash memory cells and generates a signal that identifies the threshold voltage range of the first memory cell. In an alternative memory array, a first and a second current source replace the first and second current sinks, respectively.
Claims25
A memory array comprising:
- a first flash memory cell;
- a second flash memory cell having a programmed threshold voltage;
- a first current sink electrically interconnected with the first flash memory cell;
- a second current sink electrically interconnected with the second flash memory cell;
- and
- a control circuit electrically interconnected with the first and the second flash memory cell to detect a threshold voltage range of the first flash memory cell.
A memory array comprising:
- a first flash memory cell;
- a second flash memory cell having a programmed threshold voltage;
- a first programmable current source electrically interconnected with the first flash memory cell;
- a second programmable current sink electrically interconnected with the second flash memory cell;
- and
- a reference means for determining the threshold voltage range of the first memory cells by comparing differential input signals.
A method of determining a threshold voltage range of a memory cell comprising:
- interconnecting a first current sink with a first flash memory cell;
- interconnecting a second current sink with a second flash memory cell having a programmed threshold voltage;
- applying a drain current to the first and the second flash memory cell;
- sensing the current drawn from the first and the second flash memory cell;
- and
- identifying the threshold voltage range of the first memory cell through a comparison of the current drawn from the first and the second flash memory cells.
A memory array comprising:
- a first flash memory cell;
- a second flash memory cell having a programmed threshold voltage;
- a first current source electrically interconnected with the first flash memory cell;
- a second current source electrically interconnected with the second flash memory cell;
- and
- a control circuit electrically interconnected with the first and the second flash memory cell to detect a threshold voltage range of the first flash memory cell.
Dependencies are inferred from the claim text.