Over-voltage write operation of tunnel magnet-resistance (“TMR”) memory device and correcting failure bits therefrom by using on-the-fly bit failure detection and bit redundancy remapping techniques
First Claim
1. A method for correcting bit defects in an STT-MRAM memory, the method comprising:
- reading a codeword in the STT-MRAM memory, wherein the STT-MRAM memory comprises a plurality of codewords, wherein each codeword comprises a plurality of bits and a plurality of redundant bits;
mapping defective bits in the plurality of bits of the codeword to redundant bits of the plurality of redundant bits based on a mapping scheme, wherein the mapping scheme is operable to determine a manner in which the defective bits in the codeword are to be mapped to the redundant bits, wherein the mapping comprises;
determining if each bit from the defective bits represents an open circuit or a short circuit in the STT-MRAM memory;
determining a respective position of each defective bit in the codeword; and
mapping a respective redundant bit of the plurality of redundant bits to eachdefective bit in accordance with a position of each defective bit;
based on the mapping, using mapped redundant bits in lieu of the defective bits in the codeword; and
performing an ECC correction operation on the codeword read from the STT-MRAM memory to correct any additional errors in the codeword.
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Abstract
A method for correcting bit defects in an STT-MRAM memory is disclosed. The method includes reading a codeword in the STT-MRAM memory, wherein the STT-MRAM memory includes a plurality of codewords, wherein each codeword includes a plurality of redundant bits. Further, the method includes mapping defective bits in the codeword to redundant bits of the plurality of redundant bits based on a mapping scheme, wherein the mapping scheme is operable to determine a manner in which the defective bits in the codeword are to be mapped to the redundant bits. Finally, the method includes replacing the defective bits in the codeword with corresponding mapped redundant bits.
517 Citations
19 Claims
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1. A method for correcting bit defects in an STT-MRAM memory, the method comprising:
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reading a codeword in the STT-MRAM memory, wherein the STT-MRAM memory comprises a plurality of codewords, wherein each codeword comprises a plurality of bits and a plurality of redundant bits; mapping defective bits in the plurality of bits of the codeword to redundant bits of the plurality of redundant bits based on a mapping scheme, wherein the mapping scheme is operable to determine a manner in which the defective bits in the codeword are to be mapped to the redundant bits, wherein the mapping comprises; determining if each bit from the defective bits represents an open circuit or a short circuit in the STT-MRAM memory; determining a respective position of each defective bit in the codeword; and mapping a respective redundant bit of the plurality of redundant bits to each defective bit in accordance with a position of each defective bit; based on the mapping, using mapped redundant bits in lieu of the defective bits in the codeword; and performing an ECC correction operation on the codeword read from the STT-MRAM memory to correct any additional errors in the codeword. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for correcting bit defects in an STT-MRAM memory, the method comprising:
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reading a codeword in the STT-MRAM memory, wherein the STT-MRAM memory comprises a plurality of codewords, wherein each codeword comprises a respective plurality of bits and a respective plurality of redundant bits; mapping each defective bit in the codeword to a respective redundant bit of the plurality of redundant bits in accordance with a mapping scheme, wherein the mapping scheme is operable to determine a manner in which the defective bits of the codeword are to be mapped to redundant bits of the codeword, wherein the mapping comprises; determining if each defective bit represents an open circuit or a short circuit in the STT-MRAM memory; determining a position of the defective bit in the codeword; and mapping a redundant bit to the defective bit based on the position; replacing the defective bits of the codeword with redundant bits of the plurality of redundant bits, wherein the defective bits are replaced with the redundant bits based on relative positions of the defective bits in accordance with the mapping scheme; and performing an ECC correction operation on the codeword read from the STT-MRAM memory to correct any additional errors in the codeword. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An apparatus for correcting bit defects in an STT-MRAM memory, the apparatus comprising:
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a processor; an STT-MRAM memory comprising a plurality of codewords, wherein each codeword comprises a respective plurality of bits and a respective plurality of redundant bits, and wherein the processor is configured to; read a codeword in the STT-MRAM memory; map defective bits in the codeword to redundant bits of the plurality of redundant bits based on a mapping scheme, wherein the mapping scheme is operable to determine a manner in which the defective bits in the codeword are to be mapped to the redundant bits, wherein to map the defective bits, the processor is further configured to; determine if each defective bit represents an open circuit or a short circuit in the STT-MRAM memory; determine a position of the defective bit in the codeword; and map a redundant bit to the defective bit based on the position; replace the defective bits in the codeword with corresponding redundant bits as mapped and perform an ECC correction operation on the codeword read from the STT-MRAM memory to correct any additional errors in the codeword. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification