Methods for providing redundancy and apparatuses
Methods for providing redundancy and apparatuses are disclosed. One such method for providing redundancy performs a mapping of data between an address of a memory determined to indicate a defective memory cell and an address of a redundant area of the memory, only after the data has been loaded into a buffer. The direction of the mapping is determined by the operation (e.g., programming or reading).
1. A method for providing redundancy in a memory, wherein the memory has a memory array and one or more addresses of the memory array have been determined to indicate a defective memory cell, the method comprising:
loading first data into a buffer for programming into a row of the memory array;
verifying that the first data has been loaded into the buffer;
mapping a portion of the first data between an address of the memory array determined to indicate a defective memory cell of a particular column of the memory array and an address of a redundant area of the memory array only after the first data has been loaded into the buffer and before the first data has been programmed into the row of the memory array;
loading second data into the buffer for programming into a different row of the memory array;
verifying that the second data has been loaded into the buffer; and
mapping a portion of the second data between an address of the memory array determined to indicate a defective memory cell of a different column of the memory array and an address of a redundant area of the memory array only after the second data has been loaded into the buffer and before the second data has been programmed into the different row of the memory array, and without mapping any portion of the second data between an address of the memory array of the particular column of the memory array and an address of a redundant area of the memory array.
2. The method of claim 1 wherein the data is mapped on a bit-by-bit basis.
3. The method of claim 1 wherein the data is mapped on a byte-by-byte basis.
4. The method of claim 1 and further comprising inputting the data from I/O connections prior to loading the buffer.
5. A method for providing redundancy in a memory having a memory array, wherein one or more addresses of the memory array have been determined to indicate a defective memory cell, the method comprising:
inputting first data from I/O connections for a first programming operation;
loading the first data to a buffer;
verifying that the first data has been loaded into the buffer;
mapping, after the first data has been loaded to the buffer and before programming the first data to the memory array, a portion of the first data associated with an address of the memory determined to indicate a defective memory cell to an address of a redundant area of the memory;
inputting second data from the I/O connections for a second programming operation;
loading the second data to the buffer;
verifying that the second data has been loaded into the buffer;
mapping, after the second data has been loaded to the buffer and before programming the second data to the memory array, a first portion of the second data associated with an address of the memory determined to indicate a defective memory cell to an address of a redundant area of the memory; and
writing a second portion of the second data to the memory array, wherein the second portion of the second data is written to a column of the memory array associated with the address of the memory determined to indicate a defective memory cell for the first data.
6. The method of claim 5 wherein inputting the data comprises generating addresses of the buffer for the data input from the I/O connections.
7. The method of claim 5 and further comprising programming the data from the buffer to the memory.
8. The method of claim 7 wherein programming the data comprises performing a program verify.
9. An apparatus comprising:
a memory array having a redundant area, and having rows associated with access lines and columns associated with bit lines;
a buffer coupled to the memory array and configured to store data at addresses associated with addresses of the memory array, and to verify that the data has been stored to the buffer;
a defective memory block configured to store an address of the memory array determined to indicate a defective memory cell; and
memory control circuitry comprising:
logic configured to select a bad bit or byte of data of a defective memory cell, wherein the logic is further configured to select a different bad bit or byte of data of a defective memory cell for a particular row of the memory array than for a different row of the memory array, and wherein the particular row of the memory array and the different row of the memory array are associated with the same columns of the memory array;
a driver, coupled between the logic and the buffer, configured to control the buffer; and
a column decoder, coupled between the logic and the buffer, configured to generate signals to select a byte in the buffer responsive to the address of the memory array determined to indicate a defective memory cell;
wherein the memory control circuitry is configured to control mapping between the address of the memory array determined to indicate the defective memory cell and an address of the redundant area of the memory array during a programming operation, wherein the mapping is performed only after the data has been loaded into the buffer and before programming that data into the memory array.
10. The apparatus of claim 9 and further comprising an address generator coupled to the buffer and configured to generate addresses for data input through I/O connections to the buffer.
11. The apparatus of claim 9 wherein the defective memory block is part of the memory control circuitry.
12. The apparatus of claim 9 wherein the logic comprises a decoder.
13. The apparatus of claim 9 wherein the memory control circuitry comprises a state machine.
14. The apparatus of claim 9 wherein the buffer is a page buffer.